A question for the Super Turbo tuners

[Zeitgeist]

Hello, some of you may remember that I've been attempting to put together a baby Super Turbo, with a stock turbo and injection pump, and a small front mount intercooler. I put the engine together with the modified intake and IC, but I've encountered a problem with the adjustments made to the injection pump.

I opened the back cover and turned the full load screw (2f) completely out 4.75 turns anti-clockwise, and turned the governor spring retainer (2m) in 1 full turn clockwise(+300 rpm). The problem is that now the engine no longer seems to be responding to the foot throttle anymore--it wants to race to full throttle when it starts. The throttle linkage isn't binding, so I can see no external reason for this problem. I'm concerned that maybe the fuel rack was supposed to be in a certain position prior to any adjustments to the pump. The service manual doesn't mention anything about this.

Do any of you have some advice for making internal adjustments to the stock injection pump? Thanks for your help.

[Sivonen]

You can (and must) adjust the idle speed. Screw 2b in your avatar picture.

[Perttu K]

2b srcew should be turned anti-cockwise about the same amount as the full load screw. When you turn this screw you must observe throttle linkage because it moves as you turn the screw. If it can't move your adjustment doesn't apply until throttle linkage can move freely to it's new idle position.

You may also need to turn the screw below governor spring retainer clokwise to make engine drop from high rpm to idle normaly.

[Zeitgeist]

Thanks for your replies. I'll give it a look this evening. I wasn't expecting to encounter this problem at all.

[AMG Dave]

Excellent information here... I too was not expecting to need to make other adjustments. Questions:

1) Will the ALDA need to be adjusted as well?

2) Will we need to adjust the external throttle stops (setscrews) on the linkage, outside the pump?

[Zeitgeist]

I opened up my spare OM603 injection pump in order to make some observations.

1. Adjusting screw 2b anti-clockwise moves the throttle arm back, toward the
rear of the engine -- this represents a reduction in throttle position.
2. Adjusting screw 2f anti-clockwise moves the fuel rack forward, toward the front
of the engine -- this represents an increase in fuel delivered.

Tonight I pulled the cruise control actuator and removed the ELR unit. Tomorrow, I'll play around with adjusting screw 2b, and turn it out CCW the same 4.75 turns as screw 2f. I hope that will clear up this situation. Thanks for your help.

[Zeitgeist]

Update:

I tried to adjust screw 2b on the original pump, but the idle just wouldn't settle down. I ended up swapping in my spare injection pump, with the following settings:

2f = 2 turns anti-clockwise
2b = 1 turn anti-clockwise
2m = 1 turn clockwise
Injection timing set at 14 degrees ATDC

Now the engine idles fine (very smooth), but it knocks quite loudly, with black smoke billowing out of the tailpipe--way way too much! Also, it will not accelerate beyond about 2500rpm before cutting out.

Can someone who has adjusted the settings on their stock injection pump confirm whether these settings are correct? If not, can you provide some advice as to the correct settings for maximum fuel delivery with stock 5.5mm elements?

Kiitos

[e320]

Zeitgeist have you tried gradually adjusting your pump from a normal setting? Perhaps you just went overboard with something.

Now I'm not an expert in this field in any way, I don't own a diesel or even a turbo. But my experience with overclocking computers tells me that if you turn the knobs too far, something will stop working. At that point it's a matter of trial and error - small adjustments untill you find the sweet spot.

I hope someone here will be able to give you exact settings ready, though.

[Zeitgeist]

Yes, I believe you're correct about the incremental adjustments. It's foolish to begin turning screws if you don't know what you're doing. Very few if any people in the US know much about modifying MB diesels, so we stumble around blindly.

Thanks.

[Perttu K]

Your settings seems fine.

I think that knockin is caused by incorrect injection timing. It may be wise to rechek it. If engine smokes all the time, injection pump may be one crankshaft turn wrong. When adjustin injection timing you should chek that camshaft is in right position. Cylinder number ono cams should point downward.

Problem with acceleration is a mystery. So pump will cutt of about 2500 rpm (=smoking stops) ?

Correct setting for maximun fuel delivery is all you can get from the pump It shouldn't smoke to too bad. At least mine didn't. Adjusting turbo injection pump is easier. I managed to get more power from turbo pump without problems then normal pump. So I think you should use your turbo pump.

You do know that pump should be adjusted when it's attached to engine and engine runnig? It's the only way get the idle exacly ringt when adjusting maximun fuel delivery.

[AMG Dave]

You do know that pump should be adjusted when it's attached to engine and engine runnig? It's the only way get the idle exacly ringt when adjusting maximun fuel delivery.

