2006 Mustang GT with E-Force SC Kit High Idle/Rev Hang

Hello all, I have searched high and low for a solution to this problem on this and other forums. While I have found some information that seems to be pointing me closer to an answer I have so far not found what I am looking for.

I have a customer who installed a Edelbrock E-Force sc kit (P# 15800) onto a 2006 GT 4.6 3v. Other mods are a deleted exhaust and 90mm intake/maf tube.

The tune I have arrived at provides almost perfect AFR's at idle, doing rpm steps, and under full load. Makes good power, and runs very smooth. The issue I am fighting before I deliver it do him is a persistent rev hang (while driving or just revving in neutral) and high idle. While driving and decelerating in neutral (MT) the rpms will hang at 1500 - 2000 until I come to a complete stop. At this point the rpms will settle into a lower range, but still quite high. The lowest I have seen the idle is about 950 rpm. Idle set point is stock. I am sure it is related to the single blade 85mm throttle body included in the E-Force kit, stock these use a dual blade TB.

I have not attempted any idle airflow, decel spark, or dashpot adjustments yet - I am thinking that is where I need to focus. If anyone can point me in the right direction on getting my idle set to an acceptable level (750-800 max) and removing that very annoying rev hang I would be very grateful!

Most of my experience tuning is in the standalone world - this whole "let the ECU do the work" thing is really throwing me off.


Attachment 109049Attachment 109048

Need to look at Idle>AirFlow>Idle Air Flow > P/N and Drive tables. I bet it is commanding more air flow there and making your throttle hang. I had this happening with my old tune.

I will make some adjustments to those maps and report back with results.

That helped a little, but now I'm thinking I have a mechanical issue since my LTFT's are up around +20. Being as these mustangs have idle control run through the electronic throttle body, and my APP sensor will never read less than 18%. Which means to me it's keeping the throttle plate slightly open.

Anyone have a read from a stock mustang of this year?

Really good chance you have a vacuum leak. Most likely at one of the couplers between the maf and blower, or the blower gasket, or blower is not torqued down properly. You can't tune around it. The mechanicals have to be right to start.

Here is a stock 06 tune:Attachment 109293

Here is the same car with a ported whipple, does not exhibit the problem you are talking about: Attachment 109294

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Originally Posted by B E N

Really good chance you have a vacuum leak. Most likely at one of the couplers between the maf and blower, or the blower gasket, or blower is not torqued down properly. You can't tune around it. The mechanicals have to be right to start.

Here is a stock 06 tune:Attachment 109293

Here is the same car with a ported whipple, does not exhibit the problem you are talking about: Attachment 109294

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I thought exactly the same as you, but I've done a smoke test and it's sealed up tighter than any engine I've worked on. Will the charger prevent a smoke test from giving good results? Should I try the old brake clean on everything check?

Looking at the tune, I think it has to do more with the throttle body tuning on it. I am not an expert on throttle body tuning. But that appears to be whats off. And could also cause the Hang. Also does this have aftermarket cams or any other mods?

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Originally Posted by 007GTCS

Looking at the tune, I think it has to do more with the throttle body tuning on it. I am not an expert on throttle body tuning. But that appears to be whats off. And could also cause the Hang. Also does this have aftermarket cams or any other mods?

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No other mods besides the supercharger kit and a larger cone intake. Maf has been properly scaled for the larger tube. The throttle body calibration came straight from edelbrock, I haven't made any adjustments to it.

I just learned this information from the customer today, which would have been so much more helpful to have up front, but apparently this was an issue before the charger was installed... I wish I had been told that at the beginning.

I also noticed that when you turn the steering wheel at idle or turn on the ac the idle is drug down, not kicked up like its supposed to. I'm leaning towards a combination of faulty app sensor (readings never go below 18.4%) and a possible pcm fault with the idle control circuit. I've had many of these boards burn chips and work perfectly fine except for controlling idle.

Quote:

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Originally Posted by NathanCross

No other mods besides the supercharger kit and a larger cone intake. Maf has been properly scaled for the larger tube. The throttle body calibration came straight from edelbrock, I haven't made any adjustments to it.

I just learned this information from the customer today, which would have been so much more helpful to have up front, but apparently this was an issue before the charger was installed... I wish I had been told that at the beginning.

I also noticed that when you turn the steering wheel at idle or turn on the ac the idle is drug down, not kicked up like its supposed to. I'm leaning towards a combination of faulty app sensor (readings never go below 18.4%) and a possible pcm fault with the idle control circuit. I've had many of these boards burn chips and work perfectly fine except for controlling idle.

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Well that would have helped to know before the install lol. Sounds like you have it tracked down. App sensor would be my next thought to or throttle body electronics. Did you use the electronics off the stock throttle body? Im wondering if it had aftermarket electronics on it or bad electronics. I have seen it happen from that too. Hanging idle. Not the 18.4% from the app sensor.

Try recalibrating the app sensor. If it doesn't fix it then it sounds like you have the problem figured out.

This is prob outdated but im still going to comment, For the idle rpm hang edit the Idle dashpot decay, Idle dashpot minimum, and Idle dashpot ire-position Tables, and for the Rpm hang while driving edit the Idle dashpot min (4th no decel) and dashpot min (4th gear)

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Originally Posted by tortuga281ci

This is prob outdated but im still going to comment, For the idle rpm hang edit the Idle dashpot decay, Idle dashpot minimum, and Idle dashpot ire-position Tables, and for the Rpm hang while driving edit the Idle dashpot min (4th no decel) and dashpot min (4th gear)

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You can adjust the airflow tables, a lot of people don't know rpm hang could be caused by your Spark Decel table . Too advanced timing for deceleration can prevent the rpm from falling down to idle.

can't dashpot cause this and a cruise control effect when off throttle ? may be worth it to di g into those tables

You shouldn't have to mess with dashpot. I would bet you have a vacuum leak.