Middian

72 delta 88 350. Ok. I wasnt sure where to post this wether electrical or mechanical as im not sure of the nature of the issue. Experiencing low oil pressure but as ive heard the gauge hook up is at the worst possible place to put the sensor. Driver side end of block. So i threw in some lucas oil additive which is supposed to really lubricate the motor and felt slugish pedal feel. Might i add i also cut my exhaust to a straight pipe with the mufflers ending at just before the diff. Right after that the car started to feel a little slugish which is about the same time i added the oil additive. Anyways im driving the car and it feels as if the spark to the plugs just dies off. Plugs seem fine. Pull over car starts riiiggt up and im on my way til about another 5 miles and i happens againm the eventually this happens enough to blow my mufflers. Drive the car fine. Still happens aftet a while. Pullef fuel line out amd squirts fine at crank. Alternator fine. Starter fine. Any suggestions? Just replaced fuel sending unit n went bad on the way to nevada like immediately out of nowhere. Trying to get xar going by tomorrow
HELP

scottv442

sounds like fuel starvation. next time it dies on the road check the and see if the carb has any fuel in it by pumping the throttle while looking down the primary carb throat. you should see fuel squirting into the throat as you pump the throttle. if no fuel is seen squirting immediately then you may have a weak fuel pump or partially plugged fuel sock or fuel line. the fuel sock is in the gas tank at the pickup and can collapse or plug from debris in older cars.
other possible is no air getting to the carb due to dirty air filter, but you probably check that by now.

m371961

Have you checked/replaced fuel filter?

toymobile

Check fuel filter at fuel inlet to carb, 1in wrench and 5/8 line wrench required, very bad design in my opinion but I usually replace that filter once a year JUST BECAUSE. Good luck

Johnny

scottv442

X2^^^ above also

Koda

Also when you pull over to check pull the gas cap. Notice if there is suction on the cap and a big WHOOSH of air flowing in when you pull it off. Those tanks are vented, the caps are not, and sometimes the vents get plugged, and you have no vents then. Temporary solution is stuff a rag in the filler snout and go to autozone and buy a vented cap. Real solution is fix the vents.

Troubleshooting for gas tank issues can be done by removing line from tank to pump and running hose from pump into red gas can. Be sure to plug line to tank.

Rocketowner

Does the car have a Catalytic Converter? If so,that sounds like the problem.Most muffler shops can check the pressure and tell you if it is clogged. Good luck, Larry

svnt442

72....no.

Middian

No cat. I would experience car dying while driving at highway speeds, sometimes tap the gas or floor it and car would start back up and run. Ill check fuel filter today. Ill also check the Rochester 4 bbl thats on it. Would you guys rule out coil or dist. Issues?

Middian

I ran the car for a while with the cap it came with andno issues. Pulled the air filter off all together and no start.

Middian

I think the issue with my mufflers blowing is all that unburned gas being burned after the car starts up again right after dying with my foot on the gas pedal

lemoldsnut

Another item that could be giving you issues is the control module if running HEI ignition, as well as the harness from the coil to it. If not running an HEI never mind.

Just another thought

Larry

Middian

New sending unit so new sock. Would fuel pump react to pumping pedal with car off. No fuel pump in tank just mechanical fuel pump

Middian

Points

scottv442

mech. fuel pump only operates when engine is running. i was referring to the carburetor "squirt" pump that gives your motor a shot of gas when you first push on the pedal. if you stick your face over the carb and push the throttle open with your hand you should see and hear a quick shot of gas being squirted into the carburetor's primaries.

question though....you mentioned the mufflers were blowing from too much gas collecting in the exhaust pipes at restart?
Does your car have a strong smell of gas before it shuts off on the highway?
does it shoot a lot of black smoke or blue smoke out the tailpipes when you start it?

if its black smoke it could be your car is flooding with gas when you drive it, not starving as originally thought. pull a spark plug and see if its wet with gas or dry after it dies on the freeway.
this is a sure sign of either a stuck/dirty needle valve or float in the carb.

diagnostics from a afar are tough without seeing or hearing it.

Middian

Hard to tell. When car dies i hear a hissing sound as i give it gas. Sometimes it dies sometimes it starts bacl up with a tap of the throttle or throttle completely depressed. Cant tell if i had gas odor as i was driving about 65 mph nor smoke.

svnt442

I'm wondering if the timing chain may have jumped a tooth.

Middian

Please dont tell me that... haha car doesn't run rough or anything. And psi stays at 25 oil at 70 mph. Im sure ime getting more than that on the bottom end

svnt442

That wouldn't effect the oil pressure. It can't hurt to throw a timing light on it to see what's going on.

Middian

Ok checked carb and im getting a jet of fuel after pulling on throttle. Fuel is getting to the carburetor and engine is turning over but it sounds like i may be getting no spark or bad fuel mixture? Coil? Distributor?

