Bouncy Idle

[doclees]

Hi all. I am new to posting but have followed this forum for a few months. Thanks for all the help. Special thanks to New England SHO specs.

I can not find this problem searching the old threads. If it is there please point me to it.

89 mtx

Problem 1. Fresh 60k at 150k. Idles at about 1800 in neutral with clutch out. Rythmicly bounces between 800 and 1500 with clutch in. I have reset idle with no change. This problem was not present prior to the 60k but I only ran it for a total of 20 min from when I purchased it to the time I took it apart.

I did not decarbon the manifold - just the ports on the head per 60k video

Work done - valve shims, timing chains and tensioners (with cams in), adjust timing belt tension, new valve cover, plug well and intake gaskets, new plugs, changed all fulids, new hood lifts, fix tail light gaskets, repaired leather/cloth seats, recover gear shift ****. I also degreased the engine, tranny and steering. Behind the engine at the #1 cylinder I found a single wire connector separated with one end broken off. I ASSUMED they were ment to go together so I made it so.

Any clues?

 

[David Mueller]

Well, one thing to do first is to run the codes...you can find helpful information on this at www.midwestsho.com ... and report back any codes you find.

Also, I would recommend cleaning out the intake, it doesn't take that long, and can make a huge difference in how well the car runs. The way to do this is...go to the store and buy some Berryman's B12 Intake Cleaner (it works better than any i've tried, and many here will also recommend it), you will need 4-5 cans if you haven't ever cleaned out the intake before. Then take off the intake the same way you did with the 60K. Find a place where you can safely use the Berryman's (works great as a grass killer) and spray the first 2 cans into the intake through each port/opening and let it sit for a while. Dump the contents safely and then use the rest of your cans to continue cleaning the intake until you are happy. If you have an EGR (Exhaust Gas Recirculation) system on your car you will also want to make sure the "nostrels" are clean: the nostrels can be seen in if you look into the TB opening. I use a paper clip or a small allen wrench to make sure they are not plugged. Once you have cleaned and let your intake dry, reinstall.

You may also want to make sure your IAB (Idle Air Bypass) valve is clean. You can find more information on this at www.shotimes.com.

 

[masho95]

doclees:
Behind the engine at the #1 cylinder I found a single wire connector separated with one end broken off. I ASSUMED they were ment to go together so I made it so.

Ok first disconnect what you reconnected that you "thought" was supposed to be together. If you don't know what it is leave it alone until you know what it is. Assuming timing issues are ok after what you did disconnect that extra wire you reconnected and see what you get. Without a more descript explanation of what the wire looked like it hard to tell which one it was or it's function. Leave it disconnected and try again..

 

[projectSHO89]

Issue - bouncy idle

Does this occur while the car is stationary or while in motion?

Does it occur only during engine warmup or does it continue after the engine has reached full operating temperature?

Steve

<small>[ September 10, 2003, 08:16 AM: Message edited by: projectSHO89 ]</small>

 

[doclees]

projectSHO89:
Issue - bouncy idle

Does this occur while the car is stationary or while in motion?

Does it occur only during engine warmup or does it continue after the engine has reached full operating temperature?

Steve

Thanks all for the quick response.

Once the car is moving the throttle is on and the rpms are above the range where it bounces - in perfect rhythm. Warm or cold, rolling or full stopped, if the clutch is in and no throttle is added idle can't settle. If the car is stopped, in neutral and the clutch is out - 1800 rpm idle.

I will disconnect the reconnected wire. I think it is the power steering sensor.

 

[SHOnuff93]

Why hasnt someone suggested the IAB valve? Sounds exactly like what mine would do, bounce from almost stalling to over 1500 rpm. Either remove and clean it, or swap in a known to be good unit.

 

[projectSHO89]

SHOnuff93:
Why hasnt someone suggested the IAB valve?

Because he hadn't provided enough information earlier. Now that he has, my suggestion is the IAB/ISC/BPA valve in addition to an idle reset procedure.

Steve

 

[doclees]

Thanks again Steve, Masho95 and David. I will do the cleaning on the sensors first(tonight), reset idle and let you all know if that did it. If not I will swap out the part and if not then I will pull the manifold and clean it. I was so happy I didn't have any spare parts or bolts when I got it back together that pulling it this soon was not a warm thought.

 

[SHOYourYama]

I had the EXACT problemo. After cleaning the IAB a few times, I became weary of it's performance. I bought a new one from AZ. It's the most shiny part of my engine-bay. Fixed my bounciness.