W124 220E Non-starter

[smonteith]

I've just picked up 1993 220E Saloon from eBay but in the last few days it's developed a non-starting problem.

When I picked it up last week it started fine, I stopped for petrol after about 5 minutes and all was still okay and I drove it home 75 miles.

The day after I drove about five miles, stopped briefly to let my wife out the car and then it wouldn't start - but started on the second attempt.

Next day I took it to the supermarket and after a half hour shop it wouldn't start at all so I left it. On returning two hours later it started second/third time, stalled almost immediately and then started again after a couple of attempts.

It's now on my drive and won't start at all.

I've tried jumping it from another car so I don't think it's the battery.

The car has receipts for a new fuel pump and fuel pump relay in the last six months so they should be good (and suggest the this isn't a new problem!).

I pulled the OVP relay (which is dated 1993) and checked its operation with a 9v battery and multimeter. Zero resitance across pins when voltage applied to solenoid. I checked the voltage supply to the OVP which seemed to be less than 1V which I thought was strange (expecting 12).

I shorted across the OVP temporarily to bypass it and still no starting.

Any ideas where to look next?

Cheers, Steve

 

[6pot]

has it got an immobilser?

 

[smonteith]

It's got a M-B alarm, not sure if it's an immobiliser or not. It's a rectangular remote with two buttons and a M-B logo. One opens/closes the locks and the other seems to set the alarm off if you press it.

 

[smonteith]

Just checked the manuals that came with the car and it has a Mercedes badged Scorpion alarm/immobiliser.

 

[kth286]

lock and unlock the doors, and set and reset the alarm a few times.

it may be a relay is sticking.

 

[BlackC55]

Give the OVP and fuel pump realay a tap when It wont start and see if that cures it

 

[grober]

Other possibility is a dodgy ignition switch. Under normal circumstances you should be getting 12volts supply to the main OVP relay contacts. Check all the fuses are OK and making good contact with their holders [ they tend to corrode]

 

[smonteith]

Well it looks like I've been a chump

I thought that the OVP was the green relay with the fuse on top of it to the back left of the battery, but it turns out that that is the fuel pump relay (which I thought I'd read was part of the kickdown relay).

When I corrected located the OVP attached to the body to the back right of the battery I tried to remove it from it's connector and it was very stiff. After a bit of persuasion I got it off and all the contacts were green and corroded. I've cleaned them all with some fine sandpaper and a blast of contact cleaner and touch wood it's started succesfully the last six times I've tried it.

I guess I'll replace the OVP if it starts playing up again, but for now it's all good.

Thanks for the replies.

Steve

 

[grober]

Result!