1990 Q45 Frustration.....

[aliciaford]

My 1990 Q is running terrible. Over the past few weeks it seems to have one issue after another. It has had trouble jerking when keeping a constant speed between 40 and 45 mph, mostly when going up hill. It finally threw a Transmission Malfunction code, and I went thru the AT Check, and found it it was the Throttle Position Sensor, a bad wire in the connector. So, we replaced it. Car seems to generally run better, and shift smoother, but did not fix the jerking/hesitation problems. Now, today I went out to start the car and it has a very unstable idle, very rough and its acting weird... I am starting to think that everytime its significantly colder outside, the car acts up. Any ideas?Thanks

[qship96]

Mass Airflow Sensor or its wiring/connector {square black box attached to top half of air filter housing} try unplugging the connector and look for corrosion on the pins, clean them if dirty- if that does not cure it, the MAF itself is bad- replace with new one.

[maxnix]

Ever clean the IAC valve? Throttle Body? Plenum?

Last time plugs were changed? ATF?

[aliciaford]

We followed the links to clean the throttle body and MAF Sensor. Plugs were changed about 10,000 miles ago. ATF is new. When I just ran home at lunch time, I noticed the car has lots of exhaust smoke, seems to be running rich? What about the Knock Sensors???

[qship96]

MAF MAF MAF, it is the MAF.

[aliciaford]

You sound so positive, have you had this problem, too? We cleaned it, but still having problems, got any suggestions on where to buy? What other symptoms will the car have if the MAF is bad?? Thanks a lot.

[qship96]

Yes, I recently had to replace my MAF - car ran perfect, then out of the blue it stalled a few times while at idle,then I experienced a bucking at light throttle on highway....then no problems for a day or so, then came back.The solder connections inside the maf fail and problem starts intermittant, then full time. New MAF from scottsdale infiniti is about $450,solved my problem 100%- immediatly. You could buy used maf off ebay for 50-90, but it is a gamble asthe part will be old and tired like the one you currently have.... may last 1 day,week,year????

[aliciaford]

I found one from Beck Arnley, for $150 ish. Part # 157-0353. I will keep my fingers crossed. Thanks again.

[maxnix]

Beck Arnley is the absolute low cost craptastic imitation part provider. Might be better to go with used if you can find a good one.

Check the MAF connection very carefully before you decide to replace. Determine the wires are soldered into the plugs and are making excellent contact.

[lxvp]

I beg to differ on this issue. I had the same issue with the jerking and the stalling and all those issue's every search engine search I did on this said MAF. Well Nissan/Infiniti is notorious for bad electrical, especially on the older models. If it was a mas air flow snsor you would have the problem all the time not at certain rpms. The crank position sensor connector might be corroded and it would mess with your timing, had the is same issue with my 91 and fixed it now car run beautiful.

[maxnix]

An 17 year old car with a bad connector due to lack of periodic inspection does not make said car infamous for bad electrical system.

I mean really, you need to understand how bad Lucas was in 60's and 70's British sports cars.

Lucas well earned its reputation as the Prince of Darkness.

[northt]

Ergo the explanation for why the English drink warm beer.

[maxnix]

Ergo the explanation for why the English drink warm beer.

That and the climate!

[Kiven422]

I don't believe.... non of this.

Have you had your fuel pump replaced yet?

[silkysmoothyjud]

Take that Nissan logo out of your avitar or get thrown out of this forum poser!! Who are you to dispute my mentors? You wish you had a Q or a voice in this forum! I believe an explantation to your theory be explained, since a Q fuel pump will hum before it fails. I am facing the same problem and will update when I get my used one. But anyways: Cuz, you made this thread suck by calling us liars!!!

[silkysmoothyjud]

The both of em, who obviously have never had the problem....FLOOR!!!! please remove this thread!!

[silkysmoothyjud]

MAF symptoms start out intermittent and subsequently become constant (for the most part), display three symptoms (which vary), never fail completely and fail in different ways.

[Infinitiguy19]

Was the TPS set to .44 volts with a consult?

[maxnix]

I believe.... since a Q fuel pump will hum before it fails.

Not necessarily so! There have been relatively silent failures also.

[Jesda]

The both of em, who obviously have never had the problem....FLOOR!!!! please remove this thread!!

