22re Running rich, poor fuel economy
 

I recently bought a 92 Toyota 22re Pickup. 5 speed standard, rebuilt engine in the last few years. The truck runs very rich and is getting piss poor fuel milage. My odometer doesn't work, but its getting around 250km to a tank from what I figured (knowing from driving the weekly route) I burned about 20L of fuel driving 2 mins to and from work, and around town.

Exhaust smells like gas, but isn't black, oil smells like gas, plugs were foul, especially #4 cyl, so I replaced them.I also noticed one or two backfires while at highway speeds. New fuel filter even though the old one looked new, adjusted valves, tested for exhaust leaks and found two pin holes, pre o2 sensor from the PO's bubble gum welds holding the exhaust system together, but I didn't think it would throw my fuel mixture off that much. Going to tack the pin holes shut. Jumped the Te1-e1 with a paper clip and no codes, I also jumped it while the truck was running and the idle dropped, so the TPS is working as it should? An oil change will be on the cards shortly here when I have time after work. Its a Canadian truck so no cat or downstream o2.

Any ideas? I bought this truck as a daily driver and to keep my 60 series out of the salt for the winter, and if it keeps sucking fuel the way it is, its not ideal as a daily. I had a 86 22re 4wd a few years back and it got almost twice the fuel economy as this one. I'm pretty frustrated as I spent 6k on the damn thing. Any suggestions as to what to look for next would be much appreciated.

I also noticed the idle mixture screw doesn't seem to change the idle when I screw it in, or out. Is that the sign of a vacuum leak?

Thanks

Yes, sounds like a vacuum leak. Double check ALL the vacuum lines against the sticker on the underside of the hood, upper left corner when it's open. If it's not there, google it. They are out there.

Check the timing is correct, the idle is below 1000 RPM, the vacuum lines that go to the distributor are the correct ones, and are on the correct ports. Make sure the distributor moves correctly when vacuum is applied to the lines that go to it. Make sure the diaphragm on the actuator on the side of the distributor doesn't have any leaks, and actually holds vacuum. It's a known failure item.
Make sure the sensor in the distributor has the correct air gap, and is putting out the correct signals.

Make sure the choke plate opens completely when the system is warmed up correctly. It's been known to stick. A little WD-40 to the moving parts of the carb, including the arms and such on the passenger side of it, can work wonders. I do mine about every 3 years or so, and it's paid off nicely. Again, make certain all the vacuum lines are routed correctly, and don't have any cracks, leaks, etc.

Having said all that, fuel in the oil sounds like a head gasket leak. You may well need to replace it. I would do compression, and leak down, tests.

Good luck, and let us know what you find...
Pat☺