98 300D Turbodiesel misfire on cold startup

[Kajtek1]

Originally Posted by spmarfatia

Also, there recent thread in W210 forum here that is confusing me, says some mishandled manifold gasket is causing vacuum loss. Can't image how this could be related...did not know of vacuum inside the intake manifold....could be a gas engine thing...

Thanks,
Sam

Vacuum in the intake is NA engines thing. With turbo you always have a pressure there.
Still bad gasket will loose the pressure and trigger a code.
What is your problem in taking the windshield washer reservoir out and see if you can reach the plug?

[sokoloff]

The vacuum leak issue was a gasoline car.

Excellent write up on the procedure here - Finally - Step By Step Glowplug Change - '98-'99 E300! - PeachParts Mercedes ShopForum

I say take the manifold off and do it that way. Replace the manifold gasket too. You have much better access to the plugs and lessen the chance of breaking off a plug or cross threading something trying to do some of it by feel. Also I highly recommend you do the job on a hot engine, ream the holes with the proper reamer and slather the new plug with anti-seize. Make sure you also use a Bosch or a Beru plug.

[Kajtek1]

Yeah. Too bad this forum is diesel unfriendly and we have to go to competition.
The older diesels do like to generate heavy intake build ups what is good reason to take the manifold out and clean it.
I never had to take the manifold out on W210, but than our 2 have only +- 250,000 miles each.

[spmarfatia]

I am prepared to take the intake manifold off.

How about unbolting the intake from above the EGR module. Intake and EGR module are connected via 4 bolts and a gasket.

In the discussion of the thread that follows here, Finally - Step By Step Glowplug Change - '98-'99 E300! - PeachParts Mercedes ShopForum, there is a person that has done it by unbolting the intake from above EGR module, and not from intercooler joint. He didn't say it was piece of cake that way but at least it can be done.

Wanted to see if there are any obvious troubles that I will run into. If above the EGR works, i wouldn't have to disconnect the vacuum lines and reach some bolts from under the car etc.

Sam

[sokoloff]

You seem really intent on taking the manifold off from above. I've never done it that way, so I can't comment other than to say I've taken the manifold off by unbolting the one bolt from below, done it multiple times and it isn't that hard. The two vacuum lines you have to disconnect just pull right off and push right on. I will continue to do mine from below.

[spmarfatia]

Well,

for one, reaching underneath the car, and above from there, seems to be a little bit of a challenge in my garage with no lift and I don't have long extensions to reach

Second, just looking at the manifold, it clicks to me be the more natural way to do those 4 bolts...movements only affect the manifold etc....

Only afraid, when it seems easy, there is a catch...so wanted to see if there are any gotcha to look for...

But reaching from bottom, as you said, it perfectly doable and will go that route as soon as I see any issues with those 4 bolts.

Also, curious, Glow Plugs breaking seems to happen often. What usually breaks? The GP body after threads, the carbon tip?

Thanks for help guys...

[Kajtek1]

I replaced head gasket a month ago on 603 engine and proved myself again, that there are always several ways to do a job even on job as standard as head pulling.
I had all WIS available, but those wanted me to take 1/2 engine into small parts, what did not make sense.
Than sometimes life dictate different ways of doing the work. I had a problem with manifold nuts on the pipe end, where there was no space for bigger wrenches.
I have 5 sets of metric wrenches and finally got the nut using 13mm. 1/4" drive socket. A bit scary put big torque on small ratchet, but my nuts did not have corrosion and I could remove them with fingers after loosening.
I hope you have another car, as you might run into small problems that will stop you.
Mental preparedness is important. When you have a problem, don't put sledgehammer on it. Wash up, have a cold one, or lunch, sleep on it, come back to the forum and go back with patience after thinking over next step.

[sokoloff]

Yes, and holler out if you run into issues. No matter what method you use, I can't emphasize enough to DO IT ON A HOT ENGINE. Keep us posted and let us know how it all goes.

Good luck.

[spmarfatia]

Placing online order for glow plug and intake gasket. Only one bad plug, so in no hurry.

will update the thread as I start the work.

[carl6405]

Hey guys, I realize that you have already replaced your bad glow plug.
I just replaced one of my bad GPs today and I want to share this easy method for finding out which one is bad.

Also, when I get time, I will do pics and maybe a video. But for now, please forgive my bad job at using paintshop to draw my diagram. But here it is.




Basically, You unplug your large connector at the glow plug relay. Using an ohm meter. With an alligator clipped jumper wire. Connect a jumper wire to a ground. I used the metal screw holding down the GP relay to the fender.
Then take your other ohm meter probe and touch each connector in the gp relay boot, looking for an open.
I had one open connection. So, I traced the wires to each glow plug, finding which wire went to which glow plug.
In my case, glow plug number 4 was bad.

Im sure there is a better diagram out there somewhere on the internet. But. I made my own..
Hopefully, you will find it easy to track down your bad GP with this diagram.