feul pump control unit
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mark thompson
- Posts: 5
- Joined: Tue Apr 01, 2003 5:17 pm
feul pump control unit
how can the fuel pump control unit on a 1991 Q45 be positivly diagnosed as bad
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Q45tech
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Follow the explanation in your service manual page EF&EC-25!
The 3 voltage ranges should be present in the 3 different conditions..........5.6; 7.8; and 11-14 volts.
Simply run a wire from the juction wire between the pump and controller inside the car and measure the voltage to ground under the 3 conditions.
The 3 voltage ranges should be present in the 3 different conditions..........5.6; 7.8; and 11-14 volts.
Simply run a wire from the juction wire between the pump and controller inside the car and measure the voltage to ground under the 3 conditions.
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mark thompson
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- Joined: Tue Apr 01, 2003 5:17 pm
Thanks for the reply. However, I do not understand what you mean by the junction wire between the pump and the control. Have been trying to measure the voltages by following the explanation on pages EF-EC- 243and 244 in service manual. I should add the car has l65,000 miles, won/t start, starter motor turns engine over but the fuel pump does not operate. However it operates if power is applied directly to fuel pump motor.Fuel pump relay checks out okay. Have tried test procedures as outlined on Pg. EF and EC-l77, l78but trying to elimin ate fuel pump control module as causeQ45tech wrote:Follow the explanation in your service manual page EF&EC-25!The 3 voltage ranges should be present in the 3 different conditions..........5.6; 7.8; and 11-14 volts.Simply run a wire from the juction wire between the pump and controller inside the car and measure the voltage to ground under the 3 conditions.
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Q45tech
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
The fuel pump relay supplies +12 volts to the pump. The ground terminal of the pump goes to the fuel pump controller.
This is what I called the [junction]! The controllers acts like a large [wattage] [3 position] variable resistor to ground.
When a car gets towed in the first thing we do is use a jumper [wire with two alligator clips] to directly ground the pump ground terminal [the junction of pump and controller]......supplying 12-14 volts to pump.........9 out of 10 times the surge starts the pump so we can drive it in.
The pump is still bad because the pump CAUSED the controller to burn out..............high mileage pump motors draw excessive current because they turn slower than designed. This EXTRA current overheats some component and it fails.
This is what I called the [junction]! The controllers acts like a large [wattage] [3 position] variable resistor to ground.
When a car gets towed in the first thing we do is use a jumper [wire with two alligator clips] to directly ground the pump ground terminal [the junction of pump and controller]......supplying 12-14 volts to pump.........9 out of 10 times the surge starts the pump so we can drive it in.
The pump is still bad because the pump CAUSED the controller to burn out..............high mileage pump motors draw excessive current because they turn slower than designed. This EXTRA current overheats some component and it fails.
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Tim Tucker
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- Car: Cars, Computers, Music, Astronomy
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Q45tech: is this the same theory of operation present on a '00 Maxima. I'm getting P1220 code - car runs great. Code was cleared - returned on second drive. Have followed part of the troubleshooting chart, but have not finished. Any thoughts you might have would be appreciated. I have found no harness problem, and the .8ohm resistor measured .9 with my fluke meter. Is a schematic available for the FPCM? Any ideas on the specs of the diode present in the FPCM? TIA.Tim
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Q45tech
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
I don't bother with I30/I35 or Maxima have enough problems dealing with Q...........thus my name.............to become expert you must just deal with one car.
Follow the test proceedures in the 2000 service manual.
The resistor was added in 97 so that a fuel controller failure would not totally disable the car.
Follow the test proceedures in the 2000 service manual.
The resistor was added in 97 so that a fuel controller failure would not totally disable the car.
'94 Q45 Same Problem
My '94 Q45 quit on the interstate like it was out of fuel. I noticed that the fuel pump was not humming like it usually does. I remove the old pump and tested it. I works fine. The fuse checked out ok. So, I reconnected the fuel pump plug to see if it was getting power. There was no power to the positive side with the key on. Should there be power to the fuel pump while the key is on? . Then I located the fuel pump relay at the passenger side trunk area. Could the relay be bad? How do I test the relay? Or can i simply connect a jumper wire to the correct connections to se if i get power to the fuel pump. I am trying to elemiate the simple stuff before blaming the control module. Please Help!
