dually running rich and randomly misfiring

I agree with that. But my problem is figuring out what's making it run rich. I'm getting just a bit aggrevated. Any suggestions will b appreciated

im just going to throw this out there only cause i had a similiar situation. on our old 95 blazer with the 4.3 vortech we were having the same issues. i threw everything i could think of at it to fix it and it would still run rich and blow black smoke out and idole like shit.. i was to the point that i was going to repalce the injectors also.. but i found that underneath the plenum is a fuel pressure regulator that mounts on the side of the main injector mechanism. i swapped that out and put it all back together and the blazer came to effing life. i mean i had not known there was that much horsepower in the v6 compared to what we had been driving with. and i hammerd down on it and cleaned out the exhaust and it wuit blowing black smoke out, idoled better, gas mileage went up.. so i dont know if that will help or not but i thought it would be worth the info to maybe check out.

My first suggestion back on 5/2 was injectors and regulator on the Vortec 7.4, regulator is outside the manifold, but it's in such a difficult place to reach (and remove the snap ring) that you pretty much need the plenum disassembled to do it. Be sure to replace the little vacuum line while you're at it as it's probably crispy and loose.

Richard

Ok so I pull the plentum. And got to the regulator. Filter had some small particles on it. While I was looking. Noticed that the back injector. The c clip on the side was broke. Don't know what that would cause. But also had alot of gas on top of the gasket between the plentum. Gasket looks good but Yule could there b gas on it?? New injector and gaskets maybe. Don't really got the cash right now to do all injectors.

How do the ports look from one to another? If some are washed clean and others look kind of carbon-coated, you've got shit for injectors, time to do them all. If you only try to do the ones you think are bad, you'll be back in there again soon.

Example:


Yeah the cost of the good Bosch injectors is kind of up there; a couple of people have bought "reconditioned" ones for a few hundred cheaper but man I really don't know. I'm 99% sure they're not taking them apart and actually replacing any worn parts, they're just cleaning the crap out of them and running a flow test on them (hopefully)...

Richard

so ordered the bosch injectors..and gaskets..just curious y on the inside of the intake in the very back of it..had a small oil spot....pretty wet..like a puddle about as round as a baseball or so?? and anyone know what the tourque sequence is for the plentum

Did you order the regulator too? You really should do it while you're in there, way too much work to go back in just for the regulator. Even a good made in USA one like the Standard is only $50 or so.

Beats me on the oil, can you get a pic, might help?

Shouldn't be any torque sequence that matters, that thing doesn't need to be crazy tight. Just snug should be fine. I'm sure there's a torque spec somewhere but I don't have a manual new enough to list it, maybe someone else does and can post.

Richard

Start in the center and work your way out criss crossing each time. Tighten to 44 in-lbs and then start over from the begining and finish at 88 in-lbs. Oil could be coming from the lower intake gasket. Check there bro.

Ok guys so I put in the new Bosch injectors and fuel pressure regulator. But first I went ahead and took off the lower intake also and changed gaskets. And noticed that one of the distributor screws that hold the cap down where broke. So I bought a new one. Changed lower intake gaskets. Torqued bolts. Installed regulator and injectors. New plentum gaskets. And plugged everything back in where it went. And now truck won't start. Cranks that's it. Gets strong spark from coil. But not real strong to the plugs. Think the timing is jacked up now. If so how do i fix it

O and it's throwing the code p1351