Om642 Heater plug voltage?

[Sandgrounder007]

Hi, I've been puting this off for months now but as cooler mornings aren't far away I need help. My c320 cdi is slow starting, to much cranking, I fitted a set of Bosch heater plugs then a new (Beru) relay, then a second relay, all with no improvement. I've done a little research which revealed the heater plugs require 4.5 volts, when I check the supply at the plug cap it's exactly 2 volts, the large supply cable to the relay is 12.5v so I'm looking for answers as to where the missing 2.5v have gone, can anyone help or am I barking up the wrong tree? When I plugged one of the old plugs in, just before it timed off it was just starting to glow red but nowhere near bright red or white. When cold, the glow plug light stays on for about a minute when I drive off.
Thanks in anticipation.

 

[Wighty]

Does sound like a mystery , when my Glow plugs had one become defective , the GP light came back on for a Minuite or so after startup . So my thought is that there is something wrong with a glow plug ? (are they the correct ones ?? )
Alternatively when my GP relay needed replacing because of longer cranking then this was not indicated by the GP light staying on .
Hopefully someone else will chime in .

 

[Sandgrounder007]

Thanks for your help, I've had 2 new relays both with same result so I think it's safe to say the current one's ok but I can't understand what's going on. I know that first start of the day when the frost or ice arrives is going to req a lot of cranking, which shouldn't be needed. Maybe a few turns of the key with 30ish seconds in between will be easier on the battery?

 

[M80]

I had the same issue with the same car.
It was never a serious problem so didn't put the effort into curing it, although I had replaced the plugs and the relay.
I put it down to a lazy starter motor.
Have you checked the relay for a good connection on the return?

 

[Paul1948]

Had same problem, it was not the glow plugs or relay but 2 leaky injectors, with these replaced no further problems. Hope this helps, your local Indy will help at a good price.

 

[Cole@MBS]

There are two types of plugs and relays, there are steel and ceramic plugs, both use different relays, only EPC can tell you what you need.......

 

[star]

There are two types of plugs and relays, there are steel and ceramic plugs, both use different relays, only EPC can tell you what you need.......

Just about to post the same. :tu

 

[Sandgrounder007]

Thanks for the help, in reply to the being two types of plug, I've googled the Bosch part number and the spec ie voltage, thread size, length etc all seem OK. As to the relay, on eBay and europarts there is only one available. Sorry to appear dopy (I am) but who or what is epc?

 

[Wighty]

Thanks for the help, in reply to the being two types of plug, I've googled the Bosch part number and the spec ie voltage, thread size, length etc all seem OK. As to the relay, on eBay and europarts there is only one available. Sorry to appear dopy (I am) but who or what is epc?

I think it is something parts catalogue