HELP! Hard starting 87 300TD - PeachParts Mercedes-Benz Forum

KansasDiesel · #1 11-01-2005, 08:16 AM

I need some advice and soon, My 87 300TD has been starting right up , about a month ago when nightly temps were getting low the glow plug lamp stopped working, then it started to have a problem getting started in the morning, Temps were getting 40*F and sometimes in the 30's I started plugging it in and it would start right up, let it sit at work with temps getting mid 60's and it would take so much cranking to get it started even after cycling the relay four times.

I have taken a test lamp to each glow plug ( all were replaced last march ) and they had power to them, looked at the fuseable link in the relay and it was good and had power.

Please where do I go from here? Why did the glow plug lamp stop working if all the glow plugs have power going thru them? Is the relay bad? I can hear it cycle and there is power to it. Why will it not start in the 60* weather after work? when It was before?

I need help before I put another brand new starter in it. THis problem I had last Spring and the shop put in all new glow plugs, and it still had a little dificulty starting but it also was getting warmer out,

nevremj · #2 11-01-2005, 10:02 AM

I had this experience:
87 300D wouldn't start. Temp was not a factor.
I disconnected the EGR vacuum line, and it started OK. WHY? I don't know. I now have EGR line disconected and plugged.

Brian Carlton · #3 11-01-2005, 10:06 AM

One, or more than one glow plug is not functioning. Check all glow plugs via the plug at the relay for resistance. Use an accurate ohmmeter. The plugs should be less than 1.2 ohms. Replace any plugs that are above 1.2 ohms or are open (infinite resistance).

Maybe that shop didn't put in all new glow plugs, or they used some crappy Autolite plugs.

It's a bit of a project to get to those plugs with the manfold in place, but, with a good set of extensions, it can be done.

samiam4 · #4 11-01-2005, 10:07 AM

You need to measure the resistance of the glow plugs...

If the resistance gets high, the power and heat the combustion chamber sees is greatly reduced.

Since your plugs are new, you should be 0.6-0.7 ohms @70F measured from the glowplug relay harness.

Michael

KansasDiesel · #5 11-01-2005, 11:12 AM

Quote:

Originally Posted by Brian Carlton

One, or more than one glow plug is not functioning. Check all glow plugs via the plug at the relay for resistance. Use an accurate ohmmeter. The plugs should be less than 1.2 ohms. Replace any plugs that are above 1.2 ohms or are open (infinite resistance).

Maybe that shop didn't put in all new glow plugs, or they used some crappy Autolite plugs.

It's a bit of a project to get to those plugs with the manfold in place, but, with a good set of extensions, it can be done.

They probably are the autolite plugs, what is suggested? for replacement?
I will get my meter out again and check the resistance from the relay.

Brian Carlton · #6 11-01-2005, 11:33 AM

Quote:

Originally Posted by KansasDiesel

They probably are the autolite plugs, what is suggested? for replacement?
I will get my meter out again and check the resistance from the relay.

How did I know??

Get yourself some Bosch or Beru plugs. They might even last you a few years.

samiam4 · #7 11-01-2005, 12:38 PM

Always liked Beru gps...

KansasDiesel · #8 11-01-2005, 03:02 PM

Quote:

Originally Posted by samiam4

Always liked Beru gps...

Ok I can find Bosch around here but what ar e Beru and were can I price them at?

samiam4 · #9 11-01-2005, 04:10 PM

Bosch are fine too..

I always found them the cheapest at the dealership-
Beru is just another supplier.

Michael

sailor15015 · #10 11-01-2005, 05:06 PM

Just replaced mine since its getting cold out. Beru are what came out and they all lit fine when jumped to the battery. I don't know how long they'd been in there. I put Bosch in because that's the only brand I've heard good remarks about. Glad to know Beru is a good brand too.

dieseldiehard · #11 11-01-2005, 05:45 PM

Quote:

Originally Posted by sailor15015

Just replaced mine since its getting cold out. Beru are what came out and they all lit fine when jumped to the battery. I don't know how long they'd been in there. I put Bosch in because that's the only brand I've heard good remarks about. Glad to know Beru is a good brand too.

Beru: http://www.beru.com/english/produkte/gluehkerzen/dreiphasen.php

Someone in the Forum touted Beru as being better than Bosch, I'll use either or but certainly not Champion, the WORST make of sparkplugs or glowplugs.

barry123400 · #12 11-01-2005, 10:16 PM

Never wanted to use champions as figured they were garbage. Got some free and they have been ok since installed in my vw two years ago. Kind of surprised me. Would never consider buying them normally though. Perhaps depending on type of plug they use different suppling manufactures?

nckmsn · #13 11-01-2005, 10:47 PM

are you sure you are running all of the wvo out of your fuel lines and filter? if not, this could contribute to a hard start.

KansasDiesel · #14 11-02-2005, 08:27 AM

Quote:

Originally Posted by nckmsn

are you sure you are running all of the wvo out of your fuel lines and filter? if not, this could contribute to a hard start.

Oh yes, I been running WVO for a year now, over 13000 mile, I do have the purge thing down.

Actually I got to check the GP's as stated in this post, found 4 GP's with very high resistence and 2 normal. Needless to say they are autolites and they didn't last but 7 months, I have a set of Bosch that will be here today.

Thanks Guys

lietuviai · #15 11-02-2005, 03:30 PM

Save yourself the headache and pull the manifold to change them. I tried to change them on my '87 w/o pulling the manifold and I broke 2 universal joints. Nearly impossible plus you can strip the threads in the head when trying to thread the GP's back in. Pulling the manifolds actually will save you time and end up only costing about $25 more for the needed gaskets.