201 tacho feed

Ian B Walker · 25-03-2009, 08:27 PM

Got a bit of a problem here and not being the sharpest knife in the drawer when it comes to electrics, thought I would ask here. Got a 2.6 190E that has no rev counter. Changed the cluster for a known good one, still no rev counter. So, thinking to myself, where is it fed from? Any pointers guys and gals?

230K · 25-03-2009, 08:54 PM

Hi

This is just a guess but might help you investigate..........

On older petrol cars (not MB) the tacho gets its feed from the LV side of the ignition coil. This gives the pulsed feed, the only other thing the rev counter needs is a switched live and earth. MB's could be similar

If 124 diesels loose the tacho it can be the rpm sensor or the ovp or ovp fuse.

Hope this helps

230K

grober · 25-03-2009, 09:19 PM

Think the signal comes from the EZL ignition unit on the wing via the diagnostic socket so if you look for a wire connection that goes from the EZL to the diagnostic socket and then loops onwards???

230K · 28-03-2009, 08:52 AM

Ian

Did you get it sorted?????

230K

Ian B Walker · 28-03-2009, 11:57 PM

Quote:

Originally Posted by 230K

Ian

Did you get it sorted?????

230K

Not yet mate. Having a personal week from hell. Daughter rushed into hospital and is on morphine 24/7.

popuptoaster · 29-03-2009, 12:09 AM

Quote:

Originally Posted by 230K

Hi

This is just a guess but might help you investigate..........

On older petrol cars (not MB) the tacho gets its feed from the LV side of the ignition coil. This gives the pulsed feed, the only other thing the rev counter needs is a switched live and earth. MB's could be similar

If 124 diesels loose the tacho it can be the rpm sensor or the ovp or ovp fuse.

Hope this helps

230K

Earth side of the coil, if you connect it to the live side it gets a constant feed from the battery when you turn the ignition on.

230K · 29-03-2009, 10:19 AM

Hi

Thanks for clarifying that, i wasnt specific enough by just saying the LV side of the coil. Just didnt want anyone conecting to the HV side of the coil

230K

25-03-2009, 08:27 PM	#1
Ian B Walker Hardcore MB Enthusiast Join Date: Jun 2003 Location: Kirkham Car: 300-24, E220 Coupe, E220 saloon, 190D Posts: 7,912	201 tacho feed Got a bit of a problem here and not being the sharpest knife in the drawer when it comes to electrics, thought I would ask here. Got a 2.6 190E that has no rev counter. Changed the cluster for a known good one, still no rev counter. So, thinking to myself, where is it fed from? Any pointers guys and gals?

25-03-2009, 08:54 PM	#2
230K Hardcore MB Enthusiast Join Date: Jun 2003 Location: Belfast Car: 93 124 300TD, 98 E300TD Estate Posts: 1,655	Hi This is just a guess but might help you investigate.......... On older petrol cars (not MB) the tacho gets its feed from the LV side of the ignition coil. This gives the pulsed feed, the only other thing the rev counter needs is a switched live and earth. MB's could be similar If 124 diesels loose the tacho it can be the rpm sensor or the ovp or ovp fuse. Hope this helps 230K

25-03-2009, 09:19 PM	#3
grober Hardcore MB Enthusiast Join Date: Jun 2003 Location: Perth SCOTLAND Car: E220 COUPE Posts: 8,968	Think the signal comes from the EZL ignition unit on the wing via the diagnostic socket so if you look for a wire connection that goes from the EZL to the diagnostic socket and then loops onwards???

28-03-2009, 08:52 AM	#4
230K Hardcore MB Enthusiast Join Date: Jun 2003 Location: Belfast Car: 93 124 300TD, 98 E300TD Estate Posts: 1,655	Ian Did you get it sorted????? 230K

29-03-2009, 10:19 AM	#7
230K Hardcore MB Enthusiast Join Date: Jun 2003 Location: Belfast Car: 93 124 300TD, 98 E300TD Estate Posts: 1,655	Hi Thanks for clarifying that, i wasnt specific enough by just saying the LV side of the coil. Just didnt want anyone conecting to the HV side of the coil 230K

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