1992 140 600SEL Wiring

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Hi all,

I have this car with wiring faults. The engine loom for the injectors was bad with the CTS wires shorted. I replaced this loom and repaired the wiring for both AFM's, which was as bad.

It now only runs on the right bank, but will run on 12 sometimes with both AFM's disconnected. I have only 8v supply to each MAF which I assume should be 12v. These are 5 wire sensors which I assume should be - supply, earth, signal, sensor earth and burn off?

Can anyone tell me where the supply comes from? I have followed the wiring back to the module box. If I have to I will strip the box out but this does not look too easy. Also I cannot comm with the base module but I have 10.2v on the K line at the plug. I have tried AST, Snap-On and a Star Tester. This makes me think the fault may be in the base module or the module box.

Any input welcome,

Thanks in advance,

[mbdoc]

MB offers a repair harness for the MAF's number 140-540-00-36.

[autofix]

Hi Guys,

Many thanks for the responses.

Here is an update I rechecked the repairs i had done on the MAF wiring and found a bad connection. Fixed this and it started on twelve but ran rough. Reset engine modules and it ran sweet, but right bank O2 was stuck at 900mv. As the fuel trims set it closed the inj pulse on this bank until it hardly ran at all. At least this gives me a fault to chase now.

But it gets worse

Unfortunately for me, I had the snappy on it at the time and had used this to graph the O2, being too lazy to look for the O2 plug or hook up the scope. Snappy froze when exiting the graph mode. I left it for the night and found a flat battery the following morning. Since this the alarm has been playing up. It will not dis-arm, the LED on the door will just flash red. If I disconnect the battery and reconnect it the LED will then flash green. While flashing it will hesitate when the key is flashed, but continue to flash. Wheather this is connected to the snappy freeze or not I dont know. I had to remove the snappy battery before it would boot up again but has worked fine since. I look after another 600 which has had battery problems before but never had any trouble with the alarm because of them.

So, when I get the alarm sorted I will chase the fueling fault and let you guys know how I get on,

Again, many thanks,

Alan

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Hi all,

This 600 alarm will not dis-arm. My AST and snappy does not do any security on this and the star tester that I borrow will not be available for a couple of weeks due to my dealer tech mate going on holidays.

Lack of info now has me at a standstill on this. I have checked the door switches and fuses.

The key/remote works, as the flashing led in the door hesitates when the button is pressed and the body module in the boot clicks.

Any pointers on anything to check or even locations would be apreciated.

Thanks.

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Hi,

I got the alarm sorted. It dis-armed by unlocking the boot lock. Funny it would not work from the door it does now.

Alan

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Hi all,

Me again. I may have been a bit previous in posting that the alarm was sorted. It now sets ands dis-arms since the boot lock key position was changed, but it wont crank!

As it happened, my mate called wanting to do a ford SRS problem so I agreed to work later in to my Saturday since he could bring the star tester

Short test showed nothing, He did a search on WIS and came up with something on the symptom which refered to non-crank after car being locked from the trunk. When he clicked on this it asked him for CD4, so I assume it needed an old WIS CD, which he did not have. He could not access any wiring either. I guess it is possible that there is no fault and I just need to know the procedure to reset this.

One thing I noted, there is a relay behind the left headlamp which clicks when the key is turned to the crank position. Anyone know what this is for?

Regards,

Alan.

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Hi,

Thanks, that was the exact thing that I thought I needed. Unfortunately, it didnt fix it. It seems the starter problem may be seperate from the alarm issue.

As often happens here, lack of information is the biggest problem we face. It is not possible to buy dealer data or tools. I have to rely on favours from trade contacts in situations like this. My mate with the star tester cant find the old paper manuals for this car and it is not covered on the dvd he has in the star tester.

If its not too much trouble, could someone post starter wiring and relay/module locations.

Again many thanks,

Alan.

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Hi all,

I found a DIY kill switch wired with speaker wire. At least now it cranks and starts so I can chase the rich running fault.

Special thanks to Mike for the e-mailed wiring.

Alan.