ok... here it goes.. need a little bit of help now. was taking out the seats tonight and the rear deck. seats came out without a problem.

i was taking the rear deck out, got the three powls out and the 3 clips out. the fiber matting thing was kinda stuck to both sides so i pulled it away from the frame as good as i could. was attempting to remove the deck and i noticed that there appeared to be a screw or something holding the read deck down. but i couldnt really access it because it was dark out and i couldnt quite see. it was just to the right of the middle pawl. anyone know what it was? thanks

My 92 only had the clips holding the deck down. I just pushed a few of them through from inside the trunk (they're off white) then poped the rest out with a long screwdriver from the top side. Not sure what you ran into. There shouldn't be any screws holding it down.

As for my situation...I rechecked the control module. All solders look good. I went ahead and resoldered them just to be sure. The white wire looks like it may have heated up at one point but checked out. BTW...should the module be getting that warm? I know it has cooling fins and is a large resistor but ouch! It's hot! It may just be a coincidence or just my bad luck, but now it stalls just leaving the driveway!

My only idea that I could think of is letting the thing idle for a while with me in the trunk listening and holding onto the pump. It purrs then stalled several times. The pump was even still running a second or two after it stalled. I'm starting to believe that fuel isn't the problem...Jeez! My kinda luck! Guess my only choice is to shell out more cash to my unfriendly local dealer for a Consult.

robert

yeah. i got it figured out./ it was late and i didnt see the clips. i got all of them out with ease once i knew about them. but then, i didnt know about the 4 clips around the very back edge. and since i couldnt see 'em i eventually just brute forced the deck off and it came nicely.

got the fuel pump replaced and now i dont hear a thing

You start breaking clips and not replacing them and you will end up with squeeky, rattling, vibration noises in winter time.

Every tiny piece has a function or it wouldn't be there!

As to controller heat: at idle it is having to reduce the 14 volts down to 6 while the pump draws 5-6 amps or so....roughly......48 watts plus what ever the internal circuits draw to function.

i didn't break any clips. i looked to make sure. its just i didnt know those clips were in the far back. i took all of the other ones out properly. now that i know ill get those ones too next time.

Awesome...well so far! I think I may have fixed the stalling problem. I started tinkering around before my Consult appointment this Thursday at the dealer. I ran through the self diagnostics in the service manual. I kept getting a code 55 (everything ok). I kept restarting and trying to let it stall. Well, it finally did. I ran the check again and got a code 12 only one time. Then it went back to 55 for several more checks. The manual says that code 12 is the mass air meter. Well, I pulled the K&N cone off to check everything out. The plug to the meter was a green corroded mess with the terminals all twisted sideways. I straightened them, cleaned them off with a small file, put some white grease and hooked everyghing back up. Two days later and it hasn't stalled yet!!!! Still have my fingers crossed...

As far as that K&N, I threw it in the garage and put the original box back on. I really don't think that it did anything but make the thing sound like a mean lawn mower under full throttle (which I don't like).

robert

rrack wrote:As far as that K&N, I threw it in the garage and put the original box back on. I really don't think that it did anything but make the thing sound like a mean lawn mower under full throttle (which I don't like). - robert

Ahh, you have achieved the path of intake zen, grasshopper.

So, a "mechanically inclined" guy with some basic tools and a couple hours, can change the pump in his own garage?

I'm starting to think I should go ahead and do this before I head to Cleveland to meet up w/ AZ.

Yup, the pump is just about the easiest DIY job out there... it was like the 3rd job I did on my car and it took me an hour.

Can any Q guys offer their 2 cents?

Yes, it's fairly easy. You'll need to move the rear seats and shelf for clearance, and just be ready with old towels to catch any dripping gas. Follow all precautions/instructions given earlier.

