NE frmhnd

Any ideas what could be causing it to eat the ECM? It's in a 95 FLD. Got a rebuilt ECM for it, one of the drivers went out and it was rebuilt again maybe 1000 miles ago. Rebuilt ECM has less than 5000 on it. Should we look into bad grounds or broken wires on the engine, or is it likely the rebuilt ECM that's the problem?

Hvytrkmech

Check your grounds, there should be a ground ribbon that goes from one of the ecm mounting lugs to the frame. Also check the 12v power wire, it may be chaffed slightly by one of the band clamps that secure the harness.

NE frmhnd

The driver for #5 went out, got it back, and now #4 is dead. And no, there is no ground strap from an ECM mount to anything.

Could a lack of proper ground cause it to burn up ECM components? Corry's of a mind that the metal on the back of the ECM should be grounding to the metal that it bolts down to.

Hvytrkmech

Proper grounding is the most commonly overlooked electrical problem. Most N14 I have dealt with have always had a ground strap on them. Yes they can ground through the ecm case to the block, not overly reliable but it will work. With that being said you should run a test ground to eliminate the potential for that being an issue. There were some chaffing issues also. if your dropping injector drivers than check the ecm harness for chaffing. You will need to unbundle quite a bit. Also check for a shorted cam sensor and a shorted injector pass through connection.

NE frmhnd

The truck went to the shop Sunday. They found something under the valve cover that they are replacing. Told the boss what you said, may throw a ground on the ECM when it gets back. He said that doesn't sound like much fun, chasing wires.

Hvytrkmech

Also check the injector plug pass though connectors, they fail and short to ground on the inside of the head.

NE frmhnd

Corry put a new connector on #5 before we figured out the ECM had ate the driver. He cleaned up the connectors at that time as well.

The shop had it all opened up so I hope they found anything wrong.

NE frmhnd

Well, the shop lived up to their reputation. They can read codes and swap parts, I tell the boss to take it to Freightliner but no, Case can work on it.

They changed a valve of some sort under the valve cover, that they said was the problem, because it wasn't throwing a code.

Boss brought it home night before last, Corry goes to hook it back to the hopper, and number 4 is still dead.

We're running it til we get corn picked, or it blows, whichever comes first, I guess.

New symptom- once warm it takes quite a bit of cranking to get it to fire.

Hvytrkmech

Hot extended crank to start could be several issues divorced from the original problem simply compounding. As for the later issue, look at oil pressure rise. Does your shop have the ability to get into insight?

NE frmhnd

Boss finally got ahold of a guy from Kearney who does mobile work on Cummins engines. Supposed to really know his stuff. He slapped a test ECM on and it's running fine now. Except it's down about 50 horse, and no cruise. I think he suspects the rebuild job on the original ECM.

It was dumping fuel into 4, and started knocking yesterday. Corry had to pull the plug on #4 injector to get it to the co-op for a flat tire, and they left it there for an easy place for the service guy to find. I told him to just run it, if it blows maybe we can talk the boss into rebuilding it with the parts to be able to turn it up to 450 or 475. So much for that idea.