How can you run the engine with the back covers of the pump removed? Wouldn't engine oil pour out the back? (see, we really are a little slow here in the USA... ) Or perhaps you mean to only make external adjustments with the engine running...??

[Perttu K]

Some oil will come out. When engine is running oil will start dripping from the pump. Leak is quite insignificant and you can adjust the pump without rushing. I have run engine with back cover removed about 15 minuntes and as I recall no more than two liters of oil has come out.

[Zeitgeist]

I've checked and re-checked the injection timing, and it's still right at 14 degrees ATDC. Since you say the pump adjustments need to be done while the engine is running, do you know if the engine should be able to idle with the ELR solenoid removed? I can't get mine to start, run and idle very long without ELR, which needs to be removed in order to access screw 2b. Also, my car has cruise control, and the actuator is located directly behind the pump, so the foot throttle linkage is disabled when the actuator is removed to make pump adjustments. Very frustrating. I can't figure out why I keep getting all the black smoke, though I was able to get the engine to knock less(we call it "nailing" here in the US) when I played with screw 2f while the engine was running.

Any suggestions would be greatly appreciated.

Kiitos

[Perttu K]

Yes it's sometimes frustrating. Believe we know!

This is just guessing. Have you checked that cam is at right position when cheking injection timing? I would remove valve covet and check. Just to be sure. There is also other possibility. Timing mark in the pump might be wrong. Mark in the pump may move if timing tool is in place and pump is then forcefully turned. It has happened to one member of mersuforum. Maby you should try with the original pump? That was just guessing.

Screw 2b should be turned so that engine idles normaly with elr solenoid removed. You should turn it clockwise few turns so the engine can be started and then turn it so thad it idles normaly. That's the right adjustment.

Srew 2b is actual idle andjustment screw and the one top of the pump is just for fine tuning. Screw top of the pump (outside) shouldn't be turned to much clockwise (too deep) because it causes engine to stall easily.

I'm glad at leat trying to help. So ask anything you like. (It also gives me chance to exercise my school english.)

[Zeitgeist]

Update:

Well, I was finally able to get the car running fairly well after I swapped in another pump (#3). I ran it with factory pump settings for a couple of weeks, but found out that the problem with the engine cutting out above 2500 rpm was due to a collapsing charge air tube (an old Volvo turbo hose). I turned screw 2f up one turn anticlockwise and found that my 0-60mph times dropped down to ~9.5sec. Is this the best I can expect, or can I do better with more turns of the screw? Now unfortunately, the engine smokes badly and runs rough for the first minute or so after I start up. Once it warms up the smoke and rough running go away. I turned screw 2b out anticlockwise one turn, but that hasn't changed this smoking/rough running condition at all.

A couple of questions:

1. I'm currently running at 14 degrees ATDC; should I advance the injection timing more (to 13 or 12 degrees ATDC) to accomodate the increased fuel quantity?

2. Can I continue to turn screws 2f and 2b out anticlockwise to increase fuel quantity? How will I know when enough is enough?

Kiitos!

[Perttu K]

1. More advance injection timing should decrease a bit smokin when cold. 12-13 ATDC is good but not nescecery..

2. I noticed that ennough is ennough when I couldn't fit the back plate of the pump back in place anymore.

Ennough is ennough when it starts to smoke. It should'n smoke too bad. Mine didn't smoke at all expect small cloud when begining to accelerate. It is important that engine gets ennough air and also that the exhaust gas can exit as freely as possible. That reduces smoking.

[AMG Dave]

Casey, does the smoking go away once the engine warms up? Or does it smoke at idle and light load after it's warm too? There's no smoke (or very little) at WOT, correct?

[Zeitgeist]

Dave, it belches a good size cloud of light grey smoke at startup and the engine runs extremely rough for about a minute. After that, it tends to smooth out and the smoke clears up as well. It will belch a small cloud of black smoke when I stomp on the throttle from idle during my 0-60 tests, but other than that it's smoke-free. The startup problem is really obnoxious--I can't live with it like that.

[AMG Dave]

The small cloud leaving a stop (during the 0-60 tests) *should* be adjustable by leaning out the ALDA a little bit. I'm kinda stumped about the cold start problem though. Maybe the external idle adjust screw, at the top/rear, would affect this? (I'm assuming the glow plugs are all good.)

BTW - if you have a G-Tech Pro, please try to get some 1/4 mile data if possible! I'm itching to see what those numbers are. While I'm asking for the moon, might as well mention that I need to know your elevation (above sea level) too...

[Zeitgeist]

I'm wondering if you folks running a front mount intercooler ever see intake manifold vacuum at idle or just off idle*. Most diesels aren't supposed to run manifold vacuum, but mine does. I'm running 2.25" IC tubing--is that too small? Lately, I've noticed a fair amount of manifold vacuum, and now the car is blowing blue smoke when I accelerate from idle. I suspect the manifold vacuum is drawing oil into the combustion chamber via my stiff valve stem seals. I checked the compression (good) and turbo seals (good), so I guess valve stem seals are the source of oil--thoughts?

