No crank position sensor signal

[Fuzzman]

Hi guys,
New to the forum.
I know you guys have beat this to death in a hundred different posts, but I need your help. Let me start from the beginning:

1997 GMC K2500. New crate 5.7L with LT4 cam put in (GM Hot Cam?)
I received the pinout sheet from Lextech, (Thanks again Jeff), picked up a computer, Serv# 12200411, and completed the pin swap.
Between my mechanic and I, we have been fighting to get CKP signal.
We have back probed and test the wires to the computer. We have signal to the computer. It's a beautiful, square signal on the scanner. From there, we plug the scanner into the OBDII port in the cab, and we have no CKP signal. I have fuel and no spark. We have checked power, both switched and constant. We have checked grounds. All good. I'm struggling to check through the rest of the wiring due to the fact this girl won't start.

Two questions: Is there something I'm missing with another component causing the computer to not find the CKP signal? Is there a chance there is a difference between constant ground and key on ground?
I have tried a second computer. I have replaced the CKP sensor. I have double checked and triple checked any of the wires involving the CKP sensor.

Again, I apologise for asking something you guys might have answered already.

Thanks for any help you guys can give.

[joecar]

Which CKP and CMP reluctors are you using (how many teeth)...?

[Fuzzman]

CKP reluctor wheel is 4 tooth. Not sure on CMP, but should be stock.

[Supercharged111]

I'm guessing you already put a 4X 5.7 flash on there from a van?

[Fuzzman]

Yes sir, completed pin swap and had my local tuner guy come down. He flashed the computer and then informed me he couldn't see CKP signal. At that time, I had no throttle position signal either, but I traced that to crossed wires and fixed that issue. I sure with this damn CKP signal was that easy. I've been at this for two weeks already.

[Fuzzman]

So here's a question.
How important is it that I use a computer specific to a 2001-02 GMC Savanna van, or do I just have to make sure it has the Serv.# 12200411?

[ChipsByAl]

The PCM does not have to be out of a van. Any one with the correct part #'s including the 9354896 can be used. The software including the Operating system and the Calibrations are more specific. Can you possibly post the tune file here.
Al

[ChipsByAl]

Fuzzman sorry I could not get to you sooner, been busy. Your first post has a few points I need to go over to be sure we are on the same page.

You have a "beautiful, square signal on the scanner" Are you testing the wiring for a signal at the PCM/crank sensor or looking at data? It sounds as if you are doing the former. Then the scan tool is plugged in the DLC and no crank signal is present. That would be a data input, just like the TPS.

Next point, you have fuel but no spark. Are you checking at the injectors with a noid light or is this fuel pressure confirmation?

Al

[Fuzzman]

I work at a service shop up here in Canada and one of the mechanics has been helping me try to figure out this mess of mine. We have a Snap On Modis Ultra scanner that we set up to back probe the wires for the CKP, right at the connector for the new computer. Once set up, we turned the engine over and saw signal on the scanner. After that, the scanner was plugged into the OBDII port in the cab of the truck and saw no signal and no engine RPM.
I started to think the computer was junk, but it still throws the P0335 code. So the computer can't be bad, correct? That's kind of why I was questioning if I need to have the ECM out of a van to match engine and tranny.
I know I'm grasping at straws here.

As for fuel, we have tried and tested the wires a few times now and after a lengthy engine turnover, we can smell fuel, so we know we're getting fuel. Didn't use a noid light, but did confirm fuel pressure.

[ChipsByAl]

So you probably don't have a correct crank signal, incorrect software in the PCM or bad PCM. You definitely have something coming out of the crank sensor and wiring. Can you use the scan tool and read out the Calibration ID's and Operating system information. The numbers should look like 12212156, 9358554, 9359000, 1282160, 16264444, 16264662 & 9362015. The first three should match unless you have other than a 2002 operating system.
AL

PS: I also sent you an email through this forum.

[Fuzzman]

I will try and find the ID and Operating system info to see if numbers match.

I didn't see the email though. I'll send you one.

[Fuzzman]

Can anybody tell me if there is a difference between constant power and cranking power? Or switched power and cranking power? Just wondering if at the time of the pcm swap, I missed something there.

Still have no crank signal at OBDII port in cab.

[SS2win]

Have you double checked your repin work? It's really, really easy to miss something. I'd go through the pinout one more time to be sure everything is as listed on the spreadsheet. IF that checks out, as long as you have a compatible operating system such as 12212156, check your tune to ensure that "System | Vehicle Platform | Parameters" is set to GMT610 and that "System | Vehicle Platform | Vehicle Platform Options | Low Resolution Crank" is set to yes. That will enable the low res crank and you should see the signal.

[Fuzzman]

Thanks for the info. I will double check my pinout. Again. Then I'll check into the OS info to make my numbers line up.

Here's hoping.....

[Fuzzman]

So, as it turns out, it was the computer. Got a proper computer and double checked wires and had tuner guy come and flash and install base tune. Should be all good, right? WRONG!
Still can't get this SOB to start! It turns over like it's out of fuel, and after a few tries, it smells like it's flooded. We have checked firing order, spark (it's a little weak, kind of orange. Putting in a new coil today), fuel pressure,
ohmed all the wires to the fuel injector block. Checked all the wires again to the computer. And I'm sure something else I have forgotten about.

This truck won't even pop. No try whatsoever.

Has anybody got anything that I might try??
This truck has been down for two months already and I'm starting to lose my mind.

[ChipsByAl]

Try to get your tuner to post the file that he is using.
Al

[Fuzzman]

Will do.

[Scatfish]

Fuzzman,

Did you ever get this problem resolved?