Q wont start! Newb owned for only ONE WEEK..looking for advice

[SEOK]

Well i just purchased the 91 Q for the ol lady last week and now it stranded her at the store. And now it wont start. It ran good before this with no known issues. of course Im not familiar with these, as ive always owned GM v8s, but it seemed tight with nothing more than a SLIGHT shudder at idle and i mean SLIGHT. she parked it, grocery shopped and came out to start it.. it cranked but wouldnt fire up. once or twice she said it DID fire up for a second or three & died. throttle didnt help keep it alive. By the time i got out there i fired it right up! ran for about 6 seconds and died. same thing. first things that came to mind were Fuel pump gone bad, and (from working on chevy's) a heat soaked ICM. but im not even sure if these hhave an ICM do they? anyways, we were only 5min from home so i strapped it up to the caprice and pulled it home. I search the forums for a good few hours and read some good articles. so... first thing i did was turn the key on and listen for fuel pump hummm. didnt hear a thing in the trunk at all. how loud should they be?? i put my head in there and couldnt hear a thing. my next step is to check fuel pressure tomorrow when i get home from work. im guessing pressure should be around 40+-?? cranking? Im used to screwing a gauge into a schrader valve on the fuel rail but this looks to connect to the filters rubber hoses going to the rail under the plenum correct? which of the two hoses should i connect to?If pressure is good, i will move to pulling a plug and checking spark. UNLESS I SHOULD CHECK IT ANOTHER WAY??? if the pressure is bad or doesnt hold should i instantly assume Fuel Pump? or is there something else down the line that would show the same low/no pressure? like a FuelPressure regulator or something electronic? i will also check and clean the MAF and CAS connectors. thats about as far as i can get with MY knowledge. i have a multimeter but i am DUMB when it comes to using it. i CAN follow detailed guidance tho hint hint. well its getting late and thought i would share my stress of the day. PLEASE correct me where needed with my first steps at this troubleshoot. and ANY advice or tips are appreciated!!! THANKS
Modified by SEOK at 2:19 AM 1/5/2010

[loystock]

You are on the right track. As for the fuel pressure - it's 34 PSI with engine running and 43.4 PSI with with Ignition ON but engine OFF. Here's a descriptive T/S and Fuel Pump replacement procedure, courtesy of Tangalora.

http://www.nicoclub.com/articles.php?id=164324

Other gurus in this forum may be able to chine in the morning.

[Q45tech]

What did the expert PREBUY INSPECTION outline as needed parts replacement on this 19 year old vehicle.

History has shown minimums of $3,000 and maximums of $11,000* based on $85 per hour and 55/45 cost of oem parts.

While a vehicle can seem ok to a new owner only experts can delineate the true cost to restore to near new operating condition.

* not including body work , paint, or interior restoration.

The only ones we know who chose to give a 90-93 Q to wives/girl friends are Infiniti Master Technicans who get significant discounts on parts and do the labor after hours and on weekends.

Good luck and be sure to read and study ~100,000 posts here to understand what you are up against. Every Q came with a mini FSM which will become you new best friend. I needs to be read and reread until you commit every page to memory.

[speedeast]

Every Q came with a mini FSM which will become you new best friend. I needs to be read and reread until you commit every page to memory.

[elwesso]

The fuel pump isnt very loud, but you can hear it, like a slight hissing...

Sounds exactly like a bad fuel pump/controller.. Id go ahead and replace the pump... Another thing you can try is to ground out the fuel pump controller, forcing the pump to come on. Would at least let you get the car home.

[maxnix]

If you towed the Q very far, you probably are in the market for a new transmission also. Always flatbed.

Timing chain guides?

