DT466e engine (transmission?) problem

[musigenesis]

On my last couple of drives my engine has started acting weird. Sometimes when I'm going up a relatively steep hill, I'll push the pedal down and the engine will downshift; the RPMs jump up but the engine seems to lose most of its power. If I let off the pedal it upshifts and the RPMs drop and I can at least continue moving.

Sometimes instead of complete power loss the engine kinds of lurches, producing power in short spurts. On flats with the engine in low or medium RPMs everything seems to be working normally.

No unusually high engine temps going on, no smoke or anything coming out the back, nothing is leaking anywhere.

I'm going to take it to the shop, but I was wondering if you folks have any ideas about what might be happening.

[Brad_SwiftFur]

When were the fuel filters last changed? Low power, especially on the uphills, is the first sign of needing fresh fuel filters. Basically, the filters are clogged enough that the engine is starving for fuel.

[musigenesis]

Originally Posted by Brad_SwiftFur

When were the fuel filters last changed? Low power, especially on the uphills, is the first sign of needing fresh fuel filters. Basically, the filters are clogged enough that the engine is starving for fuel.

Ah, that sounds likely. My fuel tank had gotten pretty low (less than 1/4) right before this began happening. I filled the tank back up after the first time.

The fuel filter (s?) was changed by a mechanic in May of last year, and I've only driven about 700 to 800 miles since then.

Is this the fuel filter I need? https://www.partsgeek.com/gbproducts...-07140137.html. Seems pretty cheap, but so am I.

[musigenesis]

Also, should I not drive the bus at all until I get this fixed?

[BamaBus]

Originally Posted by musigenesis

... the RPMs jump up but the engine seems to lose most of its power. If I let off the pedal it upshifts and the RPMs drop and I can at least continue moving.

Would it be a fuel issue if your engine rpm's increase? I'm not sure but sounds like a transmission issue. How is the trans fluid level?

[Ronnie]

I would not drive it much before changing the fuel filters. You are starving the injection pump, and it needs fuel for lubrication. I do agree it sounds like fuel filters need to be changed.

[musigenesis]

Originally Posted by BamaBus

Would it be a fuel issue if your engine rpm's increase? I'm not sure but sounds like a transmission issue. How is the trans fluid level?

I'm going to check my trans fluids too. It feels a little bit jerky, but it's always felt that way. It's the only bus I've ever driven so I don't have anything to compare it to. The two mechs who have worked on it and the guy who was hired to drive it down to me from Syracuse all said it's a nice driver.

[Booyah45828]

I'll 2nd fuel filters. Check the air filter for restriction too. If you have no codes and are low on power at high rpm, good chance you have one of the above filters plugged.

Dt466e is a HEUI engine, so low fuel pressure wouldn't cause issues with the injection pump. It's nothing but a high pressure oil pump, no fuel present. Fuel pressure is supplied directly to the injectors by a mechanical fuel pump mounted to the injection pump. Low fuel pressure can cause injectors to prematurely fail, so it needs taken care of if it is out of spec.

[musigenesis]

Originally Posted by Booyah45828

I'll 2nd fuel filters. Check the air filter for restriction too. If you have no codes and are low on power at high rpm, good chance you have one of the above filters plugged.

Dt466e is a HEUI engine, so low fuel pressure wouldn't cause issues with the injection pump. It's nothing but a high pressure oil pump, no fuel present. Fuel pressure is supplied directly to the injectors by a mechanical fuel pump mounted to the injection pump. Low fuel pressure can cause injectors to prematurely fail, so it needs taken care of if it is out of spec.

Do you have a link to a tutorial or something on where these filters are and how to check them and change them? I've left everything mechanical up to my mechanics so far but I'd like to handle this myself.

[Brad_SwiftFur]

Fuel filters should be a DIY item. There is much debate on whether to prefill them or not (something about the possibility of unfiltered fuel getting to the pump and injectors). Either way, once the filter(s) are changed, you'll need to purge the air out of the system. Some engines can simply be started and run at moderate idle for a few seconds, others will need to be re-primed with the manual pump.


I would find your fuel filter(s) and get the numbers off of them and cross reference. Getting spares is *VERY* highly advised! Nothing spoils a trip more than something as simple as a plugged fuel filter and being able to swap one and continue your trip is well worth the 10 bucks or so a spare will cost you. Plus you have the ability to shop for a good price rather than whatever inflated price the local truck shop will charge you.

[BamaBus]

Originally Posted by musigenesis

Is this the fuel filter I need? https://www.partsgeek.com/gbproducts...-07140137.html. Seems pretty cheap, but so am I.

The specs on that filter are different that what I have used for a DT466e through 1999. The Wix web site had a totally different setup for the model that you have listed. Definitely check what you have currently before ordering.

[Booyah45828]

Originally Posted by musigenesis

Do you have a link to a tutorial or something on where these filters are and how to check them and change them? I've left everything mechanical up to my mechanics so far but I'd like to handle this myself.

I don't. Never found the need to make one. I'll have to have a gander on youtube to see if someone has. Otherwise I'll look into making one the next time I've got one in the shop.