So this is what happens on my 1991 CRX HF with the stock D15B6 engine. Nothing has been done to it except a CAI and header with a magnaflow muffler. Everything else has been kept stock. ohh and if you think it is the EACV it isn't cause I swapped out a known good one this morning and it still did this.



And it will keep doing this for about 1 minute then it will finally calm down and stop.

 

it could be your IACV (idle air control valve) might be dirty or what about how your throttle cable/screw for throttle adjustment is on ??

 

the EACV is the same thing as the IACV. And not only is it new, as i suspected this was the problem, but I have thoroughly cleaned it and tried to adjust the idle screw to no avail. I am thinking it is a vacuum leak, as during start up there is more pressure because of the high rpms and it builds up. but thats just a guess.

 

i would think vacuum leak as well. when it's not doing that what does the idle eventually settle down to?

 

the idle settles down to normal. about 500 when at a stop light when fully warmed up.

 

I had a similar problem, it was a vacuum leak

 

where was it leaking from?

 

turns out it was my base idle being way too high. Apparently someone before I owned the car messed with the base idle screw on the bottom of the TB. Well the mechanic fixed it and only charged me 50 bucks. Now it starts up on a dime and drives wonderfully.

 

thats good my car had that same problem months agao

 

ok so now it is having a different problem. I suspect the mechanic adjusted the idle too low. For a coupld of days it had no problems. And now whenever I come to a stop and sit at a light the idle will drop way low. Like 400-300 to 200 -100. I mean way low but not to the point where its gonna die.

what could be causing this problem? Did he adjust it wrong?

 

low coolant level can also cause this problem, had a ls swapped 4 door that did the same thing everytime the coolant level dropped and it needed to have some added.

 

No the coolant is fine. Right near the top everytime I check it. It is not losing a drop.

 

check the hoses on back of manifold and check the vaccuum line running to your map sensor sometimes i've noticed on ef's they tend to get small pin holes in them recently had this problem on my 91 si hatch i just bought a few weeks back

 

the mechanic hooked a smoke machine up to the TB and checked all the hoses and found no leaks.

What I just did was I went out and changed out the plug wires that I had on for my stock ones that came with the car when I bought it. I started it up and drove it down the road and back and it didn't have any problems at all. I will keep driving it but if the plug wires were my problem, then I am going to get rid of them so fast.

btw they are the 10.2 mm ebay plug wires.

idk right now I am grasping at straws.