Stalling After Stage 1 Heads & Cams Install

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east_sidaz

New Member

Dec 21, 2004

24

0

1

Jul 1, 2012

#1

• Jul 1, 2012

• #1

Hello,

I have a 99 GT mustang with the following mods:
Stage 1 heads & cams
Cold air intake
Aluminum drive shaft
BBK “3 inch” o/r mid pipe
BBK shorty headers
Magnaflow Catback “3 inch”
BBK underdrive pulleys
70mm throttle body
75mm plenum

The car was running great but recently and after the install of the stage 1 heads and cams the idle is not really stable anymore. When the car is cold the idle is all over the place (up & down), when the car gets warm, it idles fine. The car also stalls sometimes especially when I hit the clutch while slowing down or getting into a turn. I didn’t tune the car yet, but as far as I know stage 1 cams and heads don’t need to be tuned. But I could be wrong. Anyways, I have a Diablo hand held tuner, so what do you guys suggest? Mail order tune?

Thanks

 

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east_sidaz

New Member

Dec 21, 2004

24

0

1

Jul 2, 2012

#2

• Jul 2, 2012

• #2

anyone???????

 

RedDaemon

10 Year Member

Mar 31, 2005

3,470

9

108

Atlanta, GA

Jul 2, 2012

#3

• Jul 2, 2012

• #3

hit up a dyno shop

 

trinity_gt

10 Year Member

Jan 31, 2003

3,125

81

99

Canada

Jul 2, 2012

#4

• Jul 2, 2012

• #4

It might help to know what cams and heads you've got because the term "stage 1" can mean anything.

In general, a custom tune would be a good idea with any cam swap. And the tuner has to be capable; it's not just about fattening up fuel delivery or adding some spark advance and calling it a day. There are a number of scalars and parameters in the calibration that can help with the idle stability that good tuners know about.

It can take the PCM a while to re-learn the closed loop idle control after the battery has been off for a while. Give it a few cold-hot drive cycles and see if it improves.

 

Dark04GT

10 Year Member

Apr 27, 2008

758

62

59

NC

Jul 3, 2012

#5

• Jul 3, 2012

• #5

I didn’t tune the car yet, but as far as I know stage 1 cams and heads don’t need to be tuned. But I could be wrong. Anyways, I have a Diablo hand held tuner, so what do you guys suggest? Mail order tune?

Click to expand...

As said above you definitely need a dyno tune. You have been misinformed if you were told you don't need a tune after swapping for different heads and cams..... it may run but you are more likely to have problems with idle, suboptimal performance, etc.

 

BurningRubber

10 Year Member

Dec 6, 2004

1,865

24

58

Jul 5, 2012

#6

• Jul 5, 2012

• #6

Yep.

Computer doesn't know what to do with the change in airflow at lower RPM. Once you're driving and the engine is turning higher RPM, there's no need for idle parameters to figure out how to keep the engine from stalling.

Unless there's physically a mechanical problem with the parts or the install was incorrect, a new tune should definitely fix the idle and unlock the full power potential throughout the RPM range.

What brand are the heads/cams?