1979-1993 & 94 Conv [Subscribe to Daily Digest] |
 | [Main C900 Bulletin Board | BBFAQ |
Prev by Date | Next by Date | Post Followup ]
Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
Re: intermittent boost Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Tue, 16 Jan 2001 11:52:54
In Reply to: intermittent boost, Jason, Mon, 15 Jan 2001 21:47:42 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Not the nature of the beast. You should be able to get full boost all the time.
The tough part is that a lot of things can cause base boost - knock or ping, a base boost command from a system in the car, or a problem in the APC solenoid.
First - if you're aren't running premium (91 octane US), run a tankfull and see if the problem goes away. You'll get base boost if the system detects knock. It's possible that your engine is on the hairy edge of knock, and sometimes it's there, sometimes it isn't. Make sure your timing is right, and your spark plugs are fresh and gapped properly to the spec on the decal in the engine compartment. Also, check for vacuum leaks - make sure all your hoses are in good shape - a vacuum leak will cause the engine to run lean, and lean can cause knock.
Next, the system will be kept in base boost if the brake lights are on or the cruise control engaged. So if you notice this problem only when the cruise is on, then don't engage the cruise and expect full boost. As to the brake lights, make sure the switch at the brake pedal isn't sticky. I've seen them get sticky and the brake lights stay on. Since you rarely follow yourself, you don't see it. Depending on when your '86 was made it may not have a center mounted brake light - if you have one, sometimes you can see it glowing when your foot isn't on the brake, telling you there's a problem with the switch.
Next, the APC solenoid determines if you have base boost or not. It's a cylinder mounted on the radiator with three hoses and an electrical connector. If the solenoid is not engergized, you'll get base boost. So make sure the connector is on properly - reseat it. Next, with the car idling, pulg and unplug the connector. You should hear the solenoid click. If the solenoid is sticking, you may get stuck in base boost. Next, find the APC box, and make sure it's connector is on properly. I've heard of intermittent problems because that connector is loose.
It's just a few places to start looking.
, Tue, 16 Jan 2001 14:57:21, Tue, 16 Jan 2001 11:52:54 <-- Viewing This Message
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