I live in Chesterfield and have owned two Q45s and a whole bunch of Nissans. If you'd like me to examine your car, drop an e-mail, [email protected]

I work at home so I'm dying to find things to do.

[silkysmoothyjud]

I might take you up on that Jesda, my used maf should be here this week and if that doesnt do the trick, I will hit you up!!!Current symptoms, runs fine at startup, slight cough and then a full blown out steady misfire when warm with heavy fuel consumption. It changes the note in the tailpipe, sounds like a sub woofer when it misfires. I cleaned the maf and it slightly improved, then got worse. Rough idle with a little hop (buck). I have already been through the injectors and the rest of it. No CEL..
Modified by silkysmoothyjud at 8:24 AM 1/31/2009

[silkysmoothyjud]

update: sprayed the maf this morning as per Jesda on Q45. org and nothing. Misfire still there, but it went away after five minutes!! Silky smooth again baby! But it has done this before. It will prolly come back in the morning after it sits again. Its getting warmer outside. Could old fuel lines to the fuel rail be causing misfire issues when it gets cold? I read that it could be fuel pressure related and the cold messes with that rubber makes it smell like gas. Also, I made sure my ECU was properly mounted, since I have been dabbling with my elwesso NICO ECU.

Also, I respect people's opinions on this site, but please don't trash other people by insinuating they are not true; especially when they are right.

[silkysmoothyjud]

Woke up this morning, started it up; idle 1100 smooth for 2 seconds and then dropped down to 800 with rough idle. I would guess MAF on a fluctuating idle? Although I have felt some power loss surges on the highway about a month ago (idle still was smooth at the time), my car never died completely (stalled). You would think a spark plug or four is fouled, or an injector is on the way out the way it is currently running.

An injector failure, at least for me, threw a CEL and jumped big time, but the idle never moved an inch. I had two total failures. My MAF failure (pretty sure it's it) is creating a faint surge in idle speed, hunting between 7 and 800 rpm. Its very slight and very random, barely noticeable. It seems the colder it gets, the worse it runs, where my injector failures where constant with a hardcore kangaroo hop. Big difference in a kangaroo hop and a slight misfire like idle.

My fuel pump failed about two years ago. It was loud BUZZZZ But there was no change in idle or anything else for that matter; but thanks to NICO, I caught it before it fried my FPCU. I stopped driving it as soon as the bees came out. WHO LET THE BEES OUT!!!!

[lxvp]

I know that I may not know as much as all the Q gurus on here but when I got my 91 and had all the same issues that you say you are having I replaced the MAF, worked great for 3 days then back to the same jerking issue, car even stalled in the middle of cross traffic... that sucked. I then took it to a friend that works on foreign cars and he went through every electrical component and cleaned and re-greased them and I have been driving the car for the last year and no issue. I am not saying anyone is wrong or right, hey it is a little tedious work but it really will only cost you time and the money for the grease.

[silkysmoothyjud]

That sounds like great advice! I will start with my stereo!! LOL I might use a little d-grease on the maf connector, but that statement is a little vague. If I unplug my maf, it still runs!!! Its all jacked up...

[lxvp]

basically my friend took all the electrical connectors and disconnected them and cleaned them out and re-greased and put them back. I asked him about the MAF and he replied by saying it was not that it was the electrical.

[anjero84]

look i have a problem with my 1990 q45 i was riding home one night and my car just cut off i thought i ran out of gas but that wasnt it i checked the oil and t fluid it wascool.. i tried to start it it took a while then it started it made a loud noise for a sec and then it cut off .. i towed it home and tried again the next day .. i heard a loud ratteling noise but it let me back the car up and move it to another parking spot then it idled down and cut all the way off... then while it was parked i saw a little whit smoke or maybe steam coming out my pipe does anyone have any idea whats going on with my car

[96Qowner]

Might very well be broken timing chain guides - a common issue with 90-93 Q45's.

Go to Q45.org and read everything under the heading "Chain Guides (CRITICAL for 1990-1993):"

http://www.q45.org/techhelp.html

[anjero84]

would i still be able to move the car though

[sdkhalsa]

The first question that you need to answer is whether the problem is centered on one cylinder or system wide. I would recommend using consult type software in a power balance mode to see if you can localize the problem.