The pump should get power for the first 5 seconds after turning the key to "on" before actually starting the car. Not sure where the relay is, but on any relay there should be a schematic on the relay telling you which terminals are which. Apply 12v to the coil terminals, and make sure continuity goes form open to closed on the other 2 terminals. Check voltage at the controller during the first 5 seconds. Check the manual, but I think it should be around 2-3 volts.
After reading all the posts there were, I realized I was confused by all the connectors with similar sounding names.
If you're going to perform a fuel pump & fuel pump control unit & fuel pump relay diagnosis, you'll need to distinguish between the following:
-fuel pump harness connector (blue)-fuel pump control unit harness connector (white, female)-fuel pump control unit connector (white, male)-fuel pump relay harness connector (lime green)
You'll also need to note the location of the following:- fuel pump (in the rear trunk room between the rear seat back & the trunk)-fuel pump control unit (bolted to the underside of the sundeck where you MUST peel back the rubbery sound-deadening material to access the 10mm bolts)-fuel pump relay (the lime green relay in the passenger side trunk room next to the antenna)
Alora
If you're going to perform a fuel pump & fuel pump control unit & fuel pump relay diagnosis, you'll need to distinguish between the following:
-fuel pump harness connector (blue)-fuel pump control unit harness connector (white, female)-fuel pump control unit connector (white, male)-fuel pump relay harness connector (lime green)
You'll also need to note the location of the following:- fuel pump (in the rear trunk room between the rear seat back & the trunk)-fuel pump control unit (bolted to the underside of the sundeck where you MUST peel back the rubbery sound-deadening material to access the 10mm bolts)-fuel pump relay (the lime green relay in the passenger side trunk room next to the antenna)
Alora
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Q45tech
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Again it amazes me after all the discussions that members haven't raided junk yards for spare FPCU and don't keep a full set of relays [there are 5 types used] and fuses from 10-100 amp.
Getting parts when easy and cheap sure beats list or waiting a few days.............with an alligator jumper wire [for FPCU ground] you can temp in the spare unit in 10 minutes on the side of the road if you always carry your charged electric screw driver.
Getting parts when easy and cheap sure beats list or waiting a few days.............with an alligator jumper wire [for FPCU ground] you can temp in the spare unit in 10 minutes on the side of the road if you always carry your charged electric screw driver.
Understood. Personally, I became aware of Nico only _after_ my 1990 Q45 (125K) would not start. Serves me right for habitually running on empty for days on end. I didn't even know. The dealer never said a word.
After reading all the fuel-pump-related posts, the hardest issues to grasp in the last two weeks were (for others to benefit):1. Finding the location of the components (e.g., only 1 page in the FSM shows the location of the fuel pump relay, EL-147 ) & I _still_ don't know where the ECU is located (somewhere under in the passenger dash).2. Figuring out how exactly to remove components for test (e.g., the 2 fuel pump control unit bolt heads are obscured by rubbery gunk which must be peeled back with a paring knife & which is NOT at all described in the FSM (EF & EC-168).3. Trying to understand your (q45tech) helpful hint about using the alligator clips to eliminate the fuel pump control unit (this is NOT in the factory shop manual, but it worked for me!).
The hardest part to understand about your q45tech helpful allicagor hint was:a) What was supposed to be hooked up at the time (answer = everything BUT the fuel pump control unit harness connector - which is to be disconnected from the fuel pump control unit connector - which is mounted directly on the fuel pump control unit - which is bolted to the underside of the sundeck - which can really only be well accessed from the trunk - despite the fact most posts assume you access the innards via the rear-seat bench removal process).b) What wire(s) to jump (answer = the one burnt & charred one
Honestly, that's how I figured it out! It's NOT in the FSM! It turns out the wire to jump to ground with the alligator clips is terminal 'e' (FSM EF & EC169) of the fuel pump control unit harness connector (white, female) as shown below: +-+ (white) | | Terminal Side (female)+-------+ +--------+| A B C D || E F G H | +---------------------+ ^ Jump E to ground to bypass the FPCU
c) Understanding the FPCU diagnostic procedure barely described yet well illustrated in the FSM (EF & EC 186). The key point I didn't grasp for the longest time was that I had to assemble a 4, 5, & 6-wire test fixture of assorted very tiny spade connector (can NOT be larger than 0.187 inch quick connects for the female end and no larger than 0.184 inch for the male (which ruined my nail file) which couldn't handle anything larger than 16 to 14 AWG wire diameters.
