If it's surging, that means it running too lean under acceleration...

 

YES, thats what i was telling them, they seemed to believe the timing was too aggressive and bouncing off the knock sensor, I build race motors for sleds and very fimilular with timing /fueling and I feel its too lean under acceleration also.I am doubtful this next tune will take care of the issue with the direction they are heading.

 

I told them exactly what I was running, and they tuned it specifically for my mods. All the way down to the exact amount that the throttle body was ported.

 

they take all the notes but seriously they have not dynoed an H3 with ported throttle bodies, or an H3 with full exhaust cat forward and high flow cat back with headers, It makes for a fancy form you fill out but pretty standard mail order settings, Case and point mine runs poorly and they have all my info.ported throttle body wont alter the fueling much.their form says list your header length. short ,med or long however the settings are the same for each, these are pretty generic with the few delete options for codes and trans shift points.you would need to take vehicle in and dyno for actual perfect tuning for your mods.its a shot in the dark, I have an engine dyno for the Mod powder sleds i build and every one is different in regards to optium tuning.

 

really best to have a local shop tune your H3 with HPTuners. They can adjust what PCMofNC has on there to better work with yours.

I was lucky to live close by and have them tune it for best performance for my H3. He mad a few adjustments on the test drive and reflashed updates.

 

The PCMofNC has an Hp tuners option, would that be better than the regular pcm flash?

Im going that route since Im overseas and the local guys just like to push everything to the max when tuning. Im worried that they'd destroy reliability/life expectancy of my truck

 

Well PCM4 less has returned PCM and they would not listen to the fact that i,m lean under acceleration , just has HUMVEH2 as suggested. They instead thought it was bouncing off the knock sensor and pulled timing out, Its a total dog and un -drivable.way down in power from even stock.takes several second to rev up in neutral. . Back in the mail again, Again I am lean due to the headers, aftermarket cat back and the high flow cat forward system as well. There is very little restriction which allows to breath very well. needs more fuel under acceleration. They either need to listen to the what Magnaflow says [ It is lean]or return it to stock so i can run the Jet chip which ran strong,They have not done as asked and now another week without vehicle. . I do like the suggestions to have a tuner calibrate the PCM however I cant find any shop in C.A. that provides this service?

 

even if it was triggering the knock sensor due to having too much timing, richening the AFR in that area will also fix the problem.

You are better off getting it custom tuned using HP Tuners (as what telemike said), if you are make sure that PCM4less flashes your ECU back to Stock settings. Then when you take it to the shop for a custom tune, make sure to have them check first (before any power tuning). That your fuel trims on idle & cruising are as close as they can to 0% (anything between +3 & -3 are good).. From there they can do what ever the truck could take.

Where are you in California?

 

I ,m at shaver Lake . above Fresno. I do appreciate you and Telemikes advice and believe your both spot on. A generic tune is a crap shoot with different modifications . Just trying to find a shop who can do the custom tune seems difficult. thanks

 

Call HPTuners @ hptuners.com I'm sure they can direct you to a nearest tuner...