xTraViSx

It's a stock cam. I would love to learn how to tune with EFI live. For now we'll see if Black Bear can set my a/c parameters correctly. Its Florida..its hot... and i need a/c without little annoyances.

budhayes3

iTrader: (19)

Usually when a compressor seizes it locks up and throws the belt, and it may start giving you signs by making knocking noises first The ac idle tuning is very important, I know from personal experience with my truck...when I had a PCMforLess tune (which I was happy with, don't get me wrong), I asked Bryan if he could do anything about the voltage dip when my ac compressor clutch engages and the efans come on high and he said "sure I can adjust for that", which he did. Unfortunately he made it worse, and when the compressor engaged the RPM's dipped down and quickly came back up. It was pretty annoying, but I dealt with it until my trans blew, and when I installed the FLT/Circle-D combo I got a BlackBear tune, and asked Justin what he could do about it and he fixed it no problem. The volts still dip slightly when the efans hit on high, but not bad at all.

LS1TRUCKGUY

iTrader: (7)

mine has always done this even when it was bone stock. when idling in park, you can hear the rpms dip and come back up. when driving, it bogs down a little bit and comes back up. i see a huge voltage drop when my 34" efans kick on. i also have an od alternator pulley, which helps. next on the list is the big three wire mod. wheatley has a spent a lot of time messing with the a/c tuning, which has helped some, but i think my compressor clutch is the culprit. i have rode in numerous gm trucks, stock and modded, and some do it, some dont. i think its just hit or miss with the compressor clutch

terravast4

iTrader: (25)

I have a similar problem. When my E-fans come on or when i use my electric windows it seems to make the engine stumble just for a second

budhayes3

iTrader: (19)

Well it appears that there are multiple possibilities, but the first thing that I would look at is the tune. LS1TRUCKGUY, it may be possible that your throttle body and IAC are dirty, and the throttle body isn't getting the true amount of air as it should. If you haven't cleaned your tb in a while, I'd give it a shot. If it doesn't help, all you lost was a little throttle body cleaner, and you got a little preventive maintenance done

1FastBrick

iTrader: (17)

Good sugestion and a good place to start!

BTW there is a TSB on the AC System getting sludge build up in it slowing down the compressor causing the tensioner to snap and or causing exsissive strain on the engine.

Start with the first suggestion and see what happens. If not a 100% go after the AC system.

terravast4

iTrader: (25)

I know mine is in the tune....it happened after my tune ....just have not been able to get it taken care of

budhayes3

iTrader: (19)

Good info about that TSB, wasn't aware of that one

03 BLACKOUTSSS

iTrader: (3)

The tuning could very well be an issue, but I don't know enough about it to tell you where to start. I can't imagine installing the blower would require any changes to the AC tables, but again, I have no idea. Personally, I would look at the AC first. what you are describing sounds alot like a compressor thats going bad (clutch partially locking up) and/or there is too much/not enough freon in the system. With the car OFF, you should have about 65 psi on BOTH the high and low side. With it operational, you should have about 30 on the low side, and 90-110 on the high. If there is too much in the system, the compressor will be drawing extra power, trying to compress it for cold air, and it will feel like what you are describing.

xTraViSx

I will have a look in to that avenue. It does kinda feel like the compressor locks up. You can feel the strain on the motor. Kinda feels like someone threw a trailor on the back for a second. i got to find me some gauges now to check that.