Surging with A/C

January 01, 2009, 12:12:01 PM

Hey guys. I have a few little problems I am going to be working on this winter to get the car ready for spring. I've searched the forums and could not find anything exactly like what I am experiencing.

When I run my A/C or defroster, the engine surges. It only does this when driving down the road, it does not do it at idle. The A/C blows cold and was recharged and switched over to 134a several years ago by me. When driving down the the road it is like the car goes from no load to load continuously with the A/C on...once you switch the A/C off it goes back to running normally.

EDIT: I did go out and run the car and was wrong. If you let the car idle and turn on the A/C there is a slight surge in rpm...it is much more pr0nounced though when you run the car up to 1500-2000 rpms. As soon as the A/C is switched off it goes back to running normally.

Could I have a bad compressor or maybe a sensor bad somewhere? I know this could be caused by many different things or a culmination of things considering the miles on the car but does anyone have any ideas?

On a side note: My dad has a code reader for his '87 F-250...I borrowed it to try and run codes on my car. This is probably a dumb question but where the hell do I plug the thing in? I looked on the drivers side by the coil and windshield washer tank. I also looked under the dash and didn't see anything. Maybe I'm just spoiled by newer cars with the port right under the steering column! So where is the darn thing?

Surging with A/C

Reply #1 – January 02, 2009, 06:55:19 PM

come on...anyone?

Surging with A/C

Reply #2 – January 02, 2009, 07:14:37 PM

2 plugs near the master cyl. one is a single wire.

Surging with A/C

Reply #3 – January 03, 2009, 03:30:50 PM

thanks I'll try to find that...for some reason I thought it was along the shock tower close to the coil? Maybe that's on fox 'stangs?