Hmmm. Have you pinched off, or disconnected, the wastegate hose and then tested boost pressure while driving? I assume you get 6psi max while under full throttle in 2nd or 3rd gear above 3000rpm? (Otherwise you won't get an accurate measurement.) If boost increases with the wasgate hose disabled, then the wastegate is opening MUCH too soon - I doubt this is the problem though. More likely there would be no change, indicating a jammed wastegate, or a serious low-fuel problem. A small amount of oil in the turbo housing is normal, btw. I assume you have clean fuel filters (both of them)? Hope the tank strainer is clean too.



(btw - this is post #3000 - yeeesh, I talk too much! )

Except for the tank strainer, both primary and secondary are recent.

Yes I did clamp off the hose from wastegate control to keep from opening and took it out for a spin and no changes! Also, I pulled the exhaust crossover (where the trap once was) to gain access to inspect as much of the wastegate valve as possible without removing the whole thing, and it was clean. Also, I put 3 lbs pressure into the wastegate control pod hose and actuated the wastegate open and close, several times. The spring is pretty strong. The wastegate closes and seals 100%, so I dont suspect a problem here!

I'm going to try making adjustments with the Alda tomorrow and see if this will make any overall improvements for boost and ultimately more hp.

Steve.......................

You can apply pressure to the wastegate hose with a Mityvac. It shouldn't start moving the rod (to close the flap) until 12-14psi. Assuming the wastegate is OK, I'm really suspecting low fuel delivery is the root of your problem... can't wait to hear how the ALDA adjust works for ya...

I had the Alda out this morning and here is what I found:

1. The spring loaded rod that the Alda pushes down was rusted and siezed!

2. The Alda it's self, I could blow my breath through where the switchover hose connects!

Here's what I did:

Put some WD-40 around the rod, with small vise-grips, moved it a tiny bit side to side, then tapped down on it little by little until it moved up and down the 9mm's it's supposed to travel. Put the spring and top washer and clip back together, what a bear!

The I stole off my 82 300DT engine the Alda (note: they are identical, same numbers) and installed that. Hooked back up the #4,5,6, injection lines (had to remove to gain access) hooked up my vac guage with tee from manifold to Alda and went for a very accelerating ride.....WOW...........You were right Dave, pinned me to the back of the seat!!!

The vac/pressure guage rised rapidly from about 2000 rpm and passed the 6 psi while rapidly accelerating and topped out at around 11 psi.

I broke open the seal on the old Alda just to see what's involved. I'm not sure I've got a socket skinny enough to fit inside the schroud so I can loosen it to turn the set screw.

Two questions: 1. Which way do I turn the set screw and about how much?

#2. Adding a shim is placing something between the rod and the Alda?

what is your advise Dave?

So far, I'm thrilled and wouldn't mind leaving it just as it is at 11 psi, but!

Awesome! Glad you figured out the cause. I must say, I have NEVER heard of that problem (seized ALDA shaft on the IP).

Now, every ALDA is adjusted from the factory on the calibration bench, then the tamper seal is put in place. So while ALDA's are interchangeable, each must be adjusted to the particular IP. You can do this either by turning the setscrew, OR by using shims under the ALDA. You can get much finer adjustment with the setscrew, unless you file/grind shims to exact thickness needed (via lengthy trial and error.)

To richen the mixture, turn the setscrew CCW. The general rule is to go richer until you stop feeling a power gain, then turn back CW (leaner) until you feel a power *loss*, then go back (richer) about 1/8 to 1/4 turn. This should give minimal smoking - you may see a little at WOT on a sunny day, and you may see a slight black puff while leaving a stop, that is normal and won't affect MPG (my cars do this and are still capable of 30-32mpg!) Don't pay attention to smoke at night, it always looks bad in the headlights of the car behind you.

It wouldn't hurt to test the ALDA to make sure the seal is good. With it on the car, apply pressure with a MityVac. It should either hold a steady 10-15psi, or leak down from that pressure slowly. If you can't pump it up at all (near zero psi max), the shaft seal is shot. (Don't try to test off the car, it needs to have the spring/plunger tension.) A bad shaft seal will reduce part throttle power, but not full throttle power. You can fix this for about $10 and an hour of work. I did it on two of my ALDA's, they both hold pressure perfectly now.

