SO the start issues went away when I pulled the Schrader valve and installed a barbed fitting for a fuel pressure gauge. Playing with Cetane enhancers, I have it running the best I have seen it in 9000 miles. It really is not bad, just somewhat slow. But it will get up to 70-75 mph no problem. So lets ask about fuel pressure. I see by reading that it should be between 3 to 5 psi under a hard load. I haven't been in real steep hills yet but I have floored it and had the gauge dip to 2.5 once, easily to 2.75 psi. Is this a problem? It still smokes under load.

 

nope. as long as you have 1 psi positive pressure at full throttle you are golden.
if it smokes, you may have to turn the fuel screw down a little. \you only want to see a very light haze of black smoke under full throttle at load.
smoke is unburnt fuel and a waste of money.

 

Thank you! I am going to pull the filter housing to see if it has the restricted area in the bottom first and then look at tuning it down.

 

All of the above suggestions are right.
But the one time I was stumped, it was tiny little bits of the hose coming out of the top of the pump, connecting to the first Injector return cap. The stuff partially clogged the small holes in the return caps and caused it to basically run like yours is........Why did they make those holes so small in the first place?
Once I found and cleared the debris, it ran fine again.

 

Following up on this engine. I have been experimenting with Cetane a whole bunch and I have recently dialed in the amount that I need to be about 5/8th of an ounce to the gallon of fuel. Still using the Pilot brand but recently got 2 gallons of Howes for $56. I am intending to try out the custom blend when I get some Howes meaner cleaner. BUT, if I mix a blend and need the same amount of cetane I will be adding a lot to the gallon. Not sure how this will work out.
So let me add this. If boosting cetane is the same thing as advancing the timing, should I advance the timing a lit bit to perhaps reduce the need for cetane? Cetane cost money, timing does not. What say the collective wisdom here? I do not have the means to check the timing and it is a process to take it to someone that can.

 

A cetane boost will enhance power maybe similarly to accurate timing, but not a replacement.

Perfect - perfect - timing really makes e-v-e-r-y-t-h-i-n-g for these engines, it's all the difference between a click and clack with no slack that run strong, or a turdy stop n slop.

I hear so many on youtube and online that's hardly ever dialed in and it hurts, it's real - let's just say it's totally retarded..

I time the pump by ear, and trial, like any other engine, though the process is a bit different.

I shouldn't say how I do it, because it's not official, and officially discouraged - for good reason, because if you do this wrong it - will - end in total catastrophe.

But if you do it right, it's a thing of beauty.

Without going into much detail, you can, just mark the IP to the housing with a awl, and make adjustments by rotating the pump left to right.

It takes a 9/16 wrench to loosen and tighten these 3 bolts.

- a side note -

There are special wrenches for this, or most people cut their own, because there is not enough room to fit any decent wrench in there, it's both too narrow and too short.

So I go to the Pawn shop, and dig through their loose wrenches bin.

I pick out 9/16 wrenches that are the most, puny, weak, short, narrow, any totally inadequate for tighening a flywheel.

But these will have only 1 job to do, and it's an easy one, just be small enough to fit in and work those IP bolts..

The guy at the pawn shop always looks dissapointed, hoping to see I pick out a snap on wrench he could sell for 10 dollars, then I drop a - chepo tite 9/16" from Taiwan for a 1$ a piece.

But little cheap wrenches fit, I have a few.

If you advance too far forward it can sound really great it idle, but fall on it's face pulling or going up a hill.

It's all really a trade off, while anywhere near the right spot, that is, between off the go power, and high end and pulling.

I really like mine almost, just a tiny almost near advanced but not, there is a tiny tiny spot thats just perfect.

It pulls hard and pulls up a hill very nice, but also pulls off the line and idles perfectly, it's really a very precise spot.

Just a hint, and call it snake oil, I don't get paid off commission, but I use 1/4 bottle of STP oil treatment per oil change, to give the rings just a little 'bite' to get them onto that bleeding edge of advance.

It is on the edge and the STP lets it grab ahold of that power and not let go.

Your milage may very, but mine is very good, great mpg, power, pull, and performance, with it timed absolutely precisely.

If you can't do it, pay a shop that has the equipment and know how.

It also if best if you familiarize yourself with IP base tuning, droop, idle, and advance, and everything tuned properly it is a powerful clikity claker.

