96 Q45 unexplained Stalling??

[Magnum PI]

I got the same problem going on. but since no codes thrown, I replaced the fuel pump and FP Control Module. Ran great for a couple trips then cough, and stall. Starts right up again. Cleaned the MAF and ran great for a couple more local trips then cough, and stall.

I have a used MAF on order, but will also clean the connections to the ECM too as my radio head unit was intermittant then now its comatose.

I've got my fingers crossed on the incoming MAF.

[96Q45GAL]

Thats how my started...Originally it was a loud HUMMING in my trunk...so loud you could hear it like a swarm of bees in the trunk.. Then I had some issues when it got hot outside and the bucking started on the highway. I had all this other work done..fuel system,tune-up crank sensor intake cleaning oil change fuel filter change and intake clean...The bucking and stalling got worse!!! To the point I wont even take it on the highway...If you can take the advice you've seen on here and try and tackle it before the bucking/stalling gets out of hand!!

[Haitian_King]

The buzzing sound from the trunk is indicative of a failing fuel pump. A failing fuel pump stresses the FPCU as well. Especially when the tank is less than half full. Warm temperatures are bad as well.

That might be the cause to your problems.

[96Q45GAL]

Yeah I replaced fuel pump about 2months ago... I had lots of power and performance after that and a tune up but since the bucking/stalling problem I suddenly seem to be losing power again and Im getting a slight vibration while sitting at a light...thats when it dosent decide to shut off!

[Haitian_King]

Did you replace the FPCU as the same time? I've never had any FP trouble, but I've been reading on the board about the troubles and it's recommended to replace both units. A bad FP will damage an FPCU. If only the FP is replaced, the bad FPCU will ruin the new pump. A vicious cycle really.

Idk about the car shutting off. The bucking really sounds like an injector or MAF problem.

[Magnum PI]

I can't wait to solve the bucking and stalling problem. I hope the replacement MAF is it. The car has run like a champ for the past 10 years. Must of overheard me talking about trading it in!

[96Qowner]

Did you replace the FPCU as the same time? I've never had any FP trouble, but I've been reading on the board about the troubles and it's recommended to replace both units. A bad FP will damage an FPCU.

Yes, this is important, and could be causing you trouble. The Fuel Pump Control Unit (FPCU) can overheat from a bad fuel pump and become unreliable.

Um, you still haven't wiggled the MAF plug?? Just start the car, lift the hood, reach over the driver's side fender and wiggle it. The engine will either react or not - nothing bad can happen. Then you'll know if the plug is iffy.

C'mon, you can do it.

[96Q45GAL]

OK...So this morning I went out and Wiggled the connector(mine is brown..not white like in pic..is this ok?)..Nothing happened?..Not no noise,nothing? engine stayed the same! I am thinking now it may be the MAF itself is bad? Is it the brown plastic box I should be Wiggling? same as in the pic posted but different color.

[96Qowner]

Damn, I can't remember what color my plug is, and mine's at home in the garage.

But in any case, ok, no change, we know that much now. Yeah, I think the next step is to either clean the MAF and plug, or skip it all and find a used MAF.

Or ... *cough cough* ... get a genuine new one from Joe - $460.

http://www.trademotion.com/par...gid=2

[96Q45GAL]

Yeah I will try and order one this week..I think it is the MAF and I think I will just replace it versus cleaning it out...That way I hopefully dont run into this again a few months from now!

[mklandrieu]

I have a 92 Q45 and am exhausted trying to keep it running.I have changed the MAS twice but it is still stalling.When it is running it runs perfectly. But its so frustrating.I cannot for the life of me figure out why someone can't figure this out.We can go to the moon but can't fix a Q.

Mark

[Q45tech]

We solve these problems daily! weekly, monthly annually and have for the past 13 years There are very few things [less than a dozen] that can cause the generic type stalling, hiccup problems.

Fuel pump, FPCU, MAF, KS, Injectors, CAS and of course all their harnessses and connectors.

Unless you are substituting known good parts I have seen mechanics add to the orginal problem.