Have done 2 of them and you won't do it in one hour. If you go nice and slow, maybe 2.5 hours. Make sure you empty the fuel rail, and remove the gas cap. Follow Daedalus' lead. If you vaccum all the garbage out of the back seat (who wouldn't) it will take a little longer, but is a very rewarding job. Good luck.

i did it in less than an hour on my first try. just popped the seats off, and the rear deck(prolly about 10 minutes), pull the fuse and start it 3 times then remove gas cap,(2 minutes), uplug fuel lines and unscrew and carefully remove and cahnge the parts out to the new one and replace itand fuel lines(20-30 minutes if your careful) replace rear deck and seats(5 minutes at most).

so i could see 37-47 minutes

(all approximated times)

Maybe I am getting too old (44)

who knows. i could just be young and rushing everything. or else my brain is just making up stuff for me to believe and it really took me longer?(both could be true, and im as serious as the day is long)

Well, its 10:15PM and I feel tired and will shortly go to bed. You are 2?? time zones ahead of me (after midnight for pete sakes!!), so I must be getting old. After Daedalus quits his job and he and I open a first gen Q shop in my garage, we will hire you to make us alot of money.

In my world car hours are about three times as long as real hours... my girlfriend has finally learned to tripple any estimate of time when it comes to the car. Saying I'll be over around 6:00 to go out for dinner after doing something to the Q really means 11:00 eggs at the Waffle House or something from the Steak n' Shake...

Heath

yup. 2 time zones ahead. i duno about working at a shop. kind of a sketchy deal hiring me. all i know how to do is the fuel pump. but if thats what you need i can do it!@ but someday... someday i will learn more and more once i need it.

After weeks of working on the fuel pump and a few more weeks of driving with and without the aligator clip workaround, I finally wrote up a 5-page howto which I'd like to submit to this group for the next poor soul with the same problem.

Basically, it puts in one post all the things I've learned from all of you here and at the yahoo message boards.

I'll post it next, but, I understand you may yank it due to the length.

ALora

****************************************************************************Diary of a classic 1990 Infiniti Q45 fuel pump & pump control unit failure****************************************************************************----------------------------------------------------------------------------0. One morning, my 1990 Infiniti Q45 (125K miles) wouldn't start:

The 4.5 liter 8-cylinder engine cranked wonderfully, but would not catch. It wasn't the starter motor nor the battery (as it rotated perfectly). As always, it had to be either gas, air, spark, compression, or timing.

Following is an idealized path others can follow to debug & repair.

Note: My actual debug & repair path took three weeks and much trial & error; which is exactly why I wrote this howto for others to follow.

Note: Re-assembly, in all cases, is the reverse of the dis-assembly procedures described below.

Note: This dozen-step diagnostic, removal, & replacement procedure is accompanied every step of the way with digital photos illustrating every described action.----------------------------------------------------------------------------1. I ran a quick visual/audible gas, air, spark, compression & timing check:

GAS: The gas tank was completely full (filled the night before). The 15 amp fuel pump fuse was intact (replaced it anyway). I could NOT hear the fuel pump humming (at any time). AIR: The air intake & air filter were not clogged (left it open). SPARK: I did not know how to run a quick test for spark. COMPRESSION: The engine did sound like cylinder wash (no compression?). TIMING: The camshaft rotated (looking in the oil-filler hole).----------------------------------------------------------------------------2. I soon realized no gasoline was being pumped INTO the fuel filter:

- I removed the 15 amp fuel pump fuse (by the driver-side right kneecap); - I cranked the engine in order to release any residual fuel pressure; - I removed the two 10mm bolts holding the fuel filter clamp to the body; - I removed the two #2 phillips screws holding the fuel filter hoses on; - I replaced the 15 amp fuel pump fuse and cranked the engine again. - No gasoline spurted out of the open fuel line hose.

Note: One clue was that, after an overnight sitting, with the fuel filter and activated carbon fuel cannister still on the car, the engine started for a split second. This happened for two mornings. I suspect this momentary ignition was due to the burning of fuel fumes collecting in the fuel system over long periods of time.

Note: I blew through my fuel filter and there was almost no resistance; so, despite the fact almost everyone says that a clogged fuel filter can cause the fuel pump to overwork and therefore heat up and therefore melt the solder connections on the fuel pump control unit, I suspect a clogged fuel filter was not my problem.----------------------------------------------------------------------------3. I studied the 1990 Q45 fuel system electrical & hydraulic circuits:

ELECTRICAL: - Battery voltage goes to the fuel pump relay ... - to the fuel pump (in the gas tank) ... - to the fuel pump control unit (under the rear sundeck platform) ... - which provides three resistive paths (fuel pump speeds) to ground ... - based on input from the engine control unit (passenger side dash).

