Y22 - idle speed control actuator '93 300TD

[balge59]

Well that was a bust, last chance gone, it must be the ELR after all...

As it seems to be running adequately I suppose its not actually vital to replace immediately? I expect its worth having in winter but that gives me a while to find a cheap deal? Or is it damaging anything running without it?



So..in the market for a cheap ELR after all! :lol:

thanks again for all the help

 

[Alex Crow]

just get someone to go over the solder joints, at least 50/50 chance of that fixing it.

 

[Number_Cruncher]

I think going over the solder joints is a good plan.

If that doesn't help, as the ELR is working in the sense that it is correctly interpreting the speed sensor signal, it might also be worth checking [or just replacing on spec] the output stages which power the idle speed control solenoid - if they are seperate transistors.

 

[balge59]

Had a look at the insides and that is one tight little PCB.
No visible evidence of solder problems, need a loupe or good magnifying glass to check properly I suppose, and the only connections I would consider safe to try are the actual pin connections - the rest of the board is too busy for me to feel safe sticking a soldering iron in, I spotted a 16x16 chip but that's about all I recognised... maybe with a micro manipulator lol (dont want to lose the functionality it does have, eg tach, and not sure if it affects the kickdown...)

hmmm...I will try taking some high resolution pictures of the contacts, see if that shows anything, worth a try!

 

[Alex Crow]

good point NC, i too would expect output stage to be the likely culprit and transistors are cheap enough if re-soldering the main joints does not help.

 

[balge59]

sorted

hi
well just to tidy up, got a replacement ELR and suddenly I have electric idle control!
Tickover is up to 600 rpm from cold, stays steady all the way with hot engine. Pickup and bottom end seem better as well.
Got the ECU via Ebay for £20, some robbing gets are charging £80 for these!!!

Was wondering if anyone repairs these ECU's as they can't last forever, I always worry about using s/hand electrical components....ah well it'll do for now!


once again thanks for all the help!

 

[Alex Crow]

.............. I always worry about using s/hand electrical components....

in that case buy a new car - your entire vehicle is decidedly secondhand now

glad you got it fixed, nice feeling isn't it

 

[television]

With all sensors like the temp ones its dead easy to test, if one pulls the wire off, then the car will respond thinking that the engine is cold, and it will enrich or turn on whats needed.
Most sensors run at about 900 to 1k ohm when hot,, and its dead easy to put a 2.2k resistor over the existing temp sensor to simulate correct operation at normal temp.

All the ones that I know of are around 5k cold and 1k hot

 

[Bolide]

Most sensors run at about 900 to 1k ohm when hot,, and its dead easy to put a 2.2k resistor over the existing temp sensor to simulate correct operation at normal temp

I was think along the same lines - nothing to stop you putting a pot* in there. If everything's working OK you should be able to vary the idle speed by adjusting the pot

*Pot = potentiometer = variable resistor. They cost buttons at somewhere like Maplin. Try a 5KΩ pot

Nick Froome
www.w124.co.uk

 

[balge59]

hmm, so rather than replace a duff ECU, could just a fit a potentiometer and have manual adjustment for tickover, cold starts etc? Good idea, like it ! Better than dropping £80 on something that might give up after a couple of weeks

Yup, always feels good sorting out a problem, getting stuff better... and it means I can start on the next thing...!

 

[dieselman]

hmm, so rather than replace a duff ECU, could just a fit a potentiometer and have manual adjustment for tickover, cold starts etc? Good idea, like it ! Better than dropping £80 on something that might give up after a couple of weeks

The ECU is for idle stabilisation, not just cold start speed control.

 

[zulf300]

Hello guys,

just joined the forum - and have this annoying issue with my car a 124 benz OM606.

It idles at 900 rpm, I have gone through the 124zone website for the service manual and here are the observations.

OVP relay is dated 2008 along with the wiring harness
tach on dash works perfectly
idles at 900 rpm regardless of temperature.
checked resistances of temp sensor - in spec
checked resistance of tach sensor - 1.9 kohms - generates 4.0 volts AC at tickover speed.

I have 13V at the Y22 terminals and they would briefly drop if I blip the accelerator. Which according to the manual speaks of a dead tach sensor - my tach sensor is working and in spec.

disconnecting the 4 wire temp sensor does nothing (sensor is in spec and wire continuity is perfect all the way to the ELR module base
disconnecting the tach sensor drops revs to 500 - no idle control

Ive looked for many solutions with no result - If any of you folks can chime in it would help. or even point me in some directions to buy an ELR unit from UK, it would help.