Some ideas, getting my ass kicked

[RKTMech]

Here it is, 05 lly stock motor install, long block from Blackwater engine rebuilders (cust supplied). Engine ran poorly but ran before disassembly (cracked #7 piston), with engine installed it now starts, runs smooth for about 2-4 sec, surges, stumbles and dies.
This is an all stock programming truck, no codes, has ckp and cmp signals, builds proper fuel pressure, notice nothing out of place on scan tool (tech2), inspected reluctor wheel, test fuel, have tried different FICM and ECM (just cause), Cust had injectors "checked out" by some place here in SanBernardino CA. I am running out of ideas, so before i go and pull the front cover off and check the mechanical parts of the timing again, I figured I see if anyone had any other ideas.
Thanks for your time and any consideration.

 

[SIKDMAX]

I would look at the only parts you havent yet - those injectors. Can you swap them out with known good ones you may have there? Sounds like you are apprehensive about them, Id trust your gut.

 

[schulte]

Check the MAF

 

[JoshH]

After it dies, does it start right back up?

 

[Kat]

Pat just got off the phone with Robert. It was electrical.

 

[RKTMech]

Update..... unplugging the Alt. lets it run..... different alt. truck runs and dies till unplugged.... hunting wires now..... Thanks for the replies gentlemen, to be continued.

 

[RKTMech]

So round 2 of this title fight is .............ding ding ding The truck hates voltage from the alt. as soon as it starts to make voltage it shuts the truck off some how!? Havent been able to find out how its actually shutting it off but all grounds check out, and were not loosing any ecm or ficm voltage so far......... it just keeps getting better!

 

[durallymax]

I know ive heard of this issue somewhere, a guy i pull with had the same issue. Let me do some digging.

 

[durallymax]

just talked to him If he unplugged the alt it ran fine. Ended up replacing cranck sensor and all was good.

 

[RKTMech]

Thanks for the dig, that has been done early on in my fun but i will revisit just to make sure. :thumb:

 

[McRat]

Hmmm...

The field wire is shorted? When the truck turns on the field to make voltage, it sees a short and shuts off?

Seems this is shades of Casper circa Bonneville 2... :barf:

 

[Fingers]

Grounding issue?

 

[RKTMech]

Thanks guys, All grounds have been triple checked, and the ckp/cmp wiring and sensors too. It definitely has to do with the alt doing its job, going to look into EMI tomorrow...thought about it on the crapper clearing out my mind this evening. I've seen it mentioned a lot in other diag codes but have never seen it effect anything. The wires that usually run over the intake plenum now run over the back half of the alt. in plastic wire loom, its a long shot we'll see! There is one other wire in the charging schematic that I found tonight that needs looked into a little more so that's plan "B" after i find nothing much to do with the Philadelphia experiment at the alt. Got my fingers crossed for day 5 and a call into my local neighborhood all around great guy GM field engineer.:thumb:

 

[Gasuout]

This might be a dumb ? Robert .

Does it have any kind of alarm on it .

Usually they are tied into the alt wiring for auto start crap .

 

[RKTMech]

Well I knew it would be a Homer Simpson moment when I put all the pieces together.... I had the cam and crank sensors (not the connectors) swapped in the front cover. Thanks for all the input and ideas and even views. Once again I have proved I'm just another idiot with a wrench :roflmao: GM said they have had a rash of these type of calls for people swapping the connectors but i like to be original! It sure feels good every time you get a monkey off your back :happy2:

 

[Kat]

:happy2:

Now I won't feel so bad about bothering your to work on Spooky tomorrow morning :hug:

 

[duramaxdiesel]

Glad you got it sorted out!:thumb:

 

[duratothemax]

interesting. Im surprised it even ran at all with the CKP and CPS connectors reversed.

 

[JoshH]

interesting. Im surprised it even ran at all with the CKP and CPS connectors reversed.

The way I read it, the connectors were plugged into the correct spot, but the sensors themselves were swapped. In other words, the crank position sensor was installed in the cam position sensor's spot with the cam position sensor harness plugged into it and vice-versa. I find this most interesting because I was always under the impression that the sensors were the same.

 

[Gasuout]

Good to hear you got it worked out ..... :thumb:

I finally gave in on being blind ...... I look like Hank Hill now with my Glasses . :rofl:

Getting old sucks ... lcoot: