PDA

View Full Version : BOOST gauge moves about 5psi when A/C clutch engages ??



trevino_88
06-01-2020, 06:49 PM
Hello Everyone,

I hope you all are holding up good. Not long ago I s/c my MM with the most famous Eaton swap, I love everything about the power gain, sound, torque, etc... now, I want more powaa!. However there is one thing that keeps bothering me! My RPM goes up so much when my A/C clutch goes on, im able to feel/hear/see speed gains. When I set my car on cruise control, don't remember what speed at around 2500k and when A/C clutch goes on my RPM goes up a bit and I lose about 5In.Hg , also when I come in to a stop and the A/C engages I have to add extra pressure on the brakes. I already replaced my IAC valve and the problem still there.. wait there is more! I switched one from my other MM and issue still there. I already checked for vacuum leaks and everything seems great. I even used the carburetor cleaner trick. I didn't mind back in January but now in the Texas heat coming around the corner and I want to be able to enjoy my ride to the beach with A/C and cruise control on and have no ride issues.
Tomorrow I will connect my Sct tuner and do some datalogs. Thank you very much for the past,future and present help. I got inspired and I was able to complete my own swap by reading on this page!! Thanks a bunch.

trevino_88
06-02-2020, 06:37 AM
Here is a video..https://youtu.be/X95Shko0g2c

musclemerc
06-02-2020, 07:05 AM
You have a vacuum leak.
Find the leak and the problem is solved.
Start with a EATC test

fastblackmerc
06-02-2020, 07:13 AM
Like musclemerc said you hve a vacuum leak.

Check all the vacuum hose. These cars are old and the age combined with heat / cold cycling can cause the rubber and plastic vacuum hose to leak.

Check the vacuum tank (square box on left fender).

There is a vacuum tree behind the motor on the firewall, check that too.

The '03's had an automatic parking brake release. Check the the vacuum motor on the parking brake and associated hoses.