OK, I can give more info, the truck doesn't run bad once running, about 10-15 minutes into a drive it will start to buck and cough occasionally. It only smokes when it stalls. When it is cold, it will be hard to start, but once started, runs OK until it starts to buck. I t will buck a dozen times, then smarten up for 5 minutes, then it will stall whenever you try a hard acceleration, even in neutral. Then it can run fine for a bit, then start to stall. It will do a hard start, with black smoke on startup, 5-10 times in a row, then run fine, idle fine to get back to the shop. This wa my test drive yesterday with all the monitoring stuff on it. We had checked the timing key on the pump when we installed the first reman pump on it, but never the crank key. You state it "always runs bad" but this one will run poorly with one symptom, then run OK, then later have another symptom, then run OK again, and so on. It is never the same thing all the time. And watching the datastream (which seems to be quite limited) on our OTC Genesys scanner never shows anything, no codes are set, we did have a P1689, loss of communication b/t ecm and fuel inj. pump.
Let me know what other info could help you help me- thanks, Jack
the code you just put down is one of the 5 codes that set when the electronics fail in the injection pump. Are you getting injection pumps from the same place every time? Ive had as many as 4 pumps myself bad out of the box. A couple of them wouldnt even start the truck. The code can be caused from a wiring problem between the ecm and the pump module on the pump. The reason i said about the pumps is because the pump isnt whats failing its the box on the pump. Here is a schematic for the pump. Pay really close attention to the data link circuits, this is where the code is concentrated on.
This should be all the diagrams you will need
Hi again- there is no learn mode in the DRB, several techs advised me wrong as they were thinking of a different version than the vin 6 24v diesel. we tried another known good APPS sensor, no different, still the same problem, will start hard or not at all, will start fine and idle fine, then die when pedal touched, or rev up then repeatedly stall until throttle let off (kinda like an engine hitting its rev limiter) It is still not producing ANY codes at all, I accidentally left the APPS sensor unplugged, it threw a"sensor voltage too low" code, but it started and idled perfectly. The diesl shop is suggesting checking the Tone wheel for the crank sensor (which by rights should throw a code, but never has) and I am going to hook up the Labscope to the crank sensor (Which is newly installed) to see what kind of signal it is giving.
-what is your gut feeling on- replacing the entire engine wiring harness, and if I were to disconnect the fuel pump control module, ground pin 6, power pin 7, and see if it will start and idle (Napafix techs say it should do that) Absolutely everyone is throwing their hands up with this one, running out of ideas. Any insight you can provide would be appreciated. thx, Jack
Ive got a wild guess here. Ive seen this happen very very few times, but it has happened before. Take your ECM connectors off the side of the computer and see if there is any signs of water or diesel fuel in the connectors. Look at your injection pump harness too. Ive had a couple that had a fuel or oil leak and it weaped down the wires and into a connector and started making the trucks do some weird things. One truck in particular kind of sounded like it had a hickup or sputter just randomly, never did it at the same speed or engine rpm every time it did it. If you do have fuel or oil in any connectors, you can try to clean it out really good and drive it and see if it works or your going to have to butcher your harness to rerun new wires to affected circuits or for out some dough on a wiring harness. This is a very possible problem you could be having,
let me know what you find.\
Im still thinking though that there is a wire that is shorting to power or ground going to your injection pump thats killing the power to your pump intermittently. You wont see a code in 50% of the trucks that do actually have a wiring problem. These are my two ideas. I hope it can get you somewhere on a diagnosis.
Hi again- I am just going to get started on checking the input signals into the ECM- I went to drive it into our shop, it would not even start. I went and unplugged the APPS, and the truck fired up and idled perfectly, (but turned on the check engine light) plugged the APPS back in when running, and it drove fine for 3-4 miles, then died on a hard acceleration. It started back up, turned off the check engine light, and drove fine for another mile, but started to act up a little, stalling when the throttle was jabbed, would stall momentarily but keep running. When the check engine light is on, is it at a base timing, ie a "limp home" mode? maybe your timing theory is proven here, it runs OK at base timing?
also- this truck had one new pump here, then our diesel parts supplier installed the four pumps, which all acted the same- Yet all four of those pumps are now driving around on four different trucks with zero problems reported on any of them. Now the diesel shop has another truck doing the exact same thing as this truck- no one is able to repair it either. I'm hoping I can figure this one out.... thanks, Jack
Yea, its at default for idle. The best way to describe how the fuel system works is. You hit the throttle, you are telling the injection pump to change the veins inside to open the flow to give more fuel to the injectors. Kind of like how a hand valve works on an air valve. You give it a little crack on the valve, a little air comes out, open the valve all the way, you get full flow. So if the controller is messed up or the signal is getting interrupted, then the pump dont know to open up all the way. Here is the list of whats all needed for the injection system. Injection pump, app sensor, map sensor, intake air temp sensor, fuel heater, heater grid. I have been reading up on the sensors. After the experience i had today with a diesel, i found out that anything is possible. If you have a scanner, i would have it hooked up and if you can data record, record what the truck does while its running normal and when it starts going nuts. Pay close attention to running voltage(is it over supplying voltage maybe up to 16 V), look at your intake air temp and compair it to ambient air temprature because it should be fairly close. I would pay close attention to your crank sensor reading and your intake air temp readings. If you cant find anything that changed with these, i would seriously have the pump taken off and if you could, take the pump to someone else to see if they can check the brain on the pump. If that same shop is having problems with another truck they pump their pump on and its the same problem, chances it has to be with something they did. These trucks are too simple as far as operation to have this big of a problem. Im sorry, im not the type of person to give up on something. This is bugging the crap out of me. Expecially on these year model diesels. Ive even asked a couple other guys i work with and they are going with the same thing, the pump electronics. We even called Diesel Services(local very respected diesel store/rebuilders) and they even said that some shops that build these pumps, to turn a little more profit out that they skimp on the electronics and most of the time just test half the modules and put them back on another pump if they couldnt find a problem right away. This shop said that these modules should never be reused 90% of the time because this is the main failure of the problem. Im determined to figure this problem out. Im on vacation next week so ill run by my old shop foremans shop and pick his brain on it. He has worked on these diesels and still does for the past 30 years. I want to see what he says. He has ran into quite a few screw balls on these trucks and im sure he has heard of this problem.