I'm posting this for someone else, I suggested that he join Heavy Equipment Forums but thought I'd give a heads up here in case anyone wanted to get their thinking caps on. I did tell him the first thing to do if he does come here for help would be to give the S/N and any work done before the problem showed up. Hi guys I am currently on a mission base in Swaziland Africa. The problem is a D5 Dozer with a Cat 3216 that runs pig rich on cylinder number one . We have moved the injectors and the problem stays on number one. Number one injector is being fed 24 volts with the key off and 108 volts with the key on. All other injectors are 0 volts key off everything is pointing to a bad ECM but it is very pricey. Was wondering if anybody had any suggestions of what else to check. Thank you for your time. We tested directly at the ECM connector unplugged. Ross MacPherson
108 volts!? No way that can be right.
I'm thinking that the engine listed is not right as I can not find a 3216 in the list of Cat engines, thinking it should be a 3116 or maybe a 3126? Don't see a 3116 with electronic injectors.
Not sure of this design but most injectors are turned ON/OFF by the ECM applying a ground. Seeing 24V with key off would have me looking for a short in the harness. If it is 108V then there is a floating ground
First thing I would be asking (after the S/N) would be if any Diagnostic Codes were showing on the panel.
Some models of D5N are equipped with a 3126B engine, but there are various S/N prefixes. Maybe "3216" should actually be 3126..? Either way need a S/N for either engine or tractor.
Nope Nige, the 3216 came in the D15, just like the guy says
Well have not heard yet from the guy but then he did say he was in Swaziland so no idea of his internet access or times.
Some of our Deere tier 3 and newer engines run at 90 volts.
Guess I should brush up on my tech!
If the engine is in fact a 3126B it's a HEUI. On the larger HEUI engines (3408/3412) the injectors ran at around 180V IIRC. I remember well the "High Voltage" stickers on the valve covers.
Guy did email me and say he was signing up to heavyyequipmentforums but added: Internet is limited and sketchy at the best times here so I have to plan my on times. Hope to see him sometime in the next day or so.
I am not expert on Cat engines but this what I know from experience. The 3116 and 3126 used a mechanical fuel system with a rack and fuel rods similar to 2stroke Detroits. 3126b used Heui injection. 3126c and C7 are same engine .Heui injection but with different pump and injectors than 3126 b. As far as this D5N goes even though the voltage high and AC. It is controlled by pulse width which can only be measured with a scope. Constant voltage would have the injector held ope n constantly even when not at injection timing. If the wiring diagram is available, check continuity from each of the 1st injector wires to every other wire in the harness plug as well as battery and frame ground. If not ... ECU. If no confidence replace the harnesses first, injector and engine. A short in either harness can do the same damage to the new ECU.
It seems as though my memory is failing me.......I was looking for some diagnostic information for a HEUI engine and found a training document that indicates the injector supply voltage for the HEUI system is actually 105V.
Re-reading the OP it would appear that if "our man in Africa" has permanent 108V on #1 injector and zero V on all the others with the key switch on and 24V on #1 with the key off with all the others showing zero V (I'm assuming that the master switch will still be on) it would appear that the injector driver for #1 cylinder on the main board of the ECM has failed. That's going to mean a replacement ECM. KSH, if you can contact him by any means please let him know.
Hi Guys, Newbie here reading about the heui pump issues. Bought a D5 2 months ago to find, well many issues with the 3126 fuel side. Bought it knowing it needed some work but the price was right. Except after spending some big cash on a new heui and injectors. Got it running well with all the new parts now. A friend stopped by last week, new friend because I now have a Dozer, and went on to tell me about a filter system he put on his motorhome C7 that protects the injectors and eliminates the head flushing when a heui explodes. I went to the site and found this system is very interesting. I called the guy and he explained this filter is a bolt on system capable of 5,800 psi and filters the "post" heui oil to 6 micron. No modifications to the engine except to remove the tubing between the heui and head. Has anyone heard about this? https://ifskit.com/ The price seems like a good choice rather buying six injectors next time My cat dealer told me about an inline that goes between the block to the heui but that doesn't do anything if the heui goes bang. Appreciate your opinions. Thanks, James
The perceived thinking regarding HEUI systems (both pump & injectors) is that generally they suffer from accelerated wear caused by contamination in the engine oil that is used as a hydraulic fluid in the HP side of the HEUI system, not the fact that they grenade. In that respect would it not be more beneficial to filter the oil before it gets to the HEUI pump rather than after..?
I guess thats why this seems to be a logical solution. Not to protect the heui so much but rather extend the life of the injectors. If oil/filter changes are done, to protect the heui, on relatively frequent hours then a grand investment to further protect the injectors seems to be much less then replacing six injectors whether taken out by the heui or contaminants. Personal choice I guess.
But if the contamination that might cause injector wear was removed before it reached the HEUI pump then why would anyone want to install another filter after the pump..? That’s the bit I don’t get. Experience of HEUI engines has taught me that the best way of maintaining the reliability of the HP side of the injection system is the use of high quality engine oil and filters, not parts house branded stuff. Forget the 500Hr PM intervals in the manual and change the oil religiously every 250 hours. The extra cost in oil and filters will be much cheaper than a new HEUI pump and/or a set of injectors. It’s your tractor and at the end of the day you can do what you like to it but if it was mine and I had a choice the filter would go in before the pump to protect it from oil-borne contamination, and by implication to protect the injectors downstream. Killing two birds with one stone so to speak. Those of us who’ve been working with HEUI engines for a long time (in my case over 20 years) will all tell the same story that it’s most unusual for a HEUI pump to grenade as opposed to losing performance due to wearing out.
It sure seemed like they shelled out metal into the HP side on 3126B/C7 truck engines a lot back in the years 2000-2006 or thereabouts. Necessitating a (sometimes ineffectual) rail clean out and pray that they got it all out. Sometimes the engine would never seem quite the same after that. I don't know how truck engines translate to tractor engines. And we did not do the work ourselves, the dealers did it under warranty at least until one day after the warranty expired. Then sent you the full bill for every minute spent. That has been a long time ago and there are none of those turkeys left bankrupting their owners any more around here.
In that case it may be prudent to take a belt & braces approach and install filters both before and after the HEUI pump. It all depends how much the cost compares to the value of parts & labour to sort out a failure I guess.