Anyone there in Finland experience something like this?


*I can remove the air cleaner completely and still see manifold vacuum.

[AMG Dave]

Any update on this, Casey?

[Zeitgeist]

Any update on this, Casey?

Hi Dave, wow it's been quite a while since I last posted here. I haven't been doing much with the car other than just daily driving. It now has 228k, which means I've got nearly 30k on it since I began the performance mods.

I did end up replacing the cylinder head with a new #22 version, which cured all the blue smoke issues. I gave it a mild port-matching and polish job before installation. I then opted to install a Powershot 2000 propane injection system, which really gives it a performance boost. It dropped my 0-60 times from 8 secs down to 7 secs. I had the fuel volumes incorrectly adjusted and it eventually blew up my turbo. I've since swapped in a K26 and have been very pleased with the quicker spool-up and higher boost levels than the old Garrett T3.

I'm now ready to take the next step and send one of my spare pumps over to Myna for their treatment. The best pump I have is from an OM603.97, which is factory governed to a lower max rpm fuel shutoff. I'm hoping they can modify this pump to increase the max rpm.

That's all I have for now...

[AMG Dave]

I had the fuel volumes incorrectly adjusted and it eventually blew up my turbo. I've since swapped in a K26 and have been very pleased with the quicker spool-up and higher boost levels than the old Garrett T3.

I'm now ready to take the next step and send one of my spare pumps over to Myna for their treatment. The best pump I have is from an OM603.97, which is factory governed to a lower max rpm fuel shutoff. I'm hoping they can modify this pump to increase the max rpm.

Hi Casey,

Thanks for the update. Just a couple of questions...

1) How did incorrect fuel volume damage the turbo, and how did you cure the fuel problem?

2) Is the K26 a bolt-on? Is that the "stock" 1987 KKK turbo, the same one I have now...? What boost pressure are you currently running?

3) I thought the max RPM adjustment on the pumps was just a matter of turning the big hex bolt in the governor. The spec for max RPM on the .970 is 4650, .971 is 4750, and .96x are all 5150 (all numbers are ±150 rpm). Hopefully that won't be a problem. I wonder if the 3.5L pump might actually be a little better (push more fuel) than a 3.0L pump? Maybe different cam profile?

[Zeitgeist]

Hi Casey,

Thanks for the update. Just a couple of questions...

1) How did incorrect fuel volume damage the turbo, and how did you cure the fuel problem?

2) Is the K26 a bolt-on? Is that the "stock" 1987 KKK turbo, the same one I have now...? What boost pressure are you currently running?

3) I thought the max RPM adjustment on the pumps was just a matter of turning the big hex bolt in the governor. The spec for max RPM on the .970 is 4650, .971 is 4750, and .96x are all 5150 (all numbers are ±150 rpm). Hopefully that won't be a problem. I wonder if the 3.5L pump might actually be a little better (push more fuel) than a 3.0L pump? Maybe different cam profile?

1) The Powershot 2000 is unusual relative to other propane injection units, in that it allows for progressive fumigation based upon boost levels. The unit has two adjustments; boost level "kick-in" and fuel volume under the boost curve. I had the latter adjustment set too rich. It would knock when under load and full boost. I got lazy and let it run like this for too long. I'm theorizing that either my VDO pyrometer is inaccurate and my exhaust gases were way too hot, or there was an errant flame front that blew up in the turbine housing--that's a bit of a stretch. Truth is, I'm not quite sure what happened. It blew off several of the turbine vanes.

2) Yes, it's the stock KKK turbo, but I removed the ARV and did some fairly extensive mods to the inducer in order to get the IC tubing to attach correctly. My boost gauge is a converted gasser vacuum gauge, so it just reads in relative terms. But, I believe this turbo has bumped my max boost pressure from around 16-17 on up to 18-20 psi. Not sure why, exactly.

3) I do believe even I could adjust the governor on a .97 pump, by using exactly that method. A different cam profile is a possibility, though I doubt it. It should also have the exact same 5.5mm pump elements as the .96 versions.

[Forced_Induction]

Be careful with that K26. It's an inefficient turbo, the compressor basically turns into a heat pump above 18psi.

The reason you have higher boost is that the wastegate can't flow enough for your higher performance. The small turbine housing means EMP will be high as well.

Propane is always very risky and really isn't worth it as detonation cannot be heard over normal combustion in a Diesel, as you experienced. It's much cheaper and safe to raise the maximum fuel settings than use any propane.