6v92 DDEC3 oil pressure lost

blue_goose · October 07, 2015, 01:00:26 PM

A DDEC will not make any change in oil pressure. It may not read the correct pressure.

opus · October 07, 2015, 01:28:50 PM

I'm hearing bits and pieces yet. Plenty of oil pressure but the DDEC wouldnt let it start...or crank.

opus · October 07, 2015, 01:38:01 PM

Seems turbo was on its way out. Oil lined had some sort of blockage. DDEC had been giving them fits for a few days as well.

Up and running now, all seems right in the world. New turbo, water pump and a used DDEC. Road test tomorrow before they hit the road.

opus · October 10, 2015, 07:23:06 PM

Things are a mess again. Stuck on the side of the road with no oil pressure...again. It was fine for 700 miles, 60psi then it shut them down at 20psi.

Everyone is stumped.

luvrbus · October 10, 2015, 08:16:55 PM

I would change OP sensor,if that didn't solve the problem then I would look at the oil cooler by pass valve.If the engine is equipped with a thermatic oil filter that could be a problem it dumping all the oil into the cooler and not the oil galleys when the oil temperature reaches 230 degrees.If he does have a thermatic control oil filter DD sales a kit to remove it he needs to toss it that wasn't a great idea

good luck

opus · October 11, 2015, 06:41:39 AM

I passed this info on.....

blue_goose · October 11, 2015, 08:13:47 AM

If you have a oil pressure gauge in rear of the bus check that while you crank the engine. If you see pressure short across the pins on the oil pressure sender for the emc and the engine should start. You will have to unplug the sender in order to jump across the pins in the plug.

Jack

luvrbus · October 11, 2015, 08:29:27 AM

He should have a override someplace to override the DDEC

opus · October 11, 2015, 01:12:21 PM

Quote from: blue_goose on October 11, 2015, 08:13:47 AM
If you have a oil pressure gauge in rear of the bus check that while you crank the engine. If you see pressure short across the pins on the oil pressure sender for the emc and the engine should start. You will have to unplug the sender in order to jump across the pins in the plug.

Jack

New gauges all the way around. They all say 20psi and well as the diagnostic had 20 as well [I think thats what he said]. They had bypassed DDEC but I'm afraid it didnt make any difference, still was 20psi.

They left the bus 4 hrs from home and will go with plan B tomorrow....whatever that may be.

opus · October 11, 2015, 06:13:19 PM

Quote from: luvrbus on October 10, 2015, 08:16:55 PM
I would change OP sensor,if that didn't solve the problem then I would look at the oil cooler by pass valve.If the engine is equipped with a thermatic oil filter that could be a problem it dumping all the oil into the cooler and not the oil galleys when the oil temperature reaches 230 degrees.If he does have a thermatic control oil filter DD sales a kit to remove it he needs to toss it that wasn't a great idea

good luck

They changed the OP and checked the regulators. Going to do a quick oil sample while they figure out how to check the cooler bypass valve.

luvrbus · October 14, 2015, 07:02:58 AM

1 thing I forgot to mention if they break a oil bolt on the rocker arms it won't build up oil pressure it's rare but does happen

opus · October 14, 2015, 07:17:01 AM

Thats interesting.

He is running up there today to do an oil sample, just to see what the past 600 miles did. In my mind if it were bearings the oil pressure wouldnt come and go like it has, it would be a constant, give or take a little when its cold.

luvrbus · October 14, 2015, 07:55:59 AM

I am sure they have pulled the valve covers if he has Jakes and checked for a solenoid that has came loose and blew out ?

opus · October 14, 2015, 08:22:32 AM

They didnt pull this this go around but they do have Jakes. I will relay. Thanks!

Iceni John · October 14, 2015, 09:58:41 AM

Quote from: luvrbus on October 14, 2015, 07:55:59 AM
I am sure they have pulled the valve covers if he has Jakes and checked for a solenoid that has came loose and blew out ?

When I recently rebuilt my Jakes I found one of the little oil connection tubes was cracked in half. After I replaced it I gained at least 5 PSI cold and hot oil pressures. Even a small leak of oil can cause a noticeable drop in oil pressure. It's easy to check - with the valve covers off and the engine at slow idle (don't use fast idle, or you'll have oil splattering everywhere! Guess who found that out?), put 12V to each solenoid and look for leaks/squirts/dribbles at each connection tube and around each Jake housing.

John