So not much of an update but I'm basically doing maintenance to get it as reliable as possible for the hot summer we are about to get here in Arizona. The dry heat here really has a field day on the electrical system of old merc's and a few days ago I found that out the hard way. I've been chasing down this hard starting issue in the benz and After deeming the fuel pump in need of replacing I decided to check the Cold Start Valve circuit as it is a common issue for these cars. To my surprise it was not the Temperature sensor that the Cold start valve uses nor the injector itself but the power circuit ended up being the problem. 40 Ohms across the injector circuit didn't surprise me because the insulation was cracking and the harness convulated tubing had been tinkered with previously . So I decided to test the other ECU Input circuits to see how they looked and almost all of them had trace resistance that was unacceptable. So as of about a week ago I started tearing the harness out myself and you may be surprised as to why It has taken so long to pull it out but basically there are no write ups on the removal process and its a delicate thing that I really didn't want to mess up. On that note, after breaking about 4 connectors and having three circuits literally just disintegrate by lighting tugging them I am very close.
For anyone's future reference including my own, Here is where the harness splits from the ECU inputs and goes along the backside of the firewall into the electrical center (Driver's side Engine Compartment Fuse Block) I'm still in the proccess of removing this but it seems fairly easy. You jsut have to unbolt the fuse block and disconnect.
This one really pissed me off lol. It splits from the ECU Harness and goes down the passenger footwell and disconnects under the passenger foot carpet. Funny thing is I believe it is for heated seats which my 88' does not have. At that point you pull it out and pray you are good at repairing circuits and replacing OEM connectors.
Crappy photo but while you are at it on an old w124 check your CKP. I was getting counts but this thing was vibrations away from leaving me stranded.
That's it for now folks! Once I finish the harness I'll have a ton of stuff to replace and update about. Till next time guys!
For anyone's future reference including my own, Here is where the harness splits from the ECU inputs and goes along the backside of the firewall into the electrical center (Driver's side Engine Compartment Fuse Block) I'm still in the proccess of removing this but it seems fairly easy. You jsut have to unbolt the fuse block and disconnect.
This one really pissed me off lol. It splits from the ECU Harness and goes down the passenger footwell and disconnects under the passenger foot carpet. Funny thing is I believe it is for heated seats which my 88' does not have. At that point you pull it out and pray you are good at repairing circuits and replacing OEM connectors.
Crappy photo but while you are at it on an old w124 check your CKP. I was getting counts but this thing was vibrations away from leaving me stranded.
That's it for now folks! Once I finish the harness I'll have a ton of stuff to replace and update about. Till next time guys!
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