90 LeSabre Intermittent Stalling, SEL, Temp Lights
timrice
12-05-2003, 12:27 AM
My '90 has 274K on it, and has been generally reliable. But this a.m. I hopped in, drove about 8 mi. towards work at 55 mph, and the TEMP and Service Engine lights flickered, the engine stuttered then died, and the dash lights stayed on. I coasted it off on the shoulder, popped the hood, and found no evidence of an overheat. The radiator cap was warm (not hot) to the touch. The heater was working fine. Oil level was right where it should be - changed it Sunday. I got back in, keyed it on, and the engine started, the dash lights came back, and the engine sputtered and died again. Hopped a ride w/a friend to work, then came back after work for the car. Predictably, it started right up, no warning lights, and I drove it straight to the house. Just as I approached my driveway, it happened again. I coasted it up to my shop, and turned the key off. I keep a paper clip in the car to probe the ALDL for codes, and I'd been wondering all day what code it had set. When I probed it, all I got was "12" over and over, with no codes listed! This seemed odd since it just appeared that less than a minute before it had set one. (If I'm not mistaken, the only way for the ECM to forget/clear stored codes is to unhook the neg. battery terminal for 30 sec, and possibly auto-clear after x# of engine starts without a repeat occurrence) So then I put the key back in the switch, turned it on, and the engine fired right up. I sat in the driveway with the engine idling for 20 minutes, and not a peep out of it--ran perfect. Needless to say, if the ECM is trying to tell me the car is overheating, it's getting pretty hard to buy that. Especially when the radiator fan (which I know works when the ALDL is shorted) doesn't come on.
At the risk of boring you to death or annoying you with such a lengthy post, I must include the fact that last winter, on a fairly cold day (10F), this car did something quite similar...the TEMP and SEL lights came on, and the engine died. I think in this case, though, the car went into "limp-home" mode or something. Out on the road, I could find no sign of an overheat, and rather than freeze to death, I drove it on to work about 5 mi. at the very low speed it limited me to. I did find a thermostat that had stuck shut, and the coolant was a bit low (shame), so I was willing to believe it could have been hot. After a new 'stat and topping off coolant, the car would still buck occasionally at highway speed. I pulled codes, and got an EGR-check "63." I took the EGR off the block, cleaned things up a little, and put it back on. With it being winter, I parked the car until spring since I didn't trust it, and drove my "spare" '89. In April, I got it back out again, and drove it with no reoccurrence of this problem until today. Between then and now, all I've done is put on a new battery (April), and a new 02 sensor (Sunday) to take care of a 13 code, plus oil/filter changes. Whether today's incident and last winter's are related, I'm not sure. It does seem coincidental that the problem occurs in cooler weather. (today it was 30-ish, not 10, though.)
Don't think I ever lost the main battery connections - the headlights and interior lights never wavered. Is it possible the ECM lost its connection to the battery? Bad ECM altogether? Why would a true overheat condition cause the engine to die without warning? That doesn't make a lot of sense.
I had to laugh at the fact that the car crapped out twice today going out and coming back home at the same distance traveled, almost down to the exact foot...that's cosmic.
My friends shake their heads at me and mock me for driving such a "beater." I feel a little better though when they have to take their new cars in for costly repairs *and* make $400/mo payments to boot! With the 300K-mile mark within reach, I really hate to put a bullet in this one, so any advice I can get will be appreciated!
At the risk of boring you to death or annoying you with such a lengthy post, I must include the fact that last winter, on a fairly cold day (10F), this car did something quite similar...the TEMP and SEL lights came on, and the engine died. I think in this case, though, the car went into "limp-home" mode or something. Out on the road, I could find no sign of an overheat, and rather than freeze to death, I drove it on to work about 5 mi. at the very low speed it limited me to. I did find a thermostat that had stuck shut, and the coolant was a bit low (shame), so I was willing to believe it could have been hot. After a new 'stat and topping off coolant, the car would still buck occasionally at highway speed. I pulled codes, and got an EGR-check "63." I took the EGR off the block, cleaned things up a little, and put it back on. With it being winter, I parked the car until spring since I didn't trust it, and drove my "spare" '89. In April, I got it back out again, and drove it with no reoccurrence of this problem until today. Between then and now, all I've done is put on a new battery (April), and a new 02 sensor (Sunday) to take care of a 13 code, plus oil/filter changes. Whether today's incident and last winter's are related, I'm not sure. It does seem coincidental that the problem occurs in cooler weather. (today it was 30-ish, not 10, though.)
Don't think I ever lost the main battery connections - the headlights and interior lights never wavered. Is it possible the ECM lost its connection to the battery? Bad ECM altogether? Why would a true overheat condition cause the engine to die without warning? That doesn't make a lot of sense.
I had to laugh at the fact that the car crapped out twice today going out and coming back home at the same distance traveled, almost down to the exact foot...that's cosmic.
My friends shake their heads at me and mock me for driving such a "beater." I feel a little better though when they have to take their new cars in for costly repairs *and* make $400/mo payments to boot! With the 300K-mile mark within reach, I really hate to put a bullet in this one, so any advice I can get will be appreciated!
edg
12-05-2003, 06:21 PM
My '91 had a similar problem. My wife and I used to joke that we could take it anywhere, as long as anywhere was within 5 miles of home. If we let the car set for 1/2 hour or so, it would go another 5 miles before stalling. We had it in to several repair shops and spent a lot of money with them on plugs, plug wires, coolant temp sensor, cam position sensor, thermostat, etc.
