Engine pauses at 3k then continues on after heavy vegetation off-road trip

[EROCK]

See attached video. Engine cuts out like it looses all ignition for 1 sec then continues running normally. Also the speedo flips out at the same time. This happens intermittently and will sometimes disappear for a few days and come back.

The video is a pull in 1st gear. Accelerator is pushed down the entire time. Notice how it cuts for a full second around 3k rpm then continues on. It's so violent, you can hear the tires chirp when it does it.

 

[Gunnersmate]

Maybe A Crankshaft Position Sensor

 

[Apparition]

Mine did things like that when the vehicle speed sensor on the transfer case failed.

 

[tworley]

Mine did things like that when the vehicle speed sensor on the transfer case failed.

Definitely worth looking at especially if you were tearing thru heavy heavy vegetation.

 

[Jerry Bransford]

My bet is the crankshaft position sensor wiring got snagged and was damaged by brush. I've never had an engine issue when the speedometer gear sensor on my transfer case wasn't working.

 

[EROCK]

My bet is the crankshaft position sensor wiring got snagged and was damaged by brush. I've never had an engine issue when the speedometer gear sensor on my transfer case wasn't working.

Thank you for your reply Jerry! Put a new Mopar OEM CPS in, back in 2020. Might do it again on your recommendation. I'll check wiring too.

 

[freedom_in_4low]

My bet is the crankshaft position sensor wiring got snagged and was damaged by brush. I've never had an engine issue when the speedometer gear sensor on my transfer case wasn't working.

I don't know if it's the cause of his issue, but there's definitely something in the engine control that's tied to vehicle speed, as my 99 would stall every time I came to a stop when I drove it without a speed sensor connected, and if I'm coming up to a red light and go to neutral as I decelerate, my 06 holds the idle up at 1400 or so until I've come to a complete stop.

 

[Apparition]

I don't know if it's the cause of his issue, but there's definitely something in the engine control that's tied to vehicle speed, as my 99 would stall every time I came to a stop when I drove it without a speed sensor connected, and if I'm coming up to a red light and go to neutral as I decelerate, my 06 holds the idle up at 1400 or so until I've come to a complete stop.

Yep, mine was a pain to get home with when mine failed. I think like you I was having to put it in neutral for stop and go.

 

[tworley]

My speed sensor wiring went south once and it would cause the engine to stall out. Once it was repaired, the stalling quit.

 

[EROCK]

My speed sensor wiring went south once and it would cause the engine to stall out. Once it was repaired, the stalling quit.

Did you wiring have a break in the insulation or was the copper broke inside the insulation. Did you replace the entire wire or did you find the break and cut out the bad part?

 

[SkylinesSuck]

If the PCM isn't getting a signal from the VSS, the PCM can't apply "throttle follower" parameters which basically keep the engine from stalling when you do something like push the clutch in for example. It will also eventually throw a code with enough key cycles and driving.

 

[SkylinesSuck]

Also I don't think this is VSS related. But yes, wiring related.

 

[EROCK]

Just found a likely culprit. Grounding strap broke off. Goes from the engine to the fire wall. Pic is from under the engine looking up.

 

[SkylinesSuck]

Yep, that looks like a likely culprit.

 

[tworley]

Did you wiring have a break in the insulation or was the copper broke inside the insulation. Did you replace the entire wire or did you find the break and cut out the bad part?

I had miswired the hall sensor (but we won't tell anyone that)

 

[EROCK]

Now to find the other end. It looks to have pulled out of the end connector. They're is a very obvious ground on the firewall high and center. But didn't have the detached connector ring on the bolt. Where does the grounding strap on the back of the engine attach to??? Transmission maybe?? Been looking for 2 hours. 2nd pic is from above. Where does the broke off end attach?

 

[Andy-WhiteTJ]

Check the ground strap from the hood to firewall. According to the 2000 FSM, both straps are grounded at the same location.

 

[EROCK]

Check the ground strap from the hood to firewall. According to the 2000 FSM, both straps are grounded at the same location.

You were correct. I un-crimped the hood/firewall connector. Cleaned strap, connector and firewall hole with brass brush. Recrimped both straps into the connector and reinstalled. Just took a test drive and all functions have returned to normal. I am going to call this one SOLVED!!