Archived No start-Crankshaft position sensor question

[RPA]

So, here is my story. I was out playing around, showing off last night and truck died and still will not fire. I was coming up and on ramp, at a good speed and high boost level and let of the accelerator pedal quickly and truck died. It turns over and over but will not fire. I have tried to bleed the lines, i get fuel from still nothing. The injection pump is only 10 months old so I hope that is not the problem.

After reading in here a while I found that the crankshaft position sensor could cause this to happen. I also seen someone mention that the crank sensor also controls the lift pump. Well I had trouble with my Air Dog not working when you cranked the engine which is signalled to run from the lp harness. So my question is, is it possible that the crankshaft sensor has not worked properly for a couple of months allowing the truck to run great but now all of the sudden has completely went south and does not allow it to start at all?



BTW, I ran a toggle switch in the cab and control the air dog pump from that so I don't think fuel starvation has been a issue causing injection pump problems.



Sorry for the long post,

Thanks

 

[DavidC]

The first sign of a cps problem is a check engine light. The next sign is the tach dropping intermittently. The last case is maybe limp mode. In other words I would highly doubt your problem is a cps unless the tone ring tore the end of the sensor during your jaunt. My thoughts lean toward the fuel system.



Dave

 

[wtfd6]

when you are cranking the truck is the tach reading anything. my tach was jumping on and off. then i revved the truck up a little bit. at about 2 grand i heard a noise and the truck wouldnt restart after i shut it off. the tone ring broke off my crankshaft. if it was the ckp sensor I dont think it would have died. my truck stayed running afterward. but the tach was "dead". next time it wouldnt start. sounds like fuel issue to me also.

mark

 

[americana]

my cps story:



out driving around nice and warm... ... tach would die and go to limp mode... if i stopped i would have to let the truck cool off before it would start again. it never died while driving. i've never heard of a truck just up and quitting because of a bad cps.



my $0. 02



p. s. i correctly diagnosed the problem with the help of the good members of the TDR. took me several trips to the dealer... finally i drove it there while it was acting up and waited in the service manager's office (with the truck running) until the tech put a code reader on it and had a "light bulb" moment.