HYDRAULIC: - Fuel is pumped out of the fuel tank ... - to the inlet of the fuel filter ... - to the fuel line & fuel plenum ... - to each of the 8 fuel injectors (which open at the same time) ... - with pressure regulated by the 43 psi fuel pressure regulator ... - which sends unspent fuel back to the fuel tank for recovery ... - and which allows fuel vapors to be trapped in the carbon cannister.

INTERNET: - Factory shop manual & technical service bulletins & recall notices: http://www.nissan-techinfo.com/infiniti - Infiniti mechanics and afficianados on line to help you: http://nissaninfiniticlub.net http://groups.yahoo.com/group/infinitiownersclub). - Basic USENET newsgroups (not much help compared to the above): http://groups.google.com/group...i.q45 http://groups.google.com/group...issan http://groups.google.com/group....tech - Parts: http://www.infinitipartsusa.com Fuel Pump (includes the fuel pump 0-ring): $234.99 + sh & tax Fuel Pump Control Unit: $xxx.99 + sh & tax Fuel Pump Relay: : $xxx.99 + sh & tax Fuel Filter: : $xxx.99 + sh & tax

LOCATIONS: - The fuel tank is located in the center of the trunk room (between the rear seat and the trunk). - The fuel pump & fuel pump resistive gage & filter sock is located in the top of the fuel tank. - The fuel pump control unit is located on the underside of the rear metal sundeck (near the rear passenger side speaker housing). - The fuel pump relay (lime green) is located next to the antenna and fuel tank gasoline inlet in the area between the rear passenger side fender and the rear passenger side trunk fiberboard lining. - The fuel filter is located on the passenger side of the engine compartment bolted to the inside of the passenger side fender wall.

ACCESS: - Access the fuel pump, fuel pump relay, fuel pump control unit, & the related fuel system harnesses for test from the rear trunk area. - Access the fuel pump for removal & replacement either by removing the rear seat & sundeck & storage binnacle or by dropping the fuel tank (rear seat removal access is preferred over tank removal by most).

TERMINOLOGY: - The harness connector (white, female) to the fuel pump control unit is called the fuel pump control unit harness connector. - The harness connector (green) to the fuel pump relay is called the fuel pump relay harness connector. - The harness connector (blue, female) to the fuel pump is called the fuel pump harness connector. Likewise: - The connector (white, male) on the fuel pump control unit is called the fuel pump control unit connector. - The connector (green) on the fuel pump relay is called the fuel pump relay. - The connector (blue, male) to the fuel pump is called the fuel pump connector.

TOOLS: - Two #2 phillips screwdrivers (one six inch, & one two inch stubby). - Two box wrenches (one 8 mm box & one 10mm) for bracket bolts. - One 19 mm open-end wrench (for the gas tank fuel line lock nuts). - One 16 AWG wire, about a foot long, with an alligator clip on each end. - One volt-ohm-amp-meter (Fluke 77 or equivalent) with alligator clips. - One needle-nose pliar or standard pliars (for spring-closed hose clamps). - One paring knife (or similar) for removal of sound-proofing material.----------------------------------------------------------------------------4. The fuel pump relay checked out OK for proper operation under load: FROM THE TRUNK: - I removed the trunk room fiberboard bulkhead (between the rear seat back & the trunk) by removing the 7 black #2 phillips screw-type butterfly anchor clips holding the fiberboard bulkhead to the steel supports. - I removed the trunk passenger-side bulkhead (between the trunk and the rear fender by the radio antenna & fuel filler opening) by removing the 5 black #2 phillips screw-type butterfly anchor clips from their supports. - I removed the single 10mm bolt holding the two-pronged relay bracket which held a blue relay (courtesy lamp relay) on one prong and a lime-green (fuel pump relay) relay on the other. - I pulled the lime-green fuel pump relay off the bracket tang. - I jumped 12 volts DC across pins #1 and #2 (hearing a sharp click). - The resistance fell (from infinity) as the actuator closed (to zero).

