No idles r3v. I need help *video*

[kwill22]

Car won't idle when warm. Idled rough before but idled. Sounded like a cammed muscle car.

Redid the timing and its pretty much perfect. Also replaced the valve cover gasket. Now it Idles perfect after a cold start. After about 7-10 minutes the idle will start to drop then die. Crank it up again, dies again in a couple seconds. Changed O2 sensor and still the same thing. I'm at a loss here. And the ICV is about a year old FYI.

now i just have turned the revs up to 1k and its fine. But annoying

***VIDEO***

[kwill22]

Also it never starts on the first try. It'll crank all day, then on the second try it cranks almost instantly. It will start though within maybe 5-10 minutes tops of turning it off though.

[vpilarrt]

I would check the usual culprits:

Vacuum leak, especially intake boot
TPS
AFM

[agent]

Ninja edit : whoops, never mind. Just saw this was in the M42 section.

[kyle318is]

I would check the usual culprits:

Vacuum leak, especially intake boot
TPS
AFM

^ This

[moteren_werke]

AFM or Engine to ECU collant sensor, basically it lets the car know when its warm, and leans the gas out. Its blue and under intake, its so cheap, buy a gauge sender 1 also, so you can make sure there new

[kwill22]

AFM or Engine to ECU collant sensor, basically it lets the car know when its warm, and leans the gas out. Its blue and under intake, its so cheap, buy a gauge sender 1 also, so you can make sure there new

Ill check the coolant sensor and afm with my multimeter tomorrow. It sound ecu related since it stalls when it warms up and the occasional backfire when it doesn't start.

Almost stalls like i turned the key off. No shudder or wierd noises. Just the idle gets lower and lower and just turns off

I'm sure I don't have any vacuum leaks because I've replace and checked everything when i was troubleshooting the my rough idle before I redid the timing. Only place I didn't replace or check that i believe could leak is the exhaust gasket.

Thanks for the help so far guys. I was stumped

[moteren_werke]

i had a similar issue with mine, but it stalled while driving, it was the afm...

[kwill22]

No. Dice. Tested the afm and the engine temp sensor and they tested within spec when the engine was cold and after it warmed up. I tested the TPS and it was below spec so I replaced it with an extra I had that was good and no change.

Anything else you guys can think of?

[roguetoaster]

Been reading this, but couldn't come up with anything concrete. Could you get a video of the idle dropping and then stalling?

Have you tried a warm start with the ICV unplugged? When it starts to drop RPM does opening the throttle solve the problem?

[kwill22]

Haven't tried starting it with the ICV unplugged but if I hear the revs start dropping and I open the throttle it doesn't die. Which Is why I have my revs turned up a little to counteract that problem and it drives fine that way, just a little bit higher revs.

Now that I'm thinking about it ill go test my ICV but I wasn't thinking that was the problem since its barely a year old and only won't idle when warm. Guess with cars never underestimate stuff. I should know this by now.

[kwill22]

Just checked and it idles(high) wit the ICV unplugged. So I tried another one I have and the same thing. Both of the ICV's buzz with the ignition on.

[roguetoaster]

So it will hold idle at ~975, but not at ~850?!?

I was going to say this might be a fuel pressure issue with the FPR not holding pressure, thus on the first crank it won't start, and after sitting hot it won't start? But that does not seem quite right as it is running fine at high idle.

My next thought is will it hold correct idle with the throttle cable adjusted so far back (or disconnected) so as to make sure the butterfly valves are fully closed. Seems to me that with the extra air the AFM is sensing flowing it provides just enough extra fuel which is holding the idle up.

Basically eliminate the easy ones, is it getting too much air; is it getting too little air; is it getting too much fuel (drive it, come back and check the plugs after one or two start ups); is it getting spark (cable resistance).

Ignore me if I am not making sense, I will check back later when I have thought on it more.

[kwill22]

Fuel presure would be my next guest but I wasn't sure with the ICV issue. Maybe not enough fuel? Would that cause a backfire? My car was running way rich before I redid the timing. Could be igniting unspent fueling maybe I just need new spark plugs... Idk. Ill check the plugs next to see what story they tell

[roguetoaster]

If it's too rich I would suspect an ignition issue, check both the coils and wires, cross your fingers on the DME (or just replace it). Sounds like you have a fun one!