Thread: Can't get the car to stay started at operating temp.

Alright, so here is one that puzzles me. I have a GTP with the L32

My car will start completely normal from a cold start but once the car gets up to operating temp the car will turn over, start,and then die almost immediately after it starts up. To get the car to stay on we would have to disconnect the egr sensor and then unplug the vacuum line from the brake booster on top of the supercharger and then quickly plug it back in once the car was running for a few seconds. The important part of all of this is that once the car stays started the car runs completely fine, idles fine and has full power, boost, everything.

At first we thought the egr was stuck completely open even though most times the car can overcome it. We decided to rule it out anyways and took it out of the car (yes we covered the remaining holes). Tried to start the car again, it would start and then die again right after it starts up. A scanner showed the car has the vacuum it should. We hooked a tester light up and got spark, checked to see if an injector was leaking and made sure the fuel pressure was correct and it was. We also cleaned the map sensor and still the car would start and then die immediately. So we disconnected the throttle body sensor with the key to full accessory and threw the car into reduced power mode, after which the car started right up. It had a rough idle but the car started every time we tried it while in reduced power mode (with the brake booster line connected).

Any ideas of where to look next?

So...does it throw any CEL's? So there isn't a vacuum leak or anything? Normally the '04+ cars have issues with the throttle body gunking up since they are DBW and cause hard starts, sluggish issues, etc...I'd try that since it's free as long as you have some brake clean of sorts. Are all of your rubber "T"s dry rotted? You said its holding the correct amount of vacuum...which would be about -20 or so.

Sounds like the car is having problems when going into closed loop (using the oxygen sensor to determine air to fuel ratio)
Check to make sure that the oxygen sensors are properly cycling switch between lean and rich. Check the maf sensor that its reading about 1lbs of air per minute at idle.

Also if the car is running with the throttle body disconnected, try swaping throttle bodies with somebody to see if its the cause(since if these dbw tb are the same as ls there's no iac motor) since the throttle body has to open slightly to allow air enough air to come in to allow the car to breath enough to idle

We will try cleaning the tb tonight, the vacuum was at -28 on the scanner with the car off and at a consistent 20 on the manual boost gauge with the car on. I'll let you know about the throttle body. And wouldn't the car not start in reduced engine mode if the throttle body needed cleaned?

Swapped the throttle body for my buddy's off his 04 and had the same starting issue. We deduced the problem to the cam sensor getting heatsoaked while the car is warm. Scanning the car while it was running from a cold start showed no problems when we went through the log, scanned the car from a warm start, all the sensors the scan read were fine and working properly, the only sensors we couldn't scan were the cam and crank sensors. Since the car start and then immediately dies we are pointing more towards the cam sensor. Gonna probe the cam sensor tonight after I get off work and if thats it, 38 bucks at advance and i'm all good. *crosses fingers*

I think they are cheaper at AutoZone AND have a better warranty...but I can't remember.