Starts runs ok, then rough and dies

derbman · January 12, 2012

I am looking fo help on an '89 Blazer. When I started working on it it wouldn't start at all, replaced fuel filter, cleaned of cap and rotor, repaired a few vacum leaks, found a bad coil and now it starts. Runs good for a while, then it starts to get rougher and dies. now it won't start at all. Almost like it is vapor locked? Let it sit for a while then cranks better and wil star after a while. Any help would be Great!

00Silverado4x4 · January 12, 2012

Crappy gas in the tank? If it has sat for awhile it could have sucked up a bunch junk from the tank and plugged filter again? Fuel pump getting ready to die?

Just a few guesses/ideas off top of my head.

Spurshot · January 12, 2012

Check the fuel pressure at the engine or filter. You can make up a T-fitting with the pressure guage in between where the filter goes in. Or if you just want to see if the pump is putting out anything at all, disconnect the filter, put then of the fuel line in a catch can and turn the ignition on. It should pump fuel. If you took it off before the filter and it's pumping fuel well, put the filter back on the end and see if it pumps thru the filter into the catch can. Don't reverse the filter flow when doing this because it would contaminate the filter on the wrong side and introduce crap into the injectors.

derbman · January 12, 2012

Thanks for the tips, how much fuel pressure should it be putting out?

Spurshot · January 12, 2012

Derb,

I don't have a manual for that early truck. Probably a throttle body injector? Maybe one of the GM techs over on the engine forum could tell you.

But as a quick sanity check, just disconnect the line at the filter and see if any fuel pumps thru. It should squirt like hell.

derbman · January 12, 2012

Thanks I'll try that!

Akinsmj8385 · January 20, 2012

I am looking fo help on an '89 Blazer. When I started working on it it wouldn't start at all, replaced fuel filter, cleaned of cap and rotor, repaired a few vacum leaks, found a bad coil and now it starts. Runs good for a while, then it starts to get rougher and dies. now it won't start at all. Almost like it is vapor locked? Let it sit for a while then cranks better and wil star after a while. Any help would be Great!

Have you changed your spark plugs and/or wires? How about your PVC valve? It could be clogged.