Date: Sun, 08 Jun 2003 16:13:46 GMT From: "John T. Slodyczka" <masniak2nopsamast.net> Subject: Re: 1987 9000S Blowing ECM HELP!!!!
I just put in the old ECU that i had fixed up (burnt track on the circuit board that i jumpered and a bad chip). When I put it in, the fuel pump started for a little bit then quit and smoke was billowing out of the ECU. When I took it out and examined it, I found that it burnt the track further along (i jumpered that bad part with 22 awg last time) and completed frying the bad chip. All this leads me to believe (due to simple electrical theaory, once again not familiar with electronics) that there is still a short somewhere in the system. Or is it that the bad chip (didn't fix it cause didn't have another) caused the further frying , though the pump did work for a little bit. What do you think? I'm almost at the point of just taking and examining every inch of that wiring harness. thanks in advance, John "KeithG" <noonenopsamspring.com> wrote in message news:3EE33BC8.6030605nopsamspring.com... > The way the system works is that the ECM (ECU) pulls down a ground on > the fuel pump relay which feeds a 12V source to the fuel pump. This > should run the fuel pump. Now, I think the LH2.2 ECU that you have (I am > not too sure) requires a pulse train indicative of ignition before it > will pull down the ground on the fuel pump relay. > > It could also be the fuel pump itself. When it is cranking, does the > tack needle wiggle? If so, you have an ignition pulse train. See if the > ground is supplied to the fuel pump relay (Pin '86' I think) while it is > cranking. ( This may indicate a need for an ECU, but these are very > robust - also check to see that the ECU relay gets 12V to the ECU) If > so, then check to see if pin 87 on the relay is getting a 12V signal. > (If not, you need a fuel pump relay). Then check for that at the fuel > pump itself. (If so, you need a new fuel pump). > > Check the www.townsendimports.com website for technical documentation on > the electrical system as well. > > Keith > > MarkC wrote: > > I've got a 87 9000S (I'm much more in love with my Classic 900 though) > > but I just got it so I'm not that familiar with it. Try doing a Google > > search on 'saab ecm' > > (I just did & got 295 hits). Also try the saab.net. It would also be a > > good idea to get a service manual so check your library. Instead of > > taking it to a dealer try to find a competent (via referrals) > > independent import auto repair shop > > (which you can do by posting here or at saab.net). You could take it in > > for an estimate & then fix it yourself after they tell you what's wrong > > with it (sometimes this doesn't work because they won't divulge all of > > the details). > > Mark > > > > > > "I really love this saab that I received for near nothing with the > > condition that the fuel system is not running and and if i can fix it > > its mine. Let me reiterate that I love this car. But alas, as for most > > people money is a problem so I would prefer not going to a dealer if I > > don't have to. I though I had the problem licked when I found some bad > > insulation on some wires and respliced them. BTW I am an electrician so > > I am proficient with a tester but I do not know much about electronics > > and I do not have/cannot find electrical diagrams to this car. Anyway, I > > got a new ECM plugged it in got the fuel pump working actually got the > > car to start and while it was running, all of the sudden, the fuel pump > > stopped running and the car died immediately. This leads me to believe > > that I fried the new ECM. Now my question is, should I be looking for > > more bad wiring possibly in the fuel pump and/or injector circuits or > > could this be the fault of a bad sensor or whatnot? The reason I ask is > > that the car was running for a little bit before it just stopped > > suddenly so i'm not sure if some sensor or relay or something kicking in > > didn't cause the sudden burn-up. Any and all help will be greatly > > appreciated. > > Thanks in advance for the help, > > John" > > > > > > > > >
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