I have a tier4I Doosan 825CFM compressor with qsb 6.7. Starts right up, gets to 550RPM, then dies. Every once in a while it will hit idle, validate and run perfect. Vacuum tested the fuel system from start to finish. Insite and the titan controller have zero codes and do not throw them. Actual fuel pressure tracks commanded great. crankshaft and camshaft are syncing correctly. Builds fuel pressure quick. Compression is equal on all cylinders and they are good. Injectors are not bypassing and have been tested. From my understanding, the titan controller does not take over until the cummins hits idle verification so this is issue is still on cummins side. Where do I go from here? I will pay for the help if needed.
When it dies is it instantaneous, or is it missing for couple seconds, then shuts off. You will need to do a lot of electrical testing as you probably have a harness grounding out at the perfect vibration or something like that. The fact that it will sometimes run and keep running points to it. Have you pulled apart the computer plug, cleaned , examined and put back together. Can you get a copy of the engine schematic. Would be a good idea to test with a home made 5Amp bulb that you hook up to control wires that have a disconnectible end and power the test light up from Battery and put the end of the wire being tested to ground. Need to check with a Quality multimeter the voltage loss on all the ground connections including the computer itself. Even a 0.1Volt loss on some super low milliamp controlled ground circuits can lead to shutdown or fault code. Do you know how to test these computer grounds with some load on them. You will have to start somewhere to rule out poor connections, or a dealer will fix with new harness and computer. be a good idea to test a lot of it yourself. Simon C
I have not tested the computer grounds with load on them. I will try that next. Its not the computer though. I have a sister machine a few serial numbers apart. ECU does the exact same thing. Thank you for the input sir. Also, I new engine harness is $1200
If it is the same with another ECU it would be worthwhile to test all the wires out of computer with load to find out if something is damaged in harness. Worth testing versus just changing parts. It will take some time, but I am sure that a harness is not cheap. Simon C
Forgot to mention, they had a truck that I did not get to work on at a place that I was doing some other jobs that would just die randomly. Was towed half a dozen times. They were going to buy the new Detroit Diesel DD15 computer. I told the shop foreman who was 28 years younger that he better do a comprehensive test of the power in and out supplies of the computer. He thought it wasn't the problem till he lightly tapped on the fuse box only to see the meter showing loss of potential to computer positive. He found the fuse that feeds the computer was loose and truck never died again as it had. May not be your problem, but has to be ruled out. Powering the wires backwards from the computer back towards the power source or ground with a test light is also good to do. Simon C
Yes sir. I do not change parts. I diagnose to the failure. Trying to see to some ideas if someone has seen this before. I have not encountered zero problems and ran all the hardware tests and everything has tested perfect. I do think you are correct, it has to be somewhere in the hardness. I also logged parameters while starting. Fuel valve, crank sync, rpms, fuel desired/commanded all tracked perfectly as well. I am scratching my head.
One last thing I just thought of is maybe your alternator is leaking too much AC voltage and as the engine gets up to 550 RPM the AC leakage is too much and the computer just drops out. Worth testing., go on Fluke .com and see the how to test for AC Leakage. A friends car was wonky and it failed the test and has run perfectly since changing the alternator. Just needs to be tested. Will need a recording meter to be able to see if it reached the limit of 0.5VAC by the time it was at 550 RPM. If your starter is 24 volts the number will be double I believe. Simon C
Just wanted to mention that in a Cat publication I have they say that an overcharge from alternator can cause there System Analyzer to instantly shut down. It is a possibility from your computer to protect itself . Simon C
Wondering about your compressor and wanted to mention that a guy on this forum with a Cat 216 skid steer checked all kinds of things because of his brakes staying stuck on. Was convinced it was a computer problem. In the end he sent power through the armrest switch that tells the computer to release the brakes and it failed under load. Wondered if in your situation if something like oil pressure could be triggering a shut down before the computer has time to react and post as a fault. That motor is probably at 550 rpm in only couple seconds and amybe the signal from oil pressure is weak and subsequent shut down. I had a furnace thermostat that would drop out very fast till my Fluke 87 meter caught it and problem solved with $85 part. Worth hooking up a meter to watch on start up. Simon C
I have not been diagnosing it. I will get started on it again Monday. I will 100% post if I figure it out. The sister machine I’m working on right now. It’s currently having a fuel problem and I will get back to the 550 rpm one. I will also post a video on it
Ok, here’s an update. I technically have two sister compressors and they both have almost the exact same problem. I have one that is hitting the 1150 RPM that the titan controller calls for. If I am not mistaken, Cummins is verifying idle at 700rpms. It hits the target and then dies. Doosans titan controller is saying unknown engine fault. Cummins doesn’t have any active faults but keeps throwing the multiplex accelerator lever update rate. I have the original software for the titan controller. I have an updated version of the Cummins software. Instead of .00 it’s .07. Can someone confirm this would still be compatible? parameters on the doosan screen are showing up so it’s obviously receiving canbus connections
Is there any dealer bulletins that talk about a common problem. Someone else must have similar grief. Simon C
Do you know a way to be able to see their bulletins? I would definitely assume so. I can check the accelerator wire to make sure I don’t have any resistance in there.
Maybe someone else will chime in. Some dealerships sell equipment, the fixing is your problem. Simon C
I believe where I am at is I want to make the ECM the original software. Currently, it is CC90131.07. The one the machine came with is CC90131.00. How can I acquire the original file?
A Doosan Compressor dealership should be able to help but for how much money. Dirty computer stuff is costing people a fortune. Simon C
I got ahold of Doosan corporate. They were a ton of help! He sent me an update and I will soon install the update on Doosan side. With that being said, I have been seeking more help. Almost everyone is saying it is on the cummins software side. This is ok, if the bobcat update is not the answer, cummins will come and reflash with the original software. Doosan will talk to cummins when he is here so we can for sure find a solution. I would reflash it myself but do not have the original flash.
Looks like there may be light at the end of the tunnel.Hope they solve it. Simon C
I updated it with the Doosan update. It took it three times but it cranked(fuel purging), RPMs climbed to 1250, Titan controller switched to 1500RPMs, then the engine commanded more fuel!! It worked! Ran for 10 minutes then shutdown. Started giving me an injector #4 voltage code lol. I will run down that problem next week but I can say that the Titan controller and Cummins ECM are now communicating again for the RPMs. I still can’t prove this but I believe somewhere over the years Cummins and Doosan both had updates to their existing sides and somewhere along the way they got out of sync.