BTW - 11psi is quite good. Most engines I've tested measure 12.0-12.5, where the wastegate was set to open. You might want to repeat the boost test with the wastegate disabled - if it won't go past 11psi, either it's still low on fuel, or the wastegate is opening a little early, or your gauge is inaccurate. My cars, with the wastegate disabled, will go to at least 17-18psi!

Also, repeat the 0-60 stopwatch test... we're aiming for 11 seconds (sedan) or 12 seconds (wagon), or better.

Great advise Dave, thank you for your invaluable input, and no, at 3000 posts, a lot of people listened and got A-1 advise, your Golden!

I'll do some more tweaking over the next few weeks and do some more tests. About the only other issue I will be wanting to tackle before too long will be finding someone who can rebuild and balance my spare set of injectors. I'm still not happy with my recent tampering, not as quiet and smooth as before!

I would immagine I could send them anywhere in the US through UPS and returned. So if you know anybody who is MB injector savvy and does a professional job with rebuilding Bosch injectors, I'd be interested.

The shim is the washer in there. Measure it, then figure out which way will give you more fuel, and get a thicker or thinner one.

More trouble than messing about with the screw on top (not on the 603, though, as you will have to take the ALDA of to adjust anyway!), and better since you cannot turn the screw too far that way...

You should get 13-14 psi boost.

Peter

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A thicker washer = richer. The typical washer thickness, found on most pumps, is roughly equal to 2 turns CCW (usually too rich). I think it's something like 0.040 thick? I forget now - I should measure the dimensions and post a photo on my website.

Boost spec on the 86-87 turbo engines is 0.85-0.95 bar, which is approximately 12-14psi. However all the 603.96x engines I've tested open the wastegate at 12.5psi (approx), and also give NO more power with the wastegate disabled and boost jacked up to 15-18psi. A better guide is your 0-60 times... if that's close to factory spec, don't worry about being a psi or two below spec.

Still breaking in the new head. The injector knock goes away completely after the car is fully warmed and driven, but comes back when cold. Per Dave's recommendation, I spoke to Mark (nice guy ) at Becker Diesel in Sac today and he quoted $149 to clean the nozzles by hand and rebalance them. I don't have the time, nor do I believe I have the necessary tools, so I will have my indy pull them next Tuesday upon my return from the central coast. Question: if my indy has the ability to pop test the injectors, can he also balance them with one another?

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The indy may be able to pop test them if he has the right tool. But he is highly unlikely to be able to adjust them, as this requries an assortment of internal shims that *usually* only diesel shops keep around (or really, REALLY hard-core DIY nuts. ) Also, unless he's really experienced at popping injectors, he may not know little, subtle things to look for in the spray pattern, that a guy who does specifically that for a living may pick up on. If you have them tested, adjusted, and re-installed, I'm really curious to hear the results!

This thread went off topic for a while but now I see it's back on track. It's possible to balance injectors without having extra shims. I did it by swapping shims, springs and the injector housing pieces. It can be a long, tedious process and I don't think a mechanic would have that kind of patience while working on somebody else's car unless he has the extra shims and knows what he's doing.

I'm going to the Bay Area on Saturday and plan on trying some 100% biodiesel to clean things out in my fuel system. It will probably reduce or eliminate the knock, but the question is for how long. I'm planning to stop by at the Biofuel Oasis in Berkley. If anyone knows a better place please let me know.

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Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

Does anyone know where I could send (via UPS) my spare injectors for my 603 to have professionally rebuilt and balanced?

You may have local resources.
Marina, heavy truck repair depot, etc.

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I'll ask around! I just thought that someone who is known to be savvy and trusted that they will do an A-1 job since I believe what Dave above had said about many do not have sufficiant supply of correct shims, and my guess that they may only get them marginally close. I demaaaaaand perfection!!!!!!!

Well, almost anyway! I just want them done right and I'm willing to pay more if that is what it takes!

Just did a 0 to 60 and clocked 12.97 seconds without any changes from yesterday!

I'll try again when I have better injectors installed, whenever!

Hmmm, ~13 seconds ain't bad, but I think you can squeeze a little more out. The ALDA adjust might do the trick.

About the injectors - someone posted a link to a forum member's website, who custom balances injectors to near perfection. I forget the URL though, or where I saw recently it - anyone know offhand?