OM617a Fuel usage test results
 

I did a Diesel Purge cleaning today and while doing so I did a rough test of the fuel usage at idle.

I connected the fuel lines and poured one 16oz can of DP into my clear bottle. Then I purged the system with the hand primer until the pre-filter was full and fuel was coming out the return line back into the bottle. Then I marked the fuel level on the bottle with a Sharpie. Next I poured in the 2nd can of DP into the bottle and started the engine. It took approx 30 minutes for the fuel level to drop back to the sharpie mark on the bottle. 32 by my watch, but given the accuracy of the sharpie line, lets say 30mins.

So 128 oz per gallon, 30 mins per 16 oz, that's 4 hours per gallon. My 1985 300TD idles at 950rpm, so for those of you whose cars idle slower should use less fuel at idle.

-Tad

That's interesting, I knew they didn't burn much but I never knew exactly how much.

Wow that's better than I would have expected. That's one heck of a high idle you've got, though. I bet you have to stand on the brake with that thing in gear.

It really isn't bad at idle at all. It has 2.88 gears so that helps some. I'll be backing off that idle screw once I put in the new engine mounts. It doesn't shake at idle now but I can see the mounts are not in great condition, which means that I'll want to replace them before I make the engine shake. I also need to find an engine shock mount to go with the new engine shocks. One of the mounts has ripped.

-Tad

Better than I would have thought too. It reminds me of thread I read somewhere, where a flight attendant who lived in a cold climate would leave her car running overnight while she worked her shift. I think it was hard starting in cold weather & wasn't worth the risk. She would return with the car still running & warm with the heat on. Paul.

I wonder how your experiment would work with regular diesel fuel?
Because you didn't really test fuel useage. You tested Dp useage and assumed it would be the same for diesel.

Danny

Well maybe my logic is flawed, but with a mechanical injector pump the amount of fuel consumed at a given speed doesn't change. There isn't an o2 or mass air flow sensor and computer to adjust the amount of fuel used. It's a fixed mechanical pump.

By all means, correct my assumption if it is incorrect.

-Tad

So you could use your engine at idle to run a generator and power a whole house. Hmmm...the uses for the 617 just keep getting bigger and bigger.

In fact I have an OM617 sitting on a trailer for that very purpose. I need to finish up the frame for it and find a radiator however.

-Tad