Need help from the TBI crew

Off to FL on the weekend, and I always try and do a little work on mom's 91 when I'm there. It has been smoking a bit. Sometimes a good puff on startup, but not all the time. Sometimes it will smoke while stopped at a traffic light. It's not constant, however. I know the usual suspect will be valve seals or guides, but I know that drain backs in the heads are another possibility. A third that I'm considering is PCV.

Does someone have a good image or diagram of the PCV system? Going from memory of the last time I saw it, I'm not convinced that it is plumbed correctly. Let me know what should go in both valve covers, and connected where.

Thanks, gentlemen!

No diagram, but from memory:

PCV valve goes to the front of the TBI, gets inserted in DS valve cover.

PS valve cover goes from VC to air filter housing hose after the filter.

Check the port in the TBI for blockage with a piece of wire.

Fred Kiehl wrote:

Check the port in the TBI for blockage with a piece of wire.

Can you elaborate? Do you mean the vacuum feed for the PCV?

jayoldschool wrote:

Fred Kiehl wrote:

Check the port in the TBI for blockage with a piece of wire.

Can you elaborate?  Do you mean the vacuum feed for the PCV?

The hose connects to the TBI, and the port to the intake can get clogged with gunk. A piece of soft wire and some solvent will clean it out.

Never thought of that one. Huh.

Jay:

Check under the valve covers first. Any of these cars that see any extended city driving suffer from the dreaded oil drain back blockage. For the sake of a couple of gaskets and an hour, its worth the effort. Its not a question of if, its when. Even the best valve seal doesn't work submerged.

Had two TBIs and one carb'd engine do this. The original engine in the locomotive had both cylinders 6 and 8 singing anchors away and number 7 going down for the count. Flush all the drain backs thoroughly then change the oil.

Found it was easier to pull the throttle body off the engine to clean out the PCV port. It does a 90 degree before going into the intake. The wire will clear up the horizontal part but if it is bad, the vertical channel is also plugged up. Real common problem. Again only takes about 1/2 hour to pull the TB and clean it properly and the gasket is cheap.

Will be joining the Florida bunch the last weekend in March. 4 days in the Panhandle and then down to Fort Myers for a couple of weeks, including the T-Bird show at the Edison Museum on the 4th of April. Really looking forward to leaving this weather for a couple of weeks.

Bill

^ Are you detouring to Wagonfest FL?

Stingroo wrote:

^ Are you detouring to Wagonfest FL?

Would love to come but won't be in Florida till late on the 29th, and that will be at Torreya State Park, west of Tallahassee. The Gods of timing are not shinning on us.

Bill