Has anyone ever removed the horrible EGR valve on a 94 4.3 VORTEC engine. Is this an option. I am getting large amounts of carbon and it is causeing idleing problems. Any info will help.

Thanks ahead of time.

Dont mean just remove it, but make a plate to cover the port.

 

Considering that tampering with emissions equipment is prohibited by federal law in the US and likely Canada as well... But really, the EGR system, when functioning normally, does a pretty important job in the engine. Without changing the tuning of the PCM to richen the mixture, cylinder temperatures with a defeated EGR system can result in valve damage.

I would recommend you find the reason for the excessive carbon and fix that, then clean the system. It could be a fuel leak internal to the plenum causing an overly rich burn, a lazy O2 sensor, bad state of tune in terms of the plugs/wires/cap/rotor, or the carbon buildup from 16 years of use could be flaking off of the inside of the EGR supply tube and maybe just needs a good cleaning with some sensor safe carbon cleaner and a long wire pipe cleaner.

Also worth mentioning is that you can purchase an EGR gasket with an integrated screen that will ensure that any carbon chunks that manage to get to/through the screen will be small enough as to not clog the valve.

 

Thanks for the info. I have done most of what you recommended. I might have to try cleaning a little better and see if that helps. I have replaced Egr and plenum (spider kit) and standard tune up and it ran great for a week. Now I am back to the horrible low rpm rough idle.

Maybe Vaccum lines could be causing that? It seems to be a common problem.

 

On the CPI engine which does not have a MAF sensor, a vacuum leak would typically have a high idle, but would not contribute to other driveability concerns because there is no sensor directly measuring air flow. This is a speed density system, not a true air flow measurement system like the 96+ SCFI engines have. Besides, even with a MAF sensor, the mixture would go irregularly lean until the PCM compensated by richening up the STFT/LTFT (short/long term fuel trims).

I am betting that there is just junk built up in the LIM passages from years of use that is starting to flake off.

 

thanks for your help, Ill have a go at it this weekend.