94 Lesabre stalls but starts right back up

xbassman

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94 Buick Lesabre 4 Dr limited V6
94 Lesabre, 81k orig miles, 3.8 v6. Engine will stall while driving, no pattern, might happen once a month, twice a month or once in 5-6 weeks. Here is what I have replaced...fuel filter twice, new in tank fuel pump, new plugs n wires, new battery, new ignition control module, new valve cover gaskets n grommets. Engine performs great, 24 mpg. An off wall guess......seems like there is a interruption in the fuel flow, lack of fuel to injectors...thus the stall???? When it does stall I shift into neutral, start engine (starts up every time), drop onto Drive and away I go. Could one of the relays on the firewall under hood on passenger side be the culprit? Need help. Dennis in Texas
 

Alan 55

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Florida
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2001 Buick Park Avenue, previously owned 1997 Park Avenue
94 Lesabre, 81k orig miles, 3.8 v6. Engine will stall while driving, no pattern, might happen once a month, twice a month or once in 5-6 weeks. Here is what I have replaced...fuel filter twice, new in tank fuel pump, new plugs n wires, new battery, new ignition control module, new valve cover gaskets n grommets. Engine performs great, 24 mpg. An off wall guess......seems like there is a interruption in the fuel flow, lack of fuel to injectors...thus the stall???? When it does stall I shift into neutral, start engine (starts up every time), drop onto Drive and away I go. Could one of the relays on the firewall under hood on passenger side be the culprit? Need help. Dennis in Texas
Thanks for providing quite a bit of info in your message. I agree with Homer Jay that it could be the MAF and that cleaning with the specific cleaner is the only way. Beyond this, you mentioned the relays on the firewall. I would locate the fuel pump relay and swap it with another relay that has the same part number. It is a long shot but worth a try. The next item is more difficult to arrange and safety must be given the highest priority. I am speaking of the option of rigging up a fuel pressure gauge that you can monitor from the drivers seat. When a stall occurs, note the fuel pressure. If no loss of pressure, we turn to the ignition.
 

2007LucerneCXL

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2007 Lucerne CXL. and 1995 Lesabre currently, past 1973 Riviera, 1968 Riviera
ICM and coils could also give a intermittent shut down even if they are new replacement parts. Unfortunately it is depending on the vendor and that doesn't always mean good or long lasting. Check the ICM wiring harness connector, burn or corrosion on the parts.
 

LARRY70GS

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98 Riviera, 70 GS455 Stg1
Engine stalls due to fuel are never instant. As fuel pressure drops, the engine will typically surge or buck for a bit, then stall. Ignition faults can create instant stall. Biggest cause is crankshaft position sensors. You'll need to pull the harmonic balancer to replace it. Have a look at the balancer, make sure it isn't wobbling while the engine is running.

The MAF can make the engine run very rich choking out the engine. Cleaning them doesn't hurt, just use the cleaner intended for them.
 

xbassman

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94 Buick Lesabre 4 Dr limited V6
The crankshaft position sensor and harm balancer was next on my list. Only question I have is....can they in conjunction cause such a random problem? Balancer does not wobble when motor is running. The engine does stumble just prior to the stall, not bad, sort of feels like a miss n instant stall. Re coil packs, I believe they either work or not....no intermittent fire/no fire. Bought best brand of ICM n used dielectric grease. Gonna clean MAF tom., have proper spray cleaner. This has frustrated me since I got this barn find going. Just cant trust her in a passing situation where it might stall or being in the fast lane I10 downtown Houston, Texas and it stalls 😰.
 