Note: I also checked power to the fuel pump relay, continuity from the fuel pump relay to the fuel pump relay harness, continuity from the fuel pump relay harness to the fuel pump harness, & continuity from the fuel pump harness to the fuel pump control unit harness (all asp per the factory shop manual EF & EC-169); but, not surprisingly, I'm told the fuel pump relay and these fuel electrical system wires almost never go bad; so consider this entire step an ancillary case of over diagnosis. ----------------------------------------------------------------------------5. The old fuel pump passed the basic factory shop manual test: FROM THE TRUNK: - I disconnected the fuel pump harness connector (blue, in the trunk room). - As per the factory shop manual (EF & EC-185), I checked the resistance between the top-left and the top-right (tab on top, facing terminal side) of the six male terminals on this fuel pump connector. - My resistance was 0.9 to 1.1 ohms which was inconclusive since the factory shop manual merely states the resistance to be 0.5 ohms but the factory shop manual does not supply a range value. Note: It seems this factory shop manual test is almost useless. When I tested the new fuel pump, it too tested about the same at 0.6 to 0.8 ohms. The online Infiniti mechanics noted the resistance test merely checks one (of many) commutators. Online mechanics say the clearest sign of a bad pump is HUMMING.

I must admit, the new pump barely made a sound, even when jumped directly to ground providing it full battery voltage. I didn't realize it at the time, but, the old pump actually hummed loudly. (There is so much soundproofing that I never heard the old fuel pump motor hum until the rear trunk room lay bare & exposed.) Basic recommendation: If the fuel pump has 100K miles on it; or if the fuel pump is humming at all audibly; then replace it (before it burns out the ground wire on the fuel pump control unit).

Note: The two most basic tests should have been (in hindsight): - Did the 1990 Infiniti Q45 have more than 100K miles? - Did the 1990 Infiniti Q45 fuel pump have an audible hum? If either answer were yes, then replace the '90 Q45 fuel pump.----------------------------------------------------------------------------6. The old fuel pump control unit failed the basic bypass test:

FROM THE ENGINE COMPARTMENT: - I reconnected the fuel filter (passenger side of the engine compartment).

FROM THE TRUNK: - I reconnected the fuel pump harness connector (blue, in the trunk room). - I removed the fuel pump control unit harness connector (white, female) from the fuel pump control unit connector (white, male) mounted directly on the fuel pump control unit. - Note: Nothing else was removed at this time; the fuel system was otherwise completely intact. - I filed an alligator clip's teeth so that it fit into the small female tab on the bottom left (terminal side, with the clip up) of the white fuel pump control unit harness connector. - I connected the other side of the alligator-clip one foot long 16 AWG wire to a convenient ground (expecting from 7.5 amps to 15 amps based on fusing). - I turned the ignition to "ON" and listened for the fuel-pump humming. - It hummed for about 10 seconds after turning the ignition to ON. - I started the 1990 Infiniti Q45; it ran like a charm. - The current draw was about 5.8 amps on the old humming fuel pump. - The engine shut down approximately 2 seconds after disconnecting this fuel pump control unit bypass jumper.

Note: I drove the car for more than a week (about 200 miles) with this alligator clip shorting the fuel pump to ground bypassing the three-position ([email protected] to 5.7 volts, [email protected] to 8.1 volts, & fast@11 to 14 volts battery voltage) fuel pump control unit settings.

Note: Online mechanics estimate the old fuel pump might last a few weeks (running full speed as it is when jumpered to ground); while a new fuel pump may last a few months in this temporary full-power state.

Note: It is recommended the fuel tank be kept full whenever operating the Infiniti Q45 in this state as the fuel pump is cooled by the gasoline in the fuel tank.

Note: This is NOT the procedure in the factory shop manual (EF & EC-185). This procedure is much simpler than that in the factory shop manual. The procedure in the factory shop manual requires three test jigs, of four, five, and then six wires between the white female fuel pump control unit harness connector and the white male fuel pump control unit connector. In most cases, this test is overkill.----------------------------------------------------------------------------7. Reconcile yourself to the fact you have a few hours of work to perform:

Q: Why? A: Because of these three basic facts.

FACT 1: The first fact is that the proper removal of the fuel pump control unit is from the rear-seat direction & not from the (otherwise more convenient) trunk-forward direction.

