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Air Conditioning problems at WOT and cruise

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Old 03-31-2017, 09:56 PM
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Default Air Conditioning problems at WOT and cruise

6.2 recently swapped in to a 2013 ecsb with a 4l60. I'm running into a couple of issues that I finally think is air conditioning related.

First issue
I did a little testing this week. Earlier in the week, I tried to finalize my tune for my dyno day on Thursday, but I kept getting limp mode after approximately 4000 rpm. I checked the logs and nothing really stood out, figured maybe it was transmission related. I'd get a 0300 random misfire code and an 0909 ecu code. I couldn't figure it out so I got to the dyno the other day and put a stock 2010 tune on with a stock 4l60 tune. Before the first pull, I purposely turned the A/C off and got everything ready. Truck pulled great to 6000 rpm on all 4 pulls, so I figured it must have been something I messed up in the tune.

Today I was driving around (with A/C on) and decided to do a short 2nd gear pull and it died at 4000 rpm into limp mode again (same codes). Tonight I went back out and tested again. 1st pull was a/c on (see attached log 1) and it failed around 4k. 2nd and 3rd pulls were with a/c off and it pulled strong to around 5k (see attached log 2). So I definitely think it's a/c related (I took my a/c from my previous 4.8 and put it on to the 6.2 - might be a fail here).

2nd issue
For the last week since the engine swap, the truck runs rough at cruise speeds around 60-80 mph (1800-2000 rpm). Feels like it's surging a bit, maybe slipping the tranny. Would randomly jump up 100-200 rpm for awhile and then bump back down to normal. Frustrating as hell because I trying a million different things to figure it out. So tonight I tested a highway run with a/c off and it felt perfect. Hit the off ramp and came back with the a/c on and stupid surging crap was happening again. Turned it off and it seemed normal (just put a set of bilstein 5100's on the rear so I can feel pretty much everything which kind of makes it difficult to tell).

Does this sound familiar to anyone? Did I put the wrong a/c compressor on the 6.2?

Attached is the tune, both wot and highway logs. Any suggestions would be greatly appreciated. As a side note, truck did 347 hp to the wheels at 5550 rpm on the dyno.

Thank you
Attached Files
File Type: hpt
File Type: hpl
good no ac.hpl (967.6 KB, 36 views)
File Type: hpl
fail 1.hpl (2.03 MB, 51 views)
File Type: hpl
n.hpl (2.81 MB, 40 views)
File Type: hpl
a.hpl (1.55 MB, 27 views)



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