Immediately starts on 2nd crank

[edcmat-l1]

UPDATE.

Swapped in a fresh from the junkyard OEM cam sensor.

It’s fired perfectly every beer for 10 beers.

First start was cold but the other 9 were after getting up to full temp and sitting for a beers worth of time.

Thanks for all the insight gents.

LOL Love your time keeping method LOL

[wlwarnke]

See post #22.

Had just thrown a cam sensor, at it and it turned out to be something else, then you?d be talking down to me about a parts cannon. But since I actually tried to diagnose it, I should?ve just thrown a new sensor in it?

[Alvin]

Good find.. its frustrating that these hardly ever have codes along with it.

[wlwarnke]

It could’ve turned out that my fuel map just had a nasty hole in it!

[abc]

Had just thrown a cam sensor, at it and it turned out to be something else, then you?d be talking down to me about a parts cannon. But since I actually tried to diagnose it, I should?ve just thrown a new sensor in it?

Pay no mind to it. (don't forget, he's the one that said a faulty CMS should set a code) I'm only here to gain experience based on the concerns of the other posts and basically build my library of when this happened, this was the correction. When the experienced guys are willing to help, it's usually good help, when they don't want to help, it's a crap shoot as to what shows up on your screen and for some reason they like to lay claim to who figured it out first.

The best part is, sounds like you have a functioning toy again. Sometimes it goes like that. Typically a good practice is to verify one piece of the puzzle is known good then move on to the next piece in order to rule out everything until the true issue is exposed.

Imagine if the used part you installed was also faulty, imagine how you would chase your tail at that point. Basic O-scopes are fairly inexpensive these days, might be time to put one in your tool box.

Anyway, we all know that feeling when we figure it out, good job.

[2xLS1]

Pay no mind to it. (don't forget, he's the one that said a faulty CMS should set a code) I'm only here to gain experience based on the concerns of the other posts and basically build my library of when this happened, this was the correction. When the experienced guys are willing to help, it's usually good help, when they don't want to help, it's a crap shoot as to what shows up on your screen and for some reason they like to lay claim to who figured it out first.

The best part is, sounds like you have a functioning toy again. Sometimes it goes like that. Typically a good practice is to verify one piece of the puzzle is known good then move on to the next piece in order to rule out everything until the true issue is exposed.

Imagine if the used part you installed was also faulty, imagine how you would chase your tail at that point. Basic O-scopes are fairly inexpensive these days, might be time to put one in your tool box.

Anyway, we all know that feeling when we figure it out, good job.

Just point out that most parts store brand parts you buy these days are junk. Some sensors you buy/use need to be OEM. I guess you are to obtuse to realize that. But I've also seen your tuning in your file you posted and you really shouldn't be giving tuning advise to anyone. My statement about setting a CMP code is true for all the vehicles I've diagnosed with that issue in the past 21 years of doing this. How many have you diagnosed?

[dgold]

I had the same problem on my 6.2 that's running a 24x crank. I had to order a extension harness since the sensor is now on the timing cover. First I had to re pin the wires on the extension harness. Only to find that the engine had an aftermarket cam sensor. I ordered a GM sensor and it's started first crank everytime.

On another engine, my 8.1. When I routed the harness that goes to the cam sensor I put it in the harness that runs along the fuel rail. I had tons of cam sensor issues until I moved the harness away from the coils. I guess it doesn't like too much RF interference.

[blindsquirrel]

A scope probably wouldn't have helped on this one. Sometimes it can be as minor as the signal gets pulled down not quite close enough to 0v, the rest of the pattern looks exactly the same as a good one. GM sucks when it comes to giving you anything at all in regards to scope patterns and spotting what's good and what's bad.

[gtstorey]

A scope probably wouldn't have helped on this one. Sometimes it can be as minor as the signal gets pulled down not quite close enough to 0v, the rest of the pattern looks exactly the same as a good one. GM sucks when it comes to giving you anything at all in regards to scope patterns and spotting what's good and what's bad.

I wonder how much useful something like PicoScope's Waveform library for this? There are also some online groups for sharing "known good" waveforms but I've had a real need to dig into those either.