FACT 2: The second fact is that experienced Infiniti Q45 mechanics have concluded most fuel pump control unit failures are due to the fuel pump itself beginning to fail (and thereby to draw excessive current, which melts the weak solder joints on the ground wire printed circuit board connection on the fuel pump control unit).

FACT 3: Therefore, if you merely replace or re-solder the broken fuel pump control unit, you'll eventually burn out the new or newly repaired (and much more expensive) fuel pump control unit.

The good news is the Infiniti mechanics online have reported very few (if any) failures of the repaired or replaced fuel pump control unit once the fuel pump is replaced (for another 100K miles or so anyway).----------------------------------------------------------------------------8. Remove the rear seats, rear sundeck shelf, and rear package binnacle:

REMOVE REAR BENCH: - Move the front seats forward as far as they will go and tilt the front seat backs forward as far as they will go to obtain working room. - Locate the two black clip extensions on the rear seat floor area and pull out those two black clip extensions simultaneously pulling up on the leading edge of the rear seat bench to lift it upward and out. The rear seat bench removal requires no bolts to be removed. There are only four clips in the leading edge; and two clips in the trailing edge of the rear seat bench to take into account for removal. - Scavenge the $1.35 (on average) in loose change under the rear bench that the federal government suggests wreckers earn per car on wrecked cars.

REMOVE REAR SEAT BACK: - Pop out or pry out (with a thin flathead screwdriver) the four blue solid butterfly anchor clips from the leading edge of the rear topside sundeck where the sundeck overlaps with the rear seatback. - Remove the two rear headrests by pressing the driver-side knob under each & simultaneously lifting upward until the posts clear the seatback. - Push down the rear seat armrest and pull back on the vertical backing which is velcroed to the steel bulkhead behind rear seat back. - Remove the two #2 phillips screws behind this velcroed rear armrest compartment. - Remove the four #2 phillips screws holding the U-brackets at the bottom of the rear seat back. - Pull up the rear seat back vertically, to clear three reverse-u-shaped wire brackets from their u-shaped metal brackets in the rear bulkhead metal wall. This should remove the seat (except for the seat belts). - Pull out the two side rear seat shoulder belts as far as they will go and jam a pen or other object to eliminate the return tension. The seat belts will be less of a nuisance if you perform this task. - Flip the rear seat back (still attached by the seat belts) upside down so that the foam side is facing the front & the leather side is facing the rear and the headrest portion is on the floor of the automobile.

REMOVE REAR UPPER TAIL-LIGHT & REAR SUNDECK: - After removing the three blue solid butterfly clips on the leading edge of the rear sundeck ... - Pull toward the front and upward on the rear upper tail-lamp housing; and disconnect the rear upper tail-lamp harness connector from the rear upper tail-lamp connector. Remove the rear tail lamp housing. - Pull up on the rear sundeck everywhere you can to unclip the 11 solid white anchor clips (4 equally spaced in the rear, two in the middle on each side of the package binnacle, and 5 near the front of the sundeck shelf, three of which are closely spaced near the middle front of the sundeck shelf and the other two nearer the outside edges). - Collect all anchor clips in a zip-lock bag marked "rear shelf".

REMOVE REAR SUNDECK PACKAGE BINNACLE: - With the rear upper tail-lamp & rear sundeck removed, unscrew the seven #2 phillips screws holding down the black plastic rear sundeck package binnacle (aka storage compartment basin).

Note: This rear sundeck storage binnacle is the key to removing the fuel pump since the fuel pump (with the attached fuel pump float, fuel pump housing, fuel pump level gage, etc.), can only come out undamaged through the rectangle left by the removal of this rear sundeck storage binnacle (aka package binnacle).

