3800Pro Forums banner

1 - 12 of 12 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
I have a 98 Buick LeSabre with 150,000 miles. It has been a great car.
Recently, I started having the following problem.
About half the time the car seems to run fine. The other half of the time the car will stutter while driving almost as if the engine completely shut off for a second and then it will surge. When it's doing this, it often dies upon stopping at a red light or at very low speeds while turning. The strange thing is, it will act like this on a trip to the store, but after coming home and letting the car sit for a few minutes, it will start up and run just fine again.
Any ideas?
Are these the symptoms of coolant leaking into the intake manifold?
 

·
Registered
Joined
·
1,350 Posts
I have a 98 Buick LeSabre with 150,000 miles. It has been a great car.
Recently, I started having the following problem.
About half the time the car seems to run fine. The other half of the time the car will stutter while driving almost as if the engine completely shut off for a second and then it will surge. When it's doing this, it often dies upon stopping at a red light or at very low speeds while turning. The strange thing is, it will act like this on a trip to the store, but after coming home and letting the car sit for a few minutes, it will start up and run just fine again.
Any ideas?
Are these the symptoms of coolant leaking into the intake manifold?
I had a very similar sounding problem, and I found out I had one bad, and one almost dead fuel injector.
When my injectors relay heated up the one that is almost dead now was partially good, which is why when it cooled the car would run a while for me.

I'd suggest having the fuel pressure checked first, if the pressure is a little low, then go ahead and replace the fuel filter, unless you have recently done so, if it still does not come up to spec you could consider replacing the fuel pump, or at least have the screen that covers it replaced, it may not be necessary, but these are things I had done to mine recently.
I know a place or two online where you can order some re-manufactured injectors for a decent price, around 150.00 for all 6, if you have the money I'd just get them replaced, especially if they are the original injectors.
I've read the fuel pressure regulators go bad a bit on these, so pull the vacuum line going to the fuel pressure regulator and look for signs of fuel in that, if it has fuel in it then have that replaced.

As for your coolant leak question, mine was doing as you described, and I did find my lower intake manifold gasket had pretty much disintegrated, so I am in the process of replacing my upper and lower gasket, as well as getting a better/redesigned upper intake manifold.

If you are noticing a good bit of coolant disappearing from the overflow, and you can afford to, then I'd strongly suggest not driving it anymore till you can get that repaired, or you could end up with a hydra-locked engine.
Which pretty much means you'll be buying a new engine.

I have a thread going in the intake section here, maybe it will be helpful to you if you try to fix it yourself.


Hope you get your car fixed soon!
 

·
Registered
Joined
·
5 Posts
Similar problem

I have a 98 Buick LeSabre with 150,000 miles. It has been a great car.
Recently, I started having the following problem.
About half the time the car seems to run fine. The other half of the time the car will stutter while driving almost as if the engine completely shut off for a second and then it will surge. When it's doing this, it often dies upon stopping at a red light or at very low speeds while turning. The strange thing is, it will act like this on a trip to the store, but after coming home and letting the car sit for a few minutes, it will start up and run just fine again.
Any ideas?
Are these the symptoms of coolant leaking into the intake manifold?
Howdy, I also had a stutter problem with my 2000 Buick PA. I am a DIY person. So after checking for codes and checking many different things on the car I could not find the problem. I looked for two plus weeks and got burned, cut, bloody, cussed, etc. I finally got smart and took car to a independent repair shop that knew how to work on GM Cars.

The shop found a wire that had rub through and was causing a short. The wire was in a wire harness somewhere down by the starter. They cut out the bad section and spliced in a new wire. They charged me one hour to find the problem and 1/2 hour to replace the section of wire. Cost was about $150.00. After spending so much time looking for this problem I think the money spend at the shop was worth it. good luck. :)
 

·
Registered
Joined
·
2 Posts
Discussion Starter #4
problem fixed!

Thanks for the replies.

I finally had a code come up for a low frequency from the MAFS.

I put a new AC Delco MAFS in ($250 ouch) and the car is purring again.

Isn't it funny how some symptoms are identical for a variety of very different problems?
 

·
Registered
Joined
·
1,350 Posts
Thanks for the replies.

