zeeman1951

I've got a 93 SW1 SOHC, manual trans and need some help on two Hi rev problems I've been having:

Problem #1:

With the car warmed up, I'll be sitting at a traffic light and the engine speed will increase from about 9000 to 14000, hold there a bit then drop back down. Check engine light comes on and sets a code 49. Whole cycle takes about 10 seconds. This has happened 3 times in the last 6 months or so. I replaced the hose from the map sensor to the TB after the first time: the boot at the TB end was soft, and looked questionable.

Problem #2:

While driving the car warmed up, the engine speed will increase to aprox 22000 and stay there. It acts like I've got my foot down on the gas, even when I don't.When the car comes to a complete stop, speed will drop slowly back down to 9000 or so. The car may or may not respond normally after that. No check engine light, no codes. This doesn't happen every trip, or even every day, but it happens several times a week. Throttle cable isn't binding--if I hook my foot under the gas pedal and pull UP, speed doesn't decrease.

Any ideas??

Thanks

Darth Detroit

I just had this problem too. It can be a few differnt things. Throttle sensor, EGR valve, vacume leak...

MD_BLUE_SL2

man...check those zeroes again...

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I don't remember askin' you a GOT-damned thing --Samuel L. Jackson in Pulp Fiction

Darth Detroit

Didntr yuo hear? Some European Saturns have the Pratt and Whitney turbo fan jet engines installed! They can get those hiogh RMPS!

Ssicarman

Check the PCM temp sensor and connecter. Bad temp readings to the PCM can cause all kinds of strange things to happen.

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Darth Detroit

Seriously though. I would check the throttle position sensor, and the collant temp sensor. Both can give you those rpm problems. If it was a vaccum leak, it would be more consistant. Sounds like the pcm is trying to correct the problem. So at least thats working for you. Does the engine ever bog down on acceleration?

monkeyracing

Yup, TPS, maybe the voltage from your alternator is weak, uhhhhhh, and the other stuff those guys said.

I had the same problem for about 2 minutes when my alternator died.

Jim

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You've got a 10 second car, huh? How fast does it go on the track?

zeeman1951

I guess I was so distraught after the last hi rev episode that I multiplied everything by 10. SOUNDED like 22000 anyway.

I agree that a vacuum leak would probably happen all the time, or at least more frequently. I'd considered the TPS as well, but I thought that would definitely set a code.

Engine doesn't really bog down on acceleration, but with a sohc, it's no streak of lightning either.

We had good weather yesterday for a change, so I replaced the temp coolant sensor, cheap and easy.

Next I'll drive the car around for awhile. As I mentioned, this isn't an everyday problem. If the hi revs don't happen again over the next week or so, I'll consider it fixed, if not, I'll try some of the other things.

Thanks to all.