Quote:
Originally Posted by ChevyTech
The sensor is showing a resistance that is not far off. The engine should start and run they way it is supposed to with the reading you got from the sensor.
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It's been one weird thing after another. It ran great for the last year, then all of a sudden...
Quote:
Originally Posted by ChevyTech
If the crankcase is getting fuel in it, there is another problem. Could the fuel have gotten into the crankcase before you did the TBI work and maybe you already fixed the problem like fuel leaking from the TBI?
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Definitely not. Or, maybe I should say, "not to my knowledge". :-\
After rebuilding the TBI, it started right up and ran GREAT. I was on the way to get gas, and it died about a mile down the road. Thought it was empty, but when I added 2 gallons of gas, it would not start. Came back next morning and it fired right up, but died again as I was backing into my parking spot at home. I didn't even smell gas until I went to warm it up to run tests. This is when the crankcase started filling with gas, and the oil pressure dropped WAY down. I was worried, about that, but let it run for awhile, trying to get it up to operating temp.
Quote:
Originally Posted by ChevyTech
The sensor can be good, but if the wiring to it is bad, the computer will get bad data.
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This seems unlikely on this particular truck. It was well cared for all its life (except for being parked outside). All the wires and connectors look great, no corrosion anywhere.
Quote:
Originally Posted by ChevyTech
Resistance on the wire, or wire connections, will cause the computer to think it is colder, so more fuel gets injected.
If the ground wires have resistance the same thing c an happen. The most important grounds are the ground wires at the front of the intake near the thermostat or manifold studs.
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That's one I didn't know and haven't checked yet. Will check these.
I replaced the starter and the battery right after rebuilding the TBI, because I couldn't get it to start and the battery tested "good" (but it was bad), so I replaced the starter first (it was an old rebuilt and was rusty anyway). I also removed and cleaned the battery ground wire at the engine (it was fine).
Quote:
Originally Posted by ChevyTech
The TBI trucks don't leak fuel into the oil like the central port injected trucks do. I would change the oil, because if that much fuel is getting in the oil, it should be obvious if you look at the TBI with it running.
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Good to know that the TBIs don't leak that way!
Yes, you would think it would be obvious, but it's not and I don't know why! This is why I asked how much gas I should be seeing with engine idling. BEFORE I rebuilt the TBI, I could see a thin coating of gas on one butterfly, and the other one looked DRY. At that time, the truck was running too lean and never flooded, EVER.
After rebuilding the TBI, there was a thin coating of gas on the bores and butterfly valves, but I could not see the injectors actually SPRAY gas while engine was idling. Note I said "idling". Did not check for spray at higher RPM because all hell broke loose before I could get to that.
Thanks for not giving up on me yet! I really need this truck back on the road. My other driver got wrecked last month (not my fault).
Would it help to take pictures and post them? Should I test the Idle Air Control? Is it time to dismantle the TBI again? Should I get the injectors tested by a qualified shop? Seems like the ONLY possibilities are a) Injectors are dumping too much gas in the engine (reason still TBD), or b) Gas is LEAKING into the engine from somewhere (besides the injectors).
When I replaced the fuel filter, I didn't cycle the fuel pump to relieve the pressure. First I disconnected the fuel hose between tank and filter. Then I disconnected the incoming fuel line from the TBI, and not much more gas dribbled out. Then I started disconnecting the outgoing fuel line (return line for when there's too much pressure), and it just kept on leaking and leaking gas. I finally gave up and tightened it back up again. Does this tell you anything? Is there any way that a plugged up return line could result in gas being dumped into the engine?