Turbo B7100

[TxRzrBk]

I adjusted the fuel screw out a total of 1.5 turns and i'm still seeing max EGT of 570 and I really had to bog it hard to get much above 500. Running it the way I normally would mow it runs mid 400s. The engine is not smoking or acting like its getting too much fuel, the only time I get black smoke is when it is heavily bogged.

What is the normal method of tuning a diesel via EGT? Do you just keep adding fuel and monitoring EGT or have I maybe added too much?

 

[TxRzrBk]

I'm chasing my tail trying to get this thing tuned. The adjustments to the injection pump don't seem to be doing anything. Once the capnut is removed there is a small flathead screw in the center but the thread that the cap nut goes on is also notched as if it can be adjusted. Which of the two does the adjusting? The center flathead screw or the thread that the capnut goes on?

Any other advise on tuning the fuel is greatly appreciated.

 

[North Idaho Wolfman]

Post a picture of the adjustment you are working with.

 

[TxRzrBk]

The adjustment I'm referencing is the one from post #4 in this thread...Quoted below.
Looking at it closer, the center screw and the stud turn together. Just to confirm, counterclockwise increases fuel?

On the d750 engine there is a fuel adjustment on the front of the injection pump facing the radiator. There is a small tin cap over a 19mm capnut and locknut, remove the tin cap, capnut, back off the lock nut and turn the adjustment screw counter clockwise. I found naturally aspirated dont go more than a half turn out otherwise the tractor gets extemely smokey and acually looses power and will run hotter. When i added the turbo i went out about a turn and a half to make a nice balance of power with the added airflow of the turbo. It actually doesnt smoke at all when the turbo spools up. Under full load my egt's are still only about 950 deg. F. 1300 deg. Is overheating.

All and all im very pleased with it and im glad you like it as well

 

[TxRzrBk]

I found the attached image of the adjustment and I'm now even more confused. Based on the image I would think that turning the stud and center screw together would adjust one thing will turning the center screw with the stud stationary would adjust something else. I need someone with specific knowledge to chime in

 

[North Idaho Wolfman]

You don't mess with the center adjustment, just turn the outside counter clockwise.

 

[TxRzrBk]

You don't mess with the center adjustment, just turn the outside counter clockwise.

10-4, thanks, still not getting hot enough on egt but I'll have to continue to tinker with it.

 

[JeffL]

Do you have the fuel max out? It is not uncommon to max a non-turbo fuel system out when adding a turbo. Bigger pumps and injectors help.

 

[TxRzrBk]

Do you have the fuel max out? It is not uncommon to max a non-turbo fuel system out when adding a turbo. Bigger pumps and injectors help.

I don't think it's maxed out but I don't know how to tell. Based on the posts on page 1 of this thread I expected 2 turns or less would get me where I need to be but I've noticed little change with 2 turns.

What does the center screw adjust?

 

[North Idaho Wolfman]

The center screw is a shock absorber (of sorts) to keep the RPM from bouncing up and down.
Mark the adjustment screw depth, remove the screw and check the center spring for movement.

You very easily could just be maxed out on what the old pump can put out, have you replaced any seals or had it rebuilt?
Also if your fuel system before the pump is not up to par, you could be limiting the amount of fuel the pump gets, like a plugged line, bad filter, bad lift pump, or plugged or leaking bleeder valve (jet start valve) assembly.

 

[TxRzrBk]

The center screw is a shock absorber (of sorts) to keep the RPM from bouncing up and down.
Mark the adjustment screw depth, remove the screw and check the center spring for movement.

You very easily could just be maxed out on what the old pump can put out, have you replaced any seals or had it rebuilt?
Also if your fuel system before the pump is not up to par, you could be limiting the amount of fuel the pump gets, like a plugged line, bad filter, bad lift pump, or plugged or leaking bleeder valve (jet start valve) assembly.

Filter is new, Injectors have been rebuilt. Other then that I have not replaced anything. I'll pull the adjustment and take a look. Will also investigate what I would need to give the lift and injection pumps a once over.

 

[TxRzrBk]

Is there any writeup on the injection/lift pump seals? I just checked my service manual and it doesn't cover anything on either, it only mentions how to remove them.

From the pictures i've seen it looks like I should be able to remove each delivery valve and replace the o-ring(s), looks pretty straight forward except for the safety screws on the delivery valves. I've got a couple of sets of nitrile o-rings, thinking I can probably knock it out in short order but would like to see some documentation before I tear into it.