I usually use BG44k as a partial diagnostic tool, then make sure the tank is at least 1/2 full of premium [never trust customer go to gas station and add to bill], do a power balance test [multiples loaded and unloaded] scan all the ecu signals and codes................then get a DR. Pepper and think for 15 minutes while the 44k circulates. Then do another power balance looking for changes.

Measure injectors, measure KS, measure fuel pressure on a test drive at WOT.

Tap MAF, wiggle MAF and CAS connections.

All can be done in 1.5 hours.

Sometimes the order changes but usually the confused customer just says something that sends you off on a tangent. Many can't even elocute the symptoms in a technical meaningful way:

[Haitian_King]

Spaceships and moon rovers aren't as great as the Q. I guess that's the cause of the frustration.

I know what you mean. When my 92 is running like it should, it's a blast. But other days, it aggravates me to drive it. And then i begin to discover more more problems.

Earlier today, (about 30 minutes ago), I left a red light and the sheer force of acceleration launched the stack of CD's I had in the slot below my head unit into the shifter and underneath the armrest. It was an accident really. I didn't mean to do it. But moments like that make me appreciate the Q.

[96Q45GAL]

I hear ya...But trust me whatever they tell you to do on here...Give it a try! I personally have spent too much! Dealing with inexperienced mechanics!! I came on here and within a few hours I had things figured out or at least narrowed down! I havent had any problems this whole week except for a cpl rpm dips and maybe 1 shut off...UNTIL...... Today. Oh it tried to act up and even shut off a few times and you know what I did?.. I got out of my car after re-starting after a stall and WIGGLED that connector and TAPPED the MAF box...and what do you know...It ran great:) I would have never even thought of that until I came on here( not like I am recommending u do this..lol) Im waiting for a MAF now but have learned ways to keep her runnin smooth in the meantime!!

[maxnix]

So this morning I went out and Wiggled the connector..Nothing happened?..engine stayed the same! I am thinking now it may be the MAF itself is bad?

You must examine the the wires where they connect to the plug itself. Same for CAS.

[maxnix]

I am sure anyone promoting a repair business would do the same......you find that shocking? Fact remains that Nissan,Toyota and majority of other manufacturers have lengthened platinum plug change intervals to 105,000-120,000 miles based on real world longevity in the field.Galling is extremely rare if proper plugs{ngk with the special coating on threads to prevent such} and proper torque is applied.

First, Dennis is hardly a promoter of any repair business in particular, just the concept of preventative maintenance. Replace it before it fails.

Secondly, dealers are some of the worst practitioners when the basic tasks are assigned to minimum wage lackeys and are performed incorrectly. Like Dennis said, they are saving the well paid senior tech for the more vexing diagnoses.

The plug change interval was not extended from 60K to 100K until the VH41DE I believe. A review of the respective OM is in order.
Modified by maxnix at 8:33 AM 12/1/2007

[maxnix]

the problem was with the motor,not the oil

Actually, it was with extended OCI on that particular engine, the 3L V6.

[qship96]

Brian,I never said anything about Dealership service,so your comment is puzzling.Regarding the plug change intervals,nice try with the vh41 comment-however same aluminum head and plug interface-your reply is insignificant

Dennis certainly does represent T3,afterall,his postings have recruited many of us,including me,to drive hundreds of miles to the shop he is promoting on this site-WAKE UP!!!
Modified by qship96 at 8:59 PM 11/30/2007

[goody90q45]

.......and WIGGLED that connector and TAPPED the MAF box...and what do you know...It ran great:)...... Im waiting for a MAF now but have learned ways to keep her runnin smooth in the meantime!!

If you would take 10 minutes and clean the connector and tighten up the pins you may find that you don't need the replacement MAF at all.......

[96Q45GAL]

I will clean it but couldnt do that in the middle of traffic...Did what figured might work for me at the time....Its a girl thing:) we tend to quick fix think later:) Im in proces of getting new one! So hopefully no more wiggling or tapping:)

[AlabamaDan]

Wasn't there a TSB somewhere that talked about bending a wire in the MAF connector? I read that they had done that in my maintenance history early on. They also added (another?) ground wire to the MAF. If your Q hasn't been to the dealer with problems back years ago it may need that. Anyone know the details of that?

[Haitian_King]

Zing!