[SEOK]

an "LOL" cheerleader for a semi funny quote... yay.Q45Tech, i appreciate the reply but i dont think an insulting post letting me know that i made a mistake purchasing a car that i cant afford to repair or maintain, or since im NOT a Q-ninja master as yourself it was foolish of me to purchase my girl a Q, was really the reply i was looking for. Your right though, i know nothing about this car, but thats why i am here. if we were all master Q45techs we wouldnt need this forum for advice would we. Every car ive owned I joined a forum ro learn more about it and do all my own repairs or mods. I just started my reading and researching the forum to learn what i can about the car when it broke down. i really do appreciate the advice and comments but i think some it was a bit of an unneeded insult. no hard feelings here man, i know you are a very knowledgeable tech and extremely helpfull to the forum, i just thought you would have came through with something a bit more helpfull to my problem at the moment. i will check what i can today after work and keep you posted.

[SEOK]

Loystock, thanks for the link! good info there.

[NightRiderQ45]

please check to see if the chain guides were done (plastic to metal)? if not you will need a new motor when it breaks. that's the first thing you should get checked.

[SEOK]

please check to see if the chain guides were done (plastic to metal)? if not you will need a new motor when it breaks. that's the first thing you should get checked.

for sure, i was litteraly looking into the replacement kit when it got stranded. I wanted to replace the guides within the month since i found out how important it is to do. i just hope it hasnt skippd time already or something. wouldnt it make some noise or run rough when it did fire up for a few seconds? well, if i have spark and good fuel pressure then i will move to check compression. would that be my best next step??

[Q451990]

I doubt it's the guides if it runs at all. When my guides failed the car ran really bad - backfiring and sputtering. They usually just stop, but mine just jumped two or maybe three teeth on the left bank.

I would certainly check fuel first - but if you're worried about the guides - compression would be your first step.

Don't let some of the comments get you down - we have a long tradition of "noobie beatings" here - kind of a right of passage. Welcome to NICO!

Heath

[goody90q45]

Could the engine just be flooded? The Q doesn't like short trips in cold weather.

Hold the gas pedal to the floor and crank the engine for 30-45 seconds and see if she starts. No fuel will flow and the cylinders will flush out excess fuel if they are flooded.

You're doing a good job of describing your problem so don't let the 2 or 3 naysayers drive you away. There's plenty of courteous members to make the forum a worthwhile place to get help.

[SEOK]

NO no no.. it dont bother me a bit. i know how it goes..like i said im a member of the Impalassforum among a few other forums and havent been a newb for a looong time over there. so I get to playTHAT part to the newbs over there and now IM a newb AGAIN over here! i'll figure out "whos who" in due time, its all good.

In reply.. I did try holding the peddle down for awhile, didnt help. that was one of the first things i tried just because i thought my girl might have had a flashback of driving my 68 buick and thought she'd have to pump the "4barrel" well im finally home and off to check fuel pressure... out in the rain

[Q45tech]

Make a tee with a schrader valve to insert between rubber line from filter and hard line on to engine for future diagnosis ease.There are input fuel pulse damper and output regulators but almost never cause problems 34 with plenum vacuum 43.4 WOT something inbetween during less than WOT acceleration.

Pulse crimp return line to cause psi to > 60 psi to blow out injector [screens] to longer than 1 second x 10 tries or you will give the FP blowoff valve a stroke.

Off the psi should drop to 30>20 psi and stablize around 15 for hours.

You will need access to Nissan Consult I or II for ease.

Good Luck.

[SEOK]

thanks Q45tech, I was outside checking FP as you were typing that..

removed fuel cap (to relieve pressure in the line), there was ZERO fuel in the line after the filter when disconected, I hooked up a T and gauge here...

cranked the engine.... Gauge didnt budge, ZERO pressure..
Modified by SEOK at 7:51 PM 1/5/2010

[Q451990]

The typical failure is for the pump to age and pull too much current, burning out the fuel pump controller. By way of background, the fuel pump runs at three speeds, and the controller sits between the low current feed from the ECU and the pump. It's bolted to the package tray and is visible from the trunk with the finisher removed.

You can ground a pin on the harness to run the pump at full pressure all the time - but it's not recommended except for a temporary fix. Like getting the car home...

Good stuff in this thread: zer...age=2

Heath

[goody90q45]

.....You can ground a pin on the harness to run the pump at full pressure all the time - but it's not recommended except for a temporary fix. Like getting the car home...

