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OM601 -> OM605TD and mechanical injection pump conversion

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9.5K views 5 replies 4 participants last post by  emterra.portugal  
G
#1 · (Edited)
Hello!

I am slowly gaining knowledge about swapping my 2.0D OM601 for 2.5TD OM605 with mechanical pump.

There is however one big issue I have: conversion of 2.5TD to mechanical pump. I know I can use the OM602 mechanical injection pump but the question is what pump I need. I know there are two things I need to know about: ALDA and ELR. I see that there are also manual transmission and automatic transmission versions of injection pumps, I don't know why. I simply don't know which injection pump I should choose for that engine.

So, for what I know is that ELR is the thing that increases idle RPM on cold and AC enabled. From what I see, If my car does not use ELR so it means that I should get an injection pump without ELR. Also, because OM605 will have a turbo, I need ALDA for smoke limiting.

From what I understand, ALDA is basically a cylindrical thing at the top of the IP:
Image


And ELR is a two-pin thing behind the IP, so non-ELR pump will have something like this for the vacuum tube:
Image


Unfortunately, from what I see, the 2,5TD in W201 and W124 had a IP that had ALDA but also had ELR:

Image


So it seems that OM602 2,5TD pump will not fit my vehicle.

BUT

It seems that on online parts catalogs the W124 2,5D (no turbo) had this pump from the image below:

Image


It looks like it does not have ELR and have ALDA. Now the first question, is it really ALDA? If yes, why is it there on non turbo engine? What is more interesting, I have the same cylindrical thing on my OM601 2.0D injection pump.

Now, the "???" thing. What exactly is it? For example here is the injection pump from automatic transmission car version which does not have that part:
Image



So, what exactly should I look for? Is the cylindrical thing always the ALDA even in non-turbo versions? Also, does OM605 have a thermo-valve for non-ELR idle control?

Thanks!
 
G
#2 · (Edited)
Ok, from my understanding after further research:
  • the cylindrical thing on the non-turbo pump is the ADA which is an altitude compensator. From what I read theoretically it could be swapped into ALDA but good luck finding someone selling just that part. External ALDA for example from dieselpumpuk is also an option but a very expensive option.
  • it wouldn't be wise to use non-turbo injection pump for turbo engine. What I forgot to take in mind is fuel flow. The NA pump itself would have to be tuned for turbo specs. It would be definitely cheaper just to buy turbo pump, which will also solve ALDA problem. The injection pump in turbo engine has flow tuned for boost, however the ALDA limits the actual value of the accelerator before boost is achieved, so for example mashing accelerator to 100% from a stop does not make pump send 100% fuel, it gives 100% only after boost is achieved.
  • this leaves me with another problem, turbo pumps are ELR only. From what I see it's only needed for tach(EDS) and bumping idle for cold engine and AC enabled. Because my car does not have AC nor tach, I guess I can safely ignore that and for example slightly increase min idle speed as a compensation.
  • it looks like ELR is not simply 12V to the plug, testing procedure says that putting battery voltage directly to ELR plug for more than 3s can damage it. So finding how to simulate ELR, for example to have a button for it, something like a manual choke in old cars, will be a pain.
So, the cheapest route will be to buy a turbo pump and ignore ELR.
Am I missing something?

EDIT:
  • The "???" seems to be "anti-jerk lock-on" thing on the parts catalogs and it seems it can also be ignored.
 
S
#5 ·
Alda is nice to have, but can be installed on a non-turbo pump.

If you have an automatic gearbox, a pump from an automatic with vacum-modulation for gearbox is needed for firm/soft shifts.
Besides that, ELR and other versions of idle-raising isnt needed/neccesary, its nice, yes. but you would only have to apply some throttle at cold start during winter to mitigate it.

neccesary/needed parts are
ALDA (if you want to run smoke-free before boost/and have extra power at boost
Vacum-thingy if you have an automatic gearbox
Vacum-shutoff.

The rest are "extras"
some pumps are longer, with ELR and more, and this will remove space towards the oilfilter etc, those can be blanked of.

Also, the yellow circle with the text "NO ELR" is a vacum connection, with vacum connected, you raise the idle like 100rpm.
Instead of playing/focusing on electronics you can just hook up a switch to one of those magnetvalve-vacum thingies and activate that for cold starting/higher idle.
 
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