After some consideration, and contingent on how well these new employees can handle themselves, a trip to T3 might be in order. Van Meter has been avoiding my calls, and I'm getting antsy.

I think I need to find a driving buddy. I'd hate to have to drive 12+ hours by myself.

[Magnum PI]

Bend which wire? I will try anything.

[maxnix]

Van Meter has been avoiding my calls, and I'm getting antsy.

I think I need to find a driving buddy. I'd hate to have to drive 12+ hours by myself.

Maybe you are asking the wrong questions?

Never drive out west! 14 hrs from Denver to Austin.

Computer on top of luggage on passenger floor for full secreen GPS. No room for anyone.

[maxnix]

Brian,I never said anything about Dealership service,so your comment is puzzling.Regarding the plug change intervals,nice try with the vh41 comment-however same aluminum head and plug interface-your reply is insignificant

Dennis certainly does represent T3,afterall,his postings have recruited many of us,including me,to drive hundreds of miles to the shop he is promoting on this site-WAKE UP!!!

Well, then Nissan is lying to you as they changed the interval, but they also changed the coilpack design. Beleive me it wasn't me.

The only "recruitment" Dennis has made that I recall was to local owners who could not diagnose a problem likely caused by multitude of failed componentsand /or deferred maintenance. His recounting of service proecedures employed by T-3 is hardly recruitment but information for our consideration. Maybe you've been watching too much TV while being shut in during the winter freeze overs?

Furthermore, he has never said members are incapable of cahnging their oen plugs and should employ any shop, let alone T-3, to perform that service for them.

I have never been to T-3, only flown through Atlanta, but I would go in an instant if I had avexing problem or required a 200K check up.

[qship96]

Brian,you are soo far off base here with your weak reply

Your comment on any changes nissan made with the downgraded q41 coilpacks has NOTHING to do with my original comment regarding the lengthened spark plug change intervals in later models by most manufacturers and possibilities of plugs sticking or galling into aluminum heads=nice try at deflecting,but if you have nothing of value to add...then dont!

My original comment was that Dennis promotes T3 here=get a grip,it is a GOOD thing,as I certainly benefited by having my Q serviced there...

Your comments regarding dealerships,nissan lying,etc are coming from where? I certainly never stated the dealer or nissan said squat to me?

Someday,you will have enough ***-time behind the wheel of an Infiniti to draw your own conclusions based on your own experiences,and then maybe you can contribute to this board,instead of just repeating and referring to EVERYTHING Dennis thinks and says= It is time to grow up and stop sucking on the Dennis nipple

[Haitian_King]

What's your idea of a wrong question?

"Hi, is Mr. Van Meter available? I'd like to speak with him regarding my 1992 Q45. Oh, he's under a truck you say? May I leave my name and number for him to get back to me? Thank You."

I must be going about the wrong way then huh B-Ri?

[Q45tech]

Forum business in tiny and has always cost many more hours by a factor of 5-10-20 than it generates. The annual dollar value we currently get from out of state is insignificant [maybe $15,000 per year].

Our best year was 2000, where out of state was about ~$33,000. That is a drop in the bucket when you gross more than a few million annually and have 15 employees and 3 shops to feed.

Out of state/area actually costs more because you must be extra special cautious or risk ending up towing them back from who knows where for mistakes.

It all started as a kind of a challenge to see how far I could get someone to drive to ATL, then it was used to inflate employees ego, now it has little if any emotional value.

For years I've hoped every state/region would have a T3 type place for Q45 to go but as we've seen few can make a serious go of it and survive.

It is easy to find out which independents buy the most parts from any dealers and most parts managers seem willing to help me out when I have tried to conduct surveys in the past.

[goody90q45]

It all started as a kind of a challenge to see how far I could get someone to drive to ATL, then it was used to inflate employees ego, now it has little if any emotional value.

What's the furthest owners have driven for service on their Q's?

[Q45tech]

North Dakota, New Mexico, and New Hampshire. Mass, Mn, Oklahoma, Iowa........lots of that was for chain guides and serious work. We get a good many flatbeded [and towed on dollies] from Florida or adjacent states now but they are usually just a combo of fuel pump, fpcu and MAF...........3 simultaneous things wrong seem beyond many techs.