2002 Lesabre randomly shuts off while driving - no codes (to cause this)

[BuickGirlFromMars]

Drove the car again today. Also drove it to the store two days ago. It's running good, but i still get the po401 code. This is aftr the cheap EGR Valve never got put on because it litterly broke when tightening the two holddown bolts, and I purchesed and replaced it with a lifetime delco from autozone.

So thinking back as to what all I've done and some of the problems I may have had a MAF problem, a purge valve issue..and while trying to fix it at least 1 coil pack started to act up. The coil pack issue seemd to "almost" coinside with the replacement of the ICM. That ICM gets hot. I did use heat sink greas on it.
So the cranck sensor didnt fix it. The cam sensor did not fix it.

I need to drive it more to see if it's back to the old car it was. I think I had an O'shit post some time back.

I'm not getting any po30x codes and the acceleration is good. The idle is smooth. I'll update as I can.

Wish this thread could have an ah ha moment, but it might not? Very glad so many have tried to help.

Ran great today. We'll see. PO401 is consistent, as it has been from the time I've owned this vehicle. That problem could be due to my replacing the Intake and MAP sensor when I got the car, although it ran great (several years but not a ton of miles) until it didnt.

also clean the MAF sensor with the special spray

 

[mro1974]

1974 but I think corvette got it a year earlier than others, or possibly medium duty got it a year later. I think I6 hei came out a year late too. i could be wrong but 74 a sbc definitely, under normal situations, had HEI
Later HEI with better coil, modules, advance weights, distributor other things, cap design is the best. like 77 or something maybe..

Thanks for the correction. I disliked HEI when it 1st came out. It was a cumbersome setup. This is a great forum with knowledgeable people. I've learned alot!

 

[BuickGirlFromMars]

Thanks for the correction. I disliked HEI when it 1st came out. It was a cumbersome setup. This is a great forum with knowledgeable people. I've learned alot!

Heres a 1977 HEI sbc distributor for a 350 (john deere green one)
and a 1972 points sbc distributor for a 400 (smaller one, 2 pics of that one)

For fun lol

 

[mro1974]

Heres a 1977 HEI sbc distributor for a 350 (john deere green one)
and a 1972 points sbc distributor for a 400 (smaller one, 2 pics of that one)

For fun lol

I'm very familiar with the point setup vacuum advance. You had mechanical advance & total advance was achieved by the vacuum advance. When a customer complained of poor gas mileage, the vacuum advance was the 1st thing to check. I'm assuming HEI did all that internally.

 

[BuickGirlFromMars]

I'm very familiar with the point setup vacuum advance. You had mechanical advance & total advance was achieved by the vacuum advance. When a customer complained of poor gas mileage, the vacuum advance was the 1st thing to check. I'm assuming HEI did all that internally.

Advance works the same on HEI. The difference is you dont send power over a gap like points, you dont have to adjust things, they cant weld(no points), higher energy is possible esp at rpm, and the later HEI introduced bushings for the mechanical centrifugal advance weights on their pivots so you didnt have to replace a distributor /weights with time.

vac advance is the same


here is what my distributor on my gmc looks like
I cleaned the rust and that fixed hanging rpms. but they are worn, sadly needs replacement but works fine for now.
One nice thing about HEI is you dont have to worry about separate coil or resisted wire or anything you just have 3 wires into the side there that connect into the cap for the Coil which is inside the cap.
here are some of those

 

[John Canon]

Those worn pivots are huge: you could add nylon collars into the gap. It looks to be about the same size as the nylon air line tubing on the ELC rear shocks. You could cut 1/4 inch lengths and slide them over the pivot pins. The return spring will hold it in place. Better yet, choose a diameter of nylon that is slightly too small, then cut lengthwise so they are a friction fit. It sounds like a lot of work but, if you find a piece of tubing, it could be a quick job.

Here is a vacuum advance story from my old 1979 LeMans. At a certain speed, about 35 mph, the car would start bucking wildly ... rev up, die down, rev up, die down. Eventually I found the problem: a tiny break inside the points wire would open as the points plate turned. Then the engine would die down, reconnect, and rev up again, repeatedly if you held the throttle constant.

 

[BuickGirlFromMars]

Those worn pivots are huge: you could add nylon collars into the gap. It looks to be about the same size as the nylon air line tubing on the ELC rear shocks. You could cut 1/4 inch lengths and slide them over the pivot pins. The return spring will hold it in place. Better yet, choose a diameter of nylon that is slightly too small, then cut lengthwise so they are a friction fit. It sounds like a lot of work but, if you find a piece of tubing, it could be a quick job.

