No crank. ECU?

[Perry_Browe]

Hi all, sorry for being a noob. So I have a 5.7 2007 1500. Transmission was slipping. I was trying to diagnose that when I came to a stop on a back road and the engine quit as the wheels came to a stop and would not restart. I put a new transmission in, and it still will not restart.
Found a ground strap on the back passenger head, couldn't figure out where it came from. I terminated it to the firewall.
Tried jumping the starter with a screwdriver. Wouldn't spin or plunger. So did the starter go bad at the same time?
This is combined with the fact to no codes show up on the reader but I have a flashing CEL when I try to crank.

Should I be looking for an ECU? Or possibly more ground issues. Another weird thing was I was proving the solenoid wire and I was getting 4 - 5 vdc...

Thanks so much for the input

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[Fast69Mopar]

Let's start with battery power.

What is the condition of the battery? Did it discharge while sitting waiting for the new trans to be installed?

Have you tested the battery to verify cold cranking amps?

Do you have battery volts at the B+ post on the starter? You should. If not test the battery cable from the battery to the starter?

When you turn the ignition key to the RUN POSITION, does everything power up like the instrument cluster, HVAC Controls, blower motor, radio etc?

 

[JohnnyMac]

I'm pretty sure that regardless of the ECU, if you jump across the starter terminals, it should crank. I agree with @Fast69Mopar and I'd look for corrosion on the cable to the starter or a broken connection.

 

[Fast69Mopar]

I'm pretty sure that regardless of the ECU, if you jump across the starter terminals, it should crank. I agree with @Fast69Mopar and I'd look for corrosion on the cable to the starter or a broken connection.

You are correct. It doesn't matter if the truck has a PCM installed and plugged in or not. You could take the PCM out of the truck and lay it on the bench. If the starter has B+ battery power and it is grounded like it is to the transmission then the bendix should engage if you jump across the solenoid.

If you find a good power source at the starter and it still does not crank, give it a whack with a BFH and see if you can get the bendix to engage. If it does nothing I suggest getting your hands on a new or reman starter.

 

[bugnutz]

I found that the same ground strap fractured on mine and replaced it. I found it when I was replacing the crankshaft position sensor. It did affect my cranks. I took it back off to clean the connection better and checked just for grins and got no crank while it was off.

 

[Perry_Browe]

I found that the same ground strap fractured on mine and replaced it. I found it when I was replacing the crankshaft position sensor. It did affect my cranks. I took it back off to clean the connection better and checked just for grins and got no crank while it was off.

Where does that grounding strap go on the frame/body? How did you reach it? I was having a really hard time. Lol

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[LoneWolf3574]

Where does that grounding strap go on the frame/body? How did you reach it? I was having a really hard time. Lol

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IIRC that ground strap goes from the passenger side head to the firewall and the easiest way to reach it all is to remove the wheel well liner. There should be a threaded bolt hole nearby. I found something similar on my truck, the firewall side of the ground strap is missing the bolt ring and nothing to be found on the firewall. I haven't replaced it as of yet since it doesn't seem to be causing any issues currently and it is a PIA to get to.

 

[bugnutz]

Where does that grounding strap go on the frame/body? How did you reach it? I was having a really hard time. Lol

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So sorry I didn't see your question. Yes I have my wheel well liner off. It goes on the shield under the passenger compartment and to a bolt on the manifold. It was not as difficult to reach as the crankshaft position sensor, but I would not have known that strap was broken if I had not been under there doing that. The break in it was tucked into the cross member. IIRC it took a 10mm wrench.

 

[Fast69Mopar]

I would hit the local salvage yard and snag a replacement or build your own with at some oxygen-free cable and soldered connectors.

This ground needs to attach to the stud on the bulkhead and the bolt hole on the rear of the right cylinder head.

 

[bugnutz]

I would hit the local salvage yard and snag a replacement or build your own with at some oxygen-free cable and soldered connectors.

This ground needs to attach to the stud on the bulkhead and the bolt hole on the rear of the right cylinder head.

Delco braided ground straps are less than $10 on amazon. I hope Delco isn't a bad word on this forum lol. My other great love is a Chevy lol.

 

[Fast69Mopar]

Delco braided ground straps are less than $10 on amazon. I hope Delco isn't a bad word on this forum lol. My other great love is a Chevy lol.

Hahahaha if I had to choose between Delco or peeing on an electric fence.. .

I'll let ya slide on that one bugnutz. Not everyone likes fabricating everything. If there is a way for me to Fab up a part that is what I do.