IP Pump Calibration For Economy

[SasquatchSanta]

The Rescources section of this website contains a Trouble Shooting Manual for the LDS-465-1 engine. It gives the proper full load manifold pressure specs for calibrating the main fuel and droop screw adjustments on the LDS-465-1. I couldn't find a manual for the LDT engines.

I've got power that I don't need with the LDS-1-A engine in my bobbed deuce therefore I'm going to experiment with turning down the manifold pressure for better economy. I recently backed off just the main fuel adjustement by two flats and it didn't seem to make any difference. Therefore, I've decided to do full load 2,400 and 1,600 RPM adjustements and track preformance and fuel economy with reduced main and droop screw settings.

In experimenting with and tracking the manifold pressures it would be nice to also know the standard specs for the LDT-1-D engines. Does anyone know the full load manifold spec at 1,600 and 2,400 RPMs for the LDT engines?

 

[gimpyrobb]

I have wondered about this myself, I hope you find some info on it.

 

[Jake0147]

Maybe I'm way off, TM only as knock on wood I havn't played with the injector pump yet, but that seems wrong. One fuel setting would make sense to adjust, but if you add up all those adjustments that are made to the pump during servicing, combine their function, and back them all off equally for a transparent, consistant, just less powerful engine, (I assume that's what you're after, right?) wouldn't that pretty much be the same as a taller bolt under the throttle pedal?

 

[OPCOM]

doing the same speed on the same road takes the same amount of energy. It's only the lead foot in conjunction with the turned up pump that makes it eat more fuel.

 

[SasquatchSanta]

Jake 0147 wrote:

....wouldn't that pretty much be the same as a taller bolt under the throttle pedal?

OPCOM wrote:

... It's only the lead foot in conjunction with the turned up pump that makes it eat more fuel.

You may both be right.

What I'm finding is regardless of how I try to light-foot the LDS engine I can't get over 9 MPG. With the LDT engine I could get 12MPG and I've heard stories of full fledged (non-bobbed) deuced getting over 12 MPG. The LDS has all kinds of power and even when I "lightly" press down on the accelerator I get what I feel is quite a bit of smoke. I "think" the LDS engine, having been calibrated for a much heaver truck, is now being over fueled with each move of the accelerator. I guess you could compare it to having an oversized accelerator pump in a gas engine.

When I backed the main fuel adjustment down two flats and it didn't seem to make a difference it started me thinking that the droop screw also needed to be adjusted. The way I understand it, the droop adjustment controls the fuel up to 2,000 rpm. Most of my driving isn't much over 2K.

I figure if I'm going to play with the pump settings I might as well do full load manifold pressure tests so I can track what I'm doing. If I'm all wet on my thinking I'll be thr first one to admit it. Maybe we'll all learn something.

 

[m16ty]

I'm kind of leaning tward Jake and OPCOM on this one but you may prove us wrong. I've got a feeling if you turn the fuel down too much is going to get harder to start.

I'd like to know what you come up with though.

 

[cranetruck]

Ernie, what is the weight of your truck?
What you want to go for is efficiency regardless of total horsepower.

 

[Rattlehead]

If you want less power, I will gladly trade you my LDT for that LDS!

 

[rwelker]

Somewhere I have a manual on just the pumps. In it are the settings for the various multifuel pumps. If memory serves me correct the -1C turbo engine had the lowest fuel delivery setting. I think most of all adjustable settings in the pump were different; even timing. I'm at work, but I'll try and find the book over the next few days.

 

[Rattlehead]

The TM for the pump is here, if that is the one you're referring to. It is TM 9-2910-226-34

http://steelsoldiers.com/index.php?module=pagesetter&type=file&func=get&tid=1&fid=file&pid=39

 

[SasquatchSanta]

Bjorn wrote:

Ernie, what is the weight of your truck?
What you want to go for is efficiency regardless of total horsepower.

With me in it, the truck weights 10,700 pounds. I also have spin-out front hubs.

rwelker wrote:

...1C turbo engine had the lowest fuel delivery setting. I think most of all adjustable settings in the pump were different; even timing. ...

