I just put a Y8 manifold on my Z6 block, and now I cant get it to idle below 3 grand unless I manually adjust the throttle bracket connected to the cable to fully closed. I have put as much slack into the throttle cable as I think I possibly can, but I still cant get it to idle consistently like when I had the Z6 manifold on. When I fully close it, it idles down, but it idles like it has a bad IAC valve... somebody please help!!! Im getting really tired of having the idle go to 3-4k without touching it!!!

 

Cmon!!! Someone has to know something!!! Should I try resetting the ECU??

 

Did you check for any vacuum leaks?

 

What year y8 manifold is it? is it the later [98^ i think] one with the "air-assist"?

 

The manifold is a 96-97, not the one with the air injection nipple sticking out on the intake manifold flanges. All vacuum lines are new, as well as a couple of fuel lines. I tried resetting the ecu and that solved the issue with the throttle climbing on its own. Now the problem I have is with throttle surge. Im not throwing any codes, yet the idle bounces from 1 to 2 grand, could this have something to do with the FIT valve needing to be adjusted?

The engine mgmt is converted to OBD1, theres also a blue and yellow wire that seems to have broken on the 3rd plug-in to the conversion harness, does this perhaps need to go somewhere?

 

What about bleeding the coolant system? Would that help at all? Secondly, how is it done?

 

coolant system? Idle? i dont think so. fill up the system and let the car run till the thermostat opens up, check the level and fill if needed. drive it around for a bit then check the level one more time.

 

once you get it all sorted out i am curious on what kind of gains you get with this manifold... let me know and good luck

 

This was a quote from my thread a while back.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Duane_In_Japan &raquo;</TD></TR><TR><TD CLASS="quote">

High Idle speed and Fluctuation troubleshooting
Leaking EACV- Disconnect EACV connector. Idle speed should decrease. With the connector disconnected block the hole in the intake port or pinch the hose from the air cleaner to the EACV. If the idle speed decreases the valve is leaking. This condition will not set a code. The ECM can only detect an open or short circuit. It also may clog it’s screen if it has one.

Leaking IAC- (Idle air control valve) Disconnect IAC connector. Idle speed should decrease. With the connector disconnected, block the hole or pinch the hose to the IAC valve. If the idle speed decreases the valve is leaking. May not set a code and may not be a codeable circuit on all models.

TW or ECT sensor- (engine coolant temperature sensor) voltage should be about 3.0 volts @ 60 deg F and between .55 & .7 volts @ normal operating temp. If the voltage is above .8 volts at normal operating temp, will cause rich mixture and high idle speed. May not set a code because it is not far enough out of its operating parameters. **Also this sensor will not read temperature correctly if coolant is low. (beware)

Vacuum leaks- a loose vacuum hose or leaking intake manifold gasket can cause high idle speed and/or fluctuation. Also check for bad PCV valve.

Fast Idle Valve- (if equipped) a fast idle valve that is sticking can cause high idle speed and fluctuation. Check it by removing the steel cap on the top and putting your finger over the hole in the middle of the seat under the cap or block the port just inside of the throttle body opening, when the Idle is fluctuating or staying high. When the engine is warm this valve should be closed. You can tighten the seat but it will also change the idle speed warm up values (closing).

Throttle valve- throttle position sensor voltage should be .5 volts with the throttle closed. Make sure the throttle valve is fully closed and voltage is within spec.

ECU-If all else is good, if you reset the ECU and the problem goes away temporarily, the ECU may be defective.

The idle fluxes due to the fuel control programming built into the ECU, it notices that the engine is going too fast and that there is no VSS signal to the speedo, so the ECU cuts the fuel to the injectors to eliminate a higher than normal idle speed since the vehicle is not moving. Once the idle drops to a predetermined level the fuel injectors are turned back on and the vicious cycle starts all over again.

If there is air in the cooling system, it may be trapped at the engine coolant temperature sensor and the computer does not know what the coolant temp is but it knows that the engine bay is hotter now and that the O2 sensor is working so it goes bananas trying to keep things going, air may be trapped in the idle control valve, the one with two black small rubber hoses going in and out of it, there is also a screen in there that tends to get dirty and plugged, I have seen pics on H-T before of the parts break down but it didn’t show this screen with the rubber O-ring type gaskets, it is available with the O-ring kit here in Japan.

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It has to be something with the IAC and/or FIT valve, none of the hoses are leaking coolant, and I reset the ECU. I still think the cooling system needs to be bled, I think it has something to do with air somewhere in the system... I got a brand new IAC valve a few weeks ago just for this intake manifold, and all the lines leading to it are sealed tight..

 

I went through a few tests, and when I put my finger over the top port(intake?) the idle speed decreases. Now this is supposed to be a leaking IAC valve? There arent any leaks in any of the hoses (either vacuum or coolant) what about throttle adjustment? When I disconnect the wire to the IAC valve the idle also drops dramatically, but when I adjust the throttle screw I cant get any throttle movement, just a change in idle surge

 

check your TPS voltage and make sure that you have your throttle cable tension set correctly. once that is correct reset the idle according to the helms...unplug the iacv, etc.

what throttlebody are you using...Y8?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX-Fluffy &raquo;</TD></TR><TR><TD CLASS="quote">This was a quote from my thread a while back.

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GREAT INFO can't wait to solve my idle problem

 

Im using a Z6 throttle body, I had to turn the Y8 throttle bracket upside down in order to allow it properly fit the throttle cable(which I think is the original CRX throttle cable) What all is involved in checking/aligning the TPS?

 

Which throttle body gasket is best to use with the Z6 throttle body? The Z6 or the Y8? I think Im running one for a Y8..

 

I had this same problem on an accord I swapped motors in....problem was a vacuum leak on the intake manifold gasket....on the bottom is the weak poin in the seal.....did you use a new gasket? I suggest taking a bottle of starting fluid and spray it along the mounting surface and see if this makes it rev up......that or water should make it idle consistantly....this is just to check and it is simple to do. I would much rather spend five minutes doin that than replacin a sensor
Casey

 

Ive done just what youve said, and sprayed right on the throttle body gasket. After a few seconds the idle changed and the check engine light came on. When I put the Y8 manifold on I installed a new gasket, which I assume is wrong or it wouldnt be giving me these troubles.. should I get the TB gasket to match the intake manifold, or the one to match the throttle body?

 

hmm, maybe you got an auto y8 tb gasket, and the iacv isnt getting a reading.

 

did you check where the intake manifold mounts to the head...that is the most important part that usually causes idle problems.....

 

Oddly enough, the auto Y8 gasket matches up to the Z6 manifold the best. I currently have the manual Y8 gasket installed on the throttle body. All the intake bolts are tight and theres no leakage there at all on the IM gasket.

 

Well, it worked for a little while..I guess Ill just have to order the Z6 gasket from honda..

 

Its your throttle body. I had the same problem. my y7 throttle body had a idle of 2500-3000RPMS cold or hot, and would flucuate. So at one point I had 2 IACV's and a FITV that wasnt wired up, reading that my motor was dead cold. I ended up blocking off the IACV/FITV valve from my obd2 y7 throttle body. Dont know if the y7/y8 are the same, but something worth checking out.