acranox
09-05-2004, 05:53 PM
For those that have seen my previous threads, you know that my car stalls when I take my foot off the gas. I've got the throttle stop screw cranked up, but the underlying problem still exists. Here's some new info. (kinda long post)
Today I replaced all the vacuum hoses. It took about 30ft of hose. I didn't replace the hoses that go into the "mystery box" because that seemed like more trouble than it was worth.
The problem still exists. I know my power valve is broken, so I've got it disconnected, but when disconnected, that leaves it in the 'on' position.
Here are my latest observations.
Twice this week, the car started idling really high, which would make sense if the original problem cured itself, because the throttle stop screw is set high. The first time I floored it in 1st gear, and hit 5000RPM, and then it went back to it's normal idle. The second time I just left it alone. So the problem can temporarily cure itself.
Sometimes though, it still stalls. Often when I'm braking for a red light I'll see the revs start to drop real low. The harder I brake, the lower the revs go. If I stay light on the brakes it won't stall, but if I use them moderately, it'll stall unless I blip the throttle before I stop. Hard braking can definitely make the car more likely to stall, but the brakes work fine, and according to the tests outlined in the Haynes manual, my brake booster is air tight.
The car diesels pretty bad when I shut it off. Usually just one or two clunks. But if it's idling high when I shut it off, it'll keep deiseling for 10 seconds or more, and it really bucks hard.
I did a compression test a few weeks ago. The manual said the engine should be warm, but unfortunately I had problems getting the plugs out, so the engine cooled back down before I could run the test. I tested anyhow, and got about 200psi on 3 cylinders, and about 170 on cylinder #2 (but I think i might not have screwed the gauge in tight enough)
But 200psi is high. Do you think it was high because the engine had cooled down? Or was it something else. I know carbon build up can cause a high compression reading, and that can also cause dieseling.
Does the throttle plate in the secondary barrell ever open fully? When I've used a vacuum pump to test it, it only opened a tiny bit.
I bought a used carb from eBay, it should be here next week. I'm hoping that will solve something. Anyone have any new thoughts about my car?
Thanks.
--Peter
Today I replaced all the vacuum hoses. It took about 30ft of hose. I didn't replace the hoses that go into the "mystery box" because that seemed like more trouble than it was worth.
The problem still exists. I know my power valve is broken, so I've got it disconnected, but when disconnected, that leaves it in the 'on' position.
Here are my latest observations.
Twice this week, the car started idling really high, which would make sense if the original problem cured itself, because the throttle stop screw is set high. The first time I floored it in 1st gear, and hit 5000RPM, and then it went back to it's normal idle. The second time I just left it alone. So the problem can temporarily cure itself.
Sometimes though, it still stalls. Often when I'm braking for a red light I'll see the revs start to drop real low. The harder I brake, the lower the revs go. If I stay light on the brakes it won't stall, but if I use them moderately, it'll stall unless I blip the throttle before I stop. Hard braking can definitely make the car more likely to stall, but the brakes work fine, and according to the tests outlined in the Haynes manual, my brake booster is air tight.
The car diesels pretty bad when I shut it off. Usually just one or two clunks. But if it's idling high when I shut it off, it'll keep deiseling for 10 seconds or more, and it really bucks hard.
I did a compression test a few weeks ago. The manual said the engine should be warm, but unfortunately I had problems getting the plugs out, so the engine cooled back down before I could run the test. I tested anyhow, and got about 200psi on 3 cylinders, and about 170 on cylinder #2 (but I think i might not have screwed the gauge in tight enough)
But 200psi is high. Do you think it was high because the engine had cooled down? Or was it something else. I know carbon build up can cause a high compression reading, and that can also cause dieseling.
Does the throttle plate in the secondary barrell ever open fully? When I've used a vacuum pump to test it, it only opened a tiny bit.
I bought a used carb from eBay, it should be here next week. I'm hoping that will solve something. Anyone have any new thoughts about my car?
Thanks.
--Peter