DanTheMan

@Linux Count me in! I’ll send you a PM. Would love to join. I have ordered PCBs and components to replicate this ECU, excited to get my paws into this. I like the idea of having a test bench, i thought about buying another Cummins engine and doing the same thing.

Wow! That is awesome. I am very impressed and was shocked to hear this thing run so smoothly. I’ll be honest, I’m going to start building it to play around as I restore this old Cummins. Very impressive, thank you for sharing the build with us, you absolutely didn’t have to and we all tinkerers appreciate it. And thank you for your advice and help!

@Mopar1973Man Thank you sir for the information. You rock. Nice truck, I followed you on TikTok. @Great work! I’ll check the ground, thank you. And also, yes the blowby is zero. Although it could be (if it has blowby) blowing out of the hole where the lift pump used to be that someone sealed off with cardboard… Once I get it sealed off, I’ll check again.

Thank you for the info, I’m going to use a piece of electrical 4x4 box blank stainless plate and cut it to size and use a cork gasket behind it. I wonder why there is a hole there if it’s meant to have the lift pump mount there.. I am seriously at a loss here, I’m probably going to pull the entire front end apart and really get down in there to check every inch of this harness, and really look at all connections and rewrap etc. I am now doubting ECU because it idles what seems like normal for a few seconds occasionally after unplugging and plugging in the ECM to PCM harness, I’m wondering if there’s something going on inside those connectors now. This truck has been interesting to say the least.

Good afternoon, I found a few more interesting things. I am now beginning to wonder if there’s a sensor shorting somewhere causing my 5v line to fluctuate, because my intake air temp sensor is reading wonky things. Sometimes now when I start the engine, it SOUNDS like it’s returning to normal idle when the temperature holds at 70+ degrees and not showing -40… Attached you’ll see the graph of my IAT sensor. When I disconnect it entirely, it still shows -40 and fluctuates, obviously not 70+ which is close to the ambient temp right now. So it is intermittently working, just acting as if something else is shorting that line Also, pardon my ignorance… but what goes on the side of the block just under the ECU to the right? Someone put a piece of cardboard loaded with black RTV to cover the hole.

That is interesting. I actually don’t recall seeing a cruise button on my steering wheel, but I’ll have to check tomorrow. This truck is the definition of electrical issues; windshield wipers don’t work, under dash harness hacked into, clutch pedal switch bypassed (I forget it’s in gear sometimes and I reach in the cab through the window to start it, gives me a hell of a scare every time) roofing screws screwed into the roof with some random roof rack and front facing light bar… Someone replaced a ball joint but didn’t align the truck, so I drove that thing home and wore that tire out… I am beginning to wonder if I made the right choice to purchase this thing for 3k, but then I think… These trucks resale around 12-14k, so if I throw 9 to 11k into it over time to bring it back, I won’t be losing money… Tomorrows project is taking the entire front end apart.. Intercooler, radiator, etc and really dig into that engine bay. I’m going to remove fenders as well, just start from scratch and completely rip that harness out and rebuild it, and while all that is getting redone, I’ll send off the ECU and hope for the best. I am just concerned why it runs like crap at idle with the VP unplugged, shouldn’t it technically idle perfectly? The good news is, it isn’t a 53 block.. lol

I appreciate the advice, and this truck doesn’t have cruise control. Not sure why, unless the manuals didn’t have CC? Or someone removed it. I will reach out to them, I’ve been researching their page for awhile I just need to contact them.

You make a good point! I fired it back up with the LP hot wired, and VP unplugged, it idles like crap but it ran at proper idle speed. I will be honest, I'm seriously considering a P pump swap if the ECU is shot, because ECU is easily a grand, plus another 600-900 for a used harness…. It is my understanding that I’d really just have to swap the timing cover for the 12v Cummins one, and obviously gear/brackets/etc. But that’s a different topic. Here’s the video showing what it’s doing. Side note, I’ve been ripping this thing apart to get ready to completely redo it, basically de “mad maxxing” it. Zero rust so even if I’ve got to completely redo all the electrical, I’ve got patience to do that. I actually do like automotive wiring and making my own harnesses etc; so maybe this will be a good little project for me.

