Hey hef I diagnosed 2 dead cylinders over the summer customer changed piston and head should of been right head. Now no start I haven't worked on it yet but someone plugged an et in had no communication. 2zr2108 hoping to bump a schematic. It's a 3408 motor. Any help much appreciated. I'm thinking it's a wiring issue but who knows they are a junk yard.
View attachment 988F SENR5887SENR5887.pdf Hi, you need to establish communications with the ECM as a priority, does the engine crank and not start or does not crank. Sounds like you have a power supply issue but need more info from ECM Mark
Ohmigod, a 3408HEUI. That sends shivers down my spine just thinking about what could be wrong with it. 988F Series IIs gave me nightmares in a previous life ....... As Mark says, we need to know if it won't crank at all, or if it cranks but won't start. Be aware that to light the fires you need at least 150RPM cranking speed on those things. Batteries, cables, and starter motor all need to be in tip-top condition. A trick we often used to do to see where the leaks were in the HEUI system was to plug in a porta-power to the HP oil system and pressurize it (carefully) with all the valve covers off. If you get a spurt of oil in your face while doing that you know right where to look. It's not unusual to find all 8 injectors leaking oil big-style from the weep holes - effectively that means they are fcuked and need to be replaced. If you have a "full fat" (dealer) version of ET and there is no communcation via the Cat Datalink try communicating with Winflash (ATA Datalink) to see whether or not that recognizes the ECM. I had a few 3408/3412 HEUI engines play that trick on me. Flashing the engine software again pretty much cured it every time.
3408HEUI, the company had one of those in a 769D, well actually "they" still have it but that's not my problem any more! That one developed a no start problem that would only show up on Mondays, kind of like some of the guys at the quarry. Against my better judgement we were able to get it to start with some "nose candy" the first Monday, when you are talking of 1/2 the fleet boss gets very anxious to see them running. The rest of the week it started just fine. Next Monday same thing, but this time we had a former dealers mechanic who lived just over the hill come out and after checking a few things with ET we pulled the covers and while cranking there was a nice flow of oil out of a couple injectors. Swapped in reman set and it fired right up. That was far from the only HEUI problem with that truck but that time it was fixed for awhile!
Hey guys heres the rest of the story verified no communication will crank. Checked powers at ecm +24 checked grounds all machine grounds above ( 50 ohms. ) cleaned all grounds got down to under 2 ohms. Key switch power +24 no power outputs. Owner come over well they were welding on it.... fired ecm but he has and ecm off 3412e..... install and have communication bingo. But I didn't try to start with wrong ecm. Did notice that gauge keep flashing on dash when they don't see signal from ecm. As soon as tachometer read zero I new I had it. Next problem is he has 2 other ecms with same part number but neither for 3408e I can't flash ecms unless I copy a good one first. Can a cat dealer flash ecm if I drop it off guy doesn't have a good relationship with our dealer. Big thanks to kshansen with out him would of been big waste of time today. And thanks to the rest of hef I learned so much about heui motors last night
My wording might of been poor and post was long winded so going to ask question a different way. Has anyone ever had an ecm flashed/ uploaded with out it hooked to machine is there like a 40 pin harness they just plug in and up load or is it all on machine? I had a Cummins ecm in a case they could only do on machine but wasn't an issue that customer had a good relationship with dealer. This guy couldn't get cat out if he left 20,000 cash on the counter.
Short answer is Yes with an If. An ECM can be flashed on the bench if it is blank. If the ECM already has software installed, it's possible that factory passwords will be required as it may think you're trying to re-rate the engine, and re-rate passwords can cost hundreds of dollars. The problem is finding someone in the dealership with the wherewithal to have a go at it. There probably is a ready made harness for the job, but the dealer probably won't have it. They will have to find a spare battery and make up a harness to make it happen. It is actually quite an interesting exercise if you can find the right person to take it on. Your dealer may well be wary of having someone put a couple of hours work into the job just to find a re-rate is needed and for the customer to then decide he doesn't want to pay the extra.
A dealership with a dyno can do it
Okay at least there's a chance I'm not sure if they have a dyno or not. We shall see.
At one time re-rates on HEUI engine ECM used to be just a matter of plugging the relevant numbers into the system and generating the passwords, or if you were really desperate a phone call to the 1-800- hotline and get the passwords over the phone. Today now the Dealer TC's are forced to use Cat famous DSN (aka Don't Solve Nothing) system I'm not sure sure ......... Certainly it does not need a dyno either way, but as CM pointed out the harness to flash an ECM off the engine is usually something that has been made up at some point by a dealer tech or TC and apart from a 12V battery (I used to lift the hood on my pickup and use the battery from it) it really doens't need much else. I wonder what happened to the harness I made up that lived under my desk all those years ago...?