Hi all I have a new problem, maybe two, that I'm trying to figure out. Just last week I pulled my '90 SC out of storage to drive this winter. Has only driven 2-3 times the last 18-20 month.
Well, it starts up fine. Then driving along at highway speed it starts pulse or surge engine RPM like stomping and releasing the throttle. At idle I see the tach jumping around between about 600 and 1200 RPM all by itself.
Then the other day, thinking I may have some old/bad fuel, I stop to get gas, fill up, and afterward it just spins and won't start. Something was weird here because normally after the blower builds some pressure the starter can barely turn it over and you have to wait a few seconds for the pressure to bleed off, but instead the starter just spins it like there are no spark plugs. I wait a few minutes, really trying to figure out what's wrong, open the hood and see nothing out of the ordinary. I slam the hood shut and try to start it up and after a few rev. the pressure from the blower builds up. Wait a few sec. and try again and she starts right up. However, I notice the tach. reads 0 RPM, but she runs OK. I drive her home and half way the tach. snaps to life and starts to read normal RPM.
Next morning I start it up in the driveway and let it warm up. Runs fine idle for 5 or so min. then starts surging again on its own.
I'm thinking there may be some problem here that only shows up once warmed up and EEC goes into closed loop mode, but that doesn't explain the tach at 0 RPM when running.
I'd appreciate ideas on what may be wrong or what I should look at.
Many thanks!
-Kurt
Well, it starts up fine. Then driving along at highway speed it starts pulse or surge engine RPM like stomping and releasing the throttle. At idle I see the tach jumping around between about 600 and 1200 RPM all by itself.
Then the other day, thinking I may have some old/bad fuel, I stop to get gas, fill up, and afterward it just spins and won't start. Something was weird here because normally after the blower builds some pressure the starter can barely turn it over and you have to wait a few seconds for the pressure to bleed off, but instead the starter just spins it like there are no spark plugs. I wait a few minutes, really trying to figure out what's wrong, open the hood and see nothing out of the ordinary. I slam the hood shut and try to start it up and after a few rev. the pressure from the blower builds up. Wait a few sec. and try again and she starts right up. However, I notice the tach. reads 0 RPM, but she runs OK. I drive her home and half way the tach. snaps to life and starts to read normal RPM.
Next morning I start it up in the driveway and let it warm up. Runs fine idle for 5 or so min. then starts surging again on its own.
I'm thinking there may be some problem here that only shows up once warmed up and EEC goes into closed loop mode, but that doesn't explain the tach at 0 RPM when running.
I'd appreciate ideas on what may be wrong or what I should look at.
Many thanks!
-Kurt