antman94

I was having a problem with my 1986 cutlass supreme brougham sedan dying while just cruising down the road or dying at other random times. Over the last month I went ahead and replaced various things which I believed to be culprit and some things I just know needed replacing while also figuring out a charging problem. Egr valve, fuel filter, fuel cap, checked distributor cap, removed cat, Cut belt to air pump, TCC Solenoid, Trans flush and filter. All of that with no luck. I thought I had the problem solved and have been daily driving the car with no problems for about a week with no problems. Now all of the sudden its back with a vengeance. I was stopping at a stop light and the car bucked 3 times so I immediately turned off onto the side street and limped it home. On the way home the car gave off a BIG backfire through the exhaust either while it was dying or right before it died. I pulled off and the engine came back to life at about 10 mph and I got her home. Now even if it idles for about three minutes in the driveway it dies. So now im stuck here with my hand on my head not knowing where I should go next. any suggestions? help would be much appreciated. thanks

billmerbach

Check the vacuum solenoid

billmerbach

My Dada car doing the same thing and we think we gave it fixed

MDchanic

First guess: HEI module.

Take yours to the local chain auto parts store and have it tested.
Then heat it up with a heat gun and have it tested again.

Next guess: HEI pickup or pickup wires, if the module isn't the problem.

- Eric

henryk8398

Lots of unknows here.

When the car dies, does it restart immediately or do you need to wait a while?

Before the "bucking" incident, when it died, did it "sputter" or just "cut out" immediately?

Have you checked fuel pressure?

You said you have a charging problem. Can you describe that in detail? Your ignition system needs a steady supply of electricity to sustain it. Your stalling issue may be related and should be dealt with first. Have you tested your alternator?

I'm suspicious of your coil and module. Have you replaced those or at least had yours tested? You can test your coil with a multimeter.

antman94

I will take a look at vacuum solenoid thanks!

But to answer the unknowns there was no sputtering before the "bucking" it was like it was shutting off and on while bucking.

Can say I have not checked fuel pressure.

And the charging problem has been fixed. When I cut the air belt I just had one old power steering belt, (which was installed upside down by previous owner ) turning waterpump and alternator but it was slipping too much causing the alternator to not charge the battery.

henryk8398

In that case, it's time to have a long look at the distributor. The HEI module, coil, and pickup could be bad. The coil and pickup can be checked with a multimeter.

http://www.angelfire.com/realm2/84ca...coil/coil2.htm

Check the coil for any burn marks, cracks, etc.

Most auto parts stores can test an HEI module and coil. If either test bad CHANGE BOTH. It's my understanding that a problematic coil is often what causes a module to fail and vice versa. Check the coil button inside the cap, too. If you change the module, DO NOT USE DILECTRIC grease (it's clear-ish in color), even if it comes with the module. YOU MUST use heat sink compound. It's a white grease and is available at radio shack or other electronics stores. If your module comes with a tube of white grease, you are good to go.

Also, is your check engine light illuminated? Have you pulled trouble codes?

OLD SKL 69

I agree, I would first suspect the coil and then the module. Also, if your module has never been changed, then the di-electric grease on the underside is most likely all dried up and no longer protecting it.

69 Ragtop

This is a real shot in the dark, but a relative of mine had a similar problem in an '80s Olds, and had a bad crash because of it (lost power steering & brakes on a long hill). It turned out to be the large bulkhead connectors in the steering column area. You might get the car running, then wiggle them to see if you can make it die.

antman94

With the holiday season coming around Ive finally had time to tear into the distributor. I have one quick question before I go into checking everything with a multimeter. I pulled the cap and coil off of the distributor and checked the cosmetics of coil and everything (looked okay but thats no legit way to check) but then I took a look at the cap at the top of the rotor. The 2 phillips head screws that hold it down, 1 was backed out almost all the way, and the cap had some up and down play. could that be causing my problem?

