3V S197 - Cold Start Idle Spike

[metroplex]

I have a 2007 Mustang GT, N/A, nothing extraordinary other than CMCV delete. On cold starts, ambient can be 0F up to 80F doesn't matter as long as it is a cold start, the engine RPM rises to about 1200 RPM slowly, and then ramps up to about 2100 RPM. I've tried looking for a table/setting to control this but was unable to find anything. My idle speed adder is stock for cold starts (about 380 RPM?) as are my other idle speed adders. I want to limit this to about 1200-1500 RPM max, it seems ramping it to 2000 RPM is abnormal or a bit too high. Plus, a cold start in my neighborhood seems kind of noisy in the early morning and unnecessary as I usually just chug along until I'm out of the subdivision (to let the engine warm up) before opening it up.

Any ideas on why it spikes to 2100 RPM and what setting controls this? My idle speed in drive table was 2048 RPM stock but I changed it to 1000 RPM without any effect on this. I'm also running E85 but even when it was 93 octane, it would do this on cold starts.

[Exley]

I have a 2007 Mustang GT, N/A, nothing extraordinary other than CMCV delete. On cold starts, ambient can be 0F up to 80F doesn't matter as long as it is a cold start, the engine RPM rises to about 1200 RPM slowly, and then ramps up to about 2100 RPM. I've tried looking for a table/setting to control this but was unable to find anything. My idle speed adder is stock for cold starts (about 380 RPM?) as are my other idle speed adders. I want to limit this to about 1200-1500 RPM max, it seems ramping it to 2000 RPM is abnormal or a bit too high. Plus, a cold start in my neighborhood seems kind of noisy in the early morning and unnecessary as I usually just chug along until I'm out of the subdivision (to let the engine warm up) before opening it up.

Any ideas on why it spikes to 2100 RPM and what setting controls this? My idle speed in drive table was 2048 RPM stock but I changed it to 1000 RPM without any effect on this. I'm also running E85 but even when it was 93 octane, it would do this on cold starts.

If you haven't already try messing with the "Mult" tables under Idle -> Airflow this adds airflow to the base idle airflow based on engine run time and engine coolant temp. Pretty sure the 0 second engine run time row effects cranking throttle too.

FYI my 3v has always snapped up to 2k on startup ramped down to about 1500 in about 10 seconds and then settles to 1k after about 30 seconds.

[metroplex]

Ok, I will take a look there. I think it is normal for the engine, but 2k just sounds too high/loud. My old 2V never revved that high.

[Exley]

Oh it's loud. And i still have the stock H-pipe

[Devildog1325]

There are also idle speed adders for intake and coolant temp on top of your startup idle speed adder

[metroplex]

None of those settings worked. The engine just revs to 2000-2200 RPM on its own. No rhyme or reason.

[Devildog1325]

Is your idle airflow settings correct how do stit look and have you messed with any drive demand or torque settings that low?

[wayno]

what does your max cold start spark tables look like?

[metroplex]

I didn't mess with the DD in that region or the torque table. My cold start spark tables are stock. I looked at my notes from 2006 and the car seemed to do this 110% stock as well. I played with the airflow multiplier tables but it didn't do anything.

[wayno]

try setting them all to 10* and see what happens.

i usually set them to 30 or so and knock down all the temp adders

[metroplex]

The stock tables are all negative, but my actual cold start spark goes to a max of 18 degrees.

[Exley]

What about taking airflow out of these tables in the 2200 row?

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[mstang_man]

make sure your driver demand isnt crazy high and most of the time you need to adjust your throttle angle at idle versus airflow.

[metroplex]

My DD is stock at the low TP positions. I may try the throttle angle max at idle, I think the standard SCT settings raise all of the max throttle angles to 82*, but SCT also lowered the startup adders as well. I'll check those out.

[metroplex]

I found it, it's the table of rpm adder vs ect cold start. SCT has an additional table for when it is cold and not just cold start. I lowered the adder for 70f and above. Now it starts up to 1500, drops to 1000 and then ramps up to about 1900 instead of 2200 to 2500.

[joepeek]

I have a 2007 Mustang GT, N/A, nothing extraordinary other than CMCV delete. On cold starts, ambient can be 0F up to 80F doesn't matter as long as it is a cold start, the engine RPM rises to about 1200 RPM slowly, and then ramps up to about 2100 RPM. I've tried looking for a table/setting to control this but was unable to find anything. My idle speed adder is stock for cold starts (about 380 RPM?) as are my other idle speed adders. I want to limit this to about 1200-1500 RPM max, it seems ramping it to 2000 RPM is abnormal or a bit too high. Plus, a cold start in my neighborhood seems kind of noisy in the early morning and unnecessary as I usually just chug along until I'm out of the subdivision (to let the engine warm up) before opening it up.

Any ideas on why it spikes to 2100 RPM and what setting controls this? My idle speed in drive table was 2048 RPM stock but I changed it to 1000 RPM without any effect on this. I'm also running E85 but even when it was 93 octane, it would do this on cold starts.

That was happening to me on my 2005 GT. All I did was buy a can of Throttle Body cleaner (not Gumout) and sprayed all the black soot out of the TB. I had someone sit in the car with the key on and holding the accelerator to the floor so the throttle blades would stay open. Also picked up a can of MAF sensor cleaner and sprayed the MAF pretty good as well. After cleaning I reflashed the tune and the high idle cold start issue was gone. It idles better even after warmed up as well. Also, go into IDLE/RPM and verify the time and temperature "adders" are not to crazy.

[metroplex]

The stock settings don't have any timers set. My 07 GT did this when new, and I rarely drove it below 60F over the years. I think this was the first year I drove it down into the 30s.

[jared879]

I know this one is old, but this was happening to me recently and tried everything on this. I found out that for some reason my car was reading pretty lean on first start up after about 12 hours. So I added about 5% to 10% ( Cant remember) to my MAF and it fixed my problem, it affected my fuel trims very little surprisingly. It now revs up to about 1300 rpm and quickly comes down to idle or 1000 rpm depending on how cold it is outside.

[f.creek-ranch]

maybe the intake has a leak ....
at cmcv delete there is a chance to get a leak too by assembling....