W210 glow plug issue
 

I replaced the glow plugs on my w210 2 weeks ago while replacing the engine wiring harness. No more check engine lights. I used a set of glow plugs by Bosch "Duraterm" 0 250 201 035. The electode was turned slightly to fit my harness as these were for the w124 OM606 instead of the OM606 w210.
The car now starts rough but I am not getting any error messages.
Any thoughts?
TIA,
Steve

If I remember properly the connection of the plug to harness is different from 124 to 210. It is a totally different plug connection. You are probably not getting a really good connection at each plug.

Just guessing but it may have nothing to do with the plugs at all. Often while changing the plugs the fuel lines get messed up. The very fragile fuel lines brought to you by the finest German engineering money can buy.

Does it clear up and run well after a while? If so, do you have an incline on which you can park it overnight? If so, fill the tank and park nose low for the night. If it starts right up I think you found the problem. You may also look for small fuel leaks that would otherwise let air in. Good luck.

It does clear right up after 2-3 mins and drives fine. The electrical connector was larger so I turned it to exact size on my lathe, it is a good fit now and they are brass.
Thanks
Steve

Sounds like a dead glow plug. A bad glow plug right out of the box isn't unheard of. Check the resistance of each glow plug through the relay connector.

I measured each glow plug at the relay connector.They all measure 1.2 to 1.5 ohms on a Fluke 87. I don't see a fuel leak . There is a bubble in the clear plastic line to the fuel filter - single line on the passenger side.
Steve

The short line from the fuel thermostat (in cyl head) to teh prefilter should drain back with motor not running. That is normal. Should fill immed and not have bubbles when started.

Sounds like one GP is acting up.

Thanks. That's my sense too. Not sure how to proceed from here. Should I replace them all again? Since last replacement (2 wks ago) I bought a Klann tools glow plug reamer from Samstag so next job they'll get a good clean out..
Steve

Assuming the W124 GP is the same as the W210 I would think a connector was suspect.

I guess yours came out easy? Did you anti sieze them when they went back in?

They were brutal to get out but I used a can of penetrating oil and heavily never seezed including the bodies of the plugs but not the tips. The plugs (I think) are identical except the electrical connector tips. These were 6 mm instead of 4 mm so I turned them down on my Monarch lathe to a good snug fit.

Steve

When doing the resistance test, do a hot test as well. Glow all the plugs, then immediately take their resistance. It should be high and dropping as they're cooling off. If they're all good, then you can eliminate the glow plugs as a culprit.

Well I decided the plugs must not be the right ones. The Bosch part # was different so I redid the job with the correct plugs from Fastlane (Phil). I reamed the holes with the KLann Tools reamer and the result is problem solved. I highly recommend the reamer as it made the job easy to install the new ones. I never seezed the new ones too. The resistance was different from the first set to the correct plugs. They should be 0.8 ohms on the Fluke 87 meter.