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I recently acquired this car & plan to use it as an extra vehicle when one of our main vehicles will be down for an extended period. It's basically a wholesale piece for which I have no service history. It's my first Saab & my first post here. Hello to everyone, & this seems like a very helpful site. For lack of a better term, I guess I'd be classified as an advanced DIY'er. Most of my experience is with Alfa Romeo's & VW's.
The car runs quite rich & boggs down when you first open the throttle. If I'm agressive enough with the throttle, I can stall the car. If I'm really easly with it, I can get it to rev normally. Condition is the same whether revving in neutral or under load & is constantly present regardless of temp, although it's less severe at operating temperature. It doesn't struggle to hold an idle, but it has what I can best describe as a very rythmic fluctuation between 900 & 1100 rpm's. I've covered the basics (compression, vacuum, fuel delivery) but still have some trouble shooting steps yet to cover. However, there are 2 unique things going on that I haven't seen covered in either the Bentley manual or in the archives on this site.
1- When I first crack open the throttle, I get a short burst of positive manifold pressure. This condition also coincides with the engine bogging down. At idle, I have a steady 18" of vacuum. When I fist crack open the throttle, I get a very short but intense burst of positive manifold pressure. It's hard to get a reading because the needle on my vacuum gauge bouces so quickly, but I'd estimate that it's reading about 6 psi of positive pressure. I can acutally see & feel the hose leading from the AIC to the intake manifold swell when this happens. Once I get beyond the initial throttle opening, the engine revs normally & vacuum readings are normal.
2- With the engine idling in neutral, if I pull one of the vacuum fittings in the intake manifold, the engine will actually start to rev up as if I'm opening the throttle. I don't know the extent to which it will do this as I didn't leave the fitting off for very long. I can't imagine that this is a normal operating condition, & I've never ran across such a problem before.
Other noteworthy observations:
-The mixture screw on the AMM appears to have been tampered with by someone. I have 2 other AMM's (a spare from the P/O & one from a parts car I recently acquired) that have not been tampered with, & the car will not run with either of these. It will fire & immidiately die.
-The TPS tests OK. This was my leading suspect.
-If I unplug the CTS, the car will rev normally, but of course, it runs REALLY rich.
-I swapped in the CTS & the AIC from my parts car, & there was no change in the running condition.
-CEL is on at all times.
-Spark plugs were heavily carboned. I cleaned & regapped them.
Thanks in advance for any input.
Michael Keith
Houston, TX
posted by 205.174...
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