 

[JeffL]

You know when the pump is maxed when the exh temps/HP stop climbing. Like NIW said make sure everything before the pump is perfect. Make sure the diaphragm feed pump is meeting specs and no check valves are leaking.

 

[North Idaho Wolfman]

looks pretty straight forward except for the safety screws on the delivery valves.

Your injection pump has tamper proof screws holding down the delivery valves?

 

[TxRzrBk]

Thanks for all of the input, I think i'm making some progress. I checked the center screw and it was very loose, only finger tight, I think this explains why the adjustments were not doing much if anything.

As suggested I also checked the lift pump and found it to be functioning fine however the fuel hose from the lift pump to the injection pump was a little short causing a pretty significant restriction where it bends at the injection pump. I replaced the fuel line with the same size only a few inches longer

Finally I pulled one of the valve holders on the injection pump hoping I would have an o-ring that would fit but no luck as its an obscure size. Anyone have the part number for the injection pump o-rings?

Now when I fired it up it seems to be running rich, lots of smoke on throttle changes so I think I will start over at trying to tune it.

Your injection pump has tamper proof screws holding down the delivery valves?

I said that based from parts diagrams I had seen but it does not, its a 19mm and thats it.

 

[JeffL]

OK Now turn the fuel down to no smoke or to the original setting. Record the boost and exhaust temp before the turbo. Make an adjustment to fuel setting and record. Work the tractor long enough to stabilize the temps. Make each adjustment the same: quarter turn or half turn enough to make a step in temp. Repeat this until you max the fuel, temp, or boost. Keep an eye on the engine temp it is another max to respect. You can plot this it will help down the road. You may have noticed one of these adjustments was a sweet spot. Meaning temps were good no smoke at boost, little smoke at spool up, and engine smooth. Go to this setting (you recorded everything right) and the do a half adjustment on each side, record. Of the three steps pick the best.
Remember mowing the lawn is not a tractor pull. Don't get greedy.
Think of your increases in term of percentage. 16 hp + 25% = 20 hp.
Will have the same effect on the engine as 1000 hp + 25% = 1250 hp.

 

[TxRzrBk]

OK Now turn the fuel down to no smoke or to the original setting. Record the boost and exhaust temp before the turbo. Make an adjustment to fuel setting and record. Work the tractor long enough to stabilize the temps. Make each adjustment the same: quarter turn or half turn enough to make a step in temp. Repeat this until you max the fuel, temp, or boost. Keep an eye on the engine temp it is another max to respect. You can plot this it will help down the road. You may have noticed one of these adjustments was a sweet spot. Meaning temps were good no smoke at boost, little smoke at spool up, and engine smooth. Go to this setting (you recorded everything right) and the do a half adjustment on each side, record. Of the three steps pick the best.
Remember mowing the lawn is not a tractor pull. Don't get greedy.
Think of your increases in term of percentage. 16 hp + 25% = 20 hp.
Will have the same effect on the engine as 1000 hp + 25% = 1250 hp.

Many thanks, exactly what I needed, a regimented process to tune it. I've looked around a fair amount for the pump o-rings and so far only found 1 potential candidate which is PN 04816-00150, if anyone knows if this is correct please let me know.

 

[TxRzrBk]

After pulling the valve on the injection pump i'm not getting any fuel in that cylinder. I was certain I had put everything back exactly like I found it but its clearly not pumping fuel.

When I cracked the line and turned it over, the odd thing is that the valve in question starts pumping fuel when I pull the kill switch.

I pulled it apart again to double check and believe I see the problem but I'm not sure how to fix it. The attached diagram is very similar but not identical. The question is about part #2, it has a hole in the side and a groove just below that however it does not lock in place on the groove, I am able to install it indexed any way I choose and i'm not sure how to properly align it.

Also attached another picture I found of the part in question with a red box around the hole and notch.

 

[North Idaho Wolfman]

You reinserted the pump 180 degrees out.

With the entire pump out you can look at the rack and the valve gears there are marks that you line up to time the pump.

 

[TxRzrBk]

I had assembled everything correctly however for some reason the locking pin that holds the cylinder in place was not sticking out far enough. I fixed this by removing the pump and snugging the two flat head screws on the back.

All o-rings and copper washers have been replaced in the injection pump and I'm ready to try tuning it again.

For reference the o-rings for the injection pump valve holders are 13.8mm ID, 18.6mm od, 2.4 section

Copper washers are 8mm ID, 12mm od