Here is a vacuum advance story from my old 1979 LeMans. At a certain speed, about 35 mph, the car would start bucking wildly ... rev up, die down, rev up, die down. Eventually I found the problem: a tiny break inside the points wire would open as the points plate turned. Then the engine would die down, reconnect, and rev up again, repeatedly if you held the throttle constant.

your 79 lemans had a points distributor? my 75 grand am has HEI

also, I could mess with it, but the center plate is worn and you can even get a new one of those. it needs the top end from a later SBC hei distributor, one that has factory bushings that can be replaced. also little guides that keep them from twisting and rusting/ or sticking metal to metal. also helps to lube them, gm didnt lube them but high humidity + ferrous plane metal lol...

 

[John Canon]

your 79 lemans had a points distributor? my 75 grand am has HEI

also, I could mess with it, but the center plate is worn and you can even get a new one of those. it needs the top end from a later SBC hei distributor, one that has factory bushings that can be replaced. also little guides that keep them from twisting and rusting/ or sticking metal to metal. also helps to lube them, gm didnt lube them but high humidity + ferrous plane metal lol...

I remember it was a singular wire that would flex when the vacuum advance moved. The engine was a 305. It was a Canadian Lemans, 2 door hardtop, cinnamon in color, with a nice swooping window line. Not like the Malibu straight window line. Dual exhaust, no cats. Lightweight, with a nice rumble.

 

[Mohammed79]

Time will tell. The cheap MAF seuunsor has been replaced, several parts ago. If I had to say it's fixed right now I'd say the ICM and or the Vent control Vale "Possibly" was the original cause.
I still want to drive it more and look at the info from some of the pids.
After I replaced the ICM It seemed like I sterted gatting the P030x on occasion, which was corrected by replacing a coil or two.

Anyway, I've driven it a few times now without an issue.

Hey Bro! Im practicably having the same issue withe my 02 lesabre custom. I replaced my 02 senors( up and down). Maf sensor, idle senor, coil pack modulator. New wires, spark plugs, alternator, battery. Last but nut least my fuel pump! The car randomly cuts off with a couple surges. 14.8v is what it reads till you drive about 15min. Then the surges happen, the power will jump from 14.8v to 13.2v then shoots back up. The power will steadily drop to 14.4v till the random shut off happens. Restarts after sitting a while. Stays on for a couple of seconds then has a rough idle and turns off. Did you solve your problems? If so can you give up parts with solutions.

 

[BuickGirlFromMars]

Hey Bro! Im practicably having the same issue withe my 02 lesabre custom. I replaced my 02 senors( up and down). Maf sensor, idle senor, coil pack modulator. New wires, spark plugs, alternator, battery. Last but nut least my fuel pump! The car randomly cuts off with a couple surges. 14.8v is what it reads till you drive about 15min. Then the surges happen, the power will jump from 14.8v to 13.2v then shoots back up. The power will steadily drop to 14.4v till the random shut off happens. Restarts after sitting a while. Stays on for a couple of seconds then has a rough idle and turns off. Did you solve your problems? If so can you give up parts with solutions.

although I think you are .. extremely intelligent seeming , like you have a sense of how things work and how to replace things.
But yet you threw all of that at your car as a parts canon and you still have the issue. your reaction should have been to undo all the parts changing and leave the factory good things in , no need to introduce variables you cant keep track of em all


How much improvement, if any, did you see? and what alternator brand did you get, and whats the status of your grounds all around, battery, and your charge wire to fuse box to battery daisy chain

 

[Mohammed79]

Time will tell. The cheap MAF sensor has been replaced, several parts ago. If I had to say it's fixed right now I'd say the ICM and or the Vent control Vale "Possibly" was the original cause.
I still want to drive it more and look at the info from some of the pids.
After I replaced the ICM It seemed like I sterted gatting the P030x on occasion, which was corrected by replacing a coil or two.

Anyway, I've driven it a few times now without an issue.

I need help same something bro. I replaced the alternator, idle senor, maf sensor, o2 senors both. Battery, and fuel pump! My car still just shuts off. As soon as it goes down to 14.4v. It's done. If you fixed your problem; can you help me sir?

