[Marrk]

I've just wasted 2 hours removing the crankshaft sensor on my 1992 2.3 CD Carlsson to replace it with a known good one from my 1991 spare engine and found out that they are different. The one fitted on the 1992 engine connects to a block connector similar to the DI cassette connector just above the alternator whereas the one on a 1991 engine has a standard block connector and goes all the way over to the side of the battery tray. So I've put it all back together again and am no further forward on finding out why I have this annoying missfire at cruising throttle position. If I hit the pedal I have all the performance I need, no misfire at all but back off and cruise it misses and jerks...it still does it at low positive boost pressures but mostly at around minus 0.5 bar pressure
I'm clutching at straws really as I know its not the DI cassette (tried 2 known good ones) and its not a vacuum leak (all new silicon), the throttle body is okay. Checked the pipework to the carbon canister and thats okay.
The crank sensor is only a micro switch which opens and closes as the cut out pulley plate moves between it so I am not 100% convinced it is at fault as it works at higher revs under boost but misses at lower revs under vacuum. Could it be an ECU advance and retard problem?
Any ideas?
Oh, and will a later model 9000 sensor be the same as a 1992 one?

 

[KevinC]

I'm pretty certain the 1992 and 1993 ones are different from 1994+

Is there no test possible while it is out and on the bench?

 

[boxman]

i would think its unlikely to be the crank angle sensor as your prob is only accuring under low load conditions, do you have a spare ecu to try, d/i rather than lh i would guess, also have you checked the fuel pressure, it could be low under off boost situations and as you apply the power the boost will up the fuel pressure to a usable level

 

[Marrk]

I've just taken my car off the road to fit all my go faster goodies at last, big intercooler, race cams, big injectors, uprated fuel pump, adjustable fuel regulator and a N/A 2.3 inlet manifold. I was told on saabnet that a guy had similar problems as mine and it was the amm ....although my car has just passed its mot and emissions were well within spec I assummed the amm was okay but willing to try all suggestions.