I am at my wit'* end. Two months ago, the truck started dying randomly while driving. Hot, cold, full tank, empty tank, fast, slow, did not matter. Usually it would start right up again and be fine for a week or so. Two weeks ago, it died, but would only run for a minute or two before dying again. I let it sit overnight and it was fine. It seemed like it was an intermittent fuel problem, so I put in a new fuel pump. I saw that the pump had been previously replaced and the connector was spliced in with crimp connectors. I replaced these with solder/heat shrink tubing thinking this was probably the source of the intermittent problem. It ran fine for a week, then last Friday it died on the road but would not re-start. It will fire up for about 1 second but immediately die. There was a P0335 "Crankshaft Position Sensor a" code, so I replaced the crankshaft sensor with a $12 amazon special. This made the problem worse, as it would no longer try to start and would crank very unevenly, as if the timing were way off. I was till throwing the P0355 so I replaced that sensor with a $70 AutoZone sensor and now it is back to the one second starting scenario, but no more code.

• There is no visible damage to the connector or wiring for the sensor.
• The fuel pressure is 55-60 psi and does not drop when it momentarily starts.
• I read on this forum that the engine would not spark at all if the sensor was bad, so the momentary starting points away from a crank sensor problem.
• The fuel pressure regulator appears OK (no leak from the vacuum tube)

I have seen a few postings on the web regarding a bad ground wire at the rear of the engine that could cause this problem. The ground wire appears intact and well connected. Can anyone advise where this ground wire goes after it disappears into the harness? Then I could test with a jumper without cutting into the harness.



I would greatly appreciate any suggestions as to what next to try.



Thanks in advance,
Karl

Will it run on added fuel? Anti-theft? What does the light do?

Excellent question. I will try adding fuel first thin in the AM. To which light do you refer? Warning lights behave as expected when it stalls. Check engine light is off.

Thanks!

The anti-theft light. Should turn on for a second or two and go out. If it blinks we have a problem. Do you have another ignition key?

The Security message is displayed when I get in, but goes away when the key is inserted. It does not come back or flash after stalling. Adding a dribble of fuel to the intake makes it rev a little higher when It momentarily starts, but does not increase the time until it dies. I have two keys and they both behave the same way. Thanks again for your help.

Spray carb cleaner or similar into the intake. Does it continue to run?

What carfixer007 said ^^^^^^^

. . . and I'm curious: put a fuel pressure gauge on it and watch what it does when you start it.

I have tried starting fluid and fuel dripped into the intake. It will rev a little higher but still dies after 1 second. I did put a pressure gauge on it, and the fuel pressure remains between 55 and 60 psi even when it dies. I think I need to trace the crank sensor signal back to the PCM. Thanks everyone for your help and have an great Thanksgiving!

Karl

It might sound goofy, but it could be in the ignition switch. I had a similar symptom with my '98 Cavalier. It would start, and then die right away. After scratching my head, checking out fuel and spark and all that kind of stuff, and pouring over forums, I found that some GM ignitions go bad to where the switch springs back too far when releasing the key from the "start" to the "run" position. You can see if this is the case by turning the key to "start", then after it catches, slowly turning it back to "run", keeping a little pressure on the key with your thumb. That is to say, don't just let go of the key when it starts, but manually turn it back to run. If it keeps running, that might be what you're dealing with.

So the problem has been solved, and like many such mysteries, the problem was self inflicted. During my time troubleshooting the fuel pump, I was having a problem with the battery going dead. I found a high leakage current from a fuse in the electrical center and pulled it out. The Fuse is labeled RAP#2 in the owners manual (for Rear Power Windows, Sunroof, Radio, Onstar). I put in a new battery and reinstalled the fuse and now it starts right up. D'oh! I think the original problem was caused by the bad crimp connections on the fuel pump and the rest was just me getting in my own way. Thanks again for all of your help.
Karl