This, I state, for the next virgin newbie who may never have seen any of these Q45 FP-related posts before today.
Alora (thanks everyone!)
After reading all the fuel-pump-related posts, the hardest issues to grasp in the last two weeks were (for others to benefit):1. Finding the location of the components (e.g., only 1 page in the FSM shows the location of the fuel pump relay, EL-147 ) & I _still_ don't know where the ECU is located (somewhere under in the passenger dash).2. Figuring out how exactly to remove components for test (e.g., the 2 fuel pump control unit bolt heads are obscured by rubbery gunk which must be peeled back with a paring knife & which is NOT at all described in the FSM (EF & EC-168).3. Trying to understand your (q45tech) helpful hint about using the alligator clips to eliminate the fuel pump control unit (this is NOT in the factory shop manual, but it worked for me!).
The hardest part to understand about your q45tech helpful allicagor hint was:a) What was supposed to be hooked up at the time (answer = everything BUT the fuel pump control unit harness connector - which is to be disconnected from the fuel pump control unit connector - which is mounted directly on the fuel pump control unit - which is bolted to the underside of the sundeck - which can really only be well accessed from the trunk - despite the fact most posts assume you access the innards via the rear-seat bench removal process).b) What wire(s) to jump (answer = the one burnt & charred one
Honestly, that's how I figured it out! It's NOT in the FSM! It turns out the wire to jump to ground with the alligator clips is terminal 'e' (FSM EF & EC169) of the fuel pump control unit harness connector (white, female) as shown below: +-+ (white) | | Terminal Side (female)+-------+ +--------+| A B C D || E F G H | +---------------------+ ^ Jump E to ground to bypass the FPCUc) Understanding the FPCU diagnostic procedure barely described yet well illustrated in the FSM (EF & EC 186). The key point I didn't grasp for the longest time was that I had to assemble a 4, 5, & 6-wire test fixture of assorted very tiny spade connector (can NOT be larger than 0.187 inch quick connects for the female end and no larger than 0.184 inch for the male (which ruined my nail file) which couldn't handle anything larger than 16 to 14 AWG wire diameters.
This, I state, for the next virgin newbie who may never have seen any of these Q45 FP-related posts before today.
Alora (thanks everyone!)
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Q45tech
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
The factory service manual is a basic must read, kind of like a 1st grade reader [introductory text].
We try to provide a Masters Degree in Q45 technology here.
Don't assume that dealers know very much beyond [if that] what is in the service manaual and TSB. The Launch and thick product bulletins might have been glanced over by the best technicans 13-10 years ago.
Owning and dealing with a Q for 13 years gives you an Associates Degree.
We try to provide a Masters Degree in Q45 technology here.
Don't assume that dealers know very much beyond [if that] what is in the service manaual and TSB. The Launch and thick product bulletins might have been glanced over by the best technicans 13-10 years ago.
Owning and dealing with a Q for 13 years gives you an Associates Degree.
I thank both Maxnix & Q45tech for the advice. Thanks for the honorary 13-year Q45 associates' degree also.
Actually, I've had it for 10 (I bought it used from the dealer at 40K). I've been lucky in that I haven't needed many repairs (plus the first 60K were covered by Infiniti). That's why I get the best I can and hold on to it as long as possible.
What I will do to pay back the group is (try to) write up a step-by-step how-to with digital photos (I took 'em every step of the way) so the NEXT newbie has a (much) easier debugging task.
That may take me a few weeks before I have the time. In fact, I _still_ have not put the new fuel pump in. Since Monday, I've been driving to work with the alligator clip (40 miles round trip per day, weekday shift) grounding the original fuel pump (a friend lent me a car 'till monday but needed it back). I remember what q45tech said about the pump lasting a while in this state.
Another friend of mine picked up a fuel pump for me at the local parts shop which we'll install together this weekend. It has a life-time warranty, but, it's not an Infiniti part. It's imported by the "Airtex Automotive Division" at "407 West Main Street", "Fairfield, Illinois, 62837". We were going to put it in last weekend, but we didn't get the highly recommended O ring.