What's described above bypasses the FPCU and runs the fuel pump on high speed only. Here's how it's done. The connector in found by unplugging it from the FPCU which is in the background of the pic. Jumper from the connector pin with the clip attached to an unpainted surface (the brace aft of the gas tank) and see if she starts. If it does the FPCU is fried and will need replacing.

[SEOK]

^^I will try that,so, I realize that if the pump works with this test then the FPCU will need to be replaced. but I was reading here that it can also be repaired, is that correct? im afraid to even look at how much a new FPCU costs. assuming its more than the pump.

another thing... If the unit IS fried, wouldnt that mean that the pump is on its way out also? drawing TOO much from the FPCU and fried it?seems that if this test results in the pump working and confirming the FPCU to be fried then I better replace BOTH the FP and the FPCU.. yes? no?also, if the pump does NOT work with this test could i assume that JUST the pump is bad and NOT the FPCU?

[elwesso]

I would personally plan on replacing both... if the bump comes on but makes a lot of noise, you know its bad.

The FPCU doesnt go bad unless the fuel pump goes out...

[SEOK]

just bypassed the FPCU and the car fired right up! fuel pump had a very quite buzzz couldnt hear it unless my head was in the trunk. So, I am going to buy a NEW FP so I dont risk frying my replacement FPCU but I dont want to buy a NEW FPCU (very expensive) I found a member here that apparently repairs them, im going to give it a shot. I checked every JYard around here and nobody even has any Q's, go figure. found some in the sacremento area at a pick n pull. anyone from there wanna get me a FPCU??? well, first things first.. How the heck do i remove that thing?! it looks as if i have to remove the seat, package tray etc. am i missing something??

[elwesso]

Well thats good! You might call the PO and see if the FP has been replaced recently.. Worth asking.. Ive seen instances where someone to replaces the pump, and within a week or 2 later the FPCU goes out...

Would be a shame to buy a new FP only to learn that its been recently replaced...

You have to take out the back seat and the parcel shelf and the FPCU is held on with 2 bolts onto the package shelf.. Or alternatively, you could just shove it in next to the fuel tank...

[SEOK]

damn, you beat me to it. i was just about to edit my post saying to disregard my question since I found an article that explains how to remove the FP/FPCU through the back seat/deck area. believe me.. i AM searching a lot before I post these questions lol

[goody90q45]

Pull the cover off the FPCU and see if you don't have any burnt solder joints, especially the ground circuit as it passes through the body of the FPCU at the connector. The fix may be as simple as a resolder.

[3Q Jay]

Matt- I did reply to your email.also, after replacing the pump, very important to replace the fuel filter (often the cause of overstress on prior pump), and the green relay by the power antenna in the trunk.

[SEOK]

thx Jay, replied back.pulled the FPCU and opened it up.... it is NOT burnt near or in the connector.it is however burnt in THREE other spots im gonna assume its not repairable, but what do I know lol? I'll post some fuzzy cellphone pics in a bit...



Modified by SEOK at 5:29 PM 1/6/2010
Modified by SEOK at 5:32 PM 1/6/2010

[elwesso]

or it could be the pump only operates at high speed... Not sure if thats possible, but it could be... Usually only FPCU like to fail at the connector.

[3Q Jay]

Wes, i've seen a number of different failures now on the FPCUs, not just the ground pin. this one has blown power transistors.

[Q451990]

pulled the FPCU and opened it up.... it is NOT burnt near or in the connector. it is however burnt in THREE other spots

The one on my old Q failed at the same spots - seems like they either go in those areas or near the connector. The going rate has been about $50 for a used one. I have a few on hand if you can't find one locally.

Heath

[SEOK]

E-mailed you. Thanks

[Ozzie]

This thread makes me smile.The OP is doing thorough research, and has his head screwed on right, and obviously knows quite a bit about cars.(PS: Welcome to the NICO forums, hope you stay for a while, and learn lots more about your Q)

The help coming from the old crew reminds me of how the Q45 forum used to be.... those were the days.