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Engine will not start?

Tiny
CHARLES STEELE
  • MEMBER
  • 1995 BUICK LESABRE
  • 3.8L
  • V6
  • 2WD
  • AUTOMATIC
  • 106,000 MILES
Fuel pump went out and it set for two years. Replaced pump and assemble new supply and return line new filter and clean fuel. Engine turns over and will not fire except at full throttle it tries but only on some cylinder not all. Then shuts off. Can injectors be stuck?
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Friday, February 14th, 2020 AT 7:07 PM

79 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
It definitely sounds like it is getting too much fuel. When you are holding the accelerator down to the floor, you are entering what is called clear flood mode. Basically this tells the PCM to cut the injectors off. If it is still not running on all cylinders then I suspect those injectors are still dumping fuel or there are other issues.

I would suggest starting with pulling the plugs and seeing if they are fouled. If they are wet or smell like fuel after cranking this way then it is still dumping fuel. The reason it starts this way is because it is getting fuel but when you cut the injectors, the plugs are able to fire with the remaining fuel in the cylinders.

Let me know what you find with the plugs and we can go from there.

Lastly, if it sat that long, I would put new plugs in it when you pull them all out since they are coming out anyway.
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Friday, February 14th, 2020 AT 7:26 PM
Tiny
CHARLES STEELE
  • MEMBER
  • 37 POSTS
Plugs were dry but black this morning when I pulled them, but it set all night fuel pressure had dropped to 0 overnight as expected. Does the 1995 have obd2? It has a plug but my reader just gives me a connector error will not read anything. I know some 1994 and 1995 do but some don't. I just have a cheap code reader. Check engine light is on but engine is not running. According to the Buick book I have it can be on when engine is not running and have no codes I have not worked as a mechanic since the late 1970's in automotive but worked on plant maintenance at a explosive plant. So I am not up to date on this computer cars and only work on my own stuff and that is getting harder because I am as old as dirt.
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Saturday, February 15th, 2020 AT 6:16 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
You have an OBD 1 vehicle and to confirm this you should have a connector that looks like the attached picture. In order to retrieve the codes, you need to jump the two terminals together and then count the flashing check engine light.

It should flash once, pause, then flash a certain number, pause, then repeat. It should flash 1-2 three times then give you all the actual codes, then flash 1-2 three more times. The 1-2 are the opening and closing codes and they don't mean anything other than to tell you all the codes have flashed.
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Sunday, February 16th, 2020 AT 9:35 AM
Tiny
CHARLES STEELE
  • MEMBER
  • 37 POSTS
Just checked my car has a 16 pin and the GM manual I have shows that it could have a 12 or 16 pin and is not flash capable. But my obdii wont read it. Just a cheap one of Amazon. But the manual says that the check engine light should be on with key on engine not running. So I need to go from there. I will get some new plugs tomorrow in town and replace them and see if it will start then. When I was trying before I added a can of sea foam to the gas to maybe free up the injectors after two years could not hurt I guess.
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Sunday, February 16th, 2020 AT 3:57 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
From what I can tell, your vehicle has a 12 pin connector which means it is an OBD 1 which is why your OBD II reader won't work.

Let me know what happens with the plugs and we can go from there. Thanks
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Monday, February 17th, 2020 AT 4:26 PM
Tiny
CHARLES STEELE
  • MEMBER
  • 37 POSTS
Going to get new plugs today. It is a 100 mile trip to town so it will take all day. But the connector is a 16 pin. I would send a picture but I don't have any way to get it on the computer.
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Tuesday, February 18th, 2020 AT 11:31 AM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Wow. I thought I lived out there.

