EGR valve clogging

Pnutman · April 1, 2002

Situation; '93 Blazer S-10 with 4.3L Vortec, W in VIN. I have had to take the EGR valve off every day for over a week to knock out chunks of carbon. They lodge the valve open and you can imagine how that makes it run at low/moderate speeds. Removed the plenum and found the fuel pres regulator

leaking. Replaced the CPI. (reconditioned CPI unit for 229.00). I have run 2 cans of GM Top Engine Cleaner thru the intake when running, and one into the EGR port with the

valve removed. Let it sit for 15 min then cranked it up without the valve on it. New fuel pump and strainer, new fuel filter. By the way, now my fuel pump runs all the time the engine is on, the gas gage reads full all the time, the fuel pump relay and the fuse are warm to the touch after operating for a while (whats up with that?). But when I first turn on the ignition

switch to "run" the fuel pump only runs until preasurized. I do get a big cloud of smoke on morning and late noon start up so am going to do the valve seals. Could that be building up the carbon?

No peace here.

GreenRado · April 3, 2002

All I can add is that I had similar issue w/ carbon build-up in my '95 Jimmy - ran really bad. Dealer ran GM top cleaner thru and it seemed OK after that (we sold it 5K mikes later).

Whether it's any help or not, my Jimmy's fuel pump was noisey, especially when it got below 1/4 tank - they may run all the time anyway?

Sorry I can't be more help - sounds like quite a problem. Best of luck.

BTW, welcome to the forum and site!