Note: Almost none of this removal procedure is explained in the factory shop manual.----------------------------------------------------------------------------9. Remove fuel pump assembly from the top of the fuel tank from the trunk:

FROM THE TRUNK: - Disconnect the blue male fuel pump connector from the blue female fuel pump harness connector. - If you haven't done so already, bleed pressure out of the fuel system by cranking the engine with the fuel pump fuse (driver side dash, by your kneecap) removed. Also remove the fuel tank inlet gas cap. Have a large hotel towel handy because it's inevitable that fuel will leak as you remove the fuel pump assembly from the fuel tank. - With a 19mm open-end wrench, remove the two 19 mm tubing nuts holding the metal fuel pump outlet and vapor lines to the top of the fuel pump assembly. Be careful not to break the three-line plastic separator (as I did) when bending the rigid metal fuel lines out of the way. - With an 8mm box-wrench or a three-inch stubby #2 phillips screwdriver, remove the six 8mm bolts holding down the fuel tank assembly cover plate to the fuel tank. - Gently pull up on the fuel pump assembly taking care to prevent the six-inch black rubber O-ring from falling into the fuel tank. - From the trunk, twisting gently as needed through the rear sundeck shelf package binnacle opening, remove the fuel pump assembly. - From the rear seat area, look down into the opening left by the removal of the rear sundeck package binnacle and inspect the fuel tank for debris (mine was as clean as a galvanized chambered whistle).----------------------------------------------------------------------------10. Remove the fuel pump from the fuel pump assembly: OUT OF THE CAR: - Pull out the two one-inch brown plastic alignment clothes-pins in the fuel pump wing bracket. - Remove the two #2 phillips bolts bracing the fuel pump body to the fuel pump assembly. - Remove the one #2 phillips bolt holding the fuel filter sock to the metal fuel assembly (and push out the alignment tab). - Remove the #2 phillips bolt attaching the power wire and the #2 phillips bolt attaching the ground wire to the fuel pump itself. - Gently force the fuel pump motor black rubber wings out of their braces in the fuel pump assembly leaving just the fuel hose attached. - Once the fuel pump wings are outside their slots, use pliars to open the spring hose clamp on the plastic fuel pump outlet nipple. - Remove the (now unattached) fuel pump from the fuel pump assembly. - Compare the old fuel pump (in size & shape) to the new pump (the two fuel pumps should match exactly). - The replacement follows the reverse procedure.

Note: I purchased a new fuel pump from a parts store for $312.oo while the Infiniti dealership listed the fuel pump for $320. The Infiniti dealership sold me the six-inch fuel pump O-ring for $13.oo (all numbers include tax). I noticed, afterward, that online, I could get the same pump (including the six-inch O-ring) for $235 plus shipping & tax. Go Internet, if you have the time.----------------------------------------------------------------------------11. Remove the fuel pump control unit for replacement or repair:

FROM THE TRUNK: - From the trunk, on your left side with your head facing the driver side rear fender, with your right arm through the opening left by the removal of the rear sundeck package binnacle, place your index finger on the topside location of the bolt head for the two bolts holding the fuel pump control unit bracket to the underside of the rear sundeck. - Have a partner mark the location of the two bolt heads (the actual bolt heads are buried under 1/8th inch thick rubberized soundproofing material) using whiteout or other suitable marking on the black gunky material.

FROM THE REAR SEAT AREA: - With a small paring knife, cut out the rubberized gunky black sound- proofing material on top of the two 10mm bolt heads. - Use a 10mm box wrench to remove the two bolts holding the clamp on the underside of the package shelf. Note that the clamp itself forms a U, with one portion of the bracket above and one portion below the metal horizontal sundeck shelf.

BACK IN THE TRUNK: - Check that the fuel pump control unit (white, female) harness connector is disconnected from the fuel pump control unit (white, male) connector. - Remove the fuel pump control unit (with the bracket assembly attached) by pulling it toward the rear of the car, and downward. ----------------------------------------------------------------------------12. Inspect, repair, or replace the fuel pump control unit:

OUT OF THE CAR: - Remove the four #2 phillips head screws holding the top plate (with bracket assembly) of the fuel pump control unit. - Remove the four #2 phillips head screws holding the bottom plate of the fuel pump control unit. - Inspect the wiring everywhere; notice any charred or burned areas (my ground wire on the bottom right (terminal side, tab on top) of the white male fuel pump control unit connector was charred a bit. - Also, there was infinite resistance between that bottom-right male terminal and the corresponding printed circuit board connection (marked #4 on the PCB) on the underside of the printed circuit board. - I used a 25-watt soldering iron & a blue solder sucker to vacuum up the solder around that #4 pin and I re-soldered that ground pin. - I also added a two-inch patch of 16AWG copper wire, soldered to that #4 pin and to all the connections on the printed circuit board I could identify as being that same ground connection. - Test with a ohm meter that the resistance for that one ground lead is near zero; and that accidental shorts to other traces did not occur. - Replace the now-repaired fuel pump control unit in the reverse order of removal. Note: Do not power-up the fuel pump control unit out of the car as the holding bracket supplies the main ground for the fuel pump control unit itself.

