Ok my car starts up fine, but it idles very high. I hit the gas and then it sounds normal but idles up and down, up and down but never smoothes out. I have tried adjusting the idle (screw) but either it idles high or up & down? What should I do. I just got my head fixed and put on, so should it be like this for awhile? Will it stop?

 

Are you throwing any codes ?

 

what motor?

 

Same prob with my setup.

I've been searching for a cure for some time now. I've looked for vacuum leaks and switched the MAP and TPS sensors(got it to idle there but would'nt rev right). Cold start, it revs to 4000rpm when I turn the key, I know 4k on a cold engine is very bad... Then it goes from 1000 to 3000 rpm, up down, up down, and will finally smooth out to a normal idle when it's warmed up. Then after its warmed up and been driven for a bit, the idle will drop to like 700rpm at a traffic light or stop, and seems to lack power when I give it gas again until about 2000rpm. Otherwise the engine runs really strong and doesn't do anything else retarded like this.

Sorry to hijack the thread, I just wanted to add some additonal info since our engines seem to be doing the same thing...

I'm really starting to get pissed at the thing.

 

ive had this problem as well, twice. both times for me it was the fast idle thermo valve. on my b16, its the non electronic valve bolted right under the throttle body. there are 2 coolant lines coming from it. the thermowax plug in the valve needs to be tightened. you can do this by pulling the back plate off the valve and using a putty knife or flat head screwdriver to turn the plug back into the threads.

 

hybridize - I had the same power loss problem, I just adjusted the valves today it took care of that. You may want to try that.

 

I have the original d15B1(?) in a '91 HB. It's not throwing any codes. It drives fine. Its only when I crank it up or after driving (coming to a stop) that it revs high, like the accelerator is sticking. Then I hit the gas harder and it stops revving high and thats when it idles up&down.

 

Anyone??

 

just a thought, by try replacing your throttle body gasket.. i've seen on two different occasions on two different engines this stops the erratic idle problems similar to a vacuum leak..Also, try unplugging the EACV and see if that stops it...of course it will throw a check engine light which you will need to reset after plugging it back in, but this could tell you the source of the problem..

 

It could be a few things, a couple things to look into are. The eacv, located on the back of the mpfi manifold. The second thing could be the idle control valve. And the other thing could be a vacuum leak. Or your map sensor could be messed up. I suggest picking up a manual and performing random test on these things to see what it is.

 

Well, I think I may have this problem waxed!

I did a bunch of searching through H-T archives and found a few topics that related to the probs we're having.

From my understanding there is a sensor or two under the throttle body, that need coolant running over them to read properly.

I guess if your rad is low on coolant, and air gets into the sytem, these sensors don't get the right reading and cause the screwy idle.
So I went out, started up the car, took of the rad cap, and let the car warm up. From what I read you want the car to be warm enough so the engine fan turns on while the rad cap is off. After its warm, just add coolant till the rad is full and wait for any air bubbles to come out before putting the cap back on the rad.

As simple as it sounds... It worked for me!!!
Cold start idle is at 2k and slowy works its way down to a 1100rpm idle, perfect! Also I took her for a spin and never encountered the low idle problem I was having before.

All in all, it appears this problem is related to something as simple as air in the cooling system.

HTH you.

 

i ahve the same idle problem. when i start my engine on a cold sart it idles at 2000rpms.. but after some time of normal dirving , my rpm fluctuates up and down from 1500 to 500... this has been happing ever since i out in new cams in my b16... i have no idea how to fix this so i will be keeping an ey out on this thread