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.

I will perform the test on the VP44 to see what I can come up with. I am about done being covered in fuel trying to fix these leaks tonight. Could injectors still be the issue considering the truck starts up, and idles perfectly? I mean, it idles right at about 850rpm, and within 5 minutes it’s idling 1300+ The link below shows an odd thing I noticed. I never really revved it up before until now, like really revved it up. It seems to run great but starts to shake pretty good when approaching WOT and white smoke, smells like raw diesel. I’m really beginning to think the VP44 is the issue… I’m hoping not; but will perform those tests. IMG_3748.mov

I have the TopDon Phoenix Lite, pretty much the best I can obtain that does virtually anything, it couldn’t access the error code either. I’ve tried one other scanner as well. 340,000 miles on the body, I “think” the engine has based off of the harnesses being undone, and just signs of being painted, like someone tried to clean and paint it before putting it in. I purchased the truck a few weeks ago, with the idle issue. No idea on the injectors, no tuner either. Although, I have been hearing a long beep when I disconnect and reconnect battery power, as if there’s a device somewhere, I’m assuming it’s a tracker that was installed years ago, and I can’t seem to locate it.

I will be doing some more research! That’s very interesting information, I’ll look into extracting the data off the EEPROM. Once you get your GITHUB setup I’d love to take a look!

So even though the voltage is properly calibrated, I’m assuming the resistance is what the ECU listens for to idle down? I could try to throw a potentiometer on there and see if it idles down. If you don’t mind sharing, how did you go about this project utilizing those 3 sensors? I am fairly versed in Arduino and the like; if the ECU is indeed shot, that would be a neat project. I’ve also got several devices for reading EEPROMs, do you have any information on reflashing the memory? I’m assuming that’s what you meant by the ECU is losing its EEPROM.

@Tractorman, Hey there thanks for the response! I have checked the voltage, no more fluctuations! After a while idling, it increases RPM, at that point the APPS shows zero percent when idling even when it revs up. I will go ahead and look into the bypass to check the VP44.. The only error codes I noticed was from the PCM, for IAT sensor (I just replaced it, not sure why it’s acting up. But I’ll check it again.) and the APPS voltage too low/too high, but I was initially calibrating it too low or too high. Those have gone away since I’ve calibrated the apps correctly. I’ll double check later. However I did see a P1693 code but that says it’s a “companion code”, I assume this is the Cummins ECU informing the PCM that there’s an error… How do I read those error codes? I’ve already tried the cluster method, it only shows the PCM error codes.

Perhaps you'd know what my issue is, first of all, AWESOME write up of the VP44 pinouts. I've made several ECU's for small engines before, it's definitely challenging. Have you come up with a good control system for it yet? Secondly.. My issue. I just bought my first 24v cummins, its in an 01 dodge ram 3500 dually, with the nv4500 transmission. I am having high idle issues, where the truck idles fine on startup, then idles up to 1000 (to be expected) but then continues to climb as it gets hotter, to around 1300-1400 RPM. I have replaced the Coolant temp sensor, the TPS (And calibrated), the MAP, and the IAT sensors, all without any luck.. I upgraded and repaired all grounding issues, new terminals, new batteries, new alternator. I checked all harnesses, made sure the 5v reference signal was clean, going to the TPS (APPS), and other sensors... I have literally checked everything, maybe you can give me a glimmer of hope. I wouldn't imagine its a mechanical issue with the VP44..

@Tractorman I have checked absolutely everything I could. Replaced fuel lift pump, replaced every sensor (two were actually bad), I replaced the alternator (Showing low voltage, under 12.10), I have checked the wiring, everything you said to check and nothing. I am beginning to wonder if it's a software issue, perhaps someone put a tuner on it, and increased the idle? No idea how to even check that other than buying a tuner. I should also mention, that when I do a cold start, it idles normally.. After about 2-3 minutes, it'll increase to 1,000rpm. After that it gradually increases to 1200-1300rpm, and never drops back down, no matter how warm it gets. I checked the coolant temperature sensor as well; that is working normally. I even put resistors on the connector to simulate a hot engine, still nothing. I am at a total loss here; could the VP44 feed the engine more fuel than necessary at idle somehow?

@Tractorman, I have discovered something else. When digging into the ecu harness, I discovered an electrical taped connection there. I undid it and found an Orange/black or brown I can’t tell, wire; and it connects to the shielded part of the gray signal cable, when it makes its way up to the back of the VP44, I have no idea where it’s supposed to connect. Any ideas? First picture shows the wire beside the ecu. The second shows up under the connector to the VP44.

@Tractorman, I have had a few hours to play with the truck, and I noticed a few things on my new scanner that I received. My scan shows a boost pressure of 13.2 PSI even when the truck is off. I unplugged the MAP sensor and it suddenly read 0.00, however, I do have two boost pressure graphs on tablet, one shows 1.9 psi and the other one shows 13. Not sure why there are two. Would this cause the idle to increase as well? Or is that just simply for reading boost pressure? Perhaps I’m still dealing with a ground issue and it’s causing the sensors to go haywire, but it was consistently showing 13 psi even with the truck off. I removed the entire conduit off of the harness and finally found the crimp connection, it was further underneath the diesel filter on the side of the block underneath the ECU. There is one other important thing I should note, the inside of this conduit and the cloth wrapping, as well as all of the wires were absolutely soaked in diesel, fuel, and motor oil, so I decreased everything and will continue to work on it tomorrow.

@Tractorman, I honestly used a remote ground.. Not sure why I didn’t think to use the ground coming off the connector. Wow. That was a brain fart. You’d think being a licensed electrician I’d have thought of this… I will do so later tonight when I get off of work, thank you! I’m probably going to replace the MAP as well just because. I suspect this is not the original motor because everything connected to the block harness wise was not connected, I’m going to be removing the front clip this weekend so I can really get in there to fix any possible areas for the harness to rub. Side note, I need to do the timing gear cover anyway as it’s leaking pretty bad, and also need to put a bracket over the killer dowel. Someone mentioned that to me this morning actually. I really do appreciate your help.