ac blowing wierd

I recently replaced some vacuum lines trying to locate my cruise problem and now when I am excellerating the throttle, the ac will start blowing through the defrost vent and floor and then come back to the vents when the vehicle hits the gear its looking for, is this normal ?

gore349

The AC/Heater unit uses engine vacuum to control the vents inside the car - the default (no vacuum) is to blow are thru the defroster.

The engine vacuum line goes to the firewall at a spot below and to the right of the master cyclinder. The AC/Heater line connects to that vacumm accumulator box too.

Sounds like you have a bad vacuum leak somewhere or the vacuum control diphram for your air doors is blown and leaking.

would a missing nut on the vacuum housing be a problem, i dropped it in the dark and it didnt hit the ground, I didnt think one missing nut would hurt, but I will replace it today and see if that worked

gore349

Sounds like you mis-routed your vaccum lines. Your car has a check valve in the vaccum lines to keep vaccum in the tank during accel.

I replaced the check valve and it fixed it

Thanks for your help, I have one more question, I just got home from a 90 mile trip, I was almost home driving 80 MPH on the I-55 when the dash lights all came on, egine reved up and the car jerked a little then the check engine light came on, I limped it home and sut the car off, waited a minute and turned the car back on and everything works fine I think it may be a bad ERG valve.

Its a 94 buick lesabre

Check you codes to see what caused the check enging light to come on. You can find them on this link:
http://www.geocities.com/dann8785/serviceenginesoon.html
service engine soon

Well it coded that the cam sensor was bad changed it, then it coded the EST was bad changed drove it 100 miles light came on car jerked again im changing th darn plugs and wires today in hopes that will fix it. I cannot put it on a computer today but i can tommorow.

Got any ideas? its a 94 Buick Lesabre with 97000 miles

Shattered magnet in the cam gear. They usuall last over a 100K before the come apart, however it depends on how you drive. You need a new timing set anyway at 97K. Just replaced mine with 150K & had the the exact same codes as you have and the magnet had broken in several pieces but still had enough in the cam gear to pick up the cam position most of the time. Just like everybody else, I tried all the easy and cheaper solutions to no avial, i.e. wires, plugs, ETS, cam sensor, crank sensor, coils, air cleaner, CTS, TPS, and anything else related to ignition control.

Those magnets are pesky. Mine went out at about 165K or so. Easy to check - pull cam sensor out, rotate engine slowly by hand until spot where magnet should be shows up. You may see the remnants of the *plastic* magnet holder. My timing chain & gears were in good shape when I took them out (replaced em anyhow), but the chain damper had some wear on it.

However, if you are getting both the cam code and the EST code, there might be something else going bad - EST can mean crank sensor, ignition module, ECM, or the related wiring. To the best of my knowledge it means that the ECM detected that it was not supplying spark timing to the ignition module, and so turned control of spark timing back over to the ignition module. There will be a definite jerk in the meantime.

If you are getting both CAM and EST, I'd suspect either a faulty ignition module or ECM (or a bad wire connection somewhere). When my ECM went bad a couple of years ago, I was getting an EST code plus two other random unrelated codes (and had the jerking problem, but it was also accompanied by loss of speedometer reading too).

I assume you had a code 41 & 42. There are not to many solutions to those two.

Code 41 3 flashes, pause, 1 flash = Cam Sensor
Check for faulty connections, or a faulty cam sensor. Maybe also indicate a problem with the vehicle's timing chain.

Code 42 4 flashes, pause, 2 flashes =Electronic Spark Timing
check for faulty connections, or a faulty ignition module
Code 43 4 flashes, pause, 3 flashes = Electronic Spark Control
Check for a faulty knock sensor, or Mem-Cal

Well, its getting better, the mechanic and I took a mirror and the magnet is fine. Then I got another error with the ERG valve so I took it off and cleaned it. It ran 180 miles and now the Check light is on again but this time the motor didnt jerk. Here is waht Ive done this week.

New plugs and wires

New Cam Sensor

New EST plate thingy

Cleaned ERG valve, I will check it on computer when I wake up.

Keep up the good work! Don't let the SOB beat you. Keep everyone informed.

Good Luck!

OK drove 180 miles today and no lights or probs, woo hoo, hopefully i fixed it i think it was a bad egr valve all along

Hate to jump into the Buick arena but I'm liking the answers I see. The problem I have with my 95 Tahoe is that when you accelerate, the hot air comes in through the vents for a minute or so and then the cooler air returns. Vacuum line problem? Sounds better than replacing the compressor. I guess I need to know the location of the vaccum lines so
I can check.
Thanks

get a haynes or chilton book for the vehicle and it will show you the vacuum lines. then pull off each one and replace them one by one so you dont mess up, thats what i did with my buick.

Good Luck

Sounds like a high pressure switch cutting off the compressor. Have you added any Freon lately? If not that, it could be the vacuum diaphragm (or vacuum lines) that opens and closes the door between the heater core and evaporator.