Idle problems after my tune with P-Mass Pro-tube

[xTomKx]

I got my 96 Cobra tuned with a vortech, front mount intercooler, 60lb injectors and the 3" P-mass Pro-tube. The car made good numbers (506hp). I drove it home and it seems that when the ecu started learning the idle got screwed up. The car started to stall when I let off the throttle and the idle is all over the place.

I spoke to my tuner and he says that he can't do anything about it because the maf counts are very low at idle. The tuner bumped the idle and it now is about 1k rpm but it surges up and down.

Is anybody running the Pro-Tube on their cobra?

Any help or suggestions?

 

[HandsomeRob]

Dude I have the same damn problem
my lightning maf spikes at idle and used to do what your idle does
now it's to high and turned on my cel code 1506
"high speed idle" replaced the iac and same problem
I just tuned it on Friday. I'm now deleting the imrcs and putting an accufab on
then retuning

 

[my94pony]

^ i heard accufab causes idle problem all on its own

 

[mwolson]

Can you get a datalog of your idle?

 

[goat-ee]

I got my 96 Cobra tuned with a vortech, front mount intercooler, 60lb injectors and the 3" P-mass Pro-tube. The car made good numbers (506hp). I drove it home and it seems that when the ecu started learning the idle got screwed up. The car started to stall when I let off the throttle and the idle is all over the place.

I spoke to my tuner and he says that he can't do anything about it because the maf counts are very low at idle. The tuner bumped the idle and it now is about 1k rpm but it surges up and down.

Is anybody running the Pro-Tube on their cobra?

Any help or suggestions?

I noticed in the title you say it happened AFTER the tune. So it didn't do this before the tune, or was all this installed and tuned at the same time?

Obviously if it wasn't doing this before the tune, some parameters got changed that need tweaked back. Otherwise it sounds like a possible vacuum leak. Sounds like maybe something came loose after the tune? At least that would be the 1st thing I would check!!

 

[xTomKx]

I was suspecting a vacuum leak but the boost gauge is reading 21 Hg vac at 1000rpm. I will double check all the hoses after work today.

The tuner emailed me a base tune to get the cobra drivable. It had idle problems from the getgo but I was able to drive it to the dyno. The tuner then adjusted the parameters and put the car on the dyno. Then we went on the street and it seemed fine but he was driving. Then he tweaked it some more and I was on the way home. As soon as I got about 3 blocks away and came to a light the car stole out. I figured that the car will learn itself and adjust to run better. Instead when I got home the idle was jumping all over the place and sometimes the car will die by itself.

I'm going to get a data log of the idle tonight and see what is shows. I will update later on as the weather permits.

 

[whtcobra1998]

check your o2's readings, when it was tuned it was in open loop-no learning and when finished set back to go into closed loop, o2's tell the engine how far away from stoich it is and trys to get close to it, also check your tps voltage

 

[mwolson]

Your tuner needs to tweak your dashpot settings to keep it from stalling on deceleration. This is a pretty common problem after tuning for larger injectors, and is an easy fix.

Idle issues can be very hard to get right. It involves both the IAC valve and spark advance. It is almost impossible to fix without getting a datalog of your idle.

Do you have an Xcal?

 

[xTomKx]

I have a Xcal 2 and just downloaded LiveLink software. I will datalog it when I get home this evening.

My tuner had issues setting up the idle before the dyno and couldn't get it quite right. But it was much better then than now. Now he is saying that my MAF counts are too low at idle with the Pro-Tube and he can't adjust it anymore. He was using my previous datalogs that he got last week at the dyno. Wouldn't he need a current datalog to tweak the idle properly?

 

[mwolson]

Datalog the folowing list:

Battery Volts
Coolant temp
Fuel Source
ISC Duty Cycle
ISC Integrator
Load
MAF AD Counts
RPM
Spark Advance
Spark Source
Short & long term fuel trims
TP Relative

On a side note, as a favor to me, ask your tuner what the peak Load was at the top of your WOT run. I have a theory about a software bug in SCT's 96 & 97 Cobra tunes with setups like yours that I am trying to get evidence about. When I went to my 90mm LMAF, the Load caclulations in my tune got all screwed up. There is a workaround if this is happening to you, but many tuners don't know about this topic at all.

 

[xTomKx]

mwolson....I sent my tuner an email asking what my peak load and spark advance were. I'll let you know when he gets back to me.

Took some time before the snow to datalog. The only thing I could tell that's going wacky is the spark. I don't know enought about SCT or Ford system to tell why that would be.

Would you or anybody alse be interested in looking at the datalogs?

 

[mwolson]

I would be willing to look at it. I tune my own 96 KB Cobra using SCT's PRP.

The spark is supposed to look funny. The PCM does coarse control of idle with the IACV, but it does the fine control of idle by changing spark advance.

BTW, what is "snow"?

Mark (from California) :coolman:

 

[nestmendoza98]

mwolson You tune your car on the dyno using sct software or of the dyno?

 

[mwolson]

I use SCT's Pro Racer Package with an Xcal2 and an old PLX M300 wideband permanently installed in my car to do my tuning. I do idle, part throttle and driveability tuning on the street, and WOT tuning on a local Dynojet dyno.

I MAY have done a little WOT tuning on deserted freeway on-ramps late at night, but that is pretty scary. And I would never admit to doing it. :nono: