Seems timing bumps are subjects of the past, as I haven't seen any inquiries lately. For those that have done it, does it really better your fuel mileage like I've heard? The reason I'm bringing up this old topic is for the first time ever sinc owning a first gen, I messed with the timing, except I attempted to retard it by slipping it an 1/8" towards the battery. Awhile back I PM'd a few folks, asking why ever since I removed and re installed my pump due to a tappet cover leak, the function of my KSB works backwards. Instead of ramping up the idle to assist in morning warm up, it idles low, but when I go and disconnect the electrical harness to the KSB the idle raises. Totally backwards of what it's suppose to do. Plus, my fuel mileage seems to be getting worse with each fill up.

On one of my PM's it was suspected that when I reinstalled my pump I may have accidentally over advanced it. So, last night, I slipped it backwards to retard it, then turned my power screw counter clockwise back to stock. I was also hoping to rid of some of that idle haze.
Well, the KSB still functions backwards, and the haze is still there. So, I tried it, now on to plan B, which others have told me to advance it, about 1/4" past the hash mark on the timing case. I've never bumped my timing, and was wondering if any of you that did it in the past noticed an increase in mileage, less smoke, and better performance. My thing is not so much a search in performance, I just want my KSB to function as it should in the colder mornings, and get rid of the haze.
Thank you.

 

Well since you already have the M/H spacer I don't think you need to advance the timing anymore. That is one of the nice things about the M/H spacer is that you retain your low/bottom end grunt, but have the benefit of the better mileage on the top end.

Yeah I have no idea why my KSB doesn't function properly with the M/H spacer. No idea if it works backwards though?

 

IIRC the early (pre intercooled) KSB switch works the opposite of the later ones.
has yours been changed at some point?

 

On my latest '93, I installed an M&H timing spacer awhile back. Six months or so ago I installed a loner fuel screw which got my EGT's a little toasty so I cranked the pump around almost to the head. It may be a touch rattly but a set of bigger injectors will take care of that.

I haven't noticed any change in MPG although I think it is doing better on fuel. I still get 12 to 15 MPG but instead of struggling to maintain 80 like it did before, I can cruise at 90.

 

Thanks for replying, fellas. TCows, I'm curious to know if yours does the same as mine, since your truck and mine are almost identical in mods. If you would, at first morning start up, can you take your disconnected KSB wire and touch the solenoid with it idling, and see if the idle increases, or decreases. Let me know, and thanks.
Mark, mine is the original later style KSB, with the M&H spacer on it. Read an old tread while doing a search last night, and someone mentioned that the owner of M&H told him after he installs the spacer, to disconnect the wire to the solenoid.
1972RN- I used to get 16 mpg's. Now I'm down to 12 mpg's. Before, At every 1/4 hash mark on the fuel gage, that equated to 100 miles for me. Now, I'm at like 65-70 miles at the first 1/4 mark after a fill up.

 

I too have the wire disconnected. Unless you have your timing advanced so far that it sounds like a 6.2 Chevy diesel, I don't think that advanced timing would give you such a loss in economy.

 

After rereading your post here I got to thinking, for comparisons sake, I, too installed that longer power screw, mainly for ease of accessibility. I unscrewed it two turns Tuesday night, and the truck wouldn't start. I turned it in 1.75 turns and truck started. So, I'm assuming, that I'm back at around factory settings with that power screw.
My EGT's have hit 1000 degrees probably 5 times in its life. 750-900 is its running average in temps.
Still keeping the Hungry Diesel power pin. My injectors are the DAP VCO 5x12's. Looking back, when I used to get 16mpg's, I had my POD's in, but man they hazed a lot.
So, you and TC both have 93 model years. You and TC both have the M&H spacer installed. Can you just touch the KSB wire back onto the solenoid for me at first start up to see if your idle raises or lowers? If it raises, then that will tell me it's the M&H spacer, and not a mishap on my part when I re installed the pump affecting timing.
If you don't mind, can you both just report your findings on that?

 

I did as you suggested and hooked up the KSB wire after first fire up twice yesterday.

First yesterday afternoon before heading to work, the temp was about 17*C and cloudy. The engine tone changed for sure, but no noticeable change in RPM.

Second this morning when leaving work, temp was about 12*C and dark.... Again no grid heater cycle, and the engine tone changed as before, and maybe a 25rpm drop?

My Tach is an Isspro off the factory 93 wiring, so should be pretty accurate.

