Time for new IP?

[NVW]

Messed with a bit today, it rained. It would rev to 1000-1100 rpm like before. set timing a few times. Came back later and it would rev up in park, but only with at least 1/4 throttle. ( why I thought the APP) runs rough but when it revs it is smooth.

I then found later, in park or neutral it would now only go to 1000-1100 rpm, put it in drive or reverse and it will run like a raped ape. It idles like it is missing on a couple cylinders, but runs smooth under acceleration. I now have boost, at least 1/4 throttle is needed to get it to go.

It also idles at 1000 rpm, if it is in gear and you let it pull down to 600 rpm it will stay there until it is revved up again, sometimes it just idles at 600 rpm.

FYI, the first thing I did was grounds I get black smoke now instead of grey when it is warm. (before it just smoked grey, no boost)

I am going to try a container of diesel and Sea Foam next.

I have never been stumped before.

 

[ak diesel driver]

I wonder if the puter has gone wonky?

 

[NVW]

My thoughts Les, changed it out.

 

[ak diesel driver]

And I'm assuming no change?

 

[NVW]

None

 

[NVW]

@Will L I froze the bottle of what I thought was wax. It was water as it wouldn't burn.

I ran the truck with new diesel and Sea Foam for about 20 minutes, tomorrow I will get longer tubing so I can put the jug of fuel in the pickup bed and drive it.

I had taken a video but can't remember my you tube password.

 

[NVW]

It doesn't miss as bad now as it did this morning, every time I start it, it acts a little different.

This is a video of this morning, it was puffing a lot at idle, when driving it would take 40% of the APP applied going by OBD-2. It accelerates very well and runs smooth.

The sound isn't the best

 

[NVW]

I should clarify, it take 40% APP to get it to go, then it goes. It runs smooth under acceleration but not at idle.

Cruise control also doesn't work, likely due to these issues.

 

[ak diesel driver]

After watching that I'd sure think that is an electronic issue. If it was an IP issue it shouldn't matter if you're in gear or not. That's the weirdest symptoms I've seen.

 

[Will L.]

I agree with him it is electrical or electronic.

I think the water trapped in suspension is from the additives and simple coincidence.

Annoying but act like you bought it his way- undo all the electrical connections and clean them-All. 99.99% waste of time assuming you have done this in the past and done the common ones already. But it has to be 100% eliminated from possibilities when dealing with something this weird.

Tried different pmd cable, right?

The transmission being in gear, park, neutral- going into gear & dropping rpm is obviously normal but that whole ZERO throttle response until in gear- WOW.
Maybe a dropped grounding circuit in APP that somehow is picking up a backfeed through the ECM?

Is motion of truck moving a harness that allows better connection?- wiggle test all the harnesses with throttle pressed part way via rod/stick/or brick. There is a tool that hooks on steering wheel and presses pedal- functions like a caulking gun, but wouldn’t buy it for one time use.

I hate swapping an ip without proof but if I have extra ip(s) sitting around, not sure how long I would fight it before swapping.

 

[NVW]

This morning it wasn't missing at idle, but will not rev up in park or in gear.

I have wiggled the harness connections at the back of the motor, I'll try the pmd direct to the short harness.

 

[NVW]

Update, I haven't had the desire to work on it until recently. I ohmed the engine harness and all checked good. I replaced it as well as the IP, it's running perfect now.

I really missed this truck, it is my most favorite vehicle I have owned, even better than my 69 Mustang.

 

[MrMarty51]

That's good news NVW

 

[Will L.]

Good to have an enjoyable rig back. Good for you