Detroit won't start when cold????

I've never seen a coolant level sensor not throw a code. I know the 4-3 code all too well. The truck WILL start and then shut down, at least in all 5 trucks I've owned.

 

Mine - no code, no start. Called Detroit. They said jumper the sensor. Started right up.

 

I wasn't trying to start an argument or dismiss your suggestion at all, I was simply adding opinions to yours, in case he found that it was the issue, he could avoid future problems by getting the parameter changed to warning. But if it is set to shut down, it will start, shutdown light will flash, then it will shut down. This is how DDEC III and IV work, which is what he has. Also, if it was set for shutdown from factory, it would be equipped with a shutdown override switch. A even simpler check is to use the switch, which is even easier than a jumper. But without starting at all and the engine shutdown light not flashing, than it's not the ECM shutting it down for a sensor issue. If the ECM is shutting it down, it would have a flash code. He said that it runs fine once he gets it started and will fire right back up until it sits for more than 2 hours. I'm leaning towards a fuel problem, but it could also be a TRS/SRS issue.

Also paper clips can be a bad idea to jump things, I know it works, but I've fixed a lot of plugs that were damaged from pushing paperclips in them. Female terminals can get damaged if you force something in there doesn't belong, then you're chasing an intermittent problem from poor connections. Most auto parts stores have weatherpack and metripack terminal ends for under a buck to make good test jumpers. If not, small stranded copper wire is better. For popular things, I make a jumper or break out Y harness for testing.

 

Was is a DDEC I or II? III's and IV's do not do this.

 

Mine is a DDEC IV

 

I know you're telling me how it's supposed to work, but that's not the experience that I had. Yes when the engine is running and the coolant level drops and exposes the sensor, there is a warning light and alarm for a few minutes, and then the engine shuts down.

Mine was running, I backed the truck to a dumpster and shut it down, got out to sweep out the trailer, and when I got back in I had a crank but no start condition. After checking the fuel system for air, and operating the override switch, I called the local Detroit shop for ideas. The tech told me that the only sensor inputs that would prevent a start were the oil pressure and coolant level sensors - and that the oil was on a delay. So that left the coolant level. He was right.

FYI, my sensor had been giving intermittent spurious alarms for a few months; perhaps it finally went bad.

My engine is a 98 S60 DDEC IV set for 425hp.

 

Odd, I have never seen that happen on the Detroit side. I've seen it on the OEM side. I don't understand how the engine ECM can know to keep the engine from starting, but not sense a problem to show a code. I've seen quite a few that start and shutdown, flash code 43 is set, just like it's supposed to.

I'm not saying it didn't happen, I'm just curious as to how it happened. I have a tech going to a Detroit class in a few weeks, we're putting together a list of questions for him. They probably wont get into DDEC IV's though since it's a DDEC VI class.

 

Be careful, those old timer instructors might sieze the opportunity to wax nostalgic!

Yeah, I was scratching my head about the lack of a code. There was a warning light, but that's always on at key-on as part of the self-test. Maybe it won't set codes until the engine is running? And since the sensor failed while the engine was off, there was no opportunity for a code to be set.

 

original post says when he gets the truck running it runs great. THAT would rule OUT any water temp sensor & warning or shutdown on e.c.m. my truck will shut down if water level is too low. & show code. truck hard to start after off for a period of time, but runs great when it does start has nothing to do with any sensor. other than trs & srs & most of the time it is not those.

 

Not necessarily. When the truck is running, there is a delay between a sensed low water level and the actual warning / shutdown. It could be that his water level is just low enough to trip the sensor, but comes up high enough to satisfy the sensor once the pump is creating flow, or when the engine warms enough to bring the coolant level up.

In any event, we've spent more time arguing the point than it would have taken to put a jumper wire on the sensor plug and eliminate that as a cause.