engine cuts out intermittedly

[w261w261]

Not a 3G here, but a friend's POS mid 90's Buick 3.8L, almost 200k miles. He's broke and really needs this thing to be dependable, got it as a gift from a relative. It dies while the car is driving, fast or slow, cold or hot, no seeming pattern. I'm pretty sure it's electrical, as it quits cleanly, no rough running. When it does run, it's very smooth. To restart, my friend shifts into neutral, and it fires right up, until the next time. It has quit 10 times in 10 miles, and has also gone a couple of days no prob.

He's replaced both fuel pumps and the fuel filter. I cleaned off the main ground connections, but haven't done anything else. The lights shine brightly. Sometimes the check engine light comes on when it does this, and then the next time it does it the light goes off. Sometimes there's a code, and as a result he's replaced the O2 sensor and maybe the EGR valve.

I'm thinking it's a grounding problem somewhere, or the ECU is messed up. It's very frustrating to him, as the problem is never there when his mechanic is looking at the car (of course). If it would only die and stay dead then we'd have a shot, but it won't accomodate us.

Anyone have an idea. My best shot is to get a junk ECU from eBay and plug it in, but the car isn't worth much more money than that.

Thx

[bushbean]

My pop's car had similar problems--sometimes start, sometimes won't, sometimes dies while driving. After throwing in about a thousand dollars worth of parts, the problem turned out to be a bad distributor. The car has been running flawlessly eversince. He tries to console himself by looking on the bright side: there is so many new parts on the car; it should last another 100,000 miles.

[Blkblurr]

Could be the ignition switch or main relay to the fuel injection system. I'm not sure if this car has one like ours. I also agree it could be the dist.

[2oodoor]

Reading that, the part about it dying out even at road speed indicates to me a fuel pump or incorrect fuel pump, fuel pump relay, or the connector at the fuel pump. The connectors on GM are notorious for getting damaged, Pigtails are even available aftermarket.
Other model specific problems would be crank sensor or circuit, that car is distributorless so that is ruled out but not the DIS cover, that is worth looking into.
EGR ports get pretty clogged on those too, but I dont see that killing the motor at speed really.

And last but worst is intake gaskets and cracked up intakes. Those cars can start leaking at anytime those have not been done recently. The bad thing is sometimes they leak in and bend connecting rods.

Those cars are OBD2 so the CEL will not stay on for some codes but they stay in memory.
You may be on track by swapping ECU and checking connections there but try to find a known good one to check it with.

[2oodoor]

you can usually tell a crank sensor no signal but turning the key on without cranking engine, all the warning lights light up for a few seconds, some stay on too. but if the check engine light does not come on then the crank sensor is bad or intermid OR the ECU is not juicing up.

[w261w261]

My thought was the ignition switch, as his is really loose. But sitting there and wiggling it I can't get the thing to die, so I guess that's not it. I'll look at the other things mentioned...thanks for all the comments.

[w261w261]

Pardon me for asking this elementary question, but since my cars are '85, '89 and '92, plus an '04 that I let a mechanic handle exclusively, I don't know much about OBDII. Can I trot down to Pep Boys and get the handheld reader, plug it in and rock and roll? Do I need a special adaptor for the GM port? Will even a cheap reader give me access and explain the codes? Thx.

[2oodoor]

My thought was the ignition switch, as his is really loose. But sitting there and wiggling it I can't get the thing to die, so I guess that's not it. I'll look at the other things mentioned...thanks for all the comments.
That one is at the bottom of the column, the top part is just a key cyl that accuates a rod that goes down to the switch. That is a good thing to check too as is looking at his key ring to make sure it does not have five pounds of keys and misc what nots.. ..

[Oldblueaccord]

Oh shit i know this one. My friend had the same car and it was the same thing quit for no reason. Might run 10 miles might go 100. There some sensor I thinks its the TDC sensor for the injectors. I dont think it will code out. Try and find someone that knows GM cars a little its pretty common on that type FI set up. It was like a 100$ sensor I think.

He sold the car for junk and the guy fixed it. We saw it running around a few months ago. One of the few good cars GM ever made.

wp

[w261w261]

<Oh shit i know this one>

Thanks! I hope you're right. I'll tell my friend.

[Estimated Prophet]

Yeah that was a great engine for a GM

[Oldblueaccord]

Pardon me for asking this elementary question, but since my cars are '85, '89 and '92, plus an '04 that I let a mechanic handle exclusively, I don't know much about OBDII. Can I trot down to Pep Boys and get the handheld reader, plug it in and rock and roll? Do I need a special adaptor for the GM port? Will even a cheap reader give me access and explain the codes? Thx.


Auotzone should read it for free if you have one near you.

I think on those you short 2 post on the dianostic port under the steering column and it will flash codes like our car does. The used to sell a "key" which did the same thing.

EGR code is GM famous "when all else fails" code 44 (im guessing the number) just to thow you off some.

Another thing is make sure the cat isn't plugged real bad making the car quit. The injectors can hang open and flood out.

wp

[2oodoor]

You cant short out those to flash codes

You can get a code reader for OBD2, but there are oodles of companys making them now for varying degrees of functionality. I think even the el cheapo will tell you the code in text but the better ones give you likely causes, TSB's, and real time data stream.

TDC sensor would have to be crank position sensor, but with DIS there may be a cam sensor on some models. Sometimes the timing chain can get so loose it starts rubbing inside housing and damage sensor ring for CPS.

Cat stopped up could be a place to look but since the car can go for a long time without problems, that may be less likely. On that note a piece of the cat can come loose and wedge inside exhaust somewhere and as well the muffler can come apart internally and block itself off.

The problem is intermid stalling, with no other symptoms as far as running bad before or skipping?

[2oodoor]

Just read something on a car similar to that one, turned out to be ign switch.Same symptoms, everything else checked out except voltage drop inconsistant in fuel pump circuit.