I’ve replaced my ls6 with an ls2 based 402 and have been using a tuner that has great recommendations but is about an hour and a half from me. We’re starting with a base tune and have done a total of five updates, I don’t have any idea how May updates it typically takes to to get the car close enough to run for an extended period of time. The car runs great but I have had issues with cold and hot starts intermittently. For instance this last tune after installing it took several seconds of cranking to get it started, the next day it started at the turn of the key and then today took time cranking to get it going? I did have issues at first with the car dieting at stops, that appears to have gotten better, it’s the starting issue I don’t quite understand. The tuner asked for another run file which I’ll give him, I’m just looking for some insite. Is there any thing on my end that may cause an issue? Again, I believe the tuner is top notch, I have faith in his work and undrperstand he is got a very full schedule so I’m looking for a little help in understanding what’s happening. My obvious intent is to take it to him and have it tuned on a dyno but I’d prefer having a few more miles on the engine. (When cranking it can have a muffled back fire, I’d believe up front not out the back end.

Thanks Rich

 

Start up (cold and hot) as well as drive ability are the hardest to do remote, this is coming from experience. Patience is key or an in-person visit. Remote support does take longer.

Reading your description it sounds like it starts cold just fine but when warm takes extending cranking? Is that correct? If so, some work on the idle tables are needed, your tuner should be able to sort this out (timing, or maybe RAF/idle airflow).
Do you have to give it any throttle to start it?

 

Strangely enough it was the wiring harness built by Casper, two of the wires running to the cam sensor were switched. I got lucky scanning threads and found someone else with the same issue. Thanks for the input.

 

Nice detective work! That would have made a nightmare for your tuner to track it down remotely. Glad you got it figured out.