I changed the fuel filter, oil, and transmission fluid. After putting everything back together the car will not start. It cranks and cranks and sometimes will sputter, but it will not start. I have kept on the starter for close to 30 seconds and all I get is a sputter.

Things I have checked or performed:
- The OVP 10 amp fuse is intact.
- There is spark at the spark plug end of the plug wires.
- Cleaned the spark plugs because they were fouled.
- Opened the fuel pressure regulator in and out lines and gas leaked out.
- Battery is fully charged.
- The transmission cable is connected.

I am out of ideas. Please help before my wife forces me to tow it to a shop.

Thanks, Bob.

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1987 Mercedes 260E (W124) 213,000 miles
1971 MB 220 w/ 4 spd manual (W115) "Suzy" (sold)

Check the crank position sensor where it plugs into the EZL box. My 1989 [may it rest in peace] had a gradual failure - eventually an open circuit.

Where is the EZL box? It finally started, but ran really rough and stumbled when I pushed the accelerator. I turned it off and it would not restart.

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1987 Mercedes 260E (W124) 213,000 miles
1971 MB 220 w/ 4 spd manual (W115) "Suzy" (sold)

Sounds like the HT leads aren't in the correct order.
Recheck them. 1-5-3-6-2-4

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1989 W124 260E

Well even though you did not do anything to the electrical system, some common causes of this behavior could be electrical in nature so rule out the easy stuff first - 1. Check all the fuses. 2. Check the voltage at the battery terminals with the engine running at idle speed (650RPM) - you should have 14V if the alternator/voltage regulator is working right. 3. If you haven't replaced the OVP relay but have only changed the fuse, it would be a good idea to do it now - a lot of starting problems originate from a bad OVP relay - the internal solder joints corrode over the years - I have one that I recently cut open from my 1989 300E and at least 6 joints were clearly broken (desoldered) because of heat and frequent switching cycles.

Is it possible to resolder the connections? I purchased a new voltage regulator, thinking it was the over voltage protection relay, but I am now sure where the old one is located. My battery reads 12.7 volts and the alternator was tested at a local parts store and they said it was still good.

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1987 Mercedes 260E (W124) 213,000 miles
1971 MB 220 w/ 4 spd manual (W115) "Suzy" (sold)

If you changed the fuel filter in the rear of the car chances are your disturbed the electrical circuits for the fuel pumps. Get underneath the car and make sure trhe wiring and connections are correct and tight.

Next. Sit in the drivers seat and turn the ignition on without starting the car.
For the first two seconds or so you should hear the fuel pumps working from the rear of the car. If you hear nothing check the Fuel pump relay.

Come back to the forum for more instructions after this.

12.7 volts is a bit low and suggests a new regulator is in order. Did you put the new one in? Change the OVP relay next anyway. It's probably been there forever.

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1990 300TE

"24 hours in the day. 24 beers in a case. Coincidence? I don't think so."

You can't resolder the OVP desoldered joints. I thought I would try that but opening the metal can of the OVP is a PITA because it is internally bonded to the metal for the grounding of the case. I ended up destroying it - only because I had a new one already on order from ********. It cost about $50 but it solved my problem of very similar symptoms...Also with the new Voltage Regulator you should get about 14V. 12.7 is too low if you checked it with the car running. 12.7 is OK if you checked it without the engine running.

I can hear the fuel pumps hiss for a few seconds when I first turn the key to on. Last night I pulled out and reinstalled the fuel pump relay and kilm relays. I also disassembled the OVP , scraped any corrosion between contacts, and reinstalled in the car. The battery voltage of 12.7 volts was with the car off. I would like to install the new voltage regulator, but I cannot find where it is on the car.

This morning the car started after about 6 seconds of cranking and ran smoothly. I allowed it to come to temperature, shut it down, and it started again easily. I waited another hour and it started easily again.

I think I need to buy some new relays, just in case. Where can I purchase the OVP, fuel pump, and kilm relays? Also, is there anything else I can check to prove to my wife that the car is ok? Thank, Bob.

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1987 Mercedes 260E (W124) 213,000 miles
1971 MB 220 w/ 4 spd manual (W115) "Suzy" (sold)

More than likely its the OVP -- renew this first. Most attempts are fixing it manually end up failing, or failing shortly after.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

Check the contacts where the OVP and fuel pump relay plug in and make sure they are clean and contact properly.
There is an earthing point on the inlet manifold adjacent the IACV. (A bunch of Brown wires screwed to the manifold). Take the bolt out the fastens the brown wires to the manifold. clean off an corrosion, clean the tags on the end of the wiring, clean the corrosion out of the hole where the bolt goes in.

With the engine running you should see 13.6 - 13.8 volts across the battery. This is the output of the alternator regulator. This was the charging volatge for the simple lead acid batteries which were prevalent during the era of the design of the W124.

Underneath the car there is a flat wire copper rope strap between the body and the rear of the engine. This is the earthing point. Make sure there is no corrosion anywhere here.