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wtnhunt

Question for GM mechanics

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Can the rear plugs on a 2001 buick lesabre be changed without tilting the engine forward?  Oldest daughters car needs a tune up and she is 6 hours away one way, so me doing the job for her is not possible right now.  She has the "mechanics" at auto zone telling her it is a $400 job that requires jacking the engine up and that they would not even do the job themselves because it is such a pain.    

From what I have been able to find on the car online there are mixed opinions, some say the plugs can be reached with a universal  and an extension while others suggest taking the top motor mounts loose and ratcheting the engine forward is the only way to get to them.     

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The engine doesn't have to be jacked up, that's for damn sure lol. Autozone guys... geesh! We don't have Autozone in Canada but other chains. All the guys behind the counter believe they're grand master technicians.

It's a tight squeeze and a bit of a pain to get behind the engine to get them but it can be done. Been a while since I worked on one but if I recall I would use a flex ratchet with a normal 5/8" spark plug socket with a 1" or 3" extension. If I recall there's a brace between the struts I would remove to get a bit more room. I would recommend having them do plugs and wires and a fuel filter.

The Lesabre doesn't have the two motor mounts that bolt to the rad support unfortunately. I know what you mean by removing them and pulling the engine forward with a ratchet strap. Used to do that when doing head gaskets etc on venture vans, impala's etc with the 3.1/3.4's.

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Thanks Shaun. Helps to know this for sure to help keep her from getting taken advantage of if she ends up having to pay someone.  Car was fine a few days ago but is misfiring now after a lot of recent rain. Tripped check engine light and running rough. Hopefully her boyfriend can at least get the wires on the back swapped out for her and she can get by until next time she gets home.   

I am kind of inclined to think the coil packs may need replaced too.  Hard to diagnose with the car over 300 miles away.  

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As I was reading that I thought coil pack right away, or plug wire cracked. Get them to run it and spray over the coils and wires with a spray bottle with water to try and locate the source. There's 3 individual coils, have also seen the ignition module which the coils sit on fail as well. 

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They were replacing all wires as they are going. They got the front done and one back plug changed out before it got too cold in the dark for them to continue. She said they started it and it ran much better but the check engine light is still blinking. Her boyfriend is a pretty big boy and not had much experience working on stuff, so those back plugs must not be as bad as the auto zone guys were telling her.  

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11 hours ago, wtnhunt said:

They were replacing all wires as they are going. They got the front done and one back plug changed out before it got too cold in the dark for them to continue. She said they started it and it ran much better but the check engine light is still blinking. Her boyfriend is a pretty big boy and not had much experience working on stuff, so those back plugs must not be as bad as the auto zone guys were telling her.  

Glad they're making progress. Tell them to disconnect the battery for 15 minutes or so after the repair. That will clear codes. If it's running good but the engine light is still flashing she may have to drop by a shop and have them perform a crankshaft variation learn procedure with the scanner. It basically relearns the position of #1 cylinder into the engine control module. If it is out of sync at all it will falsely detect misfires. 

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On 1/5/2017 at 9:04 PM, Shaun_300 said:

Glad they're making progress. Tell them to disconnect the battery for 15 minutes or so after the repair. That will clear codes. If it's running good but the engine light is still flashing she may have to drop by a shop and have them perform a crankshaft variation learn procedure with the scanner. It basically relearns the position of #1 cylinder into the engine control module. If it is out of sync at all it will falsely detect misfires. 

What should we be looking to expect for her to have to pay for the relearn process, Shaun?  She says it is running rough now, gets more rough as she increases engine speed, which to me sounds like could be they maybe did not get a plug wire right or the timing has gotten off.  Had her disconnect the battery but she did not leave it long enough because it was still flashing the check engine light.  Last time I talked with her she was disconnecting the battery again and going to leave it disconnected for 15-20 minutes.  

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The relearn isn't going to do anything if there's an actual misfire. That's only if the computer is picking up misfires and throwing a misfire code and there are no misfires present.

If they changed the plugs and wires, it is very possible that there's a plug wire mixed up and on the wrong cylinder. I recommend they trace the wires from the coils to make sure they go to the correct cylinders. I found a diagram that might be helpful. This is the supercharged version but the ignition is the same.

 

3800.jpg

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She was still having issues with it and getting a cel, poor mpg, and very rough idle.  They replaced coil pack for 1/4 and still were getting misfiring and throwing a p0300 code for random misfire.  

I finally got my hands on the car today and wound up figuring out the ignition control module was bad by swapping around coil packs, none of the coil packs worked on the front for cylinders 1/4, there was no spark.  Took it to autozone and had them check to verify it was bad before buying a new one and sure enough it was bad.  Replaced the module with a new one and the car runs great again.  

Oh and there is plenty of room to get to the plugs on this motor.  

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