If it is a 16 pin, I would think it is an OBD II vehicle but I could be wrong. Keep us updated. Thanks
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Tuesday, February 18th, 2020 AT 4:26 PM
Tiny
CHARLES STEELE
  • MEMBER
  • 37 POSTS
It is a 16 pin but GM manual says it is obd 1. Put in new plugs and got it started but only at full throttle and it runs rough and surges up and down and backfires shuts off if you back off of throttle at all. I think it needs new injectors maybe. Fuel pressure on gauge stays at about 40.
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Wednesday, February 19th, 2020 AT 1:14 PM
Tiny
KASEKENNY
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Yes. I would agree that the injectors sound like they are stuck open. Holding the accelerator to the floor is called a clear flood which means it cuts the injector pulse width. The fact that when you remove your foot it stalls just shows that it is too much fuel. I would try not to start it too much until you figure it out or you will foul the plugs again. Black plugs as you found earlier is a sign of carbon fouling which is caused by excess fuel.

If it were me, I would put injectors in it at this point.
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Wednesday, February 19th, 2020 AT 6:16 PM
Tiny
CHARLES STEELE
  • MEMBER
  • 37 POSTS
I will have to let I go until payday. Injectors not cheap. Try that on the first.
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Thursday, February 20th, 2020 AT 8:31 AM
Tiny
TOUGHDIVER
  • MECHANIC
  • 224 POSTS
Hello,

It also could be a Mass Air Flow Sensor. a quick check for this is unplug it and start it up should change the way it runs. It could also be the Engine Coolant Temperature Sensor reading a really low temperature. check it the same way. I'm attaching component location and repair guides below let us know if this was helpful.

https://www.2carpros.com/articles/how-to-replace-a-mass-air-flow-sensor-maf

https://www.2carpros.com/articles/symptoms-of-a-bad-coolant-temperature-sensor

Thanks
Joe T.

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Thursday, February 20th, 2020 AT 1:00 PM
Tiny
KASEKENNY
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Good point Joe. Thanks. The ECM determines fuel pulse widths based on amount of air (MAF) coolant temp and a couple others. Good easy test. Let us know what happens. Thanks.
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Thursday, February 20th, 2020 AT 6:40 PM
Tiny
CHARLES STEELE
  • MEMBER
  • 37 POSTS
I will try that when I get home Monday. Had to go to the grand kids for a couple days.
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Friday, February 21st, 2020 AT 4:34 PM
Tiny
KASEKENNY
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Sounds great. Grand kids need attention too. Enjoy. We will be here when you get to it. Thanks
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Friday, February 21st, 2020 AT 5:43 PM
Tiny
CHARLES STEELE
  • MEMBER
  • 37 POSTS
Unplugged MAS it starts and run okay. Cleaned MAS and that did not fix it so replaced it. Running okay now. Have to run a few miles and see how it works out it had set for 2 years before I got it with a bad fuel pump that I also replaced. Thanks for your help.
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Friday, March 20th, 2020 AT 4:10 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
That is great. Thank you for the follow up. Please come back to 2CarPros next time.
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Friday, March 20th, 2020 AT 4:16 PM
Tiny
JOHN MESNER
  • MEMBER
  • 3 POSTS
  • 1995 BUICK LESABRE
  • 3.8L
  • V6
  • 2WD
  • AUTOMATIC
  • 50,000 MILES
Changed the fuel pump and filter, cam sensor, battery, crank sensor, and checked the wiring. It still won't start,
it has spark, it dose not have injector pulses. We checked the codes with a tek 2 no codes but the car would run with the tek 2 attached, we took the tek 2 off and the car would not start anymore? The last thing we know to do is replace PCM. My uncle has been working on this car for weeks, he is a certified master mechanic, this not a simple problem.
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Tuesday, August 4th, 2020 AT 4:18 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
I have seen this happen on a honda would only start with a code reader attached. It was a lopse ground. Do have the 16pin obd2 style connector?
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Tuesday, August 4th, 2020 AT 4:18 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
I posted the ground I want you to check depending on the 8th digit of your vin is where the ground is located. Let me know what you find the wires to that ground should have less then 2 ohms to ground.
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Tuesday, August 4th, 2020 AT 4:18 PM (Merged)
Tiny
JOHN MESNER
  • MEMBER
  • 3 POSTS
Ob2
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Tuesday, August 4th, 2020 AT 4:18 PM (Merged)

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