I finally had a code come up for a low frequency from the MAFS.

I put a new AC Delco MAFS in ($250 ouch) and the car is purring again.

Isn't it funny how some symptoms are identical for a variety of very different problems?
That it is!

Glad ya got it fixed, sorry it cost ya so much!
I cracked the top of mine when tapping it to see if it was my issue, I put a little hi temp silicone on it, and I think it is fine for now, but I will eventually replace it, I found some re-manufactured ones for 150.00-165.00 on amazon...
I think i just found a new one on amazon, it may be a re-manufactured one also though.
http://www.amazon.com/ACDelco-213-4338-Mass-Flow-Sensor/dp/B0016IDGHO/ref=au_pf_pfg_s?ie=UTF8&Model=LeSabre|388&n=15684181&s=automotive&Make=Buick|45&Year=1998|1998&newCar=1&carId=003

Did you try to use MAF Cleaner on it before getting a new one?
Also just curious, but do you use an aftermarket oiled air filter, like a K&N?
 

·
Registered
Joined
·
1,677 Posts
is there some relation between oiled air filters and bad maf's?
i'm building another new intake for my car, this time with a box, and if there's something thats gonna hurt my maf i'm going to avoid it like the plague
 

·
Registered
Joined
·
1,350 Posts
is there some relation between oiled air filters and bad maf's?
i'm building another new intake for my car, this time with a box, and if there's something thats gonna hurt my maf i'm going to avoid it like the plague
From what I understand it mainly only hurts them if you over-oil the filter, but some say it can cause the MAF problems even if you do not over-oil, and never touch the thermistors, you do not want any of your oils from your hands on there.
I personally have had mine for a few years, and when I took my MAF out the thermistors looked fine, of course I knew to be careful not to over-oil the filter, and I never touch the thermistors.

Here is K&N's response to the claim that their filters caused MAF's to fail.
K&N Mass Air Flow Sensor Test Results

Google Dirty Maf from K&N, there's a discussion going that is a bit active, and one person there says.

"K&N air filters actually TAKE power from engines using MAF's the second a tiny bit gets on those MAF sensor wires. It happens the second its wet out or it rains.......or any fog or mist in the air. It re-activates that crap oil in the filter, and the first place it lands on is the MAF wires.

And now you see how hard that crap is to get off the MAF too. It hits it wet, then dries on there like that"


Not sure how true that is, to my knowledge I did not have any problems when it rained, only when it was hot would my car not start back up on occasion, but I am pretty sure it was due to my 2 bad fuel injectors.
 

·
Registered
Joined
·
1,677 Posts
i guess it makes sense that that oil would pull through the filter, and thus getting on the maf, i use k&n filters and recharge them with the kit, so i'll be conservative with the oil next time.
 

·
Registered
Joined
·
1,350 Posts
i guess it makes sense that that oil would pull through the filter, and thus getting on the maf, i use k&n filters and recharge them with the kit, so i'll be conservative with the oil next time.
I'd also consider pulling the MAF out and spraying it with MAF cleaner each time you recharge the K&N filter, it only takes a minute or two, that will help ensure you keep the thermistors as clean as possible.
 

·
Registered
Joined
·
24 Posts
I too have a similar problem with some detailed information in this forum. My fuel pressure regulator does have the smallest trace of wet fuel at the vac line. I'll update you on how that works for me if I can change it in the next couple of days.

edit:
ahhh, I see you got it fixed, wish I was having some luck of my own
 

·
Registered
Joined
·
98 Posts
this is yet another old thread where the car was stalling and no solution posted.

after going through my own car with this problem, it appears that this type of stalling issue goes beyond the usual diagnosis of scanning and pulling up codes- because this stalling problem can be persistent with no codes showing up.

the solution is dig deeper, and use process of elimination.

the ICM and cam sensor are involved in firing the injectors and plugs, and are relatively inexpensive, change them.

the crank sensor on these cars is notorious for just shutting off when it is defective, and stranding the car, change that too.

