Date: Thu, 14 May 1998 22:40:46 +0100 From: "Tim Ricketts ,Wales, UK ." <rickettsnopsamil.com> Subject: Re: Need Help Figuring out 1987 900T Puzzling Behavior
dbled wrote: > > I just recently discovered this group and have been lurking here a week > or so and thought I’d ask for some advice, opinions, or at least for > some sympathy about an intermittent problem I’ve been having with my > 1987 900T that’s been driving me and my mechanics crazy. > When the car is cold, it always starts and runs OK. > When I’m having the problem, the engine will momentarily cut-out as the > engine starts to warm up (it starts about the time the temperature gauge > starts to move towards operating temperature). This engine cut out only > happens when there’s a constant load on the engine. It happens at any > engine rpm and in any gear as long as there’s a constant load on the > engine. The engine never cuts out when there’s a load on it (i.e. > during acceleration, going up hills, etc.). it makes no difference > whether the cruise control is on or off, the behavior is the same. This > engine cut out continues as the engine reaches operating temperature. > During this time, the engine isn’t constantly cutting out. It will run > OK for a few minutes and then go into the cut out mode for a while and > then run Ok for a while. On 3 or 4 occasions (over a couple of years > time), after I’ve parked the car (with a warm engine), it won’t restart > unless I let the car set until the engine cools to ambient and then it > starts right up. It may or may not exhibit the cut out behavior after > restarting > The best description of engine cut out is a momentary (half-second or > less) shut-off of the engine. It’s as though the ignition switch is > quickly turned off and on. There’s no backfiring and the engine doesn’t > stumble or act as if it’s running out of fuel; the engine seems to be > either fully on (and running OK) or off. It may cut out once or twice > and then run Ok for a while or it may cut out 5 or 6 times (resulting in > a lot of jerking) before it settles down. > What’s particularly aggravating is that this behavior is erratic. I > might go months with the car running perfectly and then I’ll get a rash > of this engine cut out behavior for a while (a few days to weeks) and > then the car will run fine for until the next episode (anywhere from a > few weeks to months). > I’ve taken the car to several garages (including the Saab dealer) when I > ’ve been having this problem and of course, they can never duplicate it > and they can’t fix what ain’t broken. On several occasions they’ve kept > the car for a few days trying to get it to misbehave. They swear they’ > ve done all the normal inspections, maintenance routines and replacement > of fuel filters etc. I’ve also gone through the "bad" gas, water in the > fuel, dirty injectors and other scenarios and still have the problem > It strikes me that the problem is electrical (because of the nature of > the engine cut outs) and its relation to engine temperature could point > to some component sometimes failing when it gets warm. The intermittent > nature of the problem is puzzling as is the fact that only constant load > engine operation is affected. > I’m sure there’s a clue or two here but we aren’t smart enough to figure > out what they mean. Anybody out there have any thoughts? > Otherwise I guess I’ll just keep truckin until something breaks. I think the ignition module or fuel pump relay is most likely at fault. The fuel pump won't run unless it gets pulses from the ignition (via the fuel pump relay).So,if the ignition is faulty the pump will also stall momentarily.The symptoms you describe are often associated with faulty ignition modules.Email me privately for more if you need it.
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