You're probably right about the 1C. The timing of the LDT and LDS is definately different. I'd like to avoid having to re-time the pump but that may not be an option as the LDS timing specs may not perform well at lower manifold pressures. I guess the only thing to do is lower the manifold pressure to the 1C spec and then, if need be, address the timing issue. Any opinions as to timing would be appreciated.

Thanks for the link Rattlehead --- I'm going to delve into it this evening.

 

[Floridianson]

Ernie the only boost numbers are in the 465 trouble shooting manual. The outher TM's have the test bench figures for calibration the fuel. Since you have the boost gage already installed then getting the boost numbers should take little time and you can just post back with what you find.

 

[desertfox]

Since we are discussing the IP I would like to pick your brains. I had a pump resealed had a experienced mechanic install the pump. Following that, the truck has been had to start, especially in colder weather. He has changed the timing and setting but to no avail. Still has good power on the road, but not from a stand still. The mechanic is at a loss and so am I. Any thoughts would be greatly appreciated.

 

[SasquatchSanta]

Floridianson wrote:

Ernie the only boost numbers are in the 465 trouble shooting manual. The outher TM's have the test bench figures for calibration the fuel.

Yes, you're right, however the only trouble shooting manual listed is for an LDS-1 engine. I assume the specs would be different for the LDS-1A and LDT series engines.

 

[Floridianson]

Thought you were just experimenting Yes but lets just see what the boost numbers are saying to us.
We are going past the yellow snow on this one.

 

[cranetruck]

Since we are discussing the IP I would like to pick your brains. I had a pump resealed had a experienced mechanic install the pump. Following that, the truck has been had to start, especially in colder weather. He has changed the timing and setting but to no avail. Still has good power on the road, but not from a stand still. The mechanic is at a loss and so am I. Any thoughts would be greatly appreciated.

You may want to start a separate thread on your problem to get the proper attention...

 

[Jakob]

Whatever is learned here, can it be applied to a LD or LDT motor as well? It'd be nice to get a few more mpg out of bobbed and modified trucks. I'd really like to have a bobbed Deuce for a daily driver if it got mid-teens for fuel mileage. I could fuel it for almost free then. I'm interested to see what you "turn up" with this... pun intended.

 

[SasquatchSanta]

OK ... I ran some full-load manifold pressure tests today.

It's difficult to get the hang of doing the tests. For the main fuel adjustment test I throttled up to a steady 2,600 RPM in 1st gear then applied the brake to lower the RPM as best as possible to 2,400. As the engine wanted to loose RPM I applied fell throttle. I basically found that doing the tests requires a frantic exercise in applying the brake and throttle both at the same time. It's a pretty violent exercise. Rosie is currently taking a nap.

For the droop screw test I cranked the engine up to 1,800 RPM in first gear and once again applied brake to take it down to 1,600 while applying full throttle. The tests were quick and somewhat difficult with what ended up as being full brake and full throttle. I was fairly successful in holding close to 1,600 and 2,400 RPMs but not for long. I doubt if the tests lasted 5 seconds each.

Of the six tests @ 2,400 RPM, two came in at 9 PSI and four came in at 10 PSI for and average of 9.666.
Of the six tests @ 1,600 RPM, one came in at 5 PSI, one at 6 PSI, three at 7 PSI, and one at 8 PSI for an average of 6.666.

A few days ago I turned the main fuel adjustment down (counter clockwise) two flats. At the original setting, which was factory sealed, today's 9.666 average would have no doubt been a lot higher.

When the engine is warmed up to 180 degrees I's getting a lot of blue gray smoke when I change the throttle setting (give it pedal). Someone recently make a great post explaining what different color smoke means. I wish I could remember it, or could find it.

 

[Floridianson]

M-35 Tom was good enough to take his reading at 1600 and said he was showing 5lb. and I don't know what motor he is running.
Sounds like you had your hands full. You still thinking about lowering the numbers.

 

[Stretch44875]

May want to try higher gears for your load test. Less strain on the drivetrain/brakes.