D6T S# LAY704 At start up, this thing sounds like its running on 3 of 6 cylinders and the rpms (should be around 800) are around 300 while this is going on. The funny thing is it doesn't do this every start up. The operator is telling me that its at its worst on cold mornings, so I was thinking maybe there was water in the fuel system that was freezing overnight...…….no water found. I was suspicious of the fuel transfer pump and went ahead and replaced it since it was the original and had 7800 hours. It seems a bit better, but with the inconsistency of the issue, I'm having trouble trying to narrow this down. I would like to know how this fuel transfer pump works electrically and I have the schematic for the machine. Does this pump run fulltime from ignition on? is there a pressure switch that runs it? In the schematic its not easy to follow (which is unusual) and a bit confusing as to where exactly the wiring runs in a certain area. I need to make sure the transfer pump is working properly before I call CAT ET out. Any suggestions?
The Service documentation on the fuel priming pump for LAY00704 sent me to this......although I can't see D6T on it. What Part # of priming pump does it have installed..?
1908970 is what they got me.
Does this engine have an intake heater?
That's correct according to what I can see. The Special Instruction does apply to that priming pump Part Number. It's the 2nd one on the list. There is some info in that same document regarding how the pump is supposed to operate.
So is it my understanding that this particular pump runs continuous with ignition on? The wire schematic shows a broken dashed blue (ignition on) wire but there isn't an item in the legend for that particular color code. I have been assuming the dashed blue wire is an intermittent ignition on feed.
Not sure about that, I haven't got that far.
According to that doc I posted above, the pump runs all the time. I need to have a look at the Electrical Schematic, haven’t done that yet. We have an LAY-prefix D6T on site only 100 or so Serial Numbers from yours. If I get a chance I’ll take a look at that too.
That serial number has a mechanical fuel transfer pump on the back of the high pressure pump. The electric pump on the primary filter should only run when the key is off and the primer switch is toggled to on position.
That would be great Nige. Thank You! That's not something I am aware of. What is confusing me is the Ignition on blue dash line on the wire schematic that is leading me to believe the electric pump is supposed to be coming on, at least intermittently. I was aware of the primer switch, and that operates correctly.
To hell with the diagram for now.. u need to get it running.. hot wire the pump to RUN for now to see weather or not that's the problem.. its GOTTA have fuel to run.. THATS what I would do for right now.. get the pressure UP TO the inj. pump & see how she runs.
Believe it or not, it runs......everyday! It will start, just misses like a MOFO for the 1st 2 minutes, then straightens up and runs fine. Hitting the primer for 20 seconds before the initial morning start up has seemed to help.....a bit. I'm trying to get all the correct info I need before I shut it down to troubleshoot. At this point, Im not sure its a supply issue yet but I want to eliminate that as a problem. The inconsistency of this is what's making it difficult, some mornings it starts up just fine. Where's the hair-pulling emote?
It def. sounds like a "bleed-back" problem..if the pump isn't coming on when u turn the key, THATS A PROBLEM.. its gotta have pressure AT THE PUMP INLET to run properly.. Have u tied in a clear line or gauges yet? A clear line will show u if its draining back AND if its going to the inj. pump when u turn the key on.. Hot wire the dam thing.. lol w/ a toggle in the cab..
Yeah, I thought bleed back also, which is why I changed the transfer pump (electric) out since the check valves are in it. I don't believe the electric pump is coming on with the key, which sent me to the wire schematic...….and now the schematic is confusing! LOL Believe me, I will hotwire that B**** once I have the info I need just in case that doesn't help. I can only shut this machine down once, or if it goes down on its own. Has no active fault codes either.
What schematic are you using ...? The snip below is from KENR5131-04 (latest available dated 16/12/2014) and I don't see any wire carrying power from the ignition switch. All I see is a wire #326 Purple that is live as soon as the Master Switch is closed. If you want the complete schematic please let me know.
That is what I'm seeing, the electric pump is just to fill filters at service or if run out of fuel. Being this is a HEUI fuel system, could the starting problem be leaking seals in one or more injectors? I know this is a different engine from the 3408 we had in the 769D haul truck but the starting hard problem sounds similar. Ours would start and run good all week but come Monday morning it would crank for ever to fire up. After checking all kinds of things Cat Tech and I removed valve covers and when cranking engine we could see a flow of oil out the top of some of the injectors. Replaced injector and it started good no matter how long it sat.
Ken, if you look at post #12 I don't think it's the HEUI pump, not with symptoms like that ........ It will start, just misses like a MOFO for the 1st 2 minutes, then straightens up and runs fine. Hitting the primer for 20 seconds before the initial morning start up has seemed to help.....a bit.
Yeah, my schematic doesn't look like that one, they probably got me the wrong one. Mine is publication # KENR8916-12 (Schematic pt # 331-4065) Yours look more like what I have on the machine...……….no wonder this wasn't making any sense! Yes, if you wouldn't mind, a complete schematic on the electrical would be wonderful. Im supposing the electrical transfer pump is only for filling the filters as Ken suggested? I was expecting it to be a supply pump like a lot of Deere equipment has.
I double-checked and KENR5131 is deffo the right one for an LAY-prefix tractor. Drop me a PM with your email address. I didn’t get chance to look at our 6T but when I questioned one of the mechanics he told me that the electric priming pump on that tractor was for filling the filters after PM.
We have a 325d with a C-7 acert that had a similar issue. It turned out it was the temperature sending unit that was bad and made the computer think it was warmed up when it was cold. It would then read normally as soon as it warmed up slightly, then it smoothed out and ran fine. I plugged into it one morning and noticed it was reading hot when it was cold. Had me scratching my head for a while!
KENR8916 is for really late (current even) models of D6T, not a 2007 model such as LAY00704. You need Schematic KENR5131.