Monday, at break time, I stopped off at Infiniti and picked up the 12-dollar fuel pump O ring. I was surprised how thin it was (and flimsy looking).
The Airtex fuel pump cost, with tax about $312; but, while I was at the dealer, I asked and their pump (sans tax) was $312 ($520 for the controller). A sticker on the plastic unopened bag says "Fuel Pump, E8219M-1, Ref #17042-60U00, Made in Japan, Pac #05.26.03".
I've been debating every since Monday whether I should go with the dealer's pump or my friend's pump. Basically they are the same price. The Airtex, we was told by the store, has a lifetime warranty - but that doesn't tell me which is better.
All I know is the old pump measures 0.9 to 1.1 ohm while the FSM (EF & EC-185) says if it's not "approx. 0.5 ohms" it's N.G. (no range is specified).
Actually, I would have thought, based on the posts I read, that the resistance would have gone DOWN (more current) than UP. But, I do remember one post cautioning us that the FSM test only tests one commutator (presumably there are more that are untested that may be bad).
I brought the fuel pump control module over to the biomedical engineering test benches (at work) and we rosin-core soldered a 16 awg jumper from pin #4 and pin #8 on the underside of the fuel pump control unit printed circuit board to a few more points on the FPCU PCB. Just so when the NEW fuel pump goes in that there is plenty of ground around.
So, my only questions (always questions) are whether anyone has experience or learned recommendations regarding the Airtex imported fuel pump vs the stock Infiniti part (I tend to go dealer unless price is hugely different ... but we already picked up the pump).
Alas Brian, while I was at the dealer, I asked for the complete service record, which they kindly printed, page by page. No mention whatsoever (as I thought) of the timing-chain guides. I'm likely to be wearing plastic on my engine. Sigh. I don't have the money (right now anyway) to proactively replace them (I'm assuming 1 or 2 grand). I may just have to risk it (yes, I just now read the posts about the dire consequences. I still may have to risk it. For now. Maybe after the holidays.
Actually, I've had it for 10 (I bought it used from the dealer at 40K). I've been lucky in that I haven't needed many repairs (plus the first 60K were covered by Infiniti). That's why I get the best I can and hold on to it as long as possible.
What I will do to pay back the group is (try to) write up a step-by-step how-to with digital photos (I took 'em every step of the way) so the NEXT newbie has a (much) easier debugging task.
That may take me a few weeks before I have the time. In fact, I _still_ have not put the new fuel pump in. Since Monday, I've been driving to work with the alligator clip (40 miles round trip per day, weekday shift) grounding the original fuel pump (a friend lent me a car 'till monday but needed it back). I remember what q45tech said about the pump lasting a while in this state.
Another friend of mine picked up a fuel pump for me at the local parts shop which we'll install together this weekend. It has a life-time warranty, but, it's not an Infiniti part. It's imported by the "Airtex Automotive Division" at "407 West Main Street", "Fairfield, Illinois, 62837". We were going to put it in last weekend, but we didn't get the highly recommended O ring.
Monday, at break time, I stopped off at Infiniti and picked up the 12-dollar fuel pump O ring. I was surprised how thin it was (and flimsy looking).
The Airtex fuel pump cost, with tax about $312; but, while I was at the dealer, I asked and their pump (sans tax) was $312 ($520 for the controller). A sticker on the plastic unopened bag says "Fuel Pump, E8219M-1, Ref #17042-60U00, Made in Japan, Pac #05.26.03".
I've been debating every since Monday whether I should go with the dealer's pump or my friend's pump. Basically they are the same price. The Airtex, we was told by the store, has a lifetime warranty - but that doesn't tell me which is better.
All I know is the old pump measures 0.9 to 1.1 ohm while the FSM (EF & EC-185) says if it's not "approx. 0.5 ohms" it's N.G. (no range is specified).
Actually, I would have thought, based on the posts I read, that the resistance would have gone DOWN (more current) than UP. But, I do remember one post cautioning us that the FSM test only tests one commutator (presumably there are more that are untested that may be bad).
I brought the fuel pump control module over to the biomedical engineering test benches (at work) and we rosin-core soldered a 16 awg jumper from pin #4 and pin #8 on the underside of the fuel pump control unit printed circuit board to a few more points on the FPCU PCB. Just so when the NEW fuel pump goes in that there is plenty of ground around.
