Unwanted coal rolling

[Kerrvillian]

I have a new-to-me 1985 524TD that rolls some serious coal under full throttle acceleration. I'm sure that's not how they're intended to operate. Zero smoke under normal acceleration and 33mpg highway on the road trip home.

I'm familiar with Mercedes diesels with their ALDA. Do these have something similar that someone may have tampered with? I don't mind a little smoke with a good romp, but this is like a volcanic eruption!

[gadget73]

They do, there are a couple of adjustments on it. The full load fuel screw, the stop screw or "smoke screw", which is your no-boost fuel adjustment, under the cover you get the fuel pin and the spring that controls the application rate. I'll just link you to this which explains it better and has pictures. This is for a Rover but its the same pump and for a similar displacement engine.

https://www.google.com/url?sa=t&rct=j&q ... 92FmS_aubJ


its pasting in a stupid manner so if that doesn't work, google for "bosch VE tuning landyzone" and it should be the first link

what I ended up doing with mine was backing out the stop screw so that the pin was all the way up and rotating the fuel pin to add more fuel overall instead. I also tightened up the spring so it applies more slowly. Ends up with more fuel at full go and with minimal turbo lag, but it doesn't over-apply at low speed / low boost in order to keep the smoke under control. If I set the fuel pin to as lean as it can go it won't smoke at all but its painfully slow and the turbo just takes forever to do anything productive.


another thing that makes them smoke way too much is if the boost is low from leaks or the wastegate being improperly adjusted. The spring in the wastegate actuator gets weak and over time the boost ends up low, and those boots coupling the turbo to the crossover pipe and the intake plenum also petrify and leak. Stock boost spec I think is right around 10 psi. Would be worth hooking up a pressure gauge and going for a spin to verify it comes up to that. If its low and you can verify no leaks, adjust the tie rod on the wastegate actuator to tighten it up. Oil that before touching it though, just in case the parts are stuck.


I ended up using cheap ricer-riffic silicone hose couplers from ebay meant for cobbling up your own intake plumbing. BMW wanted quite a lot of money for 2 short bits of hose, I got both pieces on my car for less than half what they wanted for just one of the factory parts.

[Kerrvillian]

Link works for me. I'll look into it this afternoon. Car makes adequate power, it's just the insane amount of smoke at WOT that's a problem. The protection cap is definitely removed from the ALDA thing, so I'm going to start there. Turbo tube boots are in good shape and I know it's building boost. I'll have to quantify how much boost, but it's definitely boosting. I'll post back with what I find.

[Kerrvillian]

Checked into things on the car this afternoon and found a few things wrong. Boost sense line to the ALDA thing on the injection pump was rotted off. Got that replaced with new line and cleaned up the vacuum system, and deleted EGR while I was in there. The full load fuel adjustment still has the factory seal on it and has not been tampered with. The stop on the ALDA thing had been adjusted and I did adjust it with some success in reducing smoking, but what really made a difference was driving it while building boost. I drove it HARD this afternoon and the smoke production is far less. Accelerator has to be flat to the floor to roll coal anymore, and at this point I'm suspecting very worn injectors. I've got parts on the way to get into that and service the fuel system and have plans to remove the intake manifold and clean all the carbon and sludge out of it.

[gadget73]

Had my intake off when I had to send the pump out for an overhaul, there was a lot of oil sludge in there. I tossed it in the solvent tank at work overnight and a lot of it loosened up. I scrubbed out the intake ports and the oil separator while it was all apart too. The shop that did the injection pump tested the injectors and told me they were fine so I guess I got lucky there.

something I found with the intake gasket parts listing at realOEM, it will tell you that 6 are needed, but each gasket does 2 cylinders so you only need 3.

[Kerrvillian]

I noticed that about the intake gaskets. I've got a set on order and waiting on injector parts. The intake manifold is pretty disgusting inside and I have to believe it's a big part of what's going on. My old Mercedes 300SDL had the intake runners so clogged with soot/tar that it was breathing through holes about the size of my pinky finger. Deleting EGR and cleaning all that garbage out made a profound difference how it ran. I don't suspect problems with the IP on this car since it runs perfectly smooth and responsive. Starts right up every time you flick the key, so it seems healthy enough. Injectors nail loudly, especially when cold and it all screams worn nozzles to me. We'll see when the parts show up.

[gadget73]

Mine ran perfectly, then it started puking fuel out of the head seal. Apparently its a thing that sometimes happens with the VE pump and more modern diesel fuel. Found an exploded diagram and it scared me so I just paid to have it done. The seal kit is only like 60 bucks though. If I ever come across a spare pump for very little money I'm tempted to re-seal it just for the experience.


There is a cold start advance which makes it rattle more, and no guarantee the timing is right but verifying the injectors pop and spray properly on an old diesel is just a smart move anyway.