2H low fuel economy (1 Viewer)

[mcmlxxxv]

Hey everyone ,

I ve been working on my truck for a while now , did a lot of things trying to make it more fuel efficient as I get 19L/100km (12.4mpg) average witch I think is not very good compared to what I read in older posts....

fuel filters are new , change them every 12000km
fuel lines all new
fuel pickup tube , new
timing is set at 18 degree

so I consider those ok

It got better as I went from 22L/100km to where I am now after all of the above but I still feel I can get more ...

I had a bad injector recently (changed it with another one I had) and Im wondering if the 5 others can be leaky or unbalaced...

local shop charge 40$ per injector to test them . Im a cheap ass DIY so I bought a test press (80$) and will test them for leak and pressure. If you have advices or other point to look I will gladly take those advices.

these numbers can be normal too but im not sure ... I run 31s and the truck is auto

 

[duncanrm]

Hey everyone ,

I ve been working on my truck for a while now , did a lot of things trying to make it more fuel efficient as I get 19L/100km (12.4mpg) average witch I think is not very good compared to what I read in older posts....

If the injectors haven't been touched for a long time (150,000klms?) I'd just be getting them rebuilt personally..

What vehicle is this 2H in, weight, tyre size etc? What terrain is this 19L/100klm through?

I wrote a small guide on maximising performance, maybe some relevant stuff in there for fuel consumption too:

Guide to Maximising Performance of a 2H engine

 

[mcmlxxxv]

Not sure of the mileage they have, I have a serviced set .. I will bench test them before installing tho.

It's in a 1987 HJ60 , the motor was rebuilt 25000km ago according to the guy who sold it to me . But it sat for like 3years....

I run 31x10.5R15 and I'm not sure of the weight ... Stock roof rack , steel front bumper and rear swing out steel bumper ... Nothing else heavy really

 

[mcmlxxxv]

I really think the transmission is a slush box... Engine feels alive but sometime when I ask more while cruising it feels like "misfire".. that's why I have doubt

 

[duncanrm]

Not sure of the mileage they have, I have a serviced set .. I will bench test them before installing tho.

It's in a 1987 HJ60 , the motor was rebuilt 25000km ago according to the guy who sold it to me . But it sat for like 3years....

I run 31x10.5R15 and I'm not sure of the weight ... Stock roof rack , steel front bumper and rear swing out steel bumper ... Nothing else heavy really

For that setup... 19L/100klms is very bad. But you already know this.

 

[mcmlxxxv]

@duncanrm I followed your guide , still a few things to look up like valve clearances and rocker arms.

I wonder tho if adding a little timing could help ? Like 20deg instead of 18? I'm pretty new to diesel but damn they are fun to work on except for being dirtier than a stripper club ....

 

[duncanrm]

@duncanrm I followed your guide , still a few things to look up like valve clearances and rocker arms.

I wonder tho if adding a little timing could help ? Like 20deg instead of 18? I'm pretty new to diesel but damn they are fun to work on except for being dirtier than a stripper club ....

Factory spec timing is what you want.

With regards to valve clearance - inspect the underside of the rocker arms very closely, you are much better using a dial gauge than feeler gauges for a 2H.. they chronically wear the contact surface on rocker arms - I am sure the rocker arm design just doesnt flow enough oil - using feeler gauges on worn rocker arms can deliver misleading results.

 

[mcmlxxxv]

Factory spec timing is what you want.

With regards to valve clearance - inspect the underside of the rocker arms very closely, you are much better using a dial gauge than feeler gauges for a 2H.. they chronically wear the contact surface on rocker arms - I am sure the rocker arm design just doesnt flow enough oil - using feeling gauges on worn rocker arms can deliver misleading results.

Will look it up and let you know

 

[mcmlxxxv]

Well all the injectors were pissing fuel.... Probably the main cause of that poor mileage ....

I tested all 6 that were on the motor and also the 6 rebuilt I had from the blown engine that was originally in the truck.

Huge difference , the old one leaked around 1400psi and their spray patterns weren't very nice either at 1600psi. The other set was perfect , breaking around 1600psi with a nice spray.

Glad I bought the press to see it myself !

The engine run a lot smoother and is more responsive too , not 20hp more ,but definitely much better !

Hoping to see a difference on the next fuel up

 

[mcmlxxxv]

btw ... I bought the press because it was cheaper than getting them tested locally, plus I will try to rebuild the old ones myself with the manual's intructions.

Still have to look up the rockers , on my next free time. I will try to take more pictures too