3800Pro Forums banner
1 - 15 of 15 Posts

·
Registered
Joined
·
26 Posts
Discussion Starter · #1 ·
Okay so this is a 2000 Buick LeSabre. It has been sitting for several years.
So the problem I'm getting is a misfire on cylinder 4. Also my voltage is erratic on a cold start goes from 14.8 volts down to around 11.7 volts unless I give it some gas then it will stay around 14.6 to 14.8 volts. When in park I can't get it to rev higher than 4,000 RPMs but driving I can get it to go to Max RPM with a slight miss.
The onboard computer the one that shows you fuel mileage oil pressure yada yada glitches and sometimes won't show anything but warning indicators like door open trunk open or trip mileage and will not switch to the other settings.

This is what I've done so far, Replace the fuel pump on it to get it running.
New plugs, coils, wires, and ignition control module. I also replaced the upper intake gaskets I clean the upper intake and the throttle body. Accidentally bent the fuel rail so I got a new fuel rail and regulator. I also cleaned the injectors and replaced the map and maf sensors.

Test I've done.
Check the wire for spark switch the coil and wire to a different cylinder as well as the plug didn't help.
Did a vacuum test. Tapped into the master brake booster line vacuum held around 20 and when I floated the throttle it dropped down to almost zero and went right back to around 20. Although there were a couple times that went negative.
Fuel pressure test and compression test both good.
Disconnected the cat converter no change.
New fuel filter
I'm about to switch fuel injectors but I don't think that's the issue.
I'm thinking the alternator is on the way out but could that cause an issue like this.
At this point in time I'm thinking it's either the computer or the alternator.
Cylinder 4 is number three in the firing order.
Any help would be appreciated because I'm at a loss at this point.
 

·
Administrator
Joined
·
959 Posts
Sounds like a grounding issue or something in the voltage regulation, being that it's an erratic, intermittent voltage. You dug in/spent more than necessary before diagnosing it more.

Also, the rev limiter in the computer is set to 4k in Park/Neutral on purpose. Winding out a misbehaving engine is exactly what you should not be doing until it's resolved. You're able to tell it's hurting at idle/cruise, so what does revving it up like a Honda kid who just cut his muffler off do for you? There's not a mechanic waiting at the top of the tachometer waiting to fix it for you.
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #4 ·
Harsh man.... Honda kid..... Was never really in the Honda always loved big sedans an old pickup trucks LOL. I thought maybe there was a rev limiter lower at idle but I didn't know thanks for that info.

I'm not winding the motor up at idle was using a scan gauge and the throttle body cable to float it for the vacuum test then I saw it was bottoming out at 4k so I went out and did a 0 to 60 roll with quick acceleration and noticed that smoothly got above 5K RPM although a little hesitant.
It's still missing on cylinder 4.
Vehicles been setting for about 6 years that's why I just went ahead and replaced all the coils and plugs and wires. When I pulled one of the coils off the ignition control module one of the spay connectors broke off due to corrosion so I replaced that.
So after doing that I decided to do a full tune-up slash preventive maintenance.
You're saying it's a ground issue or a voltage regulator issue. I wouldn't think it'd be a ground issue because the vehicle will float voltage between 14.6 and 14.8 when it is warmed up with the lights on and stuff.
If it's a regulator issue they're built into the alternator aren't they? If so that brings me back to replacing the alternator.
 

·
Administrator
Joined
·
959 Posts
Yes, regulating is internal on these alternators. A ground having intermittent connection will permit normal operation when it's touching, and cause problems when it's not (basic, yes, but you discounted it too quickly without any acknowledgement such as checking the 3 typical places this affects).

These things can sit for years and half will behave normally with minor attention, others require lots of love to bring back. There's also Schrodinger's problems, where they won't happen unless you break the seal and cause things to break during inspection.

We're now dealing with older vehicles (some 3800 S2's over 25yrs old now) with brittle components and corroding wires/parts. They can be made reliable, still, but many new and random problems will emerge depending on vehicle history, treatment, and environment it's seen (most of us aren't 1st, or even 2nd-3rd owners, so many unknowns show up when maintaining, and especially when modding).
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #8 ·
I'm the second owner, bought it back in 2013 the other owner was an elderly gentleman that couldn't drive anymore. I drove it around and then park it when I couldn't drive.
I was dreading worse problems in this vehicle because it sat so long.
My plan for tomorrow is testing the alternator and looking for any shorts. I did switch out the fuel injector and the problem it's still there.

Oh I know about how problems that can be hard to pinpoint I was reading I think on here or on another form a thread that was over 2 years long I think about a member in his Park avenue that had an intermittent misfire and he still hadn't solved it.

