I have a 1989 900
VIN : Ys3ac46d4 k3021909
B202,I,4-CYL,4-CYL I,PETROL
with the ENGINE CONTROL UNIT / MODULE, Jetronic (LH 2.4) Bosch 0280000564 / Saab 7487135
I replaced 2 broken capacitors in this unit.
I was thinking the unit was the problem and just had reset.. or so.
When the engine is off. It wlil sometimes start but most of the time i have to wait long.
When it not starting i can see the Fuel pump and ignition is not turned on (either Engine control unit of the Bosch ingition system)
If the fuel pump isn't running when the engine is cranking, either there is no tach signal (Hall Effect sensor has failed, the ICM has failed) or the ECM has failed (no fuel pump relay engagement). The latter is a common problem on some LH 2.4 ECMs.
....yep......usually, when 1989 and C900 are mentioned in the same sentence, Fuel ECU is usually a hot topic.
For what it's worth, the white ceramic hybrid chip is the item that performs most of the fuel calculations and fuel relay control.
The most efficient use of your time would be to source another ECU and swap it in to see if the behaviour of the issue changes.
Otherwise, as Jvanabra has kindly highlighted for you - many long hours can be wasted chasing all sorts of imaginative thoughts on the suspect fuel pump relay control.
There have been a few instances where the fuel relay control might have been impacted by some other condition but with MY89 cars, the fuel ECU is a simple fix......replace it.
And, this condition is not a Saab thing....Volvos of the same era suffered the same issue.
Thanks guys. Very helpful to know I am going in right direction.
Swaping out ECM ICM or Hall sensor would be right way to find this problem. As I am probably the only one in this country with a Saab I need to investigate further. The linked in threats are very useful.
Thanks.
The 1989 LH 2.4 ECU's were known to have problems with the PCB tracks etc. for the fuel pump relay circuit, and also with the idle control loop in the firmware. I don't know enough about them to go deeper into the technical side. When I had my old 89 3ck n/a hatchback I replaced the 89 ECU with a 90 version and that sorted out some problems.
Thanks for the input.. i am sorry to report that after a long test drive... the problem came back. (engine off)
I will now replace the hall sensor (while also replacing crack shaft oil seal and oil pump O-ring.. (quite some oil leaking there)
I will open up the 9000 ECU and compare.. as electronics engineer i try to look past the broken capacitors this time. ;-)
Last action to fix this was replacing the crack shaft hall sensor. (and oil seal, that came off with the pulley....)
It all was very dirty due to leaking oil seal and leaking power steering system.
I was not able to remove engine but removing the Aircon pulley give enough space to work.
I'm cleaning up a Viggen seat install here, and find myself scratching my head on the wiring. I'd love to get heated seats given the temp here in Alaska. :)
Prior install tapped into the heated seat wiring to power the motors, so I'm looking to properly hook it up this time. I found some...
Saw an ad for this thing on CL, and I was worried it was gonna end up in a junkyard so I drove the 40 miles to tow it home.
And you're like, "Ah, it's a bit faded but not so bad." But, it's pretty bad.
It's absolutely bonkers to me, but someone actually cut off a damaged fender and...
My dad recently visited and we FINALLY got around to replacing the rock hard front brake hoses. We bought all four a year ago, replaced the rears and then were hesitant to do the fronts in fear of mangling the little brass fittings that join the hard lines to the soft lines.
We found a pair of...
In the rebuild of my front-end bingled 2.1 sedan, I've now got to to the point where most of the re-assembly is done, and I'm fitting a spare set of headlights salvaged from another slope-front c900.
I found one of the lights (the RHS one) has a broken adjuster. I note that Bill from Saabits...
Hi everyone. Its mid summer here and the Saab is running beautifully about to turn 240k.
I am replacing my passenger side headlight lens assembly and its not totally apparent how this thing comes apart. I searched here and found a couple threads but didn't find anything that answers my...
SaabCentral forum the most comprehensive Saab resource on the internet. Join our discussions on the Saab 9-3, Saab 9-5, Saab 900, Saab 9000 and all other Saab models, choose your forum.
