Ford LRG 425 shuts down after running for 35 seconds

[dwhickey]

This is a new thread but it is a continuation of trying to debug this engine problem that started with a previous thread about the LRG 425 not starting. I am able to get the engine to start reliably now, but it shuts down after running for 35 seconds. I've started the engine 7-8 times and it always shuts down after 35 seconds. Here is what I know:

This engine is used in a 25kW generator. It has a DSE 703 controller.

• It doesn't appear to be the DSE controller telling the engine to stop. When looking at the DSE 703 indicator lights when the engine stops, I notice that right after the engine stops the battery light goes on for about one second and then turns off. Right when the batter light turns off, the oil pressure light comes on and stays on (which I think it should because at this point the engine has stopped and there is no oil pressure). The interesting thing is that it appears that the DSE 703 controller still has the gas valve opened when this condition occurs. I have to hit the off button on the 703 controller to turn off the gas valve - this also clears the low oil pressure light.
• The engine oil pressure appears good. I have an oil pressure gauge and it shows 50psi right up until the engine stops.

If is is not the DSE 703 controller stopping the engine or low oil pressure, what else could be shutting the engine down?

 

[Birken Vogt]

Ignition cutting off or throttle going closed are your two remaining options. You will have to meter them with a volt meter and tell what is happening first.

 

[Midnightmoon]

Whats the make and model? We had an issue with a faulty priming valve it would run fine when it wasnt hooked up but when it was hooked up in would run the die.

 

[dwhickey]

Ignition cutting off or throttle going closed are your two remaining options. You will have to meter them with a volt meter and tell what is happening first.

Throttle (i.e. gas valve) remains open when the engine dies. The ignition input voltage (i.e. Ignition ON) remains on BUT the spark to the plugs get stop and then the engine dies. So there is some input to the ignition module or the ignition module itself that is causing the spark to stop even though the ignition is "ON".

The part number for the ignition module is Ford 1U1L-12A297-DA. I do not have the connector pin out for the module. Attached is the picture of the 23 pin connector. Can not find the pin out through Googling.

One other fact. If the engine is allowed to run at 1800 RPM it will shut down at 35 secs after starting. If the engine runs at less the ~1100 RPM (this was made to happen by playing with the butterfly valve in the throttle body) the engine will run without stopping.

Any thoughts?

 

[Birken Vogt]

That is a tough one. Note that there is one pin for power in and several to pass power through to other modules on this unit. Check that the B+ going to the coil pack is continuing to have voltage. I had one where somebody had been probing the pin holes with a volt meter and sprung them all out. Also I guess it could be the CKP giving up the ghost or possibly the ignition coils themselves getting hot and quitting.

See attachment.

Throttle (i.e. gas valve) remains open when the engine dies. The ignition input voltage (i.e. Ignition ON) remains on BUT the spark to the plugs get stop and then the engine dies. So there is some input to the ignition module or the ignition module itself that is causing the spark to stop even though the ignition is "ON".

The part number for the ignition module is Ford 1U1L-12A297-DA. I do not have the connector pin out for the module. Attached is the picture of the 23 pin connector. Can not find the pin out through Googling.

One other fact. If the engine is allowed to run at 1800 RPM it will shut down at 35 secs after starting. If the engine runs at less the ~1100 RPM (this was made to happen by playing with the butterfly valve in the throttle body) the engine will run without stopping.

Any thoughts?

 

[dwhickey]

That is a tough one. Note that there is one pin for power in and several to pass power through to other modules on this unit. Check that the B+ going to the coil pack is continuing to have voltage. I had one where somebody had been probing the pin holes with a volt meter and sprung them all out. Also I guess it could be the CKP giving up the ghost or possibly the ignition coils themselves getting hot and quitting.

See attachment.

Thanks Birken for the pinout. Just seem strange that the engine stops exactly at 35 seconds every time. While troubleshooting I have started the engine 20+ times and it is always consistent. Like you said could be the ignition module giving up the ghost but at $600 it's a part that I better be positive is bad before replacing.

