I don't see anything it would harm but then you don't say what car it is so if its newer it might.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Fair enough it is a 1992 Chevy Astro Van with a 4.3L vin W Engine and it has an electronically controlled EGR.

PCV system is supposed to be a closed system. There is a PCV Valve connected to a vacuum source up near the throttle butterfly. I cannot remember if the butterfly valve crosses over the vacuum port or not.
Specifically what I am trying to determine is how the PCV Valve would act in the face of the engine side being opened to the atmosphere.

I an speculating that if the PCV valve would remain open that would allow the Intake Manifold Vacuum to fall and that from that the computer would interpret that you were trying tying to accelerate and give you more fuel. Which would be why I was getting more fuel (hight HC) resuliting in the high CO.

Fault codes 22- Low TPS Voltage, 42- Electronic spark timing ECM/PCM open or grounded circuit and finally 44- O2 Sensor lean.

So on Code 44 carbon covering the O2 sensor could cause it to show lean. I have not pulled that yet.

After checking the fault codes I shut it off and disconnected and reconnected the electrical connectors going to the distributor and when I tried to restart it cranked but would not start.

I found that the ECM1 fuse was shot. Replaced it and it started.
Today’s plan is to drive it a bit see if the check engine light still comes on intermittently and hope it does not die on me and see if any of the codes clear.

Before I sat down on the computer I cleaned up the kitty litter I poured on the 5 quart oil spill in the drive way so I can get under the Van and see if the O2 sensor is carboned up or not and see if any of the wires got burned as there is a section of the wiring loom near the exhaust pipe.

Before the Smog Test I had replace the Destributor Cap and today I found that one of the spark wire connections was not snapped down firmly. I also rechecked the firing order.

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84 300D, 82 Volvo 244Gl Diesel