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Old 09-19-2000, 12:59 PM
otto increment
Posts: n/a
Well you asked for it, so here is the whole story...

The day BEFORE the catastrophic display of smoke and noise, the vacuum pump failed. I spent a few hours thinking and looking, and determined that there were no significant leaks, and the pump was not doing its thing. The pump seemed to be putting air out of the line that goes to the air cleaner, but there was not a corresponding amount of vacuum on the other side of the pump. I decided that this was not a big enough deal to ruin our vacation, since as far as I could tell the only significance of loss of vacuum was harder brakes, no power locks, and having to shut off the engine manually.

The next morning, we were driving down a steep hill and I downshifted to low since the brakes obviously had no boost. We drove like this for a minute or two (long steep hill!!) and then all of the sudden the car started trying to accelerate without me giving it any throttle. I quickly shifted into neutral, at which point the engine started to race, and smoke started to pour out. I quickly stopped and popped the hood to shut off the engine. Pushing the manual shutoff was not as effective as it normally would be, it took a moment before the engine started to slow down, and then another moment or two to stop. Total time from moment of shifting to neutral to the engine stopping wasnt more than 10-20 seconds, but it seemed like forever!!

After the car was stopped, it started leaking oil rather severely from somewhere on the passenger side lower half of the engine, I havent had time to jack the car up and actually find out where, but the leak was enough to turn the tow dolly black with oil while towing the car from San Francisco to Olympia.

Thats the story... Last night I spent some time looking for a correlation between the vacuum pump and the injection system, and discovered that the pump is driven off the injector timing wheel. This leads to me current theory about the nature of my problem... It goes like this: Something broke in the timing mechanism that caused the vacuum pump to fail first, and then later the timing device itself. This caused the fuel timing to become advanced and/or more fuel to be delivered, which explains the sudden revving. The high RPMs caused the oil leak either through excessive oil pressure bursting a seal/line/etc., or excessive crankcase pressure due to high RPMs blew out a oil pan seal.

This theory may be improbable to those of you who know more about these engines, but in my ignorance it seems like a pretty good explanation.

It looks to me that I can remove the vacuum pump, and then the timing device rather easily, although the Haynes manual is unclear about how you re-index the timing device to the rest of the engine when you reinstall it, whick raises another question, what is the best service manual for this car? The haynes manual seems to cover brakes, tuneup, etc, but not much else... Should I go to the dealer and get the proper service literature?? Any suggestions would be appreciated.

Thanks again...

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