if the screen grid has been removed from the throttle body, re-install it. when the car has low miles the system can compensate for that extra 25 cfm of air coming in without the screen. but as it gets older, vacuum drops a bit, and the screen also being missing, can throw the system off enough that the MAF cannot run the car without stalling. so make sure the screen grid on the air filter side of the throttle body, is in place, upstream from the MAF sensor.

try another fuel pressure regulator. they are adjustable from the factory, that little torx screw can be turned in to raise pressure, or out to lower pressure. aftermarket cheap ones are less adjustable than the factory ones. don't turn the pressure up too high. more is not better. my car ran worse the higher the pressure was turned up, and ran the best with less pressure.

check fuel pressure, it should be 52 psi with vacuum removed from regulator, and it should hold and not drop more than 5 psi in 10 minutes. if it does, either the injectors are leaking, or the fuel pump is going out. have the injectors cleaned on a cleaning rig, which runs the car on the cleaning machine, and cleans them in the car, using the machine's own cleaning fluid.

if the fuel pressure still doesn't hold to spec, change the fuel pump.

if it still doesn't hold with new fuel pump, and the injectors have been cleaned on a rig, it needs new injectors.

check engine vacuum at idle. if it's below 18", the engine may need a valve job, or rings. these engines need a strong vacuum signal to run the factory fuel and spark curve programs in closed loop. when vacuum drops off, it screws up the system, causing it to over-compensate. i.e. sensing a rich mixture, it makes it overly lean, and stalls the car. what happens is this- the intake side of the system i.e. MAF and MAP sensors, begin to fight against the exhaust side of the system i.e. oxygen sensor. if the o2 sees a rich mixture, it's going to lean out the system, against the inputs of the MAP and MAF, or vice versa. the result is a car that stalls, idles rough, and runs like schit. the more vacuum at idle, the better. 20" is very good, 19" is starting to wear, 18" is moderate wear. 17" at idle is a worn engine, stop there and have it rebuilt, or changed out. this is assuming the factory cam. if you run synthetic oil it will have good vacuum for a long time. my Monte has 199,000 and has 19" using Amsoil synthetic since it has 92,000 on it.

last but not least, high mile cars may need a new keyswitch. it's the interface with the driver that usually breaks on any car, i.e. door handles, knobs, radio controls, power window/seat switches, and keyswitches, because that's what gets worked most. seeing this video BELOW will open your eyes that these keyswitches have a tendency to not work and are finicky. they only cost $35 and aren't too hard to change. af ter you watch this vid you'll never trust the GM dash mounted keyswitch again. it can cross and backfeed internally and short the entire ignition and injection system out, and not start, or stall your car out.

https://www.youtube.com/watch?v=BqLyq2xfT_4

I'm posting all this because my own car developed the problem, and a thorough net search produced almost no results of actual fixes. 99% of the threads out there end in no fix and no reply, and no follow up. that is more puzzling than the problem itself, because it's the documentation that will enable all of us, to keep these 3800 engines going into the future. they are a good engine and worth the effort. so when you do have a bear of a problem, and finally get it fixed, taking the time to come back in and post the results, helps everyone who runs these cars.

Have a happy July 4th.
 

·
Registered
Joined
·
98 Posts
ok FWIW, I know there's a schitload of people reading these threads, cuz all these cars have these problems....

I checked the injector leakdown on this car and it was 10 lbs. pressure leak in about 3 minutes....

ran a can of STP fuel injector cleaner through a 1/2 tank of Sunoco premium, through the car...basically a "down and dirty" injector cleaning rig deal....'

checked fuel pressure again, it only leaked 5 psi in 10 minutes, dead nuts on the spec.

the gas we're being sold today, is crap. it would pay to put a can of injector cleaner in every so often. like once a month or so...

#2, in the back of the intake manifold, facing the firewall, is a large vacuum fitting for the power brakes and interior heater/ac vents control

this fitting is PLASTIC, and clips in place, is sealed by a rubber O-ring...over time it gets loose and can leak vacuum. disconnect it carefully, coat it with black permatix sealer, and put it back in. let it dry.

there is also the possibility of the interior vent vacuum hose leaking somewhere, and the power brake hose, or power brake booster. all must be checked out
 
1 - 12 of 12 Posts
Top