High idle?

[OneCleanE30]

So, I just got my first M50 swap! Best part is I can't drive it because of surgery on my hand... But it's solid! I noticed it seems to idle high, around 1,000 rpms, I don't even need to press the gas to pull away.. What can I do to fix this?

[mitchlevy7]

vacuum leak or your icv is stuck open.

[OneCleanE30]

vacuum leak or your icv is stuck open.

Thanks man, whats an icv?

[JinormusJ]

You did an engine swap successfully without knowing what an ICV is?

[OneCleanE30]

You did an engine swap successfully without knowing what an ICV is?

Bought the engine swap.. I'm only 16 man, I want to learn all I can. I realize I sound dumb.. But we all start somewhere.

[OneCleanE30]

Is it an idle control valve?

[JinormusJ]

High idle?

No, I'm glad people are getting to know their engine more and actually have the decency to know how to maintain a vehicle. Most people these days drive a car and scrap it long before it should have been had it been properly maintained.

Anyway, the ICV is an idle control valve; it will control how much your car will idle at a stop/in neutral. Typically, when these go bad you will have fluctuating idle that jumps from 500-2500, back down to 500, and repeat. There could be something jamming it from fully closing and it is getting stuck open at 1000RPM, where it should e closing further. My first e30 did this, and once I replaced it with a known working ICV, it ran cherry.
Typically this is located on the intake boot after the MAF but before the throttle body. Take it off and spray some carb cleaner into the tunnel in the ICV that air travels through. Repeat as desired until you think it's good, then replace and test

If you're still getting high idle, it might be your vacuum lines (the lines on the engine that hold air, not oil/coolant). Any cracks or holes in these lines will let extra air into the system and the ECU will inject more fuel into the engine to compensate for the extra O2 in the system and cause the engine to idle high.
Typically, this isn't a 24v swap problem, but it can always happen.


Check your ICV
Please don't pope ur tirez
Welcome to e30 24v land

[OneCleanE30]

You did an engine swap successfully without knowing what an ICV is?

No, I'm glad people are getting to know their engine more and actually have the decency to know how to maintain a vehicle. Most people these days drive a car and scrap it long before it should have been had it been properly maintained.

Anyway, the ICV is an idle control valve; it will control how much your car will idle at a stop/in neutral. Typically, when these go bad you will have fluctuating idle that jumps from 500-2500, back down to 500, and repeat. There could be something jamming it from fully closing and it is getting stuck open at 1000RPM, where it should e closing further. My first e30 did this, and once I replaced it with a known working ICV, it ran cherry.
Typically this is located on the intake boot after the MAF but before the throttle body. Take it off and spray some carb cleaner into the tunnel in the ICV that air travels through. Repeat as desired until you think it's good, then replace and test

If you're still getting high idle, it might be your vacuum lines (the lines on the engine that hold air, not oil/coolant). Any cracks or holes in these lines will let extra air into the system and the ECU will inject more fuel into the engine to compensate for the extra O2 in the system and cause the engine to idle high.
Typically, this isn't a 24v swap problem, but it can always happen.


Check your ICV
Please don't pope ur tirez
Welcome to e30 24v land

Alright, I'll go check it out now! Thank you sir

[JinormusJ]

High idle?

One surefire way to check for vacuum leaks is to start the car and pull the dipstick. This opens up your system and allows unmetered air in through the oil tube. If your car has vacuum leaks, the idle will remain the same because there is already unmetered air entering the system and the ECU is already compensating for the extra O2. If they drop almost to the point where the engine dies, but it then jumps up and idles higher than before (ECU compensating for extra O2 in system), your vacuum lines are fine and your problem lies elsewhere

[OneCleanE30]

One surefire way to check for vacuum leaks is to start the car and pull the dipstick. This opens up your system and allows unmetered air in through the oil tube. If your car has vacuum leaks, the idle will remain the same because there is already unmetered air entering the system and the ECU is already compensating for the extra O2. If they drop almost to the point where the engine dies, but it then jumps up and idles higher than before (ECU compensating for extra O2 in system), your vacuum lines are fine and your problem lies elsewhere

This is why I joined the forum.. People are a lot more helpful and have a better understanding of cars.. Thanks again boss

[5Toes]

to get to your icv you will need to pull the intake manifold.. not too hard. Just 7 nuts on top and the fuel rail comes off easy enough too.

My car had a dirty ICV - cleaning it did wonders

[bonobo]

Besides everything already posted, there's also an idle screw on your throttle body you can try playing around with. If your P.O. happened to be fucking around with it during his ownership, there's your easy solution.

As for cleaning the ICV, I recommend q-tips and a can of brake cleaner. Works like a charm.

[JinormusJ]

^^^^^
Don't mess with that screw until AFTER you've diagnosed the problem to not be your ICV or Vacuum lines

That should be your last resort

[OneCleanE30]

Thanks everyone!

[Pipes]

So, was it the ICV?