Adjustments to fuel setting

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Remember you should all look in a fsm before adjusting. Lantec your engine is a 3b II ...Correct? Thats why it may not be in the fsm.

If you go in the more fuel direction, you can get a lot of heat prior to smoke, from what I saw in my BJ. So beware if your turning the wrong way.

Drive and test, if it feels peppier, you went in the wrong direction. It is noticeable on a non turbo engine. The thing just sucks. No power at all. But no smoke.
 
I have some early, preliminary data. It looks like all my complaining about this truck not getting average fuel economy is pretty much entirely explained by the fuel adjustment. My early calculations show approx. 1/2 turn down in fuel has resulted in a minimum of 20% better fuel consumption and MUCH lower EGT's, approximately 200 F across the board. I have to work hard to get it near the red now. Much, much better. I'll probably put up some good data once I have more.
 
Remember you should all look in a fsm before adjusting. Lantec your engine is a 3b II ...Correct? Thats why it may not be in the fsm.

If you go in the more fuel direction, you can get a lot of heat prior to smoke, from what I saw in my BJ. So beware if your turning the wrong way.

Drive and test, if it feels peppier, you went in the wrong direction. It is noticeable on a non turbo engine. The thing just sucks. No power at all. But no smoke.

Yeah, I drove it around town today on the highway and off, it does lack a lot more power esp going from 2nd to 3rd gear. It was dog slow esp. if I was going up a slight incline and I change from 2nd to 3rd, it just would not move at all.

I did manage to hit 1000F but that's after going up a LONG incline (Burnaby mountain for those locals that know) and I pinned it to the floor so see if I can actually hit 1200F on the pyro.

So yeah, I think I didn't notice a difference before because I was only driving >10km in local 40-50km/h traffic.
 
You've turned it down a little too far (stating the obvious). Bring it up again a little until you find a spot you can live with. I've found that it's the low RPM performance, from a standstill or near idle, that is most effected, and that once the engine hits it's torque peak at 1800 RPM it's fine with almost any fuel setting. I brought it up about 1/8 turn from it's "too sluggish" point and that has worked well. Dont' think I will adjust it much any more.
 
fellows, please help me get this....... I own a 1990 Australian market hzj80.

When the fuel delivery screw is adjusted, the rpm drops/increases accordingly.

Suppose
pre adjustment the rpm was at 600/800(idle up)

post adjustment the rpm drops to 400/600(idle up)

and then the idle is adjusted from 400/600 back to the 600/800 setting, would the pump be delivering the same amount of fuel as pre adjustment of the delivery screw ?
 
I think there is more to it than that. I noticed the same effect when I turned my fuel down. Idle dropped, though even so it's smoother now. BUT. I have very significantly better fuel economy under driving conditions. It is my understanding that the fuel adjust screw actually effects the amount of fuel pushed out by the pump. Which is a constant. I have also noticed that off boost performance is significantly less but on boost, it's not far off what it was before I turned it down. Regardless, I will take the 20% + better fuel economy for a loss in power. Although when I first did this I turned it down too far.

Hmmm in reading that I realized it's a bit unclear. When I say "constant" I mean that less fuel is pumped at all speeds, so the fuel consumption is actually less, at all speeds than it would have been before. And that is exactly what I've seen in my own truck.
 
Well what ever you adjust, I would still go with the full load temp of 1200-1250 max. Find a huge hill, find the right gear and floor it.

now that said, you have to pick the gear you would drive it with. Don't put it in 5th if 4th would be the gear. 5th might make 1500 lugging along.

But I do drive partially to the pyro. Look down, if the temps getting high, downshift and slow down.
 
Allow me to clarify, my 1HZ is not turbo charged and manual. I have since the last post turned the delivery screw anti-clockwise roughly 10minutes of a clock face and adjusted the idle back to 600/800rpm. The result was a noticable drop in the 'take off' from gear to gear, but the fuel economy was really noticable, from 17.9l/100km highway down to 15.7l/100 city driving. Will try to do some higway test and see if it improves
 
That is interesting information. That's a huge improvement with a small adjustment. If you have a pyro that will also help tell you where you are at with your adjustments.
 
It only takes a quarter turn to alter fuel economy dramatically. My 60 has the 2H engine and it was way under power, so i adjusted the screw out half a turn and went for a drive. Couldn't see the road behind for black smoke!!:o So I wound it back a little at a time and test drove with each adjustment until the smoke stopped unless I really hammer it uphill. results are all good with more overall power with only a small increase in fuel usage.:cheers:
 
I spoke a bit too soon. I turned up my fuel a little bit again, about 12 minutes of a clock, so to speak. I think I'm FINALLY at about the right point. EGT's are good, and power is good. I got a little carried away before with fuel economy. LOL. It's an ongoing thing.
 
I have since the last post turned the delivery screw anti-clockwise roughly 10minutes of a clock face and adjusted the idle back to 600/800rpm. The result was a noticable drop in the 'take off' from gear to gear, but the fuel economy was really noticable, from 17.9l/100km highway down to 15.7l/100 city driving. Will try to do some higway test and see if it improves

Today going down the same route as before, I was able to achieve 11,9l/100km in slightly less time, but same road condition as it took me previously !!! I don't think I will touch anything again until the fuel prices go up again.
 
Well, I adjusted my fuel setting by 1/4 turn down fuel a bit. I was getting 19 US MPG before the adjustment with a mix of highway and city about 70/30 respectively.

Now I've tested with the 1/4 turn down from when I first started. I've travelled 536km on 57.040L of diesel which yielded 10.64L/100KM or 22.1 US MPG.

This is on a 3B in a BJ73.
 
hey guys.. I don't mean to Hijak this thread, but this is my story... everytime I hit the throttle hard my 1HD-T seems to drop past where it should when it goes back to idle...I am also experimenting with the tinkering you guys are with regards to the fuel, and am pretty happy with the results, but lately (since the colder weather) i've had the idle drop problem... any help guys!!??
 
hey guys.. I don't mean to Hijak this thread, but this is my story... everytime I hit the throttle hard my 1HD-T seems to drop past where it should when it goes back to idle...I am also experimenting with the tinkering you guys are with regards to the fuel, and am pretty happy with the results, but lately (since the colder weather) i've had the idle drop problem... any help guys!!??

Don't quote me on this but it might be because of the colder weather. Since diesels combust with pressure and heat, the fuel may not be combusting as well as it should be. You can adjust the idle by turning the manual throttle knob. I'm not sure if your truck has it.

Just a guess if that solves the problem. That's what I would go for at least. I could be wrong though.
 

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