Senile 94 Q Now it doesn't like to go slow...

[nnicholas]

Where to start...Codes 34 and 51...Injectors ohmed, 6 of 8 are on their way out ohming between 19 and 30, 2 at 11, KS okay...(planning a plenum job soon) I read the forums about MAF symptons (I experienced the same), running great from cold start-up in the mornings, turn it off for 30 minutes, then stumbling between 2000 and 3000 RPM over 3000 for a few minutes, then smoothing out (accelerates like a scalded dog once it gets to 3K). I ordered a new MAF which hasn't been delivered yet. Then yesterday I was pulling out into traffic and had to get on it a little, heard 2 bangs, and its been idling rough and stumbling bad between 2K and 3K rpm since, runs great over 3K.

I checked the MAF sensor plug and it was tight and clean on the inside. I cranked it again, still idling rough just like it has a fouled plug. Listening to the left side of the engine I can hear a frequent but intermittent tick like an arc, which in my old Chevy was a loose spark plug wire. I sounds like number 1 or 2.

There's a lot going on with the injectors, however could the miss be caused by something loose with one of the plugs? I'm going to check the MAF voltage tomorrow as well.


Modified by nnicholas at 7:03 PM 3/13/2009

[Infinitiguy19]

Apparently you did'nt check the Knock Sensors coreectly or you got a bad reading... But code 34 is Knock Sensor. And code 51 is Injector Analysis, and as you know you have 1 or more bad injectors.

but since the ECU is throwing that code the timing is retarded a bit hence why its slow at low RPM.

I would remove the plenum and replace the injectors and knock sensors and replace any hoses that are brittle or break.

Or go the "Good for 10 years" or less route ad buy the ultimate under plenum kit from Infiniti of Scottsdale now that they have the 7% off (lucky7 is the code). http://www.infinitipartsusa.co...=3221

When were the plugs replaced?

[nnicholas]

No idea when the plugs were replaced...I've only owned it for 6 weeks.

[Infinitiguy19]

Might want to change them when removing the plenum since it will be slightly eaiser and there also on sale too at IOS.

[maxnix]

You have multiple problems. Maybe even the wrong plugs.

Fuel pressure at idle and WOT? have you not changed all fluids and filters since you don't know their provenance?

Might do you a world of good to get to T-3 once car is running correctly.

Have you carefully inspected your MAF connector?

[Q451990]

I tend to agree that the fuel pump and controller are suspect. I noticed a bit of uphill bucking right before I had a fuel pump failure on my old Q. Injectors ohming at those numbers should not cause that much of an issue for you... not saying they shouldn't be replaced, but a 20 ohm injector doesn't "feel" different than a 12 ohm one in my experience.

Heath

[nnicholas]

Did change all the filters and fluids first thing. Had the fuel pump replaced at T3 a week ago. I'm a little disenchanted with them. They damaged my right rear speaker and want me to bring it back, which I will when time permits. The mgr at T3 is a really friendly guy but doesn't listen well and doesn't follow through on promises. He gave me a list of items as said he would price them out but when I called back it was like we never had the conversation. No doubt they know their stuff, but I'm simply not willing to make them signors on my checking account just yet.

I looked at the MAF connector last night--it was tight and is not burned or brittle.

[nnicholas]

Heath, I concur with you on the condition of the injectors, sure, they're headed on their way out, but still decent. Even at T3 the first thing out of their mouths is plenum job and injectors which I'll get to soon enough. I had T3 replace the fuel pump one week ago and assume they checked the controller as well.

Since I've been experiencing the MAF symptoms I ordered one then symptoms worsened to where it is constant rather than intermittent. I still wonder about the electrical arc--the tick I can hear on the left side of the engine.

thanksNick

[Q451990]

If you have a new fuel pump, I would think you can rule that out.

Remember that injectors can be clogged but still ohm test in spec. or close. Assuming your engine is in otherwise good conditon, I think I would bite the bullet with new injectors and under plenum hoses, knock sensors, etc.

If your spark plugs are questionable (as in unknown brand or unknown age) I would replace them as well. The boots from the coil packs to the plugs are available separately - but rarely fail.

You have so many suspects, sometimes it's best to just overhaul everything that's old and almost shot and then see how it all turns out. Of course, installing the new MAF before getting started is a good idea.

Heath

[nnicholas]

I ran a can of BG and a couple of Lucas treatments through it when I did the fuel filter so I'm not inclined to believe a clogged injector because it runs well over 3K rpm. Of course, for that matter the engine is, by genetics, so strong that maybe I just think its running well above 3K. I'm going to try the MAF and a round of Redline first and continue to assemble my plenum job parts. Thanks for the input.

Nick