So, my only questions (always questions) are whether anyone has experience or learned recommendations regarding the Airtex imported fuel pump vs the stock Infiniti part (I tend to go dealer unless price is hugely different ... but we already picked up the pump).
Alas Brian, while I was at the dealer, I asked for the complete service record, which they kindly printed, page by page. No mention whatsoever (as I thought) of the timing-chain guides. I'm likely to be wearing plastic on my engine. Sigh. I don't have the money (right now anyway) to proactively replace them (I'm assuming 1 or 2 grand). I may just have to risk it (yes, I just now read the posts about the dire consequences. I still may have to risk it. For now. Maybe after the holidays.
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maxnix
- Posts: 22627
- Joined: Mon Jul 22, 2002 8:11 pm
- Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45
New chain guides for Christmas! I would recommend a call to Joe at http://www.infinitipartsusa.com for the fuel pump, O ring and sock. OEM is almost always better than after market.
Seriously, you may be running on a prayer. There is a guy in NJ Vanmeter who is reasonable. Don't lose everything (or at least your car) because of neglecting this critical item.__________________Brian1995 Q45 & Q45t & 2000 Q45
Discover the power of the button!
Seriously, you may be running on a prayer. There is a guy in NJ Vanmeter who is reasonable. Don't lose everything (or at least your car) because of neglecting this critical item.__________________Brian1995 Q45 & Q45t & 2000 Q45
Discover the power of the button!
> The hardest part to understand about> the q45tech helpful allicagor hint was:> What was supposed to be hooked up at the time ...
I must admit it took me days ... no ... more than a week before I understood (even after reading every fuel pump post in this forum & in that of yahoo & google) what the common problem & resolution was.
Here is a series of pictures which (I hope) distill my 1990 Q45 fuel-pump failure down to the basic essence.
This first picture shows the burned ground pin on the fuel pump control unit connector (caused by the fuel pump drawing excessive current).
I must admit it took me days ... no ... more than a week before I understood (even after reading every fuel pump post in this forum & in that of yahoo & google) what the common problem & resolution was.
Here is a series of pictures which (I hope) distill my 1990 Q45 fuel-pump failure down to the basic essence.
This first picture shows the burned ground pin on the fuel pump control unit connector (caused by the fuel pump drawing excessive current).
This second picture shows the corresponding 16 AWG 1-foot jumper alligator-clipped to the complementary #4 pin of the white female fuel pump control unit harness connector.
The other end of the patch wire wsa alligator clipped to a convenient ground.
Note the 'correct' pin to patch to ground is surrounded by empty sockets (so you can't really miss it once you know the secret).
The other end of the patch wire wsa alligator clipped to a convenient ground.
Note the 'correct' pin to patch to ground is surrounded by empty sockets (so you can't really miss it once you know the secret).
This third photo shows the exact point of failure in the fuel pump control unit.
Specifically, there was an open circuit between the #4 white male fuel pump control unit connector pin soldered to the underside of the fuel pump control unit printed circuit board ... and any accessible point on that very same trace (even the first test point only 10mm away from the open solder point). Voila!
Specifically, there was an open circuit between the #4 white male fuel pump control unit connector pin soldered to the underside of the fuel pump control unit printed circuit board ... and any accessible point on that very same trace (even the first test point only 10mm away from the open solder point). Voila!
This fourth photograph shows the repaired and reinforced 1990 fuel pump control unit. Don't laugh; that 5 cm 14 AWG copper wire seems to have worked (thereby saving me hundreds of dollars in replacement cost).
Those of you who are EEs might help me out here. Did it do me any good to make the 14 AWG booster wire travel half way across the trace? Does that help with cooling when excessive current (6 amps) is coursing from the battery to the fuel pump relay to the fuel pump to this fuel pump control unit ground path to ground?
I suspect the most important segment is the metal path from the #4 FPCU PCB connector to its corresponding trace which was accomplished by solder alone.
Those of you who are EEs might help me out here. Did it do me any good to make the 14 AWG booster wire travel half way across the trace? Does that help with cooling when excessive current (6 amps) is coursing from the battery to the fuel pump relay to the fuel pump to this fuel pump control unit ground path to ground?
I suspect the most important segment is the metal path from the #4 FPCU PCB connector to its corresponding trace which was accomplished by solder alone.