engine dies in 15 minutes
 

1970 GMC probably a '72 engine, 350, Q jet, auto tranny. Just replaced the mechanical fuel pump. It still dies at 13 to 15 minutes, and it will have to cool down for at least an hour, then do it again. Any help would be appreciated.

Re: engine dies in 15 minutes
 

What does it have to cool down for an hour? Will it not restart or?

Re: engine dies in 15 minutes
 

It will turn over, but not fire. I've checked the gas cap, no vacuum in the tank. Just replaced the fuel pump, I can pull on the throttle and squirt fuel in the carb.

Re: engine dies in 15 minutes
 

Do you have an HEI distributor? Almost sounds like the control module or something is bad and when it gets heated up, it's causing the truck to die. Another thought I had was the motor is running too rich and maybe flooding itself out? Are your spark plugs wet?

Re: engine dies in 15 minutes
 

Sounds like it could be a plugged fuel filter to me

Re: engine dies in 15 minutes
 

Just had the same thing on my 67 GMC. It had the points distributor on it. After it ran for a while, 10-15 min it would die, then not start again, Wait an hour and it would fire up and again after 10-15 min it would do the same thing again. I went through EVERYTHING and finally put a new HEI distributor in it and it runs perfect now, no issues in 2 months.

Re: engine dies in 15 minutes
 

The HEI modules can get flaky when hot - if you have a spare distributor, that'd be my guess. My first guess was tank venting, but you said no vacuum, so HEI it is!

Re: engine dies in 15 minutes
 

Thanks for the ideas, I'll get back to it next weekend.

Re: engine dies in 15 minutes
 

Had a 1990 Suburban do the same thing. Just needed new cap/rotor, plugs, and wires. Ran perfect after that. Check that distributor too.

Re: engine dies in 15 minutes
 

Something else, there is a short rubber hose below the tank, if its getting old and rotted it can collapse and restrict fuel flow, that includes any rubber line between the tank and pump, make sure its actual fuel line that is reinforced and not non reinforced rubber hose...

Check the filter like previously mentioned, try and back flow it with some air and see if there are any fine white chards of material in it, if there is that is the pickup sock deteriorating, time to replace the pickup screen.

Re: engine dies in 15 minutes
 

+1 on ignition related components failing after heating up. Not too long ago, I purchased 64 Corvair and installed all new ignition parts. A mile or so down the road and it stop dead in its tracks. I decided to replace the points, condenser and ignition coil again...all was well the second time around. So, BOOB (Bad Out Of Box) parts are not uncommon.

Re: engine dies in 15 minutes
 

If it is the old points and condenser distributor, sounds like the coil is breaking down. To test it, remove it, then shake it, If it makes a sloshing noise replace it.

Could be the same for HEI.

Re: engine dies in 15 minutes
 

Thanks for the ideas, I'll check them out.:gmc2:

Re: engine dies in 15 minutes
 

Check that the fuel tank is venting. If you remove the gas cap and the problem goes away, then that's what it is.

Re: engine dies in 15 minutes
 

I would bet its the coil.

Re: engine dies in 15 minutes
 

Also, if you replaced the hei module recently and didn't use the dielectric grease,the module will fry to a crisp.... just sayin'
Ben
:metal:

Re: engine dies in 15 minutes
 

He said no vacuum in the tank in his initial description.

Re: engine dies in 15 minutes
 

fuel filter

Re: engine dies in 15 minutes
 

Tank vent > fuel filter > distributor.................More likely distributor than fuel filter, but a filter is cheap and easy. If all that fails, I'd replace all fuel lines, including the vent line. If that fails, couldn't tell ya.

Don't know if that could be a fuel pump. Seems it would work or it doesn't.

Re: engine dies in 15 minutes
 

Just something to check, but is there any fuel coming out the "Weep Hole" by chance? might want to make sure you have no fuel getting into your oil pan also....
Ben
:metal:

Re: engine dies in 15 minutes
 

Hello to anyone reading this, I put a new coil in today and doubled my run time. Now it will run for about 30 minutes. I bought a remote starter, but haven't figured how to hook it up, the directions are for a more modern vehicle. Can a part store test my module for me?

Re: engine dies in 15 minutes
 

I don't think so. They sure can sell you a Chinese one that won't last either though. I have a stash of GM ones incase I ever need them. Go to the JY and grab a few if you can. Around here you won't really find anything that old but maybe you have a yard with older stuff nearby.

Re: engine dies in 15 minutes
 

I still say it's a fuel issue , The dist ,coil,capacitor ,and anything else wouldn't continue to start multiple times and just run for 13-15 minutes ,It would have completely failed already .

Dirty fuel pick up in tank
Fuel line between tank and hardline under cab collapsing / cracked
Inline fuel filter
Bronze fuel filter in carb

it starts ,runs until crud in fuel line restricts flow .Won't restart ,wait an hour fuel flows back clearing line and restarts .Dies if 13-15 minutes . Why no pictures ? a good look at the condition of the rest of the engine/fuel lines and ignition could let someone give a further diagnosis .have you tried starting it once it dies using carb cleaner to see if it will fire even for a few seconds ?:chevy:

Re: engine dies in 15 minutes
 

I just red back thru your threads ,You've been dealing with this issue since 6/2012 ? Take it to your local mechanic .:chevy:

http://67-72chevytrucks.com/vboard/s...d.php?t=528601

http://67-72chevytrucks.com/vboard/s...d.php?t=529028

http://67-72chevytrucks.com/vboard/s...d.php?t=534240

Re: engine dies in 15 minutes
 

"I bought a remote starter, but haven't figured how to hook it up, the directions are for a more modern vehicle".

If you bought the Actron Remote Starter I believe it is in the instructions (Figure 5) - (see attached pdf)

Re using the remote starter I found it more convenient to just install a permanent 12 gauge wire from that "S" lug on the solenoid up to an insulated lug (really just a 1/4"-20 x 1" bolt through a chunk of plastic) mounted on the inside passenger side fender well next to the factory distribution block - then you can hook up the remote starter wires - one to that bolt and the other to your positive on the battery - without having to thread the leads through the headers and into the cramped space around the solenoid where it is easy to short against the positive cable.

Always turn your key to the run position before activating a remote starter (as advised in most repair manuals)..