Mo' Miles, Mo' Problems

[jimmys G50]

OK, my 93 Q45 has always been givin me problems ever since the first day i bought it. right now it has just a little under 150K and one problem is becoming more frequent and it's really bothering me.it started about 8 months ago, the weather was chilly and i went to start my car but wait.... it doesn't want to stay on. wtf? the motor turns and starts, but it will not stay on unless i hold the gas. i dealed with it and the problem went away.that was until december '05 when the same thing happened, but this time i tried to restart it to see if there was any progress and it didn't want to start. then i got really mad. i called my father and he kept turning the key and giving gas. after a few tries it started but it was shaking pretty bad.time has passed and this problem won't go away. whenever i try to start the car with the key or remote in cold weather, it won't stay on without holding the gas pedal.there was an attempt on sunday to try and fix the Q. i called a mechanic friend and asked for his snap-on OBD troubleshooter to try and remedy the problem. and this is how it went.here is a picture of my father using the OBD tool and running some diagnostic tests. it was hooked up when the car was warm, about 60 degrees outside, no humidity or precipitation. after nearly an hour of checking here and there under the hood, the scanner found the car "OK TO DRIVE".however, in a possibly unrelated situation it was determined that cylinders 4 and 6 were not firing (most likely the injectors).anyways my father thinks its the idle speed control motor, but i'm thinkin more like the fuel pump or control module. does anyone have any solutions? we checked the IAC and thats not it.

[guadofreak]

Your friend should update his scanner to a MODIS

[BlackBirdVQ]

check fuel pressure, repleace all the injectors with the underplenum hoses. Most likely your MAF might be shot as you are saying it wont stay runing. I would ohm out the injectors with a DVM to see which ones you can keep as spares if anything. You can use 90-94 300ZX Twin Turbo injectors or 90-93 Q45 injectors- whichever ones you can get your hands on eassier. If you end up getting good but used injectors use our sponsor- Deatsche Werks to clean the injectors and test them, its like 106 bux or something like that for the service. I had mine done and the car runs butter smooth.

[jimmys G50]

i'd question the MAF sensor, we were tappin at it a few times... no change. however, i'm told that a maxima MAF would work just to test it out.
Modified by jimmys G50 at 9:05 PM 4/5/2006

[maxnix]

Might post this in Infiniti Online Mechanic with some recent maintenence history.

Dubs don't count.
Modified by maxnix at 10:10 PM 4/13/2006

[EQwhipD]

I had the same problem, but before you go throwing money at parts try doing basic clean up. Make sure MAF connector is in correctly (not loose), and also do what I did two weeks ago. Take out your MAF and MAF hose, and get a little scrubber that can go in tight tubes (plumber tool at home depot). Spray carburetor cleaner in ti and scrub it out clean. A dirty TB caused my engine to shut off at low RPMs and shake a bit as it was desperately tring to get air. Try that to see how that works. Worse case scenario is that it will not work and you are out $5 for cleaner and scrubber.-EQwhipD

[96Qowner]

Spray carburetor cleaner in ti and scrub it out clean.

Not carb cleaner - electrical parts cleaner:

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

[Q451990]

I would use brake parts cleaner inside the sensor (no residue) vs. electrical parts cleaner. The connection should be cleaned with electrical contact cleaner and then treated with dielectric grease (or stabilint 22? - if you can find and afford it). Some contact cleaners leave an oily residue to prevent corrosion so that's why I wouldn't use it on the MAF sensor itself. I would also use brake parts cleaner on the throttle body.

Heath

[elwesso]

moved to online mechanic.....

I echo what everyone else says, and I will reserve further judgement until the said topics are covered.

[DominickJ30]

My car is doing the exact same thing.

I am suspecting, IAC, Fuel Pump, Control Module, or CAS.

If you ever figure it out let me know.

Just for kick next time you want to start your car, leave the key in the ON position for 10 seconds before starting the car. Let me know what happens.

[Aus94Q45]

Does the OBD work on a 93?

Do not replace all of the injectors yet. Test them. The test is well documented if you do a search. It is unlikely that they would all fail at the same time.

Check the MAF connector first. This issue is also well documented in a search. Probably the most likely issue and the cheapest to fix.

The IAC is next. How did you test it? Did you adjust it at all?

There is also a cold start relay on the Throttle Body that adjusts based ont eh warm-up of the motor. You need to run the diagnostic on that too per the FSM.

[jimmys G50]

well i don't think its the IAC because when the car is on for like 20 minutes, the idle becomes normal.it can't be the TB because i cleaned it recently.this afternoon, it was about 70 degrees outside, and of course it didn't want to start. so i held the gas down for a few minutes so it can idle just a little bit (slightly under 500 RPMs). i opened the hood and tapped and wiggled the MAF connector. no progress so i looked at the TPS. i did the same and still no progress. i opened the trunk to listen for any noise... nope, no noise.i have a 94 maxima at my dissposal and i'm thinking this weekend to swap the MAF sensors. it's worth a shot. and if it doesn't work then i'll probably scream and curse at the car like i always do.o and about that cold start relay, can you help anyone help me with the diagnostic process. i got a dial up connection and 5 dollars in my wallet so a FSM is kinda out of my reach.
Modified by jimmys G50 at 9:43 PM 4/13/2006

[sheadee240]

i have a 94 maxima at my dissposal and i'm thinking this weekend to swap the MAF sensors. it's worth a shot.

Modified by jimmys G50 at 9:43 PM 4/13/2006

Has any one else heard of a MAF being swapped to a '94 Q45 from a maxima for diag purposes? sounds a little fishy, but I too am suspecting my MAF

[Q45tech]

Tell us how the $20,000 in maintenances and repairs have been spent over the last 12.5 years.............. 150,000 miles. To maintain to as new.

MAF voltage output is calibrated to the air flow............a 3 liter MAF vs a 4.5 liter MAF should make for some interesting numbers that ecu will have to decode.......................a difference in diameter will be hard to correct.

[sheadee240]

I was thinking that swapping a maxima MAF didn't sound like the best idea also. I'm not sure if the maintainance question was really directed towards me or not. I'm not sure of my maint hist, because I only purchased the car recently without any repair hist??

[maxnix]

I'm not sure of my maint hist, because I only purchased the car recently without any repair hist??

Why the wise buyer always obtains the dealer performed service history before inspecting the car so he knows where to look.

Fortunately, it is still available after purchase so the trusting buyer can see what he overlooked and plan his finances accordingly.

[Q45tech]

YES he /she can see that he over paid for a car that need $5,000-$10,000 worth of work to return to as new..........not counting paint/interior/glass

A 13 year old car just short changed $500 per year needs $6500. Of course it doesn't work exactly that way but you get the idea.

When you buy a used old lux car always have $3,000 in cash to immediately fix things that caused the car to be sold in the first place.