Just getting back to this machine. Supply pressure is within specs. ………….stay tuned. I am suspecting leakage in the high pressure side of the fuel system. Machine has 7988 hours and no record of any engine fuel system repairs or replacement.
For a HEUI engine to still be on original injectors and pump at those hours is almost unheard of in my experience.
Amen to that Nige..
If it only does it when it's cold and only for the first few minutes it's probably stiction in the injectors. You can use et to cut out cylinders and see which ones are dead on startup or try hotshot secret or one of the other anti stiction additives in the engine oil.
Feel free to call me crazy, but my similarly houred 2006 6R with C9 had exactly the same issue. Worse actually. CAT and I went round and round and round on it for years, and got nowhere. However, what was clear was the computer retarded the fuel at cold start to protect the engine for the first few minutes. Sounded like crap, and made obvious knocking and missing sounds, but CAT insisted it was a feature, not a bug. I have a long thread on this site about it.
In cold mode the ECM keeps the injector actuation pressure lower so that's less pressure to move sticky injectors. You can usually figure out which ones are likely dead on cold start with a solenoid test in Et. It may show good but if they don't have an audible click they're likely gummed up. Or crank it up and cut out individual cylinders to find them. The series 2 6r did seem to be a little tougher running engine than the later ones. The decelerator is especially touchy on them.
I'm with newguy. A solenoid test when then engine is cold should give a really sharp "TACK" sound from any injector that is good. If the noise from the solenoid is a dull thud then it's probably at least partially stuck.
Pull the radiator cap when cold before starting and let us know if there's any diesel floating on top
UPDATE*. After my last post I had enquired with CAT field service to schedule an ET hook-up. At that time they were 2 weeks out so I moved on to other repairs around the area, and the customer elected to continue to run the machine until Cat showed up or it quit. Field service was supposed to contact me when they were heading to the dozer so I went on about my business, got through many jobs, pretty much forgetting this machine until I am notified. The owner calls me late last week and asked me whats going on with this machine. After a few questions I realized CAT never called or showed up and neither of us were ever notified of anything. So, I called Cat field service again Monday and asked for a field tech with ET on this same machine...……...He had him there the next day (Think they knew they screwed up). He has been there 2 days straight and has come up with the following (by phone) 1. All engine fuel system checks are within operating parameters. (ALL the tests performed) 2. 2 service error codes will NOT clear ( he told me over the phone but I didn't write them down) 3. The diagnostics ran for those codes are not reading all the parameters correctly. 4. With all tests run, nothing is evident at this time to pinpoint a fault. 5. 1 of the 2 codes is basically saying (eminent ECM failure). ECM is $2400.00, but I was told we could go ahead and run the machine until it failed if we wanted because it wouldnt damage anything else and the cost would be no different. I am waiting on the owner to make a decision. No wonder I was having trouble figuring this out. It doesn't look like they are having any better luck. Stay tuned.
I'm curious to know what those codes are. Sounds odd for an ECM failure but I just saw one fail in a new way last week. If it needs an ECM I hope they saved an ECM replacement file while they were there. In the even the ECM just dies they'll have all the settings, totals, trim codes and timing calibration to load directly into the new one without having to pull the valve cover and calibrate the timing.
I'd also love to know what Codes they came up against. Changing tack a little (sorry). Somebody help me out here. When you pull an ECM Replacement File using ET for a 3512C HD engine equipped with an ADEM 3 ECM does it contain the Timing Calibration..? I had a dealer guy telling me the other day that it doesn't. I could have sworn it pulled everything including FLS/FTS settings, injector Trim Codes, etc.
Most of the time they do but I want to say there have been a few engines that haven't for me. Could also be that they were only copying configuration vs making an actual ECM replacement file. Opened the file on the one I did the other day and it had some text/code for timing offset
Tech texted me the codes: 268.2 1250-9 He said both of the above are active, and the "service code" staying on is an event code logged. He said that he needed a factory reset password to remove a E198 stored code that is not active but will not clear.
268 is incorrect parameter. Very well could be the ecm failing. Sometimes the internal battery or something fails and they lose the fls/FTS settings and won't record hours on faults. That can set that code. 1250 is for the product link, disregard. 198 is low fuel pressure if I remember right. If that's active it could definitely be the, or part of the problem. If he needed passwords to clear it was a level 2. If it's actually active the fuel indicator on the dash should be on.
CID 268 could be something as stupid an a missing value for an injector E-Trim file. But you're right, if the ECM is starting to crack up internally it could have lost something in the Configuration File, or even the basic operating system. I've seen this before a few times and often it was fixed simply by flashing the ECM with the same Part Number of software that's already in it. E198 Events can often be logged after a fuel filter replacement, but generally only a Level 1. An E198 Level 2 Event would also cause an engine derate. I would be surprised if E198 required factory passwords to clear, but then again I've been surprised before.
Sounds like the tech was on the right track then. The customer has elected to continue to run the machine until an eminent failure occurs.
TBH I would not be confident of extracting an ECM Replacement file from the currently-installed ECM for fear that whatever bit of data that is either corrupt or missing right now and causing the problems might transfer over the the replacement ECM and make it behave the same way. I WOULD, however, make a "Copy Configuration" file to keep safe so that if the ECM had to be replaced at some future date then at least most if not all the Configuration Settings could be manually programmed into the replacement ECM at the time of installation. New ECM's are great (if a tad pricey) - because a new one is blank you get one "free" attempt to enter parameters into it without requiring Factory Passwords to do it.
Copy configuration really isn't all that on a d6t. There are few settings that you really need to set. On a truck or industrial engine yes but not a bulldozer. What I absolutely would do is take a screenshot or somehow record the injector trim codes. Copy configuration won't do that.