A little background.... My 66 Impala with a completely stock 2006 GTO LS2 with a added Edelbrock supercharger.......Got 45K miles on the car......Now to my issue.....when the engine is cold and I go to start it.....the engine starts and immediately the RPM goes up about 1000 rpm then the rpm drops, the engine stutters and quits running.......When I hit the key to restart it starts immediately stutters for a second or two them smooths out and runs perfectly........In the past when started the engine RPM dropped to about 5-600RPM and then went to the set engine idle speed of around 750 RPM........Any ideas on what's going on??????

Thanks in Advance
Ken

 

A data log of the issue is a start.

 

DBC or DBW??
Plus what Old Buzzard said.
We need ALL the info....

 

DBW,,,,,


After thinking about it ,....... It has to be a programming issue........Need to get it back to the Tuner

 

Another thing I noticed is when starting with a fully charged battery in the cold condition.......when it starts it runs up to 1000 rpm and immediately starts stumbling and the rpm drops to 600 then stumbles and quits running......after thinking about it after starting in this condition the voltmeter drops down to around 10 volts before the Alternator starts charging...... After restarting a couple of times the voltage stays up around 14 and the engine runs perfectly........Hummmm!!!!

 

I think I just answered my own question..........Gonna get a new Battery...Don't think the battery voltage should drop that much.........????????

 

Put a brand new fully charged Battery in and the same issue........Time to take it back to the Tuner and cry on his shoulder to see if he can take the time to check it out,,,(He's booked for weeks)........I need someone a lot smarter than me to figure this out......LOL

 

I have the same issue on the Chevelle. Usually if I haven't started it in a while, it will sputter on first start up, stumble, then smooth out. I think it's only died on me once or twice. Upon restart, it stumbles a little, but then runs fine. And it didn't do that when I first completed the build. Some research shows I might need to re-learn the throttle position or idle re-learn. However, I can't find a clear answer on the procedure for that. Keep us updated. I'd be interested on what your tuner says

 

The Tuner explained to me the complexity of a DBW system on cold start..........You have throttle plate position, Fuel mixture, ignition timing all mixed together on initial start up....... I have to take it back to him when he gets time.......He said he had to get the table of settings out of the computer and then going in and reset and set everything the way it should be.......Problem Gone!!!!!.....I was blown away listening to him about the complexity of all the details talking to one another...... Way above my pay grade for sure......LOL .......I'll stick to changing oil and spark plugs....LOL

 

We can see how and why the engineers can make the big bux.

 

Base Running Airflow table might need a bump in the particular temperature range of your starting issue... AFTER first making damn sure you have a nice fresh alternator drive belt installed, and the tensioner is behaving correclty.

 

Got it figured out.......Doesn't make any sense to me but it worked........I was told to take the air inlet tube off and get a rag and squirt some brake kleen on it ......then open the throttle blade and wipe the manifold side of the blade completely.....and then wipe the throttle body area that the blade sits in........Started the car up and everything perfect again.......Don't understand why but it worked........Just thought I would post this info for future reference..............

Ken

 

You just eradicated a bunch of ugly poopoo-nasties that were messing up your day....