I will check on the particular piece of rubber you're talking about.

I have gone through the "proper" linkage adjustment, and have double checked that the pedal to the floor does in fact move the IP to the full throttle position.

When Brandon (superturbo moderator elsewhere) from Portland area looked at this car a couple years ago, he grabbed the linkage with the car running, and 'gunned' the engine.

He laughed, as he moved the linkage to 'full', and the engine "strained" to build speed at all. He laughed, and wondered how we drove it like that!

He showed us how to adjust the rack dampener, and also checked over the linkage...
That's when he shrugged his shoulders with a look of "hmm - not sure what to tell ya" on his face.

He played with the ALDA screw, turning it one direction, saying that would give us more 'under-boost' power - did the opposite - so we played with it on the road to find the best "middle" position.

That's also when he said he replaced his IP with a fresh off the bench unit...

... :/

I meant pop the ALDA (take it right off the car) and try it (go drive the car).

Forget about diagnosing an ALDA... just drive the car and find out if it is the ALDA or not. If it's not, leave it off until you find the problem. Then if you want put the ALDA back on. Then, take the ALDA off again because you won't want it back on...

The screw is covered by a plastic cap and metal cup.
The third pic is of the bottom of the ALDA, the fourth is of the top of the IP ALDAless.
The fixed nut on the bottom is 24mm and the spinning nut on the IP is 27mm.
I adjusted it ccw and now the car starts in first gear, is more responsive and I get worse fuel mileage.

if Brandon looked at it and was at a loss for an explanation, you will probably have to go through the entire fuel supply system piece by piece.

start with small, easy to fix items, work your way through the whole system.... everyone will just be guessing until you find more information.

filters, tank screen, bad hoses, bad clamps, poor ventilation... get busy.

OK, wow, some time spent, annnnd, spent over an hour going through checks and possibilities with our trusted PP tech Roy. We came to 2 basic things, which I tried yesterday.

The first being the fuel over-pressure valve (I'll call it that, anyway) on the block side of the IP. Pulled spring from 22 to 27mm - reinstalled - made no difference, but nice to know that's done.

THEN I removed the ALDA...

OMG - it's instantly like having 2 of the same motors as I've had. And hill climbing?

Well, let me illustrate it this way. The closest 'highway hill' to our house: Ava has been climbing that hill at barely over 40mph for 'ever'. Yesterday's test: She rolled right up, without even shifting down, with 63mph the lowest on the steepest part...

Crap - didn't know she had it in her!!! :)

I then replaced the ALDA, and played once again with the adjusting screw - doesn't seem to do much of anything, and I'm back to having the most gutless car in the world...

So, as a diagnostic test, does this confirm the ALDA is bad?

Or does it simply point to some other possible issue????

You may want to check the cam timing and fuel timing.

I understand if you turn the screw too far counter clock wise, you may damage the ALDA.

Try adjusting it more.

The poor ALDA - I took it apart to check it out - it has been apart before, I believe, by the near stripped head of one of the 4 screws. The seal around the shaft comming out the bottom is definitely shot - I could see daylight around the shaft when it was through the seal...

Hey Joe, glad to hear you've figured out your issue. I'd hit any local junkyards around and see if you can find a couple ALDAs and put one of those on.

Hate to say I told ya so, but... ;) Betcha wished you did this on June 18 as suggested in this thread.

Mine is still off the car. I put a boost gauge in the car instead of trying to find another ALDA... As some people are nervous w/o having an ALDA because it's part of the over-boost protection circuit on this car. Funny thing is, there is not one story out there about a turbo overboost fault on these cars. The rest of the protection circuit is likely plugged with gunk anyway or non-functional (solenoid stuck, etc).

The boost gauge showed I was only getting sub-par boost, I added a manual wastegate controller ($20 EBAY) and set it for 1 bar (14 psi). That showed me new top end power / hiway speed. I have to push the car really hard fully loaded up a hill to see anything near 1 bar on the gauge. There just is not enough fuel coming out of these IP's to push into the danger zone, or worrying about melt down.

Mine had a similar problem, fixed with a replacement ALDA. I could have just removed it, but I didn't want the smoke.

Yes, after 3 years of messing with her, it's nice to finally hit her "sore spot"! So I'm shopping for a good ALDA :)

Reading posts here sure give one an education. I now understand the ALDA for the most part, and how having a compromised chamber can render the car gutless.

As I now understand it, the chambers are sealed in a vacuum, and therefore even at under-boost, they're already 'squished' to some degree; then simply squish more as boost comes on. So, if one (or both) develops a leak, it will relax (thicker than stock) into a state which cuts available fuel to a minimum...

I also see the value in having both the fuel and valve timing checked by a pro - I can imagine things getting a little 'off' after near 30 years, and 340k miles ;)

1982 300TD - Ava

If that was true, the ALDA would not be capable of compensating for anything but transient pressure changes. Unless one aneroid is vented and the other is not. The 617.95 manual doesn't mention that arrangement, however.

Well, happy day:) I kicked myself when a friend suggested I take the ALDA off the 81 300SD in the yard, and put it on Ava... ;)

Well, not so fast. Even though the SD has a nasty-wasty knock, it still gets up and moves pretty good. However, the SD's ALDA placed on Ava gave me the same result as before - little power...:(

What the heck? So, I removed the ALDA, and had the wild but simple idea to blow (with my mouth to the banjo-bolt hole) and see if it was sealed. NOPE - I could blow right through it...

So I dismantled both (man, those screws are tough to get out!), and used the top casting and chambers from the SD, and the O-ring and lower casting w/seal from Ava (couldn't blow through hers, so I knew the bottom seal had started working, thanks to a soaking with 3M wet-type spray silicone), and installed the completed unit on Ava.

Wow - not only is she up and running, but nice smooth power, and the transmission feels a whole new world - shifts on time, and so well.

...and on top of that, the ALDA still even has the cap on it!

What can I say - thanks for all the help!

Kinda funny - I've known the front brakes were due for refreshing, and the steering box is overdue, but now that she really moves down the road, it's real obvious!

:)

ps: after this interesting ALDA education, makes me wonder just how many ALDA's have either a bad chamber or a bad seal, which lead the owners to pop the cap, and start trying to adjust the thing.

My 2 cents? First check to see if you can blow air (mouth, NOT from a compressor) through your ALDA, and go from there.

In retrospect, I wonder just how much these chambers are flattened at atmospheric pressure, and how consistent they are one to the next.

Would be interesting to put a micrometer on known good ones, and bad ones, and see if a tolerance could be established, so we could simply mic them, and determine if they're good or not...

The FSM has a procedure for adjusting the ALDA, which is basically visual/smoke threshold, and mentions that it is a maintenance item so I doubt that many 20-year-old cars are out there with properly adjusted ALDAs, I've never bought one. However, after several 60x cars with mis-adjusted ALDAs, I've not (yet) run into a ruptured one, all seem to respond well to the 1-1/2 CCW adjustment.

Seems like the blow-test is a simple first step though, sure beats spending 20minutes getting to the adjusment just to find it's bad.