Idle drops and dies when stopping

yogibear357 · Oct 28, 2007

I have 347, AFR 185, Comp 282 XE cam, 1.6 rockers, 70mm TB, 80mm Pro-M, under drive pulleys, 200amp ALT, SCT chip, TPS, IAC, VSS, Map, Clutch safety switch all this is new.
When coming to a stop my car Drop to 500 RPM usual dies or bounces back up. It only happens when pushing the clutch petal in. I by passed my clutch safety switch no change. I've rechecked all the Idle procedures. I have no codes. I have it Idling at 1000. If anybody has any Ideas would be great

jrichker · Oct 28, 2007

See "Surging Idle Checklist for help with all your idle/stall problems. The first two posts contain all the updates to the fixes. I continue to update it as more people post fixes or ask questions.

yogibear357 · Oct 28, 2007

.

jrichker said:
See "Surging Idle Checklist for help with all your idle/stall problems. The first two posts contain all the updates to the fixes. I continue to update it as more people post fixes or ask questions.

This was very helpful but I have no codes. I did the Idle set TPS and IAC
It only does this when rolling

HISSIN50 · Oct 29, 2007

Was anything recently done under the hood?

Did your tuner mess with the dashpot or rolling idle (it's commonly changed)?

Good luck.

ShortThrow50 · Oct 29, 2007

yogibear357 said:
This was very helpful but I have no codes. I did the Idle set TPS and IAC
It only does this when rolling

In my case I had to raise the TPS setting to 1.2v. Regardless of the flaming that Ill get for saying it, just try it. Remeber to unnplug your neg battery cable for 10 min. before starting the car after your done. Sounds like the same prob I used to have after the mods in my sig. Other people have had the same problem as well and this was the fix. Worked for me. Ill be picking up a tweecer rt soon though and reprogram everything

ninety15.0 · Oct 29, 2007

Well this seems like a problem with the tuner/tuning. This is really an easy problem to fix. Like hissin said this is an ISC dashpot problem. This is a function that controls the ISC airflow when a sudden RPM drop occurs...like when you depress the clutch while slowing down. There is also an ISC function/scalar that sets a minimum vehicle speed (usually around 7mph) where the computer will finally drop to low idle. These two settings can be altered to get this problem solved easily. You need to contact your tuner.

yogibear357 · Oct 29, 2007

I haven't change anything lately. I took the chip out just to see if it still does it and it does

yogibear357 · Oct 30, 2007

ISC function /Scalar

ninety15.0 said:
Well this seems like a problem with the tuner/tuning. This is really an easy problem to fix. Like hissin said this is an ISC dashpot problem. This is a function that controls the ISC airflow when a sudden RPM drop occurs...like when you depress the clutch while slowing down. There is also an ISC function/scalar that sets a minimum vehicle speed (usually around 7mph) where the computer will finally drop to low idle. These two settings can be altered to get this problem solved easily. You need to contact your tuner.

I have to ask him What is a ISC function /Scalar

PUNISHER RACING · Oct 30, 2007

Old school trick but you can drilla 1/8 hole in your throttle body blade it helps compensate for the lack of air when blade is closed

yogibear357 · Oct 30, 2007

Dash pot

HISSIN50 said:
Was anything recently done under the hood?

Did your tuner mess with the dash pot or rolling idle (it's commonly changed)?

Good luck.

Only thing change was Clutch safety switch and Speedometer cable. I even bypassed the safety switch no change so I hooked it back up

yogibear357 · Oct 30, 2007

1/8 hole Idea

PUNISHER RACING said:
Old school trick but you can drill a 1/8 hole in your throttle body blade it helps compensate for the lack of air when blade is closed

Won't that affect my tune?

NKau · Oct 30, 2007

yogibear357 said:
Won't that affect my tune?

Shouldn't. With the throttle blade cracked, the hole shouldn't have an effect. I have to give that a try myself.........

yogibear357 · Nov 1, 2007

Well I found on my VSS switch harness plug only had on wire hanging on. So I re did the wire and pin seems my exhaust has melted it. I had my tuner change the settings that you all mention about ISC Dash pods air flow it doesn't die now but it idles up and down until I fully stop the car. Progress I guess

jrichker · Nov 2, 2007

yogibear357 said:
Well I found on my VSS switch harness plug only had on wire hanging on. So I re did the wire and pin seems my exhaust has melted it. I had my tuner change the settings that you all mention about ISC Dash pods air flow it doesn't die now but it idles up and down until I fully stop the car. Progress I guess

Go back and work your way through the "Surging Idle Checklist. The answer is in there. Incidentally, the VSS sensor is item #14 on the checklist.

ninety15.0 · Nov 2, 2007

First off you are running an SCT chip right? What computer are you running?

Ask your tuner what definition file or strategy you are running. For most foxes with an A9 series computer you are going to want to change the following scalar.

The scalar name is/should be something like - Dashpot Minimum Clip (DASMIN) - This the ISC minimum dashpot clip for Declutch. It has units of PPM or Lb/min....effectively a flow rate.

The stock value is 14 PPM i believe...and you should bump this number up to 25 PPM or so. This will let the RPM's hang up a little higher when you declutch. This value is not set in stone...but a good place to start. Let me know how this works or if you have any more problems/questions!

yogibear357 · Nov 2, 2007

?

ninety15.0 said:
First off you are running an SCT chip right? What computer are you running?

Ask your tuner what definition file or strategy you are running. For most foxes with an A9 series computer you are going to want to change the following scalar.

The scalar name is/should be something like - Dashpot Minimum Clip (DASMIN) - This the ISC minimum dashpot clip for Declutch. It has units of PPM or Lb/min....effectively a flow rate.

The stock value is 14 PPM i believe...and you should bump this number up to 25 PPM or so. This will let the RPM's hang up a little higher when you declutch. This value is not set in stone...but a good place to start. Let me know how this works or if you have any more problems/questions!

I have SCT flip chip and A9L computer
I will mention the Info to my tuner

Again thank you all for help

yogibear357 · Nov 3, 2007

Well i took my car out for a ride and it still does it. It dies when coming to a stop. I don't even know why my car has Vss sensor. I don't even have cruise control. I have clearly no codes. I have change every sensor Went over the idle surge list many times. Swapped out ECM just to see if that would help nothing. This car sucks

yogibear357 · Nov 3, 2007

My car worked fine before with no chip. It dies when decell with clutch in and braking.

Clear codes
New parts
speedometer cable
Clutch petal safety switch twice
brake switch
VSS switch
TSP
IAC three times
O2 sensor
A9L
Pro-M 80
347
TKO 600
full griggs sup
baer brakes
and more

I have had this in shops spent to much and Nobody can fix it. Would take a decent offer if you would like to buy it sick of ford

PUNISHER RACING · Nov 4, 2007

why dont you pull the chip

yogibear357 · Nov 4, 2007

PUNISHER RACING said:
why dont you pull the chip

I did it still does it

Idle drops and dies when stopping

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