Fuel??? Ignition??? I dont know
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Fuel??? Ignition??? I dont know
So my 99 1500 4wd w/ a 5.9 died on my way home from work. It acted like it wasn't getting any fuel. I assumed it was the fuel pump got it home pump was working but I went ahead and dropped the tank just to see if the screen was plugged and decided to go ahead and put a new pump in. This didn't help truck still wouldn't start. replaced plugs, wires, coil, cap, and rotor still nothing. So I put a new PCV valve, MAP sensor, and TPS, still nothing truck will start and run for about a second maybe two as long as I hold the throttle about half open. Thinking about trying a crankshaft sensor. I am at a loss any help would be appreciated.
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crank position sensor is a good starting spot after everything you now replaced. Do yourself a favor though, and check the ASD relay in the fusebox under the hood. The coil and injectors are fed off the same power feed from the ASD.
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SO I pulled the pre-cat o2 sensor she fired up and has been running about 20 minutes with no problems, I am assuming this means my CAT is clogged. Would that assumption be right or is it hopefully, just the o2 sensor
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Also if it is the CAT, are there o2 eliminators for this truck so I can run without a CAT. I havent been able to find any online It would be really easy for me to just run straight pipe.
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From: Clayton MI
You don't want to eliminate the pre-cat O2 sensor. Your engine depends on that one too much. To test if it is the sensor, or the cat, screw the sensor back in, and unplug it. See how the truck runs. If it dies pretty quick, cat is your issue.
If it IS the cat, then you need to find out WHY it clogged. Best guess is, your plenum is blown, and that is what plugged up the cat. Check out the stickied plenum thread at the top of this forum for help with diagnosis on that. If you have a blown plenum, fix that, deal with the cat, and REPLACE the front O2 sensor.
If you don't have emissions testing in your area, you can indeed eliminate the cat, either by hollowing it out, welding in a straight pipe, or, picking up on one of the "off road" y-pipes that Jegs, or Summit sell. (they have both O2 sensor bungs) The Y-pipe is one of the biggest restrictions in the exhaust on these trucks, so, some flavor of replacement would certainly get my vote......
To avoid the problem of codes for cat efficiency, you can do the non-fouler trick on the post-cat O2. There is a DIY in the faq section for that. The pre-cat O2 just doesn't care if there is a cat after it or not.
If it IS the cat, then you need to find out WHY it clogged. Best guess is, your plenum is blown, and that is what plugged up the cat. Check out the stickied plenum thread at the top of this forum for help with diagnosis on that. If you have a blown plenum, fix that, deal with the cat, and REPLACE the front O2 sensor.
If you don't have emissions testing in your area, you can indeed eliminate the cat, either by hollowing it out, welding in a straight pipe, or, picking up on one of the "off road" y-pipes that Jegs, or Summit sell. (they have both O2 sensor bungs) The Y-pipe is one of the biggest restrictions in the exhaust on these trucks, so, some flavor of replacement would certainly get my vote......
To avoid the problem of codes for cat efficiency, you can do the non-fouler trick on the post-cat O2. There is a DIY in the faq section for that. The pre-cat O2 just doesn't care if there is a cat after it or not.