This is my '89 EF body with a D16Y7 swap, original OBD0 dizzy and ECU with DPFI.

Had a burned exhaust valve on Cyl. #2. Got a valve job, new valve stem seals. The exhaust doesn't smell like gasoline anymore but I'm still burning oil. In particular when I coast down a hill in 5th gear, and then hit the gas at the bottom. Lots of smoke in the rearview.

Probably burns a quart every 1000 miles. Maybe a bit more, if I'm in low gears or there are lots of hills. Spark plugs show fouling but they're all about the same.

So I did a compression test:

Cyl. 4 - 120 psi
Cyl. 3 - 110/105
Cyl. 2 - 95/100
Cyl. 3 - 110/100

Then a leakdown. @ 10 psi and TDC, ~25% loss. Consistent across the cylinders.

The PCV valve is also defective. So I am going to get a new one in there and see if that makes a difference.

What do these numbers say about my piston rings? Is there anything else I should look into to address my oil consumption/rough running problem?

Specifically, what about the temperature sensor/cold start injector? The D16Y7 doesn't have the coolant sensor port in the back of the block like the B motor. My temperature sender is on the thermostat. I've been told the EF radiator was massively oversized for the engine, so I've had that connector dangling without (obvious) problems. Does the OBD0 ECU use the coolant temperature to change engine performance, or is the temperature sender only used to turn the radiator fan on when overheating becomes an issue?

 

Does the OBD0 ECU use the coolant temperature to change engine performance, or is the temperature sender only used to turn the radiator fan on when overheating becomes an issue?
no it affects fuel maps and ur fan keeps the engine at a set temp...id say you have bad compression,and your leak down test is also bad,(not realy supposed to loose anythin) thats probibly y your burning oil

 

There is a pretty simple way to check whether or not your issue is by worn rings or valves not sealing/ seating. Get out your tools for your compression test again. Get all your #'s fresh again. Then once you have those with the plugs still out pour a SLIGHT amount of oil straight into the cylinder through the spark plug port. If your compression goes up then you need new rings, if it stays the same you need to be looking at your valves.

 

also, no your PCV system will not cause your readings and results.

 

It looks like the D16Y7 compression numbers should be 180-210 psi on a healthy engine. So mine do seem too low :(

I am going to look up book values for the D16Y7 at the library tomorrow.

I am still planning on replacing the failed PCV, and checking into the temperature sensor wiring.