2000 DT200TCXY Issues - Check Engine and Overheat Alarms

[creamofwheat]

Hello -

I recently bought the above engine because I had the exact same engine previously that lost compression. So this year I bought another one used and swapped them out since the controls etc. were the same. All 6 cylinders had even pressure at 125 when I went to buy it.

The only issue I am having is the check engine light and overheat light come on, seemingly sporadically. It sometimes runs an hour without an issue and other times both alarms go off continuously. Other times just the check engine light, not both come on. Sometimes the check engine light comes on just turning the key half way to get power, not even to start it.

The water flow seems good, doesn't seem to be actually overheating, the thermostats open and close when in a pot of boiling water, so I don't know where to go now.

The check engine light blinks once then 5 or 6 times, what does that mean?

Any idea on what is actually happening and how I can fix it?

Thank you!

[Nasher]

I had a similar issue on my 1998 DT200EFI, but just the overheat alarm.

I cleaned all the earth attachments under the hood, plus cleaned and re-made the connections to the cylinder wall temperature sensor and that sorted it.

Unfortunately I did it all at once, so don't know if it was a dodgy earth or a specific issue with the sensor wires.

However, I had already eliminated the engine actually overheating by checking the tell-tale and changing the impellor as part of my annual maintenance.

Even with a new impellor each year, I find if I run with the engine trimmed out on the limit of stability for too long I can get an overheat alarm from water starvation. Perhaps if your impellor is on its way out it's struggling at times.

Sounds like it's probably a dodgy connection somewhere though.

Nasher.