tecsun

I recently completed an ls1 swap into an older porsche. It has a TSP 228r cam that I put a rough tune on to get it running before sending the computer to frost for a good tune. With my tune initially it would start right up and idle fine the many times I ran it in the garage to check leaks and systems. I then took it out for a first drive and since it will only start if I give it about 20% throttle for the first ten to fifteen seconds and then it idles and drives just fine from then on. It does this on cold and hot starts. If I don't give it any gas it starts, runs about 1-2 seconds and slowly dies. I thought it was just my crappy tune but it does the exact same thing with the frost tune which we all know should be a good tune. I'm thinking it may be a hardware type issue. I went through and made sure my TPS volts were around .45v and all was reset to 0%. In hptuners my IAC reads around 60 counts hot idle usually but sometimes when I start it reads around 130 and stays there for a long time or stays there until I turn it off again. I don't want to bug Steve at frost just yet because I know he's a busy man and I'm not yet sure if its a tune issue since it was doing the exact same thing with both tunes. Keep in mind it changed its great idling characteristics after my first moving test drive, just around my neighborhood for about 20 minutes, with my initial tune, drove fine turned it off in the garage, went to start it ten minutes later and has been goofy since. Any ideas, experiences, or diagnostics you guys can think of would be very much appreciated as I've been messing with this thing for days and have hit the limit of my small amount of LS knowledge.

tecsun

Just wanted to follow up on my issue in case it may help someone else down the road. Turns out it was a MAF issue. I had installed a new K&N filter with my conversion that sits about four inches upstream of the maf. I had cleaned the used maf prior to install. It ran fine idling but my guess is the increased airflow during driving pulled some of the oil from the filter through the system. I cleaned the MAF very well and it ran great again, no issues at all. After about 100 miles of driving now I'm noticing it idling a bit rough again. My hope is that over time I'll have to clean it less as the oil dissipates or else I'll change to another filter.