 

Wow, great post. A little mystical and voodoo. I am very mechanically inclined, but not classically trained. I chose wood working instead, I like clean hands....with splinters...The problem with your method is making small changes and trying it out. I am not sure the fuel is that consistent. Plus, knowing when you have hit that spot. I am pretty confident that my timing needs to be advanced some....what is some? I read people change it by a dime....lol Canadian or American? But your point is taken and I knew about making wrenches from previous reading. The adventure continues and I will add I think I have one weak injector as at its best, there is a subtle miss and at its worst it shakes.

 

Thanks, I'm glad to pass on my learned experiences, and take it all as a continued learning journey.

As I'm sure you've discovered, us people who own these trucks and work on these motors are 'not normal' in that you can't drop it off at a townie garage and expect them to do competent mechanic work, so you will have to learn and basicly become your own fleet mechanic.

Likewise I moved trades to commercial hvac and refrigeration, because also I like clean hands, and paint and body work, much stuff was bad for my health, inescapable harmful dust and chemical solvents exc.. But I do still work on my own stuff.

If you're not sure of good fuel delivery, it's an absolute must to hammer that down first..

Right, a great quality fuel pump, clean lines and valves, injector returns I rings, hard line doughnuts, fuel filter, everything.

The easiest way I use to identify a sloppy injector is to get a cheap doctors stethoscope, remove the diaphragm, unwind a steel clothes hanger and insert it into the hose.

You can carefully press it against each injector body while it's running to isolate and listen to the clikity clack motion of each individual injector.

This isn't a guarantee, sometimes they could sound good but spray bad or drip, but you can generally get an idea for which ones sound sloppy, and that's usually the problem.

I'm on 6 of 8 oem imjectors still, painted the International Harvester grey, and replaced one each at a time with that method that got sloppy. That fixed an ocasional miss or stutter.

I went with genuine stanadine injectors, because it's in stock performance, I believe the real ones are the ones made in Italy, they're only 30 each new for the genuine article.

 

a dimes width of timing is a good movement to judge better from good. and you should be able to see, feel , and hear a difference with that small change. i do not use any additives other that a dash of Howes during winter to keep from gelling. and one a year i will remove fuel filter, dump it out and fill with ATF.
put the filter back on and fire the engine letting it idle for 30-45 seconds.
then shut it off and leave sit for 24to 28 hours.
after sitting i fire it up and drive it like i stole it. the ATF breaks down all the gummy nastiness in the injector pump and injectors, running it like you stole it blows all that crud out the exhaust. i can hear and feel a difference after the ATF treatment.

 

If you don't use any additives, do you know what you are getting at the pump? It seems if additives didn't work I would not hear and feel the difference in a good way when I use them. Although after literally humming down I75 to I59 and on for 45 minutes this morning, this afternoon running home was a little choppy. I may not get time for a few weeks to play with it. Will get a wrench made. Counting down less then 2 weeks to kill bambi in Va.
Seems the major difference between this morning and tonight would be temperature.

 

well, when i bought my 88 new cetane was in the 65 rating. now we are lucky to see 40 cetane.
i went from 20+ mpg back then to 11-12 mpg now.
truck runs the same , but i had to adjust timing quite a few times to keep it running that way.

 

Ok, I get about 11 to 12+ on a good day. And that is an ambulance. I would have to add a whole bunch of cetane to make 65! I have noticed it runs much better with oil in the gas so I am planning to create a mix

 

Cetain boosters really do boost power, modern diesel has been detuned, and is most recently only about 40 cetane.

Newer fuel standards work to,

Drop the cetane to reduce efficiency, cut the lubricity to increase wear and more frequent fuel system repairs, and introduced corrosiveness to damage plastic and rubber fuel component parts.

It's intentional, and it adds up to planned damage and requires more service, and it encourages obsolescence and purchasing new vehicles and higher operating costs for all types of diesel vehicles.

Big money.

But yes, anyways our engine was designed when cetane levels were normal about 10 points higher, 50 is ideal.

I also add a dip of fresh cheap motor oil at fill up to replace that lost lubricity, every of these moving parts are all metal on metal, with no tollerance for error, clacking 1000 times a minute, so yeah, taking out the lubricating properties of diesel is yet another scam.

 

I am going back to 1 oz of 2 stroke for every 5 gallons of fuel. May bring up the cetane # today as I have a fair amount of driving to do. I am sure it is at 5/8th of an ounce to the gallon right now.