Caterpillar 277B Interlock ECM Repaired, Running Rich and Won't Start

[Dcastrnod123]

I recently had diagnostics ran on my fathers 277B when we realized the parking brake would not release. The machine started and ran fine, but would not release the parking break. The code came back with a faulty ECM. We sent it for repair and the mechanic said the parking break driver within the ECM had a burnt out track(See attched picture). We installed the repaired ecm and the machine would not start. We jumped the starter and the machine started and released the parking break, but now the machine is running really rich and burning a lot of fuel. The machine will not start without jumping the starter and is running rich, could this be a programming issue and could this cause the machine to not start ? Any help would be greatly appreciated.

 

[ianjoub]

I would call the folks who repaired the ECM and explain the issue. My bet is they offer to 'look at it' if you send it back, and it will come back to you working properly.

 

[Nige]

And there lies the difficulty of successfully repairing ECMs. There are so many flash files and options I don't think anyone has been able to devise a bench setup that's capable of reliably testing the repairs.

 

[92U 3406]

Did anybody copy the flash file and configuration from the ECM prior to sending it out? Could be as simple as needing to reflash the repaired ECM and setting up the proper configuration.

We don't see many old B's come thru our doors anymore but I seem to recall some of those older mechanical engines had a cold timing advance on the fuel pump. Could be turned off in the configuration and making it hard to start.

Generally speaking, if it worked before you messed with it and it doesn't now, chances are the root cause is what you did to it.

 

[Dcastrnod123]

I would call the folks who repaired the ECM and explain the issue. My bet is they offer to 'look at it' if you send it back, and it will come back to you working properly.

Yes, I am in Chicago and they are in Texas. That was what i was afraid of. I just wanted to know if it had anything to do with the fuel. I am sure it does, since it was fine before.

 

[Dcastrnod123]

Did anybody copy the flash file and configuration from the ECM prior to sending it out? Could be as simple as needing to reflash the repaired ECM and setting up the proper configuration.

We don't see many old B's come thru our doors anymore but I seem to recall some of those older mechanical engines had a cold timing advance on the fuel pump. Could be turned off in the configuration and making it hard to start.

Generally speaking, if it worked before you messed with it and it doesn't now, chances are the root cause is what you did to it.

No, there was no copy of the flash file and config. I recall them saying they just needed to fix the one little burnt track and there was no need fore them to reflash, but obviously I am seeing different. I agree, if it was fine before, it has to be something they messed with. Do you guys know of any good companies for reflashing ECMs ? I don't care where it is, just seems hard to find a good service company, aside from CAT reps(Prices are high).

 

[92U 3406]

I think you'll need to have the dealer plug in and read the flash file version/upload latest file if required. I honestly don't know if customer version of ET has the ability to perform ECM flashes or change parameters and perform calibrations.

 

[Nige]

I think you'll need to have the dealer plug in and read the flash file version/upload latest file if required. I honestly don't know if customer version of ET has the ability to perform ECM flashes or change parameters and perform calibrations.

The Customer version of ET will do everything highlighted in bold. To upload flash files requires the Dealer version of ET.

This gentleman's experience is why many people shy away from even thinking about having ECMs repaired. A Reman ECM would probably have been the quickest and most cost-effective solution - and it would have come with a warranty.........

 

[92U 3406]

The Customer version of ET will do everything highlighted in bold. To upload flash files requires the Dealer version of ET.

This gentleman's experience is why many people shy away from even thinking about having ECMs repaired. A Reman ECM would probably have been the quickest and most cost-effective solution - and it would have come with a warranty.........

Good to know, thanks. I've only ever used the dealer ET so had no idea what the customer level ET could do.

 

[Nige]

Customer ET can do everything except Winflash basically.

 

[rmllarue91]

Okay walk me through beginning. the burnt contact strip looks more like park brake solenoid shorted or was jumped ? Too me.
By running rich and burning excess fuel could it excessive hydraulic load? Does it seem like it stalls at low idle or down on power?

 

[rmllarue91]

I'd diagnose starter first. pull starter relay with multimeter two wire should show low resist a ground and solenoid wire. A hot wire and a signal wire

 

[rmllarue91]

 

[rmllarue91]

 

[rmllarue91]

I would ohms out park brake solenoid 10 ohms
Appears to be an 1.5 amp circuit unprotected both wires back to ecm

 

[rmllarue91]

If they just soldered track I'm not sure they did any programing

 

[Nige]

If they just soldered track I'm not sure they did any programing

Agreed. It shouldn't have been necessary. They would've been nowhere near the Processor.

 

[rmllarue91]

And there lies the difficulty of successfully repairing ECMs. There are so many flash files and options I don't think anyone has been able to devise a bench setup that's capable of reliably testing the repairs.

Hey nige do you know what cats reman department does for testing I'd imagine they do large batches at a time. But there still is tons of inputs and outputs to check.

 

[Nige]

A bit of an unknown to me I'm afraid. Speaking under correction I would imagine that ECMs go to a specialist external contractor who will first "wash" them (remove the Config file in other words , because the same Part # of ECM can be used in multiple machine models), then put them on a test bench and figure out what's wrong - then fix it and test again. Maybe they even replace certain of the internal components whether they are bad or not, just because The Book says they get replaced. A bit like Certified Rebuilding an engine, you junk certain parts even though they might still look OK.

 

[partsandservice]

So if I recall correctly that machine control module monitors engine peramiters and controls the fuel shut off, but other than that the engine is mechanical. So after checking the air intake, including turbo, and fuel solonoid
for complete engagement in run, look for the parasitic hydraulic load mentioned above. There is likely an electrical issue that caused the short in the circuit board that still exist. The failed mcm was likely progressive damage.