engine bogs down when A/C on
 

What would cause my idle to bog down and bounce a few times when my A/C is running? My idle is set to 1000 by PFC and when i turn on the A/C it'll hit about 750, then bounce back, then down one or two more times. This will happen randomly, but fairly frequently the whole time the A/C is on. I can run with the A/C button de-pressed (OFF) with just the fans and this will not occur. Any thoughts? Thanks

yep happens to my Fd also, BUMP

is the ac charged correctly? what is the min idle set to? have you established the pfc has the ability to even raise the idle to 1k (meaning the iac is ok)?

you might want to check your a/c system. when you turn your a/c on, your idle should move up not down. you might have a vaccum leak or bad ac swith?

I will have to check to see if the ac is fully charged, i know i have a can around somewhere. The minimum idle is set to 1000, since below 1000 my idle is rough. Don't have that answer either... maybe TPS. I am not sure how to check the idle air controller.

I would check your TPS first. Shouldn't be hard at all with the PFC. Also, the ISC gets dirty sometimes and just needs to be cleaned.

i was under the impression the PFC has had issues with the a/c working correctly,

has this been remedied now?

your problem is with the pfc and the a/c fan switch ground. a lot of us have this problem with the pfc you need to do the relay switch wire mod. (search under a/c fix for pfc) . my a/c works on setting 1 & 2 just fine. but the idle bounces and the compressor turns off on settings 3 & 4. my a/c works fine on all settings with the stock ecu. so its a problem with the pfc.

Jeff

If it is a problem related to refrigerant then you likely have TOO MUCH refrigerant in the system. However, I doubt that is the problem.

What does the screen on the PFC that shows all the sensor data reflect as far as A/C status? Is the PFC getting the signal that the A/C is on? I suspect that for some reason it is not and therefore it isn't bumping up the idle.

I will check in the morning... How would i fix it if that was the case?

Oh crap I have a PFC also, that may be the problem??? Ill search Thanks

do a sensor check on the pfc commander. if you turn on the a/c and the sensor check light for the a/c turns off you have a ground problem as I stated above. many of us have this problem with the pfc. like I said mine works fine on settings 1-2 but 3-4 settings something goes wrong with the ground. the a/c fix mod is the answer to your problem.

Jeff

Read the thread linked to above. That may or may not fix it. If that doesn't fix it then you would have to do basic electrical troubleshooting to figure out where the problem is.

The AC sensor on the PFC will come on in 1 for a second or two, then go out and not come on for 2, 3 or 4.

I read the AC fix thread and will give it a shot when I have time. Hopefully that'll fix my problem, too. Thanks for the help...

I searched for threads with information on TPS and VTA1 and VTA2, and didn't quite come up with what I thought i needed... so I took a picture of the PFC with the engine off, throttles open and closed and this is what I got:

http://i490.photobucket.com/albums/r...8/IMG_0418.jpg
http://i490.photobucket.com/albums/r...8/IMG_0419.jpg

How is that looking? The PFC is literally like Japanese to me, since the manual is in Japanese ;)

Also make sure your idle settings for the PFC with a/c load on are higher and not for some weird reason lower. Mine are set for Idle A/E 900 Idle E/L 950 Idle A/C 950.

My setup is similar, though a little higher. I thought about that at first too.

Your TPS appears to be in range.

VTA 1 should be closed throttle 0.1 to 0.7. Fully open throttle 4.2 to 4.6.
VTA 2 should be closed throttle 0.75 to 1.25. Fully open throttle 4.8 to 5.0.

I am haveing the same thing with mine. I dont understand it at all ive checked for vacuumm leaks and still have a poor idle and and even worse with A/C on car almost dies (shakes real bad). y pipe down pipe mid pipe and a PFC.