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Engine cuts out in reverse

G

Goose57

Well-Known Member
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Location
Eureka Mo.
Hi all, I just got done w/ a new Optimizer build on my 95’ Duelly. It just started to cut out when backing up. Just a hiccup always in reverse. Never in drive. One time it did shut off. New 5521 IP, LP, known working PMD behind bumper, everything new. Any ideas? Thanks.
 
Bad motor mount/trans mount has shown me the two and twist differently in reverse than in forward. So when idle and going forward no issue but when loading them the other way :
Possibly pinched fuel supply or return line?
Possibly tension on wires disconnecting a little?
Possibly shorting wires getting squished?

Can you do a couple videos of it?
 
Really? I’ve never noticed anything that we didn’t find an issue to.
Can someone do a video?
If electronic then I would definitely jump to a harness somewhere ot being happy.

Now I wanna snag up one or two of the 6.5 trucks at work today and go play with it on break time & lunch at work today to see if I notice any difference vs the dmax. We get issued the truck we use so I’m in an 08.

But it died? That ain't right… would keep me worried about reliability.
 
Thanks guys. Yea I am concerned about reliability. I forgot to mention it also hiccups once or twice after start up too before moving the truck. I do remember on the old motor the hiccups coincided with the wait to start light blinking.Seems to only act up before it warms up. I’ll get under her and inspect all of the wiring and grounds. The only thing not new is the PMD and harness. They were working fine before. Maybe harness pinched somewhere. I’ll also check for DTC. I’ll try to do a video. Like I said it happens so fast it’s just a hiccup
except when it died one time. I’ll report back. Thanks again guys.
 
when you did the install, did you remove the noise filter that connects between the harness and the optic sensor on top of the IP. it's the large square connector on the top of the IP. the noise filter was something GM installed from factory, looks like a short harness adapter with a rectangular black box in the middle. those things are known to give issues. if you remove it from the harness and connect the harness straight into the IP it might help.

I'm sure someone here has a picture of it.
 
Thanks guys, I ran through the wiring shaking them while engine running and checked codes. No dice.


Watch the tach two little blips. I’m convinced it’s happing only on first start up cold. Like I said on the old engine it coincided with the wait to start light blinking. The light is not workin now I still need to troubleshoot it. On the old engine I always thought the blip and WTS lamp was the GP firing because it was still cold and not burning the fuel correctly💁. It doesn’t have the optic sensor any more. New upper engine harness going to the IP from Quadstar. New ECT,s It use to do it on the old engine too. I have two working PMD,s. I can’t remember which one I ran on the old engine. Maybe I’ll switch to the other PMD. Maybe try another harness too. Since the harness was on the old engine. Sure hate too spend the money. I shook the hell out of the extension harness too😂. Maybe I’ll put a fuel psi gauge in cab to see what’s going on on cold start up. I have a new Raptor LP coming 😎. Sure hope it’s not the ECM🙏🏻. Thanks guys for helping me. I’ll report back.
 
Paveltolz said:
Did your IP Timing and TDC Offsets get done after the install?

Try hooking up the scanner and get a read on the offset and with the parking brake set and wheels chocked, see what, if anything happens to IP Timing and Off Set when you shift into Reverse, and Or Drive.
Click to expand...
Paveltolz said:
Did your IP Timing and TDC Offsets get done after the install?

Try hooking up the scanner and get a read on the offset and with the parking brake set and wheels chocked, see what, if anything happens to IP Timing and Off Set when you shift into Reverse, and Or Drive.
Click to expand...
Thanks Pav. I haven’t got to it yet. When I do what do I have to look at on the timing and offset numbers? If they change? The problem I have is I enter the truck data with the key on engine off then start it and the scanner disconnects and I have to re-enter the data after it is running. It happens so fast the event happens before I get done entering the data. Also sometimes it won’t do it in gear. In my previous post I stated I believed it only did it when cold. I was wrong it is also starting to do it after it’s warmed up after a start up. It’s so weird that it happens like clockwork in the morning and hit and miss the rest of the day. It seems to be happening more frequently and I’ll probably find out sooner than later. I just don’t want to get stuck somewhere lol😂
Will L. said:
Gonna need to set up a video camera on the clear ip return line looking for a one time burp of air.
Outside of that possibility (which I doubt now) that is in yonder electronicals of the ip/pmd/ignition power to them/ magical pixies are not happy.
Click to expand...
What do you think Will ? It’s hard to tell.
 
Goose57 said:
Thanks Pav. I haven’t got to it yet. When I do what do I have to look at on the timing and offset numbers? If they change? The problem I have is I enter the truck data with the key on engine off then start it and the scanner disconnects and I have to re-enter the data after it is running. It happens so fast the event happens before I get done entering the data. Also sometimes it won’t do it in gear. In my previous post I stated I believed it only did it when cold. I was wrong it is also starting to do it after it’s warmed up after a start up. It’s so weird that it happens like clockwork in the morning and hit and miss the rest of the day. It seems to be happening more frequently and I’ll probably find out sooner than later. I just don’t want to get stuck somewhere lol😂

What do you think Will ? It’s hard to tell.
Click to expand...
What's the known condition of the IP?
 
Hi all here are some more videos. One is of the clear return line and the other two are Tech 2 data and battery voltage on start up and when the event happens. Hope you can make it out. Still working on getting the WTS light to work. I wish I could narrow down the event of being a fuel or electrical issue. Maybe I’m overthinking thinking this because it did it on the old motor? Worried about long road trip reliability. Thanks guys.

 
Hi all, I’m back on here working on my truck doing the stutter after startup. I do have another thread started about my instrument cluster. I’ll probably be jumping back and forth between the threads. Ok you all recommended checking all the grds. and wiring harnesses. I have checked the grds. And wiggle test all the engine bay harnesses. Also yesterday went through all the harnesses unplugging the connectors and applying dielectric grease. Did some voltage and amp readings videos while the event happened.
If the videos get mixed up I can’t see which is which. The video with the big molded lead connector plug into the Big meter is the one showing the GP amp readings.
First video: Big meter voltage reading of the fuel shut off solenoid back probing the connector

Small meter: voltage at the ECM-B fuse
Not sure I seen anything on the video. Did see the voltage reading fluctuating on the fuel solenoid (Big meter) not sure.

Second video: Big meter amp readings during GP cycle. You have to read the amps. On the MV scale because of the type of DC clamp used.

Small meter: voltage at the ECM-1 fuse
Not sure either on this one too.
Did see a small voltage drop (small meter ECM-B) when the GP were warming up and also on the second little stutter. You can see on the amp meter the GP firing again on the second stutter. There are two stutters you have to zoom and play it a couple of times and listen.

Did see the voltage drop on the the small meter on the second stutter. You have to play it a couple of times and zoom in and listen and stare at the small meter (ECM-1fuse). What do you guys think?

Some things I thought about: still haven’t changed out the FSD ext. harness (work on the old engine). Still have the stock smaller battery cables but it does start very easily. I do have a new gear reduction Powermaster starter installed. In the process of upgrading to the Raptor LP. Still have to go through the ECM connectors and the connectors I can get to without pulling the dash back out. Final thought it is so weird that it does it like clockwork in the mornings and sometimes if I stop for awhile depending on how long it sits. I haven’t started it for the day and have a battery charger on it to boost the battery voltage to see if the stutter happens. Not very optimistic.
Sorry for the long one boys. Thanks.
 
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