I recently completed a 6L swap in my truck (specs below) it is an '06 engine into a '03 truck. Problem is it surges as soon as i give it any gas. It will idle but as soon as i touch the gas the a/f gauge goes to full lean and starts to stall and then surge back again. Watching the injector volts they are pretty steady but dive to zero when i touch the gas and will spike up then to zero again until i let off. I hooked an injector diode light to one of the injector plugs and it is bright at idle but fades or quites when i try to rev. There is good constant power to the injectors. Fuel pressure stays perfect. I've tried the tune i built for it, my old tune, a couple other guy's similar tunes, and tried a million settings. They all run a little different but all do the same surge. I triple checked all grounds and i pulled the pcm plugs and checked all eight grounds with an ohm meter - all good. Anyone know what could be shutting them off? can anyone think of any settings in the tune that could be shutting them off? Any ideas would be awesome, i got three days into this problem and am starting to lose it!!! Thanks!

 

Still using the same injectors and harness from the old engine? If so, sounds like a tuning issue. Can you post a tune file?

 

Same injectors and harness as before. Here is a log and the tune. Check the log around the 725 mark, you can see throttle is constant through the 600's then around 725 i move the throttle and it really starts surging.

 

Hmmm unfortunately I don't have HPT installed so I can't look at your files, but I'm sure someone will soon

 

problem ended up being that i un-checked the 101, 102, 103 MAF codes instead of switching them to "no light" so the pcm would not enter speed density.

 

glad to see you got it though!