Help diagnose a problem ?

[Jesse Jaymes]

Need help please. Just gimme a clue of where to start looking.

Problem: Out of nowhere 1974 Blazer 350ci with headers, Edelbrock intake and carb, starts to die in the middle of the road. Just running like crap. Seems as though we went from 8 cyl, to 5, to 3. It would run, but poorly. This was after starting it and letting it warm up about 1 minute. It ran OK for the first 1 mile or so, then it started acting up.

I would restart fairly easy. Runs OK to good in neutral. Then I would put it back in drive, and it would run OK for just a minute, then repeat. I was able to limp it the 2 miles back home. Would backfire, and it needed the pedal to be feathered to keep it running.

This happened to my girlfriend a month ago. I fired it right up and drove it home. Made her look a fool, but it ran fine for me.

This was never a problem to me prior, and it seems as nothing "crept" up on me or was increasingly worse.

I am not sure what happens when fuel pumps go, or distributor problems, but I did not tweak or mess with anything, other than top off the T-case and diffs.

Could it be the carb and choke stuck ??

Any other ideas of where to begin to troubleshoot the problem ?

I don't think it was electrical, or wires touching, as nothing changed from running great to hardly running.

 

[chiefheaphy]

timing, fuel delivery, vacuum leak...

 

[RedBrute]

When it dies next time, pop the aircleaner lid and actuate the throttle linkage while looking into the throttle bores. Check to see a healthy squirt from the accelerator pump jets. If not, you have a fuel delivery problem, if it squirts it may me spark or a vac leak that comes and goes.

 

[Jesse Jaymes]

Seems simple enough and easy to do. Thanks for the direction

 

[throttleissues]

Does it have an HEI distributor? If it does, you may have a bad module. They often run fine cold, but take a dive once they warm up. If this is the case, I would recommend authentic AC Delco part. Good luck with it regardless.

 

[Hogback Fabrication]

When it dies next time, pop the aircleaner lid and actuate the throttle linkage while looking into the throttle bores. Check to see a healthy squirt from the accelerator pump jets. If not, you have a fuel delivery problem, if it squirts it may me spark or a vac leak that comes and goes.

That only guarantees that it has fuel at all.


IMO, as chiefheaphy said, timing is the most likely culprit. Then fuel delivery (i.e. carb, choke most likely).

 

[Thunder]

X2 on the distributor module if you have HEI.
Most auto parts store like NAPA, Autozone ect will test them for you. If you pull it out and take it down to them.

 

[Mike D]

I would replace the float needle and seat. I bet a piece of dirt or worn needle gasket has raised the fuel level a bit, enough to almost flood the engine . This very rich mixture would try to fowl your spark plugs. While you have the carb apart replace the float, They loose boincy or get gas-logged when they get old.