PCV dumping crud into throttle body
 

I had been getting an EGR code and tried everything to find and fix the problem. I finally found the reason. The PCV line coming from the PCV valve was dumping crud (sludge? carbon?) into the throttle body and clogging some vacuum passages, including the EGR vacuum passage. I cleaned it all out (it was really tough to remove because some of it had hardened) and the EGR code went away. After driving a few hundred miles, I have the same problem again. What can I do to keep this from happening again? I am totally against getting rid of the PCV system, so don't even suggest it. Will I need to take the engine apart and clean it, or is there some sort of chemical treatment I can use? I'm not positive, but I think the reason there is crud in the engine is that I have been needing to change the valve seals for a while. The PCV valve and lines have all been changed, as well as anything else to do with the EGR operation. Any suggestions?

I could be all wet here, but on my TPI set up the PCV does not flow back into the throttle body. There is a vent (hollow/empty hose connector) on the passenger's side valve cover that connects to the throttle body, but that is a source of filtered fresh air FROM the throttle body to the valve cover to feed the suction being created by the PCV valve on the driver's side valve cover. On mine the PCV "out" flow, which might contain some oil or oil vapors, goed into the intake manifold itself (doesn't flow back to the throttle body). If you want, you can use a filtered breather on the passenger VC and remove/plug the hose coming from the TB. Only problem with that is the breather might not flow as well as the feed from the cars main air filter.

This is how my speed density system is set up. If you're running a MAF I suppose it could be different. Just trying to help....

My car is has a 305 TBI engine running off of speed density. The vacuum line that runs out of the throttle body (the one that the crud is coming out of) controls the PCV valve in the driver's side valve cover. Coming out of the passenger's side valve cover is a tube that goes up and into the air filter. This tube has a breather filter on the end of it, inside the air cleaner. This allows fresh, clean air to circulate into the crankcase, while the PCV valve, with the help of the vacuum created at the throttle body, pulls nasty air out of the crankcase, depositing it into the throttle body to be reburned. The stupid thing is sucking more than air out of the crankcase though. :(

You could always do what a lot of folks on here have done - add an oil trap to the line between the PCV and the TB/intake. Some have used a can full of steel wool. Others, myself included, have added a semi-transparent canister type fuel filter in line before the TB. Catches oil so it doesn't make it to the TB. Can get a pic and part number tonight if you're interested....

I have considered doing that, but I would really rather find the cause of the problem and stop it where it starts. Could you go ahead and give me that part number just in case?

Any other ideas?

Cause would almost have to be blow by, wouldn't it?

That's all I can figure. I hope it's valve seals and not piston rings. I am having the valve seals replaced soon. Is there any way I can clean this sludge out without having to tear the engine apart?