 

So sounds like yours drops in rpm also, when hooked up, and increase when disconnected. And, my sir, you are almost dead on with your rpm estimate as I have an optical tach that takes a laser reading off of the Fluid Damper. I use that every so often to verify that my Isspro is accurate, or if I need to see actual definite numbers. I checked the rpm differences with connected and disconnected, and it is about 28 rpm. Thank you, sir.
After chatting with another member here on DTR, and finding out he gets 20 and over mpg's with his 1990 non intercooled 4x4, manual tranny, with no haze, I'm on a mission to find out what's going on with my mileage drop. He has it somewhat hopped up with a larger turbo, and 5x11 injectors. He also likes to put the pedal to the floor a lot more so than I do, so hear me out, and tell me if my theory makes sense:

A normal functioning KSB will raise idle to aid in warm up, then drop down in idle as the truck has been driven for a few miles. Less rpm = less fuel. My KSB is working backwards, low rpm at initial start, then when the truck gets warmed up Im assuming for sure that since the KSB is functioning backwards, the idle raises. Higher idle = more fuel. Yes, my truck has been driving sweet when it's all warmed up, feels like a lot more power. But I am wasting fuel with that higher idle.
My idle set up is above the FSM spec, which most folks with automatics do cause they run better and doesn't lug when the A/C compressor kicks on. But that shouldn't hurt the mileage by that much. It seems most of the averages I hear for 4x4 trucks with auto trannies are about 16-18 mpg, and guys with the manual trannies are getting 16-22 mpg's. I'd like to at least get my 16 back. This 12 mpg's is ridiculous.

 

Tried mine out, just Like TC's, the tone changes and I think it drops RPM ever so slightly.

Other than that, I have no idea.

 

Okay, thanks for verifying TCows and 72RN. Really appreciate it. Soooo, that validates everything, then. No one could give me that answer when I asked awhile back, not even the maker of the spacer. Sounds like that the nature of the beast with that spacer install. The KSB will function backwards.
As a check, I pulled my solenoid off, cleaned out the electrical connections a, then applied 12v to the solenoid cause I wanted to actually see the plunger lift. I have a new solenoid on hand, as a back up should this fail one day, and the spring pop is still as good as the new one. The rubber tip at the end was as good as new, also.
I was going to remove the spacer as another functionality test, but just as the install of that thing went, the bolt head closest to the fan I rounded off the Allen and could not get that bolt off. I have the special EZ out nut driver to remove it, but something in my brain said, don't open up that can of worms, so I let it be.

 

Well, for the first time since I've owned the truck, I finally bumped the timing up a sting 3/16" past the T-case mark. Before I go on about the results, just a sum of all the things I did to the fuel and throttle these past couple of evenings:

1. Adjusted the throttle to spec, by following the FSM for the first time- gotta say, I feel like an idiot as I've owned the FSM since the day I took ownership of the truck. What always confused me, was the drawing of the break over spring, and it's explanation of where it's supposed to sit against the rod. Very very confusing to me. Always has been. Then it hit me the other night. So for all these years, my throttle settings have been all wrong. I had to compress that throttle rod a ways, after I understood how that break over spring went along with the throttle stop against the low idle screw. So good there
2. I've owned the bell crank bushings, two new ones, for over a year now, and finally just swapped them in and re lubed that shaft. All good there
3. With the assistance of NJTMans tread, on him replacing his bushings, I was able to see a great pic of the throttle cable adjustment, to achieve that gap of .180. The FSM has a crappy pic of it, I feel. So now my transmission cable is adjusted properly
4. Idle- always have known to adjust this, but my mistake has always been to ramp up the RPM's so while at a stop idling in gear, I didn't haze. So, as it sits, with A/C on in park, 864. A/C on in drive, 730 RPM's. 30 over spec, and I'm OK with that
5. Power screw- yeah, power is nice, but at my age, fuel savings are better. I backed that thing off to the point my truck wouldn't start, then in 1.5 turns. I have to say I'm probably at stock settings.

Okay- results from the timing bump. My mom always said I was always a bit behind, and this mod is no different. All I can say, is, WOW! I'm driving a totally different truck. I took that thing for a spin to get it up to temps, and I can see where one can increase their fuel mileage. No lie, I probably had the pedal down a 1/2" if that, and I was up to 50 mph in no time. It's as if, all the upgrades I've done over the years- bigger intercooler, piston high pressure lift pump, power pin, etc. all finally came off of their huddle and scored a TD! If you've never bumped your timing, you ought to do it, just to experience it. Okay, I'm done, LOL!
My low end power with that M&H spacer actually got better, and top end for sure got way better. Thinking about it, a mechanic buddy of mine also on DTR said when I re installed my pump awhile back, even though the pump to T-case cover all lined up, I must have retarded the timing, as it's been hazing badly since. So bad, no rpm increase would clear it.
I'm curious as to how the KSB functions tomorrow morning, and will check back on the haze.
Man, what a rush....feels like Christmas today

 

Don't own a ratchet strap, so I had to improvise using some 2x2 furring and wedged some commercial HVAC rubber compressor bushings as spacers that made the tightening of the pump bolts a breeze

 

Lastly, always thought hitting 25-30 psi of boost was somewhat easy. When compared to now, after bumping the timing, well, let's just say I think I need to be careful, cause it is very very easy to always hit 30 psi. It's as easy as hitting 10 psi.
Weird thing, is I thought my EGT's would spike up. When I hit that 30 psi it hovered at 950 degrees.

 

Very interesting information...thanks for the break down of your findings. Makes me wonder if a small timing bump would help my motor as well?