This is my first car that I will be working on for myself. I've been wanting to do it for a while but could only recently start on LeSabre because I didn't think I was going to get the title and that's a long story of fighting three state DMVs...
I have experience working on other vehicles so i have some knowledge. I guess you can call me a backyard innerweb mechanic lol.

In conclusion tomorrow I'm going to hunt for a short if my alternator is working properly.
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #9 ·
I actually just thought of something. I wonder if there could be a problem with the serpentine belt. I mean it's not squeaking and it looked okay when I glanced it over but did not do an in-depth inspection. I know they always don't squeak when going bad. But then again that should affect other things like power steering.
Also checked my timing chain with a long flathead screwdriver and it sounded fine, unlike the noise from a timing chain (might have been a belt) started making noise and about a week after that it blew out on a 96 cavalier.
 

·
Administrator
Joined
·
959 Posts
Good luck with your search.

The 3 grounds in the engine bay are:
  • under the ignition module, bolted to the head (this important sub-harness can also be crushed/shorted if routing isn't careful during re-assembly... It's also replaceable)
  • below battery negative terminal on frame (W-body, so H's may be slightly different)
  • on transmission bellhousing bolt near starter (up to 3 wires)

I'd check each wire/terminal condition, since they're exposed, and look for unique ones on a LeSabre. Also, ensure your positive terminals aren't growing corrosion crustaceons along the way, and dab everything with dielectric grease or anti-seize on the way out.
 

·
Registered
Buick Lucerne CXL 2007
Joined
·
1 Posts
Okay so this is a 2000 Buick LeSabre. It has been sitting for several years.
So the problem I'm getting is a misfire on cylinder 4. Also my voltage is erratic on a cold start goes from 14.8 volts down to around 11.7 volts unless I give it some gas then it will stay around 14.6 to 14.8 volts. When in park I can't get it to rev higher than 4,000 RPMs but driving I can get it to go to Max RPM with a slight miss.
The onboard computer the one that shows you fuel mileage oil pressure yada yada glitches and sometimes won't show anything but warning indicators like door open trunk open or trip mileage and will not switch to the other settings.

This is what I've done so far, Replace the fuel pump on it to get it running.
New plugs, coils, wires, and ignition control module. I also replaced the upper intake gaskets I clean the upper intake and the throttle body. Accidentally bent the fuel rail so I got a new fuel rail and regulator. I also cleaned the injectors and replaced the map and maf sensors.

Test I've done.
Check the wire for spark switch the coil and wire to a different cylinder as well as the plug didn't help.
Did a vacuum test. Tapped into the master brake booster line vacuum held around 20 and when I floated the throttle it dropped down to almost zero and went right back to around 20. Although there were a couple times that went negative.
Fuel pressure test and compression test both good.
Disconnected the cat converter no change.
New fuel filter
I'm about to switch fuel injectors but I don't think that's the issue.
I'm thinking the alternator is on the way out but could that cause an issue like this.
At this point in time I'm thinking it's either the computer or the alternator.
Cylinder 4 is number three in the firing order.
Any help would be appreciated because I'm at a loss at this point.
I would check wires, intake box, and just make sure it's not a vaccum leak. Oxygen sensors, also.
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #13 ·
Well I found the problem and I'm a freaking idiot.
When I swapped injector cylinder 4 and 1 and then check my scan gauge it's still had error code for the misfire on cylinder 4. This is why I'm an idiot, I forgot to clear the codes. I realize this today when I checked for shorts and then check my alternator when I plug the battery back up and started it back up the vehicle gave a cylinder one misfire only code. So it's a bad injector.
Lucky me I'm within 30 MI of four major pick and pulls that have a plethora of 3800 platform vehicles including several LeSabres.
I have to go there to get brake lines, tie rods outer if they have any good ones, front struts and coils from a Bonneville, and a wheel bearing, so I might as well get an injector there seeing as I already replaced the one injector that was dead completely from one from the Pick-n-Pull.

It's funny though I pulled cylinder for injector out and cleaned it hooking up a fuel line to it with a can a throttle body cleaner and a 9-volt battery and it seemed to fire good to me but obviously not as the misfire followed the injector.

I'm going there Monday or Tuesday so I'll post an update then.
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #15 ·
And wow on the prices for a tie rod outer for this LeSabre. I mean tie rods I'm used to paying at most 20 bucks for an outer one. They want 50 bucks for a new one from one of the big automotive stores that's just for one.
Fuel injectors I knew would be expensive new but I can get one for six bucks at the Pick-n-Pull
 
1 - 15 of 15 Posts
Top