 

[Birken Vogt]

What I would be doing is checking DC voltage to the coil pack and scoping the pulses to it to see whether it continues to get voltage and pulses beyond when it stops firing. If it does then it is the coil pack. If it does not then it is the ICM doing something. I notice my drawing shows a coolant temperature sender. I wonder if that is for timing only or also for overheat. That would explain the 35 seconds if it was an overheat shutdown. Do a sanity check on the coolant temp sender.

 

[excavator]

I'm watching this closely as I've had a customers JLG lift with the same engine that hasn't run in over a year. It will fire a few times then quit, we've checked most everything we know of. Oh, and that ign. module I've seen listed anywhere from $3000.00 to $5000.00.

 

[Birken Vogt]

I'm watching this closely as I've had a customers JLG lift with the same engine that hasn't run in over a year. It will fire a few times then quit, we've checked most everything we know of. Oh, and that ign. module I've seen listed anywhere from $3000.00 to $5000.00.

Check cam timing first. Earlier in the thread I believe that was the OP's major problem. They love to jump time.

 

[excavator]

Thanks, we checked that and it seems to be OK. Don't want to hijack this thread, just going to watch and probably start another thread when I have time to work on it again.

 

[dwhickey]

I'm watching this closely as I've had a customers JLG lift with the same engine that hasn't run in over a year. It will fire a few times then quit, we've checked most everything we know of. Oh, and that ign. module I've seen listed anywhere from $3000.00 to $5000.00.

You can get the ignition module here for under $600

http://www.pittauto.com/default.aspx?page=item detail&itemcode=FOR+1U1L12A297DA

 

[dwhickey]

Did some more troubleshooting this morning:

• Tested the B+ voltage at the coil pack. It was 14.2v with the engine running. It stayed at this voltage for about a second or so after the engine stopped. So the coil pack was getting voltage when the engine stopped. I don't have a scope to test the coil control leads, but I have to assume they stopped since I saw that the spark stopped which shut the engine down.
• I measured the MAP sensor voltage. It was 1.0v with the engine running and then went to 5v after the engine died. When I took off the electrical connector to the butterfly (this keeps the engine running indefinitely but at a very rough and reduced RPM) the MAP sensor voltage was at 2.0v. It appears the MAP sensor is OK.
• I measured the resistance of the crank position sensor at the ICM connector. This was 330 ohms. This is in spec.
• I measured the resistance of the temperature sensor. This measured open. Not sure about this one.

My ICM connector has 20 wires going to it. The schematic that Birken forwarded only had 13 wires. So I'm missing a few that I somehow have to track down.

 

[Birken Vogt]

The 35 seconds thing makes it sound like a temperature thing but the reduced RPM running indefinitely thing kind of screws up my theory.

Nevertheless I would try sticking a 5k, 50k, etc resistor in place of the sender and see what happens. Resistance value charts for them are all over the place so I have no idea what this one is supposed do be but open is not the right value for sure.

 

[dwhickey]

The 35 seconds thing makes it sound like a temperature thing but the reduced RPM running indefinitely thing kind of screws up my theory.

Nevertheless I would try sticking a 5k, 50k, etc resistor in place of the sender and see what happens. Resistance value charts for them are all over the place so I have no idea what this one is supposed do be but open is not the right value for sure.

Birken - I did not have my meter on the correct range when I did my initial reading for the temp sensor. I went back a verified and it does read ~12k which seems correct. I also put a 10k resistor in place of the sender with the same results. Like you, the reduced RPM running screwed up my theory.

I am now trying to find the pinouts for this ICM connector. Also, trying to find if there is a data port for the ICM. This picture might be it but I have no way to know what it interfaces with.

 

[excavator]

Yes, that is the diagnostic connector. Check with JLG or Genie to get the diagnostic cable and software.

 

[Birken Vogt]

Well lacking a scope, I would meter the coil pulse/trigger wires with an AC voltmeter and try to get an idea what is going on. Only thing is a good Fluke meter would be best. Measuring frequency would be the thing to look at but off-brand meters seem to do a terrible job at this. If you see the signal drop off when it cuts out then you know the ICM is the source of the problem. But why it is doing that is still the question. Powertech engines in California is the expert on this stuff for me. I have not had this exact problem before.