 

[Mohammed79]

although I think you are .. extremely intelligent seeming , like you have a sense of how things work and how to replace things.
But yet you threw all of that at your car as a parts canon and you still have the issue. your reaction should have been to undo all the parts changing and leave the factory good things in , no need to introduce variables you cant keep track of em all


How much improvement, if any, did you see? and what alternator brand did you get, and whats the status of your grounds all around, battery, and your charge wire to fuse box to battery daisy chain

Wow! I just wanted my car to stop turning off. I kept looking up my problems and looking up my parts that can cause my car to shut off. So I need to check the ground wire?. I said what I did so you guys/gals could eliminate those reasons out. Step 1? What should I check?

 

[BuickGirlFromMars]

Wow! I just wanted my car to stop turning off. I kept looking up my problems and looking up my parts that can cause my car to shut off. So I need to check the ground wire?. I said what I did so you guys/gals could eliminate those reasons out. Step 1? What should I check?

I would check your grounds. Does your battery have the original cables on it, and the original hold down bolts? You can use a tap to clean the threads on battery, and you can peel the rubber away from the post to clean the metal(it corrodes where you cant see it)
I would pick up a new bolt as well, and then securely attach to your battery. Then look for grounds underhood and clean them up and check em.

 

[jknotts81]

Pretty sure i got them at rockauto. ACDelco. Not at home so can't tell you the # but were purchased for the car.
The only time i get the po306, and it was only twice befor changing the plug and looking at the injector, was when i was under load like going up ramp to enter freeway.

I've put about 300 miles on the car the last week or so. It never shuts off anymore, so maybe progress has been made. Still havent put the ICM on it and I do remember replacing the center coil pack at 1 time. (but it was bad as they come so an easy fix that time.

Hello I have a 2002 Buick with almost identical problems changed or had changed out a ton of parts.
What was the last item you changed when it stopped dying?

 

[jknotts81]

Time will tell. The cheap MAF sensor has been replaced, several parts ago. If I had to say it's fixed right now I'd say the ICM and or the Vent control Vale "Possibly" was the original cause.
I still want to drive it more and look at the info from some of the pids.
After I replaced the ICM It seemed like I sterted gatting the P030x on occasion, which was corrected by replacing a coil or two.

Anyway, I've driven it a few times now without an issue.

@dadymurano what fixed the problem?

 

[G-521130]

a comment from the peanut gallery.🤣

lol

 

[2000ltd]

Early on I checked for vaccume leakes with (dangerous i know) starting fluid. Found no leakes. I just removed the entire throttle body and used a can of MAF cleaner. It was in ver clean condition. The computer sits in the bottom of the air box. Why its so big. I've checked the wires from my ICM to the cam and crank sensor.
I replaced the intake manifold when i 1st got the car and changed the water elbows. The water level while a bit low hasn't dropped down from when i winterized it last year. I've seen some people wiggle wires until they damage them. The plugs to my sensors on the throttle body all have good O rings.
-air duct isnt sealed- hmmm yes I need to rotate the airbox to throttle body rubber a bit, but it is sealed, not sure where you see that... - I took off the throttle body and it was getting dark as I put it all back together.

As far as the LTFT goes would a rich condition cause that reading at idle? and what would be a good reading? I always though as close to zero was the target when not under load just idling. I took those readings with the car not up to temp as I saw your post and went outside but only sat long enough to make sure I was in closed loop. I think the IAT showed 71 degrees which is about what the outside temp was around dark last night. (also about as cheap a meter as can be purchased.

OK gotta run. Took off today.
Guy coming by to drop off the title to a suburban he traded me for a residential cam job. Also have the interior in a mess on my Murano. The sunroof drain tube came unplugged from the passenger side firewall and drivers side was full of s--t, gonna tear it up enough to check the rear drains also. (i will never buy a convertable or a car with a sunroof) i guess with proper maint and a garage/basement to park em in you'd be OK.
I've gotta get rid of a vehicle or two. The Muramo would bring the best price......probably.View attachment 34894View attachment 34895View attachment 34894View attachment 34895
Befor i cleaned it. Was hoping it was very dirty.

How did you get the screen off the throttle body? I'm about to try to clean mine but need to know how to remove that part first.

 

[02LTD2.0]

How did you get the screen off the throttle body? I'm about to try to clean mine but need to know how to remove that part first.

A small pocket screwdriver or a metal pick can be used to remove the retaining ring.

 

[2000ltd]

A small pocket screwdriver or a metal pick can be used to remove the retaining ring.

Thank you🙂