RROLDSX

Try disconnecting your fuel line from the carb and let the carb drain out. Sometimes if you've run your gas tank lower than you normally do your carb bowl can contain a bunch of water and green stuff.

Middian

Disconnect fuel line and crank the engine til the carb runs dry?

Middian

How many times should i crank it if so?

RROLDSX

No! Just drain the carb. Do not crank the engine over or you will be pumping fuel all over. Just remove the fuel filter in the carb, replace if necessary and drain the carb. Not saying this is the problem but it could be the solution. Have something to catch the fuel like a cap from an aerosol can. Hope this helps.

Middian

INDEED IT DID. fuel filter was dirty, However i drained the carburetor and caught the fuel from the gas line in a gas tank, replaced, pumped gas twice, and voila! SOMETHING is causing the plugs to loose spark. Coil maybe? Any ideas gentleman?

RROLDSX

A faulty ignition coil can act like that as well. Not sure if someone like Napa can test those but it's worth a shot.

76olds

Did you say your blowing mufflers out (expanding them) ? Is it backfiring up through the carb at all, or just exhaust ? I'm wondering if its really carboned up under the choke plate in the intake manifold. Also the return line from the carb to the carbon canister may be an issue if equipped. Sounds like your getting sudden surges of fuel, filling the bowls then backfiring and cutting out. Are you having any issues with your choke?

Fun71

Since gas floats on water (and therefore the water would be at the bottom of the tank all the time) wouldn't the water get sucked up no matter how much fuel was in the tank?

toymobile

With a points Dist the wire that goes to the coil from the points inside the dist has to move with the vacuum advance and can break and pull apart but when the advance releases the breaker plate GO BACK together now you have ignition again.

Just a thought easy enough to check just remove the cap and gently pull the wire where it passes through the dist housuing.

Good luck

Johnny

nsnarsk65cutlass

What kind of distributer does it have?Sounds like you are loosing spark.

Railguy

Condenser can go bad to. Also a common mistake with points is leaving the key on without the engine running . Like you start it up and it shuts off and you don't turn the key off. Can burn the points. Do you remember doing that recently?
I've had condensers go bad and work for a while then not then work again.
Railguy

Railguy

Also the plastic on the cam gear for timing can come off. That makes it really sloppy and throughs the timing way off. And clogs up the oil pick up. You might want to drain the oil and see if anything besides oil comes out . Good luck.
Railguy

RROLDSX

Your absolutely correct, all I know is I've had a carb bowl full of water and green slime before. It happened several times before it finally cleaned out. It was my father in laws Plymouth and it was never run below a quarter tank until I got it. I suspect Middian's issue is spark related anyway.

Railguy

I ve heard of that happening with dirt.
I thought water wouldn't go through the filter
Railguy

fleming442

Check to make sure the coil wire is securely plugged into the cap.

I was cruising my 63 88 300 miles from home when it started acting up, and died in traffic. We pushed it onto a side street, and I couldn't find any awry. This old timer tells me how to check the points signal as I was clueless. I had a little spark when i pushed on them with a screw driver, so I put the cap back on. That's when I noticed that the coil wire had wiggled up out of the cap. I shoved it back down, fired it up, and down the road I went!

MDchanic

Because of the backfiring on re-start, I'm on the electrical side of this problem.

Coil and condenser are top candidates for progressively poorer running until stall on the highway, because this is a sustained draw of more current than a lower speed, which will cause more heat build-up and higher spark voltages, which will find and unmask insulation flaws.

Points and distributor wiring is lower on the list, because they will cause a sudden stop with no warning.

Spark plug wires are not excluded - they can do something similar if they are bad, but it will usually be on only one or two wires, and so will cause roughness rather than stalling.

This is a fine case for a SUN machine, but those no longer exist.

Since coils and condensers are both cheap, this is a case where just plain replacing one at a time may be the best way to diagnose (especially if you or a buddy has known-good used units sitting around).

- Eric

Octania

I vote for new pts & condenser

and tug at and closely inspect the wire on the dist'r that flexes during vacuum advance use.

then the coil and its terminals.

I wonder if the R bypass wire from coil to starter is shorting out on something down by the starter?

Indy_68_S

Had a similar prob with mine years ago. It'd die unexpectedly on the highway & I'd roll to a stop. After a min or two it'd restart & run fine. This happened maybe 3 times in 3 months. Finally it did it and wouldn't restart. No spark. Point set spring was cracked. I dug around in my trunk tool box and replaced the point set with an old one. It fired up & I set it by ear. Drove for a couple of weeks on old set with no probs. Replaced with a new set and never had the problem again.

oldcutlass

I agree with Eric, leaning towards electrical because of the backfire. It can also be a bad/corroded/poor connection HV coil-distributor wire.

Railguy

Could also be that cam gear . That would through the valve timing way off. Along with the spark timing. Wouldn't take long to drain the oil you don't have to change if nothing is wrong with it just dump back in. So it wouldn't cost anything.
Railguy