Note: The #4 terminal is the ONLY terminal on the male white fuel pump control unit connector which is surrounded by EMPTY pins in the white female fuel pump control unit harness connector.----------------------------------------------------------------------------POST MORTEM: THINGS I LEARNED THE HARD WAY: - Basically, I should've replace the fuel pump at 100K miles! Apparently they all eventually go bad. I should have also listened for the now tell-tale hum (I never even noticed it before). - Also, once before, about six months ago, my car would not start for about an hour; and then, all of a sudden, started. At the time, I chalked it up to cylinder wash (loss of compression due to gasoline washing the oil off the piston walls causing rings to temporarily not seal); but now I realize it was probably the fuel pump control unit #4 pin solder heated up and, when it cooled, it re-connected itself. - It was recommended we should fill up when just about on one quarter of a tank (or so). The (unsubstantiated) argument states that the fuel pump heats up, causing more current draw (how?) which causes the solder connection on the fuel pump control module ground circuit to heat up which, if it melts, can cause the open circuit that I found in mine. - The new six-inch fuel pump O-ring looked EXACTLY the same as the old one (condition was imperceptably different). So much, I ended up mixing the two accidentally, and I couldn't tell them apart. Be advised. - The new pump made almost NO SOUND. I didn't even realize that until I had replaced it. Even with the full-power jumper bypassing the fuel pump control, the new fuel pump hummed vastly less than the old fuel pump hummed. - The current draw and resistance measurements of the old fuel pump and the new fuel pump were almost the same; so do not rely on these figures as a diagnosis test (listen for hum or check your odometer): OLD FUEL PUMP: NEW FUEL PUMP: 0.9 to 1.1 ohms 0.6 to 0.8 ohms (from the blue male FP connector) 5.6 to 5.8 amps 5.8 to 6.7 amps (with the FPCU bypass to ground) - The factory shop manual makes NO MENTION of the quick and easy test jumpering the fuel pump control unit harness connector to ground. Instead, the factory shop manual walks you through an apparently unnecessary lengthy step-by-step debugging process requiring the use of a three, four, and then a five wire jig to debug the fuel pump control unit. Don't overdiagnose. Just use the jumper and if the fuel pump operates, then replace BOTH the fuel pump and the fuel pump control unit (or repair the fuel pump control unit). - For the longest time I was confused about the various debugging procedures in the factory shop manual. What cleared it up was the realization of all the proper connector names! I've made a sincere attemp in this note to use the proper names at all times. - Many folks say you can test the deliver of fuel past the fuel filter (in the engine compartment) by squeezing the hole while the engine is cranking to feel for fuel pressure. I can't tell. I recommend removal of the fuel filter. It provides proof positive. - The factory shop manual goes into the engine control unit debugging. It was not needed in my case so I'm glad I skipped that part. - The hardest thing in the world was to find the locations of the various units; and to find out how to remove some of them. In this note, I take special care to describe both the name of the unit and the precise location, for others to benefit. - Most folks recommend disconnecting the battery & removing it from the car when working on the fuel tank. I didn't do this, but you should.----------------------------------------------------------------------------****************************************************************************

Wow!

Way to go.

I have photos of every step of the way (especially the most revealing fuel pump control unit solder connections & resultant re-wiring job).

But, alas, I do not know how to post photos.

Is there an easy way to both post a set of (over 30) photos which will help the next person immensly & to associate those photos with steps in the howto I wrote above?

Please let me know.

> BTW...should the module be getting> that warm? I know it has cooling fins > and is a large resistor but ouch! > It's hot! It may just be a coincidence > or just my bad luck, but now it stalls > just leaving the driveway!

