I have a 740b that has regen issues. It will fail a regen and set a code for loss of ignition and ard nozzle heater voltage above normal. Customer replaced the spark plug, ard head and nozzle heater. Ard nozzle heater code was cleared, but will still fail a manual regen and set a failure to ignite code. I put the nozzle heater/dpf inlet heater on. I have also tried a engine ecm, air control valve and fuel check valve. Fuel pressure during manual regen is 270 psi., there is spark at the spark plug with an inline tester while in regen and the nozzle heater is 4 amps. The flame tip temp always cools down during regen, it will never warm up. I have 11 psi boost at high idle no load. I am running out of ideas and wondering if anyone has had this problem.
Please can you post a Serial Number so that those with access to technical information can look it up.
What Code numbers is it throwing.? Are you reading Codes with ET or with something else.?
Definitely need a lot more info but based on what you’ve posted I’m guessing you’ve for a failed to ignite event when attempting a manual regen. Need to confirm you are actually getting a hot spark by doing an override of the primary transformer in ET. I have seen weak transformers cause an issue. Another thing we need to look for is the presence of raw fuel in the ARD combustion chamber after attempting a couple regen cycles. There are two ARD fuel solenoids, a pilot and a main. The 270 psi confirms you are getting fuel to them but doesn’t confirm getting it past them.
The serial prefix is t4r. I have swapped the ignition transformer and coil wire with another 740 that was working properly with same results. The code numbers are e1025-2, e992-3, e995-3. It has also set an e991 and I have pulled the dpf for cleaning. I am getting the code while trying to do a manual regen. It is getting raw fuel in the combustion chamber after a failed manual regen. I have noticed that fuel is getting behind the swirl plate and it is also wet at the elbow for the air inlet. Not sure if this is normal or if there is an issue with the air control side. I hadn't thought about the fuel system too much because it was wet every time I pulled the ard head off after a failed regen but there could be an issue with that but judging by the flame temp sensor it doesn't look like there is any light off of the fuel.
Have you done the diagnostic procedure for the E1025 event?
Yes I have. All tests passed. Originally the nozzle heater was bad and the customer had replaced the spark plug and ard head. I have put the harness to the nozzle heater on as well. It has ignition with a spark tester. It passes the ard air test. Fuel pressure to the CEM is 270 psi.
If you still have a e1025 you need to start over because if it passes everything then it wouldn’t have a failed to ignite event. I’m going to guess you have a spark issue. Post some pictures of the ARD head swirl plate and anything else you see that could be relevant. You do have access to SIS and ET correct?
I do have access to sis and et. I am going to the machine today to put the dpf filter on and do further troubleshooting. I am bringing a new ignition transformer with me and I am also going to look at the fuel circuit as I haven't looked closely at the fuel except to check the pressure coming to the cem.
One thing I may suggest is running a datalog in ET while trying to run a manual regen. It may help you see what’s going on with the fuel side. Also make sure you override the primary transformer with the ARD head pulled back so you can visually see the spark quality.
I got to the machine and installed a cleaned dpf filter that customer had extra as their one out of this machine was cracked. Got the filter in and reset the ash interval and reset the codes. Could not reset the first level high soot level code. Before I could even get the engine warmed up, the soot level high -3 set and it went into temporary lockout. Looked and soot level was at 116% Reset ash level again and soot level stayed at 116% Had to look at another machine that the customer wanted me to look at instead of the 740 but am going to order a differential pressure sensor and the steel tube from the doc as it was stripped out and not tightening up. Will check the spark tomorrow first thing to see how good the spark is.
You’ll have to run a manual regen before it will go to zero. That’s the only way once it codes for high soot level.
Pulled off the ard head and went to override the ignition transformer and watched the spark. It is jumping across the gap but i am not sure if it is strong enough. I am also seeing some spark from up in the porcelain to the housing. I will upload the video when i can get my computer to accept it
Here is a picture of the ard head.
HEF will not accept uploads of videos. You would have to load it to Youtube first then link it.
I’ve got a thread on here that talks about weak spark on a 627k. On that one, the swirl plate had high resistance and wouldn’t spark well. Ended up wiping out the primary transformer also. I have only seen that the one time. Use an ohm meter and check resistance from the ground probe on the swirl plate to the ARD head body.
https://m.youtube.com/shorts/pGbP9L3db84 . Hopefully this is the correct one.
There’s definitely an ignition issue there. I’ve never seen one spark down inside like that, must be an easier path than the probe at the end. Do that ohm check on the swirl plate.
I was wondering if the spark jumping down around the porcelain was not normal. One other thing I was thinking is that I had the ard head just laying there and it was sitting on some hoses. Would the white wire ground the ard head? I am not sure where that white wire goes to at the moment. When I get back up there I will check the resistance
I believe it goes back to one of the mounting bolts on the primary if I remember correctly so, yes it should ground the ARD head. When I was doing the 627K I could put a screwdriver to frame ground and use it as the ground probe for the spark plug and I got good spark but with the swirl plate I had about what you’ve got, cool yellow spark.
Yep, i slept on it and i remembered it does ground at the mounting bolt for the coil. I have tried a coil wire off of another machine that was working correctly and no change there so i guess i have eliminated one link in the chain. Unfortunately we got 7 inches of snow last night so i wont be able to get to the machine today.
Well I finally got this beast figured out. I put a new coil and wire on it and still had the spark jumping around and weak. I then put another spark plug in which makes it the third new one to go in and i got a better spark and it wasn't jumping around. Tried to do a regen and it still failed but the aftertreatment temperature would go up instead of just going down. It wasn't jumping up like it should, it just slowly went up and it didn't get up to temperature in time. I then stuck a reman ard head (customer had put a brand new ard head on) and ran the regen and it went right in and lit off. Ran a successful regen. I am not sure why there were so many new parts that were bad but it seems that the new ard head and spark plug that the customer installed are bad. I am not sure about the coil and coil wire but I left them on just for good measure.
Glad you got a satisfactory result but it always leaves a bad taste when you have to load the parts cannon so many times.
Makes me wonder if it was a similar metal issue with the swirl plate.
I did do an ohm test on the swirl plate to ard housing and it was .4 ohms. I ran jumper wires from the swirl plate and the ard housing back to the coil bolts and there wasnt any change in the spark.