Can anybody make my 01 cobra idle?!

[Badaz01]

As the title says I’m beating my head off the wall trying to figure this thing out. The car idles fine when sitting parked. Try and back out of the garage, blip the throttle, or come to a stop and it dies. I’ve so far changed the pcv valve l, iac, cleaned my maf a while ago, put new oil cap on(it was sloppy and loose), and had my tuner make adjustments and data log the car. To no avail the car still stumbles as stated above. Any help would be greatly appreciated. Thanks.

 

[01yellercobra]

What throttle body are you running? Can you datalog?

 

[Badaz01]

What throttle body are you running? Can you datalog?

We did data log some. I had a twin blade accufab on then went back to the stock tb. We did this because the accufab was completely closed and it was still saying it was pulling to much air through the accufab at idle. The only other major change I made to the car was I went from autolite plugs to ngk tr6’s. I’m kinda wondering if the intake spacer I have is making the plenum space to big and throwing something off. My tuner said to throw the accufab back on and try it one more time then if that doesn’t work to bring it back idk.

 

[01yellercobra]

I doubt the spacer is the issue. I ran a spacer on my 01 and it idled pretty solid.

The engine may not like the TR6's, but I doubt it.

I'm guessing you didn't happen to see what the IAC duty cycle is when he datalogged did you?

Oh, and the blades shouldn't be completely closed. If you can datalog yourself you can set the throttle body up in a few minutes.

 

[Badaz01]

I doubt the spacer is the issue. I ran a spacer on my 01 and it idled pretty solid.

The engine may not like the TR6's, but I doubt it.

I'm guessing you didn't happen to see what the IAC duty cycle is when he datalogged did you?

Oh, and the blades shouldn't be completely closed. If you can datalog yourself you can set the throttle body up in a few minutes.

No I didn’t see the iac numbers. He did mention the 99/01 cobras were finicky with idle and that we would have to keep at it until we find what the car likes. He also showed me a list of parameters that all showed zero not sure exactly what they were and he said the 99/01 cobras all did that. So he populated those parameters with numbers from an 03 cobra to try that out. The car seemed ok at first then the next day it started acting up again. I wonder if the whole unhooking of the battery trick would do any justice.

 

[cobracide]

As stated above, IAC voltage and tip in the throttle blade so a little air gets in on idle.

 

[Badaz01]

As stated above, IAC voltage and tip in the throttle blade so a little air gets in on idle.

I can try that again. Accufab sent me a throttle body that was completely closed I called them and they said turn the set screw until it touched then go 3/8’s of a turn. The iac I had in was new ford oem then we even went back to the original ford oem iac and it’s still acting up. We also smoke tested the vacuum lines no visible leaks. Idk.

 

[03cobra#2]

Just a thought but if it idles fine while parked but it stalls when coming to a stop / blipping the throttle ect actually sounds like a dash pot issue. Sure if your iac duty cycle is out of wack it could be that but first things first. Get acceptable parameters while during a warm stable idle. Then I would start looking at dash pot settings in the tune.

 

[Badaz01]

Just a thought but if it idles fine while parked but it stalls when coming to a stop / blipping the throttle ect actually sounds like a dash pot issue. Sure if your iac duty cycle is out of wack it could be that but first things first. Get acceptable parameters while during a warm stable idle. Then I would start looking at dash pot settings in the tune.

Ok I’ll mention that to my tuner when I take it back.

 

[01yellercobra]

Just a thought but if it idles fine while parked but it stalls when coming to a stop / blipping the throttle ect actually sounds like a dash pot issue. Sure if yoir5iac duty cycle is out of wack it could be that but first thing first. Get acceptable parameters while during a warm stable idle. Then I would start looking at dash pot settings in the tune.

I had that thought too, but the closed blades caught my attention. I'm guessing the IAC duty cycle is way off.

OP, get a laptop and set up your datalog to watch IAC duty cycle. With the engine running open the throttle blades until you get about 30%. The RPM will increase for a couple seconds while the IAC adjusts. Once you hit the 30% lock the throttle stop. Then check your TPS voltage and adjust as necessary. After all that have your tuner adjusts dashpot decay.

Honestly, this is all basic tuning and stuff your tuner should have done before anything else.

 

[Badaz01]

I had that thought too, but the closed blades caught my attention. I'm guessing the IAC duty cycle is way off.

OP, get a laptop and set up your datalog to watch IAC duty cycle. With the engine running open the throttle blades until you get about 30%. The RPM will increase for a couple seconds while the IAC adjusts. Once you hit the 30% lock the throttle stop. Then check your TPS voltage and adjust as necessary. After all that have your tuner adjusts dashpot decay.

Honestly, this is all basic tuning and stuff your tuner should have done before anything else.

I agree and he may have all this is Japanese to me to be honest.

 

[01yellercobra]

Well, it's never too late too learn. Learning to datalog is a very useful tool on these cars.

 

[Badaz01]

Well, it's never too late too learn. Learning to datalog is a very useful tool on these cars.

The guy I go to is pretty knowledgeable when it comes to tuning. Like you said I need to learn to data log and actually be able to spend more time checking all the idle parameters and what not. Probably hard to do things perfect in an hour.

 

[Badaz01]

Well, it's never too late too learn. Learning to datalog is a very useful tool on these cars.

Ok idle speed valve on my handheld reads around .5 at cruise and idle. At wot it reads .98 when I come to a stop or blip throttle it dips to .34

 

[01yellercobra]

Open up the blades a little. It gives the IAC a little more room to work. WOT doesn't matter as the engine isn't idling.

 

[Badaz01]

Open up the blades a little. It gives the IAC a little more room to work. WOT doesn't matter as the engine isn't idling.

I just did that with the accufab. I reinstalled it along with the other oem iac I had and the gasket that came with the accufab because it seems more restrictive than the oem gasket I figured that would help since he said to much air was getting by. Well so far so good the idle dips a little low for my liking when I blip the throttle but I’ll give the computer a chance to learn it for a while. And with all that on my readings actually dipped to around .25 to .30 at idle and about . 75 at wot.

 

[01yellercobra]

I don't understand the whole "too much air is getting by". You shouldn't need to restrict anything with a proper tune.

Have him bump up the dashpot decay a couple percent. It'll drop a little slow back to idle, but it shouldn't stall anymore.

 

[Badaz01]

I don't understand the whole "too much air is getting by". You shouldn't need to restrict anything with a proper tune.

Have him bump up the dashpot decay a couple percent. It'll drop a little slow back to idle, but it shouldn't stall anymore.

Idk either that’s just what he said while on the computer that it was showing to much air getting by the tb at idle.

 

[01yellercobra]

JMO, but I'd have someone else look the tune over. See if someone on here will look over a couple of datalogs for you.

 

[Badaz01]

JMO, but I'd have someone else look the tune over. See if someone on here will look over a couple of datalogs for you.

I just may have to do that once I get set up to data log.