Learning from you, I left the rear fiberboard bulkhead panel between the rear seats and the trunk off so I could check the heat eminating from my now resoldered & reinforced 1990 Q45 fuel pump control unit (aka fuel pump modulator).

I haven't done any raceway driving yet, but, even after 20 miles on the highway on the way to the hospital, when I put my hand on the FPCU cooling fins, I can merely tell it's slightly warm.

For sure, it's not hot by any means. I've been checking this for two weeks now, with nary a rise in temperature.

It would be nice if others posted their results after their R&R jobs so we can benefit from statistics of more than just two.

> I was taking the rear deck out, got the three powls out > and the 3 clips out. the fiber matting thing was kinda stuck> to both sides so i pulled it away from the frame > as well as i could. I was attempting to remove the > rear sundeck when I noticed there appeared to be a screw > or something holding that package shelf down. > But i couldnt really access it because it was dark out and I couldnt quite see. > It was just to the right of the middle pawl. > Anyone know what it was?

I was also wholly unfamiliar with the number and location and type of butterfly clips holding down the rear package sundeck which needed to be removed once the brake light was pulled off.

Attached is a photograph with each of the 11 butterfly clips identified (5 in front, 4 to the rear, two in the mid section).

By publishing this photograph, I'm hoping the next person who has to remove this sundeck has a heads up that we never had.

Alora Duncan

Shows the need to not resist the urge to have a fuel pressure monitor.......remote electric pressure gauge.

The nice thing about modern digital gauges is that the sensors are similar in voltage/resistance.......a oil pressure sender can be a fuel pressure sender [if the sensor survives the gasoline].

2 gauges in car one for pressure one for temperature and rotary switches to monitor multiple sensors.......nice clean looking diagnosis panel.

A 3rd which might read voltage for TPS, battery, other things......voltage reading can translate to current reading with shunts.

Read the following before your next fuel pump removal & fuel pump control unit repair:

a) NICO Forums > Online Mechanic > Infiniti Online Mechanic > 1992 Q45 fuel pump modulatorhttp://www.nissaninfiniticlub....=3984b) NICO Forums > Online Mechanic > Infiniti Online Mechanic > Installing Fuel Pump Control Module??http://www.nissaninfiniticlub....36948c) NICO Forums > Online Mechanic > Infiniti Online Mechanic > problem after changing fuel pump[/http://www.nissaninfiniticlub.com/f...&threadid=14348d) NICO Forums > Online Mechanic > Infiniti Online Mechanic > q45 fuel pump/control modulehttp://www.nissaninfiniticlub....34503e) NICO Forums > Online Mechanic > Infiniti Online Mechanic > Fuel pump problemhttp://www.nissaninfiniticlub....11900f) NICO Forums > Online Mechanic > Infiniti Online Mechanic > feul pump control unit (sic)http://www.nissaninfiniticlub....18148g) NICO Forums > Online Mechanic > Infiniti Online Mechanic > Fuel Pump Replacementhttp://www.nissaninfiniticlub....=6268h) NICO Forums > Online Mechanic > Infiniti Online Mechanic > Fuel pumphttp://www.nissaninfiniticlub....47728i) NICO Forums > Online Mechanic > Infiniti Online Mechanic > q45 fuel pump controllerhttp://www.nissaninfiniticlub....73822j) NICO Forums > NICO General > Infiniti General > Fuel Pump Pictureshttp://www.nissaninfiniticlub....d=454k) NICO Forums > NICO General > Infiniti General > Q45 fuel pump modulatorhttp://www.nissaninfiniticlub....13588

Hi TANGALORA, When I attempt to access the links with pictures that you posted I get a 404 "page not found" error. I need to replace my fuel pump soon and your excellent write up couldn't have come at a better time. Thanks for documenting the entire process. Could you email me your document and any associated pictures to [email protected]? (that is a underscore reno)

Thanks, Again

Adam

Shouldn't that beautifully written FP R&R be in the articles section? BTW aren't the dates screwed up? How can the piece be written before the person registered? Am I really in a time warp?

Hey Tangalora, I am too going to attempt fuel pump replacement (94 q 45) and your pictures would be most appreciated, please email at [email protected] or send link, Thanks

Hi Tangalora, Any chance that you could email me your documentation and pictures? [email protected]