1G 93' talon bad idle?

[simons3z]

just picked a 93' talon up.
-no boost leaks(shaft seals changed)
-no exhaust leaks
-new tps, iac, cam sensor(black cover), coolant temp sensor.

was told shop did all the new sensors along with new timing belt pulleys allocated with them and set everything.

guy said it ran great? had slight idle surge when i bought it(minuscule?) was drove by a 45 yr old laid back.

i pushed the car a few times, runs great, 14psi all the way to redline.

DOESN'T hickup, misfire, chug, or any of the sort while cruising through town, highway or doing pulls, it pulls GREAT. Yet when at warm idle, or coming to a stoplight.

Cold idle will idle @ 1900-2000rpms then drop down to 1k then will hit 800rpms and start misfiring\idling bad to almost dieing 300rpm?. hit gas it will go away for a second or two when the rpms are up.

When the rpms come back down, yet again LOW idle surge. looking to get ideas of what it is, i can get a video of it ASAP. looking for ideas.... i have chiltons so anything that could be thought i can check the specs.

checked the plugs, alittle white for my liking, but nothing i'm too worried about.


thanks in advance

 

[Lofty]

Hello from Wisconsin!
Change the plugs, really, that'll probably help a lot.

Also, how are you so sure you have no boost/vac leaks? How did you test this?
It could also be a fuel problem or maybe a CAS problem.

If you're ever in the Waukesha area, I'd be happy to look at it for ya

 

[simons3z]

Hello from Wisconsin!
Change the plugs, really, that'll probably help a lot.

Also, how are you so sure you have no boost/vac leaks? How did you test this?
It could also be a fuel problem or maybe a CAS problem.

If you're ever in the Waukesha area, I'd be happy to look at it for ya

why hello! the first thing after I purched the car is change the plugs, all the fluids, and pulled the timing cover. I boost leak tested it up to 20psi. Some reason I'm leaning more towards either maf or cas\timing issue. I don't think its fuel, but i'm not throwing it out the window yet.

 

[XiKeiyaZI]

Was the TPS/Biss properly adjusted? And was the CAS set properly as well by grounding out the wire near the battery?

 

[doayamaha]

Does it do this even when the car is at opperating tem if it does then take a look at the fiav could just be low on coolent or the sensor its self is bad if it seems to go away when warmed up which mine did when I first bout it and mine turned out to be that the o2 was bad also make shure that the bov recirc tube is connected and not leaking in unmetered air

 

[simons3z]

Was the TPS/Biss properly adjusted? And was the CAS set properly as well by grounding out the wire near the battery?

i have no idea, the shop that did the timing most likely did or didn't do it? not exactly sure, last owner discretion.

Does it do this even when the car is at opperating tem if it does then take a look at the fiav could just be low on coolent or the sensor its self is bad if it seems to go away when warmed up which mine did when I first bout it and mine turned out to be that the o2 was bad also make shure that the bov recirc tube is connected and not leaking in unmetered air

it only happens after it falls off of cold idle\operating temp @ idle only.

 

[inix92]

Check the iac/egr valve?

 

[simons3z]

Check the iac/egr valve?

check it for?

 

[doayamaha]

If you have a logger see if you are getting the correct voltage from the o2 if you don't have a logger use a dvom and see if there is the correct voltage at the ecu

 

[simons3z]

what does it mean if i disconnect the Idle Speed Control when its running and nothing changes? is that ok or bad?

anyone?

 

[donnie2783]

I am having this exact same problem. My car is a 91 talon. I changed the MAF and can unplug it.Still runs the same and the same thing with the idle air sensor.When it revs it sounds good ,But when it goes to idle for a few seconds it shakes bad and sounds like it is missing bad. I was about to start going crazy trying to figure it out.Also if driving at low rpms it's like every now and then it has a small jerk all of a sudden.Not all the time just like at random pretty much. Any tips of what else to try would be greatly appreciated.

 

[razrman8]

what does it mean if i disconnect the Idle Speed Control when its running and nothing changes? is that ok or bad?

anyone?

Not necessarily. If your car is warmed up chances are it would not. If your car is fully warmed up, it is not having to compensate rpm to keep the motor idling correctly. Though it could when your car is cold. Think of it this way, when you start your up from a dead cold start, do you get a high idle or low idle? Chances are its a high idle. The idle speed control compensates for the car being cold by allowing just that much more air through to bump your idle up to warm the motor up and level out your rpm's to normal level. I am surprised that nobody suggested it before. They are simple to check. All that you have to do is get the motor pulled out of there, and have a friend or somebody turn the key to the on position without cranking the motor. The sensor should move and make a noise. You will know it when you here it. Are you just experiencing a high idle or is it surging?

I am having this exact same problem. My car is a 91 talon. I changed the MAF and can unplug it.Still runs the same and the same thing with the idle air sensor.When it revs it sounds good ,But when it goes to idle for a few seconds it shakes bad and sounds like it is missing bad. I was about to start going crazy trying to figure it out.Also if driving at low rpms it's like every now and then it has a small jerk all of a sudden.Not all the time just like at random pretty much. Any tips of what else to try would be greatly appreciated.

How long has it been going on? Did it just start? Did you perform a boost leak test to assure that you have no vaccum leaks? Any check engine lights? More information would be helpful.

 

[simons3z]

i would be having low idle issues, wish i just had a logger so i could check the TPS to factor it out.
maf works fine, i'll post a video up next week. i blew a coolant line off last night.

 

[gtbread77]

I say it is the BISS screw or ISC, but i am no expert so don't quote me.

It sounds a lot like what mine was doing, check these out helped me a lot.
try this first idle should be set at 750 rpm http://www.vfaq.com/mods/BISS-1G.html if this doesn't work read this and i hope the first one fixes it, Good Luck
http://www.vfaq.com/mods/wayback/BradBauer/engine/surge.html

 

[razrman8]

And it has been doing this since you got it?

 

[gtbread77]

Sorry that last url didn't work try this one Idle Surge FAQ

 

[donnie2783]

Well when I originally got the car it was all in a rusted out red talon. The car in my pics. But now i took everything out and put it in a black talon and fixed the no compression problem so now after driving it for 3 blocks it started doing this. I found out when a cop pulled me over haha I think its allergic to cops(just picking).So it has been doing it for almost a week now. I am going to check out that biss screw deal that was mentioned a few messages ago.I hope that works because this is annoying .

 

[razrman8]

Ok. There are only so many things that can be causing you to be experiencing idle surge. I recommend taking a look at this -->Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge) . If you are experiencing idle surge, this guide will help you narrow down the possible culprit.

 

[donnie2783]

Well I have figured out my ISC is bad so i changed it withone that worked and still does the same thing. I even idled it up for giggles and laughs and it still done it.I even sat down and thought about the things I done right before this happened and changed it all back and still the same thing. I have another ecu somewheres if I can find it then I am going to try that. It is out of a 90 and my complete drivetrain and wiring is out of a 91. It ran it before so im hoping it will run it again ha.I made new gaskets for the throttle body also. I wish i had my old phone because with it then I could have taken a video .When i got the car it's side mount intercooler looked like swiss cheese and even then I never had this problem haha. I know I am runnig out of ideas. Does anyone have any other tips to try?