Cascade Crew

aaron_sK · Posted: Thu Oct 06, 2011 11:23 am Post subject: Diesel guys: Got a tech question

I'd post this on a proper diesel forum but those guys are too busy comparing their pipes... Squint

Should I expect to see any change (up or down) in fuel mileage when increasing injection timing? This is on my non-turbo IDI engine if it matters.

Twilightoptics · Posted: Thu Oct 06, 2011 11:40 am Post subject:

Generally not much to be gained. I know most rigs, turbo ones I deal with, if you're off a few degrees either way it'll run like shizzle and have crap for power.

Kinda like ECM gas timing.... ECM thinks its at X. If it's not, it throws stuff outta whack.

aaron_sK · Posted: Thu Oct 06, 2011 8:31 pm Post subject:

Okay that's good, I'm not going nuts then.

When I first swapped the injectors it ran real flat, had no power, and a lot of light grey smoke. Upon reading more I found that replacing injectors on these engines lowers the relative timing (tight new springs in the injectors, but the pump pressure is the same).

I bumped up the timing a bit then, but it hasn't been right. The other day got a wild hare and maxed the timing as far as I could with all the lines still hooked to the pump. That lowered the EGT's under load, darkened up the smoke and gave marginally more power, but the mileage is the same or a shade less than it was.

This thing needs a turbo, or just a CTD. Laughing

IROCDave · Posted: Fri Oct 07, 2011 5:41 pm Post subject:

You miss typed that, what your trying to say is DTD (DuraMax Turbo Diesel). Also need an Allison transmission.

aaron_sK · Posted: Fri Oct 07, 2011 5:44 pm Post subject:

I kinda need my truck running, Dave, not broken down with bad injectors or a burnt up turbo. Wink

chevymad · Posted: Fri Oct 07, 2011 5:48 pm Post subject:

Says the guy who just changed injectors.

Twilightoptics · Posted: Fri Oct 07, 2011 5:48 pm Post subject:

aaron_sK · Posted: Fri Oct 07, 2011 5:52 pm Post subject:

chevymad · Posted: Fri Oct 07, 2011 6:03 pm Post subject:

Ford and chevy are both cartridge fuel filters I think now.

Though last duramax I did was a spin on.

Twilightoptics · Posted: Fri Oct 07, 2011 6:34 pm Post subject:

Dirty max are spin on. And the fuel water sep is the main fuel filter.

rjmcgee · The Hammer Joined: 08 Jan 2004 Posts: 2328

Just find a stock 93-94 turbo setup cheap. I lost the 7.3 in my 93 with the factory turbo and replaced it with a 6.9 that my dad had. Put the turbo injection pump and injectors on it and it is pretty freakin strong. Not like my powerstroke but deffinately alot more power than NA.

Also, LOL at a pyrometer on a NA diesel. Laughing

aaron_sK · Posted: Sat Oct 08, 2011 6:46 pm Post subject:

rjmcgee · The Hammer Joined: 08 Jan 2004 Posts: 2328

aaron_sK · Posted: Sat Oct 08, 2011 7:16 pm Post subject:

I bought a great big NAPA water separator/filter and mounted it on the fender. I spliced into the factory line down where the old separator was and ran hardline up to the new one. Seems to work great. Shrug

IROCDave · Posted: Sat Oct 08, 2011 9:09 pm Post subject:

Twilightoptics · Posted: Sun Oct 09, 2011 9:16 am Post subject:

The injector failures we deal with are excessive return rates most of the time. Not electrical failures.

It's crap getting into the injector and now alowing the plungers and stuff inside to do their job, so alot of the pressure ends up on the return side and thus you have an injector that is way under fueling.