Weird Idle Issues 2.2 t2

[89ShelbyGuy]

Hey guys, i have my 89 daytona shelby, well, i am having idle issues, when it warms up i will let it idle and it will keep bogging down to about 500 then bounch back up to 1000, then settle to 900...i thought it was the ais motor, so i replaced it with one from a 52mm tb...i then proceded to reset the position of it...also, when the fan comes on the rpm will go up...and i think that means the ais is doing its job????.well, still doing the same thing...theres one other thing, i think it might be and that is an exhaust leak at the d/p donut..i only could get one of the spring bolts on...so it has a exhaust leak right there...you think that would cause it stumbling? The vacuum lines are all redone...theres no codes...i also took the tb off and cleaned it...any suggestions would help...thanks!

[BadAssPerformance]

The exhaust leak could cause idle to fluctuate if it is alternating between sealing and unsealing which would change the backpressure load on the engine.

Any codes?

[89ShelbyGuy]

its throwing no codes...sometimes it will even out at 900 for a minute, then start to stumble...it will never die out...i will have to get under there and try and fix the leak...i need a stock d/p....anyone have one??looks like the one this previous owner put on is a 3", looking to go back to 2.5"

Hey JT....nice pic....lol.....

[BadAssPerformance]

Thanks

Hmmmm.... If you have a spare HEP that might be worth trying too?

[89ShelbyGuy]

really? a hep? yea i got a few laying around...i will give it a try. thanks! and can we get a close up of the left/middle of your sig please

[BadAssPerformance]

May be a HEP, they do flaky things sometimes, easy thing to try since you have a spare...

Thats the largest sig pic i got, sorry bro

[badandy]

It's definately the exhaust leak sealing and unsealing. I'm having the same issues right now.

[89ShelbyGuy]

Thanks for the help guys, it was the exhaust donut. I replaced and this thing is perfectly smooth now )))

[87glhs]

I'm having the same erratic idle issue with a GLHS T2 engine right now--see other thread in this forum.

Over the weekend I'm going to check out that donut gasket, but in the meantime could someone define "d/p" (downpipe, or exhaust pipe?), and "HEP" (no idea).

Thanks--

[black86glhs]

D/P:downpipe....pipe that comes down out of the swingvalve. Has the exhaust donut on it.
HEP: is the black disc under the distributor cap that has the 2 sets of wires coming out of it. This is what tells the LM(logic module) or SMEC(single module electronic controller) when to fire the coil and the injectors.

[BadAssPerformance]

Thanks for the help guys, it was the exhaust donut. I replaced and this thing is perfectly smooth now )))

Sweet!

[CDNTurboZ]

sorry to bring up an old thread, so what you guys are saying is an leaking exhaust donut could cause an erratic idle?

I'm having idle problems on my charger where it jumps around 900-1100 rpms. I also notice an exhaust smell inside the car when driving(I have 3 inch exhaust all the way to the back)

It has also been stalling occasionally when first started.

[BadAssPerformance]

sorry to bring up an old thread, so what you guys are saying is an leaking exhaust donut could cause an erratic idle?

I'm having idle problems on my charger where it jumps around 900-1100 rpms. I also notice an exhaust smell inside the car when driving(I have 3 inch exhaust all the way to the back)

It has also been stalling occasionally when first started.

yep, it could be... an exhaust leak is a disruption in flow which if it seals then doesnt seal then does again it is like blocking and unblocking flow...

The exhaust leak could cause idle to fluctuate if it is alternating between sealing and unsealing which would change the backpressure load on the engine.

Any codes?

[CDNTurboZ]

thanks I'll have to check it out, hopefully its not the exhaust manifold gasket and just the donut.
Is this donut specific to the TU 3 inch down pipe? or can I get a universal three inch donut somewhere?

[BadAssPerformance]

Should be a standard flat on one side 3" donut? Just make sure it looks the same as the one that comes out. Also, make sure the angle of the DP is in like with the SV outlet, the 3" DP's do not forgive for off angle as much as the smaller ones.