Mechanics

CAR HAS HIGH IDLE AND STALLS WHEN BRAKING

1993 Saturn Astra • 200,000 miles

Hi I am having a problem with my car. It idles at about 2300 rpms and sometimes fluctuates down to under 800 rpms. When I press the brakes or turn the headlights on the engine stalls. What could be the problem and how would I go about fixing it?
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NickFrasier
October 10, 2011.




Sounds like a vaccum leak and possible a charging system battery issue. What model do you have because its not a astra your car was made way before that model came out. Do you have any codes?

Saturntech9
Oct 11, 2011.
Sorry it's a saturn sl1. I don't have any codes and when I brought it to advance auto parts I was told that they couldn't check for codes because of the year model

Tiny
NickFrasier
Oct 11, 2011.
The auto parts stores usually only have a scanner to read obd2 codes not obd1 like yours. That year and model was prone for vacuum leaks I would look at the hose that runs from the pcv in the valve cover to the intake manifold for holes splits etc. Also on the backside of the throttle body injectiin check all those vacuum elbows for leaks there end up getting holes in them. Also do you have a multimeter?Let me know what you find.

Saturntech9
Oct 11, 2011.
I already changed the pcv hose while looking for a vacuum leak, I tried to take it off of the pcv valve and it was dry rotted and broke. I can't visually see anything wrong with the vacuum elbows or tubes coming from behind the throttle body and I did use carb cleaner to try to find the leak and still no results. I'm not sure if I overlooked anything but I know I didn't find and major changes in the idle when using carb cleaner. And yes I do have a multimeter

Tiny
NickFrasier
Oct 11, 2011.
I would also check the vacuum lines going to the canister purge solenoid under the intake and the egr solenoid under the air box. Also make sure your egr valve isnt sticking open. Make sure there are no leaks going to the brake booster. Let me know what you find.
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Saturntech9
Oct 11, 2011.
How can I tell if the egr valve is sticking open?

Tiny
NickFrasier
Oct 11, 2011.
And what's the best way to check for leaks in the brake booster line? I can't visually see or hear anything wrong and I ran out of carb cleaner so I really don't know how else to check for leaks

Tiny
NickFrasier
Oct 11, 2011.
The best way to check for leaks on the intake gasket and lines and hoses is carb spray. Also while it is idling high move vacuum lines elbows etc and see if the idle changes. Also use the handle end of a hammer to tap on the top of the egr valve and see if it idles down. Also tap on the idle air control valve. Also you can rent a hand vacuum to pull. And vacuum and make sure the brake booster is holding vacuum. Also step on brake while the booster is under vacuum about 20 inch pounds of vacuum on the gauge. You could also remove the brake booster hose off the intake and pull a vacuum with the hand pump on the brake booster and line to see if its holding vacuum. Also at idle see what the voltage is at the battery cables.

Saturntech9
Oct 11, 2011.
Would it make a difference in the testing of vacuum hoses if I took the air box off while testing with the car in idle? Most of the vacuum tubes are under it.

Tiny
NickFrasier
Oct 11, 2011.
No its fine only the breather hose goes to it no vacuum lines.

Saturntech9
Oct 11, 2011.

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