94 Lesabre stalls on road maybe bad connections. - Page 2 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


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Old 08-25-2015, 01:01 AM   #11
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Okay, they must have changed it since '93 then. This is my configuration:


The bolt in the center between the two banks of fuses bolts the cable terminal to the hot rail, and it'* hot at all times, and from there, is a large fuse labeled ignition switch which I assume runs inside.
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Old 08-25-2015, 02:11 AM   #12
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The pictures look to be similar to what is there on the '94. In the manual there is no connection I can see to the always hot rail to the battery. The manual shows a 60A fuse between the ignition switch and the battery and there is one 60A fuse labled Ig SW. this is likely to be the connection to the always hot rail. The bolt shown in the middle must be always hot too. My manual is not helping me as much as it should.

94 Le Sabre 252 Fuel ups
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Old 08-26-2015, 03:10 PM   #13
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What brand of Crank POS should I buy. The last time I bought a BWD brand and if it is indeed the problem, the BWD Crank Pos. Sensor lasted only about 1.5 years. Not good enough. I have not yet exhausted checking on the wiring connections so I have not gone out and purchased a CPS yet. I am tempted to throw in the original as changing the BWD did nothing for the other problem I was having at the time. That was likely the Ig. Control Mod. One thing that is worrying is the other symptoms that are going on that would seem to indicate a bad connection. Could it really be the ECM/PCM behind all of it? And how would you know?
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Old 08-26-2015, 11:50 PM   #14
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The easiest way to tell usually is to put a scanner on the computer and see what is going on. Bad PCMs do all kinds of things when they fail, and usually have you chasing gremlins all over the place.

If you can find a salvage unit, it may be worth considering, if anything, to have as a spare. To be clear, I am not saying to run out to your local parts chain store and buy one now.
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Old 08-28-2015, 10:06 PM   #15
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Yes it seems to work better using the Firefox browser. Firefox resizes the photo a lot faster than IE. Easier to sign in also. Been too busy lately to work on the car. Maybe tomorrow... does anyone know what brand is the OEM Crank POS sensor?

where do you go to get the fuel economy widget?

Jimmy544 94 Lesabre 3800 with 107000 miles
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Old 08-31-2015, 01:59 AM   #16
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Tried to drive the Buick a short distance had much trouble starting. There was this buzzing or rattling kind of sound behind the glove box. While this was happening there was no start though the starter motor was cranking the engine vigorously. I was able finally to start and it tried to die several times in the driveway but I kept it going and seemed to stabilize. I was able to drive a few blocks where it died and I have not been able to restart it since. There are lots of symptoms like I have described before such as the flickering dash lights, coolant fans switching off and on cyclicly. This time I thought I could hear the fuel pump cycling on and off also. I put an Acuratron CP 9190 scannner on the port and it was unable to establish communication with the system. This would seem to indicate a problem with the PCM/ECM, a poor connection to the scanner or no or low power to the PCM/ECM.

The dash lights are controlled by the PCM/ECM. The fan motor relays are controlled by the ECM/PCM. The fuel pump relay is controlled by the ECM/PCM. All of these were doing something unusual as well. So it would seem that either the power input to the PCM/ECM or the PCM/ECM itself that is the fault. Power input to the PCM/ECM is not clear in my schematics. I need to check that there is spark at the plugs during cranking as there should be with a working Crank Pos Sensor. The battery voltage is somewhat low at 12.3 volts. It is lower when the dash lights are flickering and the fan motors are cycling on and off.

Is there any way that a bad Crank Pos sensor could cause the problems that I am seeing? It will be another week until I can work on it again.
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Old 08-31-2015, 11:37 AM   #17
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You will have no idea what is causing your problems until you get the charging system working up to spec. A weak charging system will affect all sorts of electrical functions, and you won't know if you are trying to fix issues that are only issues because the charging system is not functioning properly.

Check the grounds, check the battery cables, check acid level in the cells, have your battery load tested, and (if necessary) change the alternator.
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Old 08-31-2015, 02:03 PM   #18
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Quote:
Originally Posted by 2kg4u View Post
You will have no idea what is causing your problems until you get the charging system working up to spec. A weak charging system will affect all sorts of electrical functions, and you won't know if you are trying to fix issues that are only issues because the charging system is not functioning properly.

Check the grounds, check the battery cables, check acid level in the cells, have your battery load tested, and (if necessary) change the alternator.
Battery is now charging was run down by cranking and emergency flashers. Battery did pass a load test a week or so ago. The fluid levels are up. The battery is almost exactly 5 years old and has 72 mo. warranty. Never had problems that I know of before. The alternator is Bosch unit replaced at 51,000 miles and 4 years ago. the car now has 107,000 miles. The alternator puts out between 13.8 and 14.4 volts depending on load. Did I miss something.
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Old 08-31-2015, 08:24 PM   #19
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Just grasping at straws here, but it never hurts to re-seat the wiring connectors on the PCM.

I would wait until the car is playing nice (maybe first thing in the morning?) and see if you can pull any codes off of it then, which there probably won't be if the battery was just out, or at least there shouldn't be.
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Old 09-14-2015, 10:31 PM   #20
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Ok began to work on the car again as I now have some time for it. There appears to be no change from a week or so ago; whatever has failed now seems to be a complete failure now not intermittent. Again the starter motor cranks the engine lustily but the car will not start. Again there are flickering dash warning lights and a vague rattling sound under the front passenger dashboard. I did not hear the fuel pump start however it is a faint sound and I may have missed it.

I checked for spark and it appears that there is spark at two separate coils. I sprayed some starting fluid into the air cleaner and cranked it. The engine started and ran for a very short time and died. I repeated this action twice and confirmed that the engine would start if there was fuel. So I am not getting fuel into the cylinders. Since I did not hear the fuel pump running this is not surprising. I believe this testing result eliminates the Crankshaft Position Sensor since if it was bad there would be no spark. This also eliminates the Ignition Control Module since if it was bad there also would be no spark. As I understand the engine starts on Ignition Control Module and the Crankshaft Position Sensor alone with of course some gas from the injectors which are not operating or are not getting gas because the fuel pump I believe is not running. Looking over the circuitry I see there is a signal from the Ignition Control Module to the ECM/PCM that I still need to check.
Tomorrow I will look for the fuel pump signal from the Ignition Control Module and clean, with electronic contact cleaner, and reset the connectors on the ECM/PCM. I believe that this unit is under the dash on the front passenger side. I do not expect that this is the problem but it is certainly worth checking.
Then I will check the power wiring to the ECM/PCM and the relays and fuses for bad connections. Failing this I have no idea what else to try other than a new ECM/PCM which has been said to be the very last thing to try.

Anyone have any better ideas?
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