Help this Q.....

[My_Q45]

Hey I have a 94 Q45 that has been sick for a long time now! I have been doing work on it when I had the time & money but am getting no where. Any ideas, suggestions or comments are welcome, I just want to get this car running great! I've done most of the work myself but am not by any means a mechanic just mechanically inclined.

The problems currently with the car are a bouncy idle & it stays bouncy until 2000 RPM's, a code 21 & lack of power for a car with that powerful of an engine (I've always felt that since day one). If I remember code 21 has to do with the ignition system. This code appeared after replacing the knock sensors, temp sensor & wire harness. It's possible I mixed up the vacuum lines under the plenum & that's contributing to the bad idle.

Since having the car I've replaced knock sensors, temp sensor & harness, 2 fuel injectors, fuel pump (replaced before it destroyed the computer), egr parts, all coil packs, spark plugs, some suspension parts & other things I can't remember.

I've also been aware of the maf sensor problem. In the past I've touched the wires & the idle changed so I hard wired the maf sensor with new wires & soldered everything together. Since then I touch the wires & nothing happens. I also screwed up & installed AC Delco plugs before I knew NGK was necessary. Would this create the problems listed as well as the code 21? I would like to test the MAF sensor & add the ground strap, so if anyone know how to add the ground strap & the test procedures, please list them. I also wanted to check my oil pressure but have no idea how to. If you know that as well please let me know.

Sorry about the long post. I would really like to get this car going once & for all so any thing you can think of, let me know! Thanks in advance.

[elwesso]

I got a code 21 sometime back also... Dont know how to fix it.......

I dont know about the idle, but it may be that the IAC is just adjusted too high!!

How much was the temp sensor???

Did you replace the KS harness also? I bet somewhere underplenum there isnt something plugged in......

[My_Q45]

Hey elwesso

I remember a while back you had a code 21 around the same time as me. I wanted to get my injectors before continuing with this car. I wounder if bad plugs could throw that code? It's probably a long shot.

Is the IAC located on the butterfly valve? How would I go about adjusting it? I've also remember reading they stick.

I reconnected the plenum as I remember it coming off. Do you have a suggestion of how to track down the incorrect hose(s)?

I got my temp sensor for under $20 from calling Joe at Infiniti Scottsdale.

[elwesso]

I replaced my plugs about 4000 miles ago, and the code came up after the plugs.... So i doubt that...

I checked codes a week ago, and didnt get code 21...... And the diagnostic procedure in the FSM is very confusing so im not gonna bother......

The IAC is the little thing on the back of the plenum (near firewall).... You should have cleaned it when you removed the plenum....... Im not sure how to track down a hose besides checking every connection you can see, and if you cant find anything you may need to dig in there!!!

I may just replace my temp sensors (i have 3, stupid CA model) for good measure......

[My_Q45]

Ok

I pulled the IAC & degreased it & tried to adjust it with no positive affect (I was able to get it running worse. I didn't know that was possible.).

I listened very closely to the engine & possibly heard a vacuum leak. It sounded like it was coming from the IAC. Is the air going through it audible? I also pulled the 2 easiest plugs to check them & they look fine.

Does any one have a suggestion of where to go from here?Also one thing I forgot to ask in my original post. A while ago I had to remove the cylinder that's located under the air box & managed to break one of the hose nipples. I temporally crazy glued it back together. I forgot all about it until today when checking all the visible hoses I managed to break it again. Anyway what is this thing & what does it do?

[elwesso]

Did you re connect the IAC vacuum hose???

[My_Q45]

Did you re connect the IAC vacuum hose???

Why would I do that?:rolleyes

JK!

Yeah, It's all connected. I also stuck my hand under the plenum in that location to find a disconnected hose/line with no luck. It really sounded like it was coming from the IAC. I'm gonna go to a car store this weekend to get a automotive stesascope.

[My_Q45]

Last nite when I was going to bed I beguan to think about my car. Getting back to the basics of car engines made me start to think my ignition timing is off. This would also explain my low power & bouncy idle since day one. If I remember right I have to rotate my CAS. Will I just want to rotate it until the idle is correct?

If you have any other ideas as well let me know.

Thanks

[VimyJ]

Q are notoriously fickle about their spark plugs. I understand they are a real PIA to change but lots of weirdness has been ascribed to non OEM plugs.