That is incredible… Interesting. Thank you for sharing that. Update: The YouTube link below shows before and after. Fortunately for my VP44, it’s working fine.. Unfortunately it’s looking more and more like my ECU is bad. However this harness is a clusterf…. I will probably be trying to source or repair this harness just to make absolute certain it isn’t the harness. Every freaking part for this truck is atleast 600-1000 bucks. Harness? $800.. ECU? 600-1000….

@Tractorman, The cam position sensor has been giving me issues since I’ve had the truck. Saying a signal can’t be found, but someone already replaced it, it’s still not working. Also, the tachometer hasn’t been working either. But I did the gauge cluster test and it was fine. When the VP44 is unplugged, and it’s jumped, the lift pump does not engage. Conversely, when the VP44 is plugged in, the lift pump runs continuously once I try to start it, and then it’ll start running just fine. The engine was not already warmed up and high idling… I totally disregarded that. I will be performing the test again right now, and will follow up in 30 minutes or so.

So here’s the verdict…. i went and jumped pin 7 and the one directly above it, and I heard a click. Great, I started the engine and it idles perfectly for maybe 15 seconds, then it died and it won’t restart. It took me a few days because I’ve been dealing with some major fuel issues and I had originally thought that my new lift pump went bad, turns out that the ground wire coming off of the VP 44 connector had been snapped clean in half and I assume that is what controls the lift pump, because when I reconnected it, the pump ran and the engine fired up. So I am wondering, does the VP 44 tell the lift pump to run? Because I am getting absolutely nothing.

@Great work!, I will pitch in where needed as well. If you’d like to drop a form of payment (if allowed), I can drop some cash to help your development, or if you need something specific. Again, I’m fascinated by this stuff, and actually wouldn’t mind buying a “dev board” from you so to speak. You’re very well going to revolutionize the 24 engines at some point if you continue this, add to the scarcity because everyone would like to run them, but these ECUs are way too expensive and soon will be obsolete and impossible to find for reasonable price. I am convinced that all this new stuff coming out, some may last a very long time but it’s the proprietary technology that drives them that would be the reason this stuff ends up in junkyards prematurely.

I am genuinely curious if you’ve gotten any further on this build. I find this fascinating, I’ve built a small “ECU” with fuel maps for a small fuel injected engine from a generator some years ago, but this would be neat to have for my old truck. If you're willing to, I’d love to take a peek at your project and try my hand at it on my truck. Incredibly talented, this stuff fascinates me.

Thank you @Mopar1973Man, I found a killer deal on a set that I’m going to try anyways, just because I don’t really want to pour a whole lot into injectors at the moment. It’ll be temporary anyway as I troubleshoot and figure things out. I do also have a cheap injector tester that’s had a lot of good reviews, they’re under $100 from Amazon, it seems to work well. I wish I could find the nozzle/pin (I think that’s what it’s called) kit for these OEM injectors, IIRC, Bosch used to sell them according to several YT videos showing folks “rebuilding” and shimming them. @Tractorman, I started to do the test until yet another leak had developed at the fuel filter housing, I got it fixed last night so hoping to spend some time tonight on it.

@Tractorman, I have not had a chance to test the VP44 standalone just yet, I will try it tonight and see what happens. The worn injectors possibility is starting to look more likely, especially when revving the engine up how it starts to miss and throw a bunch of white smoke. However, I noticed a thin stream of diesel spraying out from the back of the VP44, turned out to be a loose fitting to injector #4, but I tightened it back down, as well as the other 5, and they were pretty loose oddly. No more leaking, but no change. @Mopar1973Man I had no idea that a worn injector could cause high idle issues like that. I have been researching for hours on end, and the only help I have been able to receive was off of your forum, so thank you for creating such an awesome helpful forum. I am new to the diesel realm and have already learned a tremendous amount in the short period of ownership. I will look into replacing the injectors, do you have any suggestions on what to buy for stock to start? I have seen people rave a lot about the Bosch "RV275" 40HP injectors during my research, they're relatively cheap so I can just go ahead and get those and throw them in if not fixing the problem, then just having fresh injectors.