Was running fine. Parked under shadetree---next day wouldn't crank. I put my superchip programmer on it and it gave 2 codes. one was bad cam position sensor and the other was ambient air sensor. Replace both but still won't crank. Will run on starter fluid for a second or two. Help greatly appreciated

 

Sorry, but your description of the problem is confusing. You say it will not crank, but then you say it will fire up with starter fluid, which tells us that it DOES crank.

To clarify, are you saying that it turns over with the the starter just fine, but will not fire? Or are you saying that it will not crank - the starter does not turn the engine over?

BTW, NEVER, NEVER use starting fluid of any kind on these engines.

 

Yes the engine will turn over and it tries to crank but will not run.

 

Thanks, that clarifies it, but now have another question.
You say that it TRIES to crank, but will not fire up. Your words imply that it is not cranking very fast. These engines require a fast crank to start.
Sorry, but can you clarify if it is cranking at the normal fast rate, or if it is turning over very slowly.

 

Thanks for your patience . Yes it is cranking at normal speed but it tries to kick back like something is telling it to stop, if that makes sense

 

OK, now we are getting somewhere. Kicking back could (but not always) be a symptom of bad timing.
You did say that you had a code indicating a bad cam position sensor and that you changed it, so that should eliminate that problem.
Suggest that for the next step you crack one of the injector lines, crank it over and see if you have high pressure fuel squirting out.
CAUTION: Keep your hands well away from the cracked fuel lines as that high pressure diesel can penetrate the skin and cause all kinds of nasty body problems.

Prior to the problem, was there ANY hints, such as hard starting, hesitation when accelerating, white or black smoke, poor power etc. Do you have a fuel pressure gauge installed?

 

No prior problems, was running fine when I turned it off. I do not have a fuel pressure gauge. We already cracked a fuel line to the front injector and had good pressure. Thanks again

 

Hmmm, now I am not sure. Hopefully somebody else will chime in soon.
Going back to your first post, do you have a programmer installed? If so, did you try removing it?

 

I programed back to stock about two weeks ago and about 250 miles back

 

Today I programmed back to towing then back to stock but still would not run in either program. ????????

 

Surprised that nobody else has chimed in yet.

This is a bit of a long shot, but you have nothing to lose. Remove the electrical plug from the back of the CP3 and try starting it.

Been thinking about what you said about it trying to kick back. Disregarding the possibility of bad timing, that could possibly also be an indication that the engine is not turning over fast enough and as it fires, it kicks back. Presume the batteries are factory, but are they in good condition and fully charged? Even tho you say it is turning fast enough, have you tried a boost?

Once you get the problem resolved, please let us know the fix.

 

Mexstan you're a genious!!! I pulled the wire off the cp3 and walla it fired right up, however it still runs rough. I plugged it back up and it still cranks and runs. Now tell me what this does? Is the cp3 bad? THANKS MANY TIMES OVER!!!!

 

Pulling the wires off the CP3 just allow it to deliver full pressure. I am not expert enough to tell you the next step. but it I am wondering if it could be a bad CP3. Hope not for your sake. You did say that when you cracked an injector line that there was lots of fuel, so that threw me. Now suggest that you crack one line again with the pump unplugged and see if there is any difference in flow. Remember to keep your hands away from that high pressure fuel.
Maybe clear all the codes, get it running and check for any new codes that are set.
Hopefully a real expert will jump in here with a full analysis, but it is sounding like you need a new CP3. Sure hope I am wrong.

 

Just had a thought. What if you have a leaky injector which was not allowing the CP3 to build enough pressure to get that engine started? Then when you pulled the plug on the CP3 it delivered enough pressure to override that leaky injector.
Did you check your oil level and smell the oil to see if there was any diesel in it?

 

I went out this morning and it cranked and ran smooth as ever. It did have 3 codes:#1.poo88-fuel rail/system too high #2.po628-fuel pump A ctrl circ low #3. PO251- injection pump fuel metering ctrl A error. I cleared the codes and after it run for a while, the codes did not come back. Yesterday, before I got your post to pull the wire to the cp3,I had changed the fuel filter. It still did'nt crank until I pulled the cp3 wire. Just maybe it will be okay now. AGAIN MANY THANKS!!