thebleek

This will be my last thread I make about this. I am hoping this will be resolved, because this **** is driving me nuts. I made this thread so new people wont have to read thru 10+ pages.

Scenario:

I have a bouncing idle. It goes from 1800 to 2400 over and over. When I start it on a cold start, the idle shoots to 3000 or 4000, stays there for like 4 seconds, and then drops down slowly to 1800 then the 1800-2400-1800 cycle starts.


Things tried:

New PCV valve
New TB gasket
New Intake Manifold Gasket
4 different IACV's

The car is a 97 hatch 5spd. The motor was from an automatic d16y7. I dont know if the dude used the auto motor harness, or the 5spd. I now have a 5spd throttle body on it.

I try to cover the throttle body completly and the idle lowers down quite a bit. It stays steady for a moment, then bounces, stays steady, bounces..etc. prior to that I had the battery disconnected, and even pulled the under hood "backup" fuse.

I am willing to send money to whoever can diagnose and help me fix this problem.

by the way, my IACV is on the tb. not the back of the mani.

Former User

Even though you have replaced the throttle body and IM gaskets, this information surely indicates that you have a significant intake air or vacuum leak. Carefully recheck those gaskets, as well as all of the vacuum hoses and their connections. Have you also checked the rubber seal of the IACV?

thebleek

all gaskets on the throttle body are in perfect shape. I tried a propane enrichment test but it didnt do ****.

Former User

I don't know what to say. If you can't kill the engine by covering the throttle body with your hand then, almost without a doubt, you have an intake air/vacuum leak somewhere.

thebleek

How can I diagnose where its coming from? I dont know if its because the rpms are so high, but it sounds like my intake is sucking in alot

iluvmyhnda

yah i would say you may have a vacuum leak... if you have access to a vacuum pressure tester or a compression tester then you should do that. it could be a map sensor too... is it throwing any cel's?

thebleek

I am not getting any cels yet. I reset my ecu by removing the back up fuse, and also the neg bat cable.

also what would a compression test do? Thats just to tell me my comp in the cylinders is good.

Former User

Have a buddy block the top of the throttle body with his hand while you spray carburetor cleaner around all suspected leak locations, like the throttle body and IM gaskets, vacuum hoses and connections, etc. The idle speed will change when you spray the source of the leak.

thebleek

**** friends, I use a cap from the auto wipes container. It fits perfect!

Ill give it a shot, I just gotta go pick up some carb cleaner.

please keep the ideas coming tho.

iluvmyhnda

yah but sometimes the leak can be so small on a vacuum hose like on the underside or something, he may not spray it... with that you also eliminate the possibility of any internal problems with the engine like piston seals or cylinder leakage.

Former User

Based on the information, this appears to be a large rather than a small leak.

thebleek

this makes me want to kill myself. its been like this for 3 months

iluvmyhnda

well if it was that big of a leak from a hose dont you think youd be able to hear it? i dont know, im just trying to think of everything i can... egr valve?

thebleek

here are the results. If your standing at my front bumper going left to right

190 190 180 190

wtf?

Former User

The statement above by the OP suggests that he may be hearing the leak.

Again, if you can completely cover the top of the throttle body with your hand without killing the engine, then there must be major intake air/vacuum leak. I can't think of another possible explanation for this observation.

Former User

Your cylinder compressions are fine. You need to locate the leak.

thebleek

why is one 180 and the rest 190

could a vac leak cause that?

Former User

The difference between 190 and 180 is insignificant and no.

thebleek

where the **** is this leak

what can i clean the surface of the head with? It had a caked on IM gasket, and i thought I got everything off. ill remove it, and put a new one on after i clean it

this is stressful, and you rock. Im going to send you some cash.

iluvmyhnda

possibly an intake valve or valve seat, you might be able to hear that but i dont know

thebleek

why would you say that? are you just pulling things out of your *** and telling me them?

Former User

Reduce your stress level. High stress won't help in this situation. Instead, be comforted by the fact that you are quickly closing in on the solution. Before you just replace the IM gasket, try to find some evidence that it is indeed leaking (as I mentioned above).

Also, hold on to your cash. This a free internet forum where we all benefit by the exchange of information. Finally, don't be hard on iluvmyhnda, as he is also trying to help you.

hoffmanb16

why don't you get something that creates a small trail of smoke maybe like a cigarette and slowly run it by all the areas in question. the smoke will be sucked in by the effected spot.

kinda like the carb cleaner idea.

Road_Runner

don't know if this help but
try using OEM gasket for throttle body and intakemanifold gasket.

I have a simular situation like yours where my idle was jumping up and down when i did a Y8 intake manifold with y7 throttle body swap to my Y7 motor. my problem was because of the throttle body gasket. purchase it from an auto advance, ( crap y7 gasket).
but good thing i had a oem used y7 gasket in hand. after swaping the crap gasket with the used oem y7 gasket my idle problem went away.

thebleek

the bubbler i just smoked, I should have used that thick smoke damnit! lol.

anyway, I checked my TPS and now that i tested the middle wire [i was told to do farthest right] my middle wire reads .63 and 6.28open. milliamps

omg and my car finally cel'd. it said MIL 7 and thats tps right?