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WUR / ECU

Started by scraf, 13 August 2012, 01:55 AM

scraf

so............. got my 450SEL D-Jet ( on LPG ) through the technical test for a couple of years of what should be pleasurable driving, she's handling like a dream after replacing a lot of the rubber stuff up front.

BUT, no oomph, as in low idle, having to rev the engine as it feels like it will stall when taking off, which will probably be due to me adjusting the fuel mixture to far too rich to achieve at least some sort of idle.

When warm and on the highway, she's fine.

To the internet, done a lot of research in a layman sort of way, come to the conclusion that the WUR might need some attention.

First test, is the WUR getting power? No ( after starting ). Follow wiring loom to where I think the ECU should be, I find seven or eight cut off wires under the glove box where I assume the ECU should be.

Question, is it feasible that I've been running the thing for the last four years without a ECU ?

Secondly, is there a mechanical method to adjust the idle up, as in screw or bolt somewhere, as opposed to adjusting the fuel/air ratio ?

scraf

Quote from: scraf on 13 August 2012, 01:55 AM
Secondly, is there a mechanical method to adjust the idle up, as in screw or bolt somewhere, as opposed to adjusting the fuel/air ratio ?

The library has probably answered that question for me .......

http://handbook.w116.org/Engine%5C107%5CM117_45%5C073-100.pdf

TJ 450

Not that I know much about D-Jet, but I'm pretty sure it doesn't have a WUR... Do you mean the air slide/AAV for idle speed regulation?

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

scraf

.... pretty sure I've got a WUR, not so sure that I've got a D-Jet though  :( , got "manual" trigger point in the distributer, but the motor has been changed.

Anyway, just got my hands dirty trying to look for trottle linkages, got ambushed by the LPG system making the removal of the air filter a rather complicated affair, but in a hit and miss twiddle of the LPG mix and idle screw, I seem to have got my acceleration back from takeoff !!!

Not 100%, but much more driveable.

Still wondering about the lack of an ECU though.

Big_Richard

#4
.

scraf

Quote from: Major Tom 6.9 on 13 August 2012, 04:27 AM
does the car still run on petrol or only LPG now ?

Running on petrol ( last time I checked ) and LPG, but running good enough at the moment to put down all my false diagnosises to a relay bad fuel mix.

Quote from: Major Tom 6.9 on 13 August 2012, 04:27 AM
if its been converted to run straigh LPG it wont require any of the D-jet stuff to run, it will only need a basic version of ignition distributor too.

That will come in dead handy if I ever get the nouce required to troubleshoot properly.

kastad

The D-jet has the ECU under the glove box on the passenger side in the outer wall. I would think a converted car would have a different control system as I thought the power output from the LPG is quite different from the gasoline output. And as the D-jet ECU don't have any adjustments(without changing hardware inside the ECU) it shouldn't be possible to convert it with the original line up. Am I correct here guys?