RROLDSX

Kind of stating the obvious but you could try to tighten them and them see if it still happens. It could definately be the problem. Does your car have an OBD1 plug in? If so, use a dianostic tester and check for codes. Doing things like checking the bulkhead plugs and wiggling the ignition switch (everyone has heavy keys that wear out ignition switchs) and things like that can lead to a solution. I have a diagnostics procedure in one of my GM manuals that leads you through. So a manual will help as well. It all takes some time and patience. Good luck and keep us posted on what your eventual solution was. Hope this helps.

69 Ragtop

I re-read your first post. In it you said you checked the distributor cap. I assume that means you had the cap off. Since you had the problem before and after you did that, I'll also assume the loose cap is not the problem (although the loose cap won't help performance).

That said, I don't see a lot of feedback saying that you performed the valuable tips you've gotten here so far. Because of the way you have described the worsening of the problem, I'm particularly interested in henryk's suggestion that you check the fuel pressure. The following test is even easier than that.

DO THIS NEXT AND REPORT BACK: Since the car now dies at idle in the driveway,
1) Start it up, then let it die at idle.
2) Shut the key off.
3) Pull the air cleaner.
4) With the engine off, look down the carb with a flashlight and repeatedly pump the gas. Look for a squirt of gas while pumping the accelerator. Count the number of squirts until it doesn't squirt anymore. The fuel bowl will then be empty.

Let us know the following:
1) How hard was it to start the car at the beginning of the test?
2) How long did the car idle before it died?
3) How strong were the squirts?
4) How many squirts did you get before the fuel bowl was empty?

Then we'll tell you what to do next.

Good Luck!

White_Knuckles

Captain obvious say's, you're solving for one of two things. Loss of fuel or spark. In my experience, loss of spark seems likely here. You say it only idles a couple minutes and dies. Fuel demand at idle is very low and even if your pump was shot, it would keep the float bowl full at idle. Post 12 suggests you calc your float height and check for fuel presence via the throttle pump. He seems like a good Chevy guy but you better wait a couple hours after flooding your car from that test!

I don't trust auto-store HEI diags as you have intermittent issues. Change out the HEI module as posts 5 and 7 detail. They are notorious for instant death and healing themselves. Just swap it and keep your pull for a spare.

The problem here is both loss of fuel & spark have similar death symptoms. Loss of ignition voltage such as a worn key switch contact will be instant. No sputtering or bucking involved. What you describe is a death rattle on the way down. An excessive lean fuel condition acts like this where normally noticed under cruise or throttle transition. A clogged fuel filter is suspicious. The pump is easily checked disconnecting the line at the carb and sticking it or a test hose cutting into a clear container like a plastic pop bottle. Disconnect the distributor tach/power connector (so the car doesn't start) and have someone crank the car while observing what should be consistent pulse streams. Change the fuel filter while you're in there.

Based on that bugger kicking around before it croaks, I'd chase it in this order:

Test for obvious vacuum leaks - HEI/coil - Fuel Filter - Fuel Pump.

69 Ragtop

You could be right, White Knuckles. I agree that out of 10 times, 9 times it's ignition. I'm keying on the fact in this case that the problem is worsening. I also wanted to give the poster an easy test. (Not knowing the skill level I was reluctant to have him disconnect the fuel line and subsequently burn the house down.)

I do respectfully disagree about the fuel filter. Symptoms of that are typically observed under load.

I'm not exactly a Chevy guy. My buddy and I raced a '68 442 for about 5 years in the '70s.

We need a little cooperation here antman94! Is it warm where you are? We need you in the garage diagnosing the problem! :>)

Jamesburke01

I know it's been 7 years and you probably fixed the issue. I had the same issue 2 months ago and it lasted until i completely ran it out of gas. And since then it hasn't shut off while going down the road. Be wary of putting seafoam in these systems it seems like the 80s Oldsmobiles don't like it

Jamesburke01

you opened the wrong part. If it's like the one on my cutlass it should have 4 L shaped hooks to turn and pull off. That's how you get to the pick up. Don't worry I did the same thing at first too