Eventually, I took a crack at it myself and discovered the water pump was defective. Replaced the water pump and flushed the radiator and now we really can drive anywhere. We've gone as far as 300 miles without a problem.
Eventually, I took a crack at it myself and discovered the water pump was defective. Replaced the water pump and flushed the radiator and now we really can drive anywhere. We've gone as far as 300 miles without a problem.
timrice
12-06-2003, 01:32 PM
Hmm...that's interesting, edg. The water pump does have 120K on it. (which seems like more than one has any right to expect...) If the water pump weren't circulating coolant, it would tend to explain the "TEMP" light business... The only way I've ever seen these water pumps fail, though, is a) when the bearing goes out--makes noise, pulley has excessive play; or b) when the weep hole starts weeping. I don't believe this one is doing either, but I can certainly check. Is there another failure mode for water pumps? edg, did you get dash lights and stored codes when this happened to you? (I'm still hung up on the fact that the SES and TEMP lights came on during the stall, yet the ECM reports no codes.) The latest is that I just took it out and drove 10 mi. or so and had no problem--ran great.
RABarrett
12-11-2003, 08:21 AM
Guys, the temp light illuminates in response to a ground on the temp light line, whether from the sensor grounding the connection or the ignition circuit in the dash. Both of these come from the ECM, which I would , at this point, give the hairy eyeball. Since the engine had not overheated, I suggest that the sensor was giving false indications, or the ECM is responding incorrectly. A scan done during the crisis will offer a clue here. Ray
timrice
12-12-2003, 08:26 PM
Thanks for the reply, Ray. I have a nagging feeling it's the ECM, too. The other night it was pretty chilly out, so I started it up and let it idle in the driveway, with the heater maxed out, and after 15 minutes, it was still running fine w/no dash lights. I suppose my next course of action is to check the wiring on / replace the coolant temp sensor (I'm guessing that's about $25-30) and try driving it some more on nicer days when I won't freeze to death walking to the next farmhouse... I could set up a test for the temp sensor where I work to see how the voltage output changes with temperature. I don't know if it's a positive thermal coefficient (PTC) or negative thermal coefficient (NTC) thermistor, but it's about got to be one or the other. I wonder if the ECM has an internal pull-down resistor that would "ground" the ECM's coolant sensor input if the sensor circuit went open. I know some off-road vehicle controllers (my line of work) operate that way. If it does, and the sensor is PTC-type, then an open sensor circuit would look like a "hot" temperature to the ECM. Why this condition winds up completely killing the engine, I'm not sure. I could understand limiting throttle in an "engine hot" scenario, but the engine kill I get with this problem makes me think it could be more than just a flaky temp sensor circuit.
I believe I've located the sensor on the top of the block by cyl. 6. Not sure how hard it's going to be to get out of there.
Beyond that, it's probably another trip to the salvage yard--and I certainly know the way--to see how much they want for an ECM.
(Surely less than $100 for an oldie-but-goodie?)
Just out of curiosity, would my '89 LeSabre's ECM work in my '90? (My '89 has been intermittently running rough--see separate thread--and maybe I can make one good car out of two questionable ones...) I'm not scared of changing EPROMS if that's part of swapping ECMs.
- Tim
I believe I've located the sensor on the top of the block by cyl. 6. Not sure how hard it's going to be to get out of there.
Beyond that, it's probably another trip to the salvage yard--and I certainly know the way--to see how much they want for an ECM.
(Surely less than $100 for an oldie-but-goodie?)
Just out of curiosity, would my '89 LeSabre's ECM work in my '90? (My '89 has been intermittently running rough--see separate thread--and maybe I can make one good car out of two questionable ones...) I'm not scared of changing EPROMS if that's part of swapping ECMs.
- Tim
joshey
12-17-2003, 06:02 PM
sure swap the brains, but another sugestion, when did you put a new fuel pump in, is the fuel filter new? thats the smptoms my car had, i changed the computer, icm, eprom and maf. to no advail, so i went to change the fuel filter, it was from the factory and still there 230,000 later. when i tried changing it i cracked the line i chased the line up to the tank, by now i cut the straps, and droped the exaust. then i decided to change the sock. long story short it was the sock or the fuel pump but it was definatly heating up then loosing power missing at highway speeds, unfortionally i replaced the injectors first(ever see someone jumping on a fuel rail in front of autozone? turns out all you need is engine oil *duh* but if you never did the pump i would!
timrice
12-17-2003, 07:28 PM
In response to joshey: The fuel filter has about 35K on it, and the fuel pump--amazingly enough--has at least 130K on it. The fuel pump was looked at 35K ago, because the level sender was replaced then; apparently the tech thought it was still good to go at that point... Guess I could hook a fuel pressure gauge, go sit in the driveway and watch it idle to see if the pressure's goofy or starts dropping off after a bit.
joshey
12-18-2003, 02:15 PM
good idea but i only saw it on long trips at first after the pump got hot and i could rev the motor all day with no sputter, but i dident have a guage so its something to try.
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