HotZ28

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Has the MAF ever been replaced? If so. what brand?
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xbassman

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94 Buick Lesabre 4 Dr limited V6
Has the MAF ever been replaced? If so. what brand?
Stock. As I mentioned, she is a barn find 2 yrs ago with 58k orig miles. A Granny bought it new, maintained well till her kids said "no more driving". Sat in here garage for years till I found it...$200.00. Her kids did start n drive it around the block once a month, even kept up the registration!!! The MAP, CPS, EGR, etc are all original equip.
 

xbassman

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Buick Ownership
94 Buick Lesabre 4 Dr limited V6
Stock. As I mentioned, she is a barn find 2 yrs ago with 58k orig miles. A Granny bought it new, maintained well till her kids said "no more driving". Sat in here garage for years till I found it...$200.00. Her kids did start n drive it around the block once a month, even kept up the registration!!! The MAP, CPS, EGR, etc are all original equip.
Ment MAF
 

xbassman

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94 Buick Lesabre 4 Dr limited V6
Also coil packs are original, did replace the Ignition control module .. the stall prob occured prior to ICM replace and in tank fuel pump replace. At a loss to say if its elect or mechanical?
 

LARRY70GS

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98 Riviera, 70 GS455 Stg1
MAF problems usually don't show themselves except at operating temperatures. When the engine is cold, the sensors are open loop. When the MAF fails, they usually tell the PCM that there is more air going into the engine than there actually is. The PCM ramps up fuel injection and floods the engine out. Then the engine will start and stall until the engine cools down enough. In a situation like that, you can disconnect the MAF and the PCM will make a guess on fuel injection based on the other sensor values. The engine will not run as efficiently, but it will run and drive.

The OP's problem sounds like the crank sensor to me. Sudden stall at speed? I don't see that being the MAF.
______________________________
 

xbassman

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94 Buick Lesabre 4 Dr limited V6
A
MAF problems usually don't show themselves except at operating temperatures. When the engine is cold, the sensors are open loop. When the MAF fails, they usually tell the PCM that there is more air going into the engine than there actually is. The PCM ramps up fuel injection and floods the engine out. Then the engine will start and stall until the engine cools down enough. In a situation like that, you can disconnect the MAF and the PCM will make a guess on fuel injection based on the other sensor values. The engine will not run as efficiently, but it will run and drive.

The OP's problem sounds like the crank sensor to me. Sudden stall at speed? I don't see that being the MAF.
Agree. Stalls have occurred 100% after engine has reached operating temp. At 70 mph with cruise on, making a left turn after red to green light @ 4-6 mph, 35 mph in town driving. As u can see.....no pattern. I have calculated mpg since purchased and 23-24 mpg is magic consistent number. Being a barn find can be a bad thing as gremlins love cars that just sit. So...crank pos sensor n balancer are next big ticket item.
 

xbassman

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94 Buick Lesabre 4 Dr limited V6
Checking relays, looking for fuel pump one. Can anyone ID each one for me. First one on left....I took it out n forgot to put back for picture.
 

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Mad_Coachman

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2002 LeSabre Limited
MAF problems usually don't show themselves except at operating temperatures. When the engine is cold, the sensors are open loop. When the MAF fails, they usually tell the PCM that there is more air going into the engine than there actually is. The PCM ramps up fuel injection and floods the engine out. Then the engine will start and stall until the engine cools down enough. In a situation like that, you can disconnect the MAF and the PCM will make a guess on fuel injection based on the other sensor values. The engine will not run as efficiently, but it will run and drive.

The OP's problem sounds like the crank sensor to me. Sudden stall at speed? I don't see that being the MAF.
I've had sudden stalls while driving. Was a flaky ICM. What brand of ICM was used?
 

Mad_Coachman

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Baldwin, New York
Buick Ownership
2002 LeSabre Limited
The crankshaft position sensor and harm balancer was next on my list. Only question I have is....can they in conjunction cause such a random problem? Balancer does not wobble when motor is running. The engine does stumble just prior to the stall, not bad, sort of feels like a miss n instant stall. Re coil packs, I believe they either work or not....no intermittent fire/no fire. Bought best brand of ICM n used dielectric grease.
Original coil packs may be damaging the replacement ICM. What brand of ICM did you use?
______________________________
 

Alan 55

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Florida
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2001 Buick Park Avenue, previously owned 1997 Park Avenue
Checking relays, looking for fuel pump one. Can anyone ID each one for me. First one on left....I took it out n forgot to put back for picture.
Is there a diagram on the plastic cover that shows this info? Another possibility is the owners manual, if you have that. I understand that the owners manual is a free download but I do not have a link, perhaps google would help.
 
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