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300GD Fuel tank....biting the $2,000 bullet?

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Flanker525
Posts: 1519

Re: 300GD Fuel tank....biting the $2,000 bullet?

Post#31 » Wed Oct 23, 2013 11:34 am

Ok sitrep......

Getting pretty damn frustrated. Just to recap, my indy supposedly tested all my injectors and said all but one injectors sprayed fine and this one was replaced. I noted that after this work the truck became a bit more difficult to start when it had sat for a few days.

As previously mentioned I ordered a spare IP and injectors off of a Euro 300D. I also got the Mercedes-source pop tester and new monarch nozzles for good measure. I did all of this thinking that my truck had turbo injectors not realizing until today that it does indeed have the right injectors. (Like an idiot I didn't realize that the pressures are stamped on the side) However in an ironic twist, the injectors that came off the 300D WERE turbo injectors so this sort of thing definitely can happen. (The pop testing confirmed this) I wanted to extra set so I could A. Have a few around to play with and B. Just be able to open them up, replace the nozzles, clean and then have a set ready for installation. Technically I could still do this but now i'm wondering if the injectors are even the damn problem.


However now i'm wondering if my indy installed new crush washers or not.... i've read that my problems can be tied to this. (Calling him later today....)

Also I will answer a stupid question in advance. No I have not done a compression test. The truck has always started perfectly on the first shot every time so I have never had any reason to think that the compression is bad.

G Nome
Posts: 7766

Re: 300GD Fuel tank....biting the $2,000 bullet?

Post#32 » Wed Oct 23, 2013 12:24 pm

I did not read through all the old posts but...have you replaced the glow plugs? It can make for challenging starts as it gets cold out.

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Flanker525
Posts: 1519

Re: 300GD Fuel tank....biting the $2,000 bullet?

Post#33 » Wed Oct 23, 2013 12:30 pm

G Nome wrote:I did not read through all the old posts but...have you replaced the glow plugs? It can make for challenging starts as it gets cold out.


Sorry, this is a loss of power issue.

The harder starting is related to a low idle. (should have specified)

Just did a pop test on 5 injectors

1. 1650 psi (New injector)
2. 1640 psi
3. 1600 psi
4. 1640
5. 1700 psi but it sprays inconsistently

Also I now have number 1 and number 5 heat shield stuck....

G Nome
Posts: 7766

Re: 300GD Fuel tank....biting the $2,000 bullet?

Post#34 » Wed Oct 23, 2013 12:34 pm

Fuck...

Sorry.

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Flanker525
Posts: 1519

Re: Power Loss

Post#35 » Wed Oct 23, 2013 4:37 pm

Ok new monarch nozzles are installed on all 5 injectors and they are balanced as well (I got just around 1700 psi on 4 and around 1650 on another) I had to leave #5 crush washer in as I went through complete torture removing #1 :evil: (In the end I had no choice but to chisel it out) I hated to do it like that but nothing else worked. Tomorrow when the engine is warmed up again i'm going to try and remove #5 one last time.

Results? inconclusive :( There is a bit more pep and reaction but nothing significant. One thing for sure is that she is idling a lot better (Less vibration, engine no longer shakes) So at the very least i've eliminated another area of potential problems and made her just that little bit better. I have yet to find the core of the issue and for the rest of 2013 until the spring of 2014 i'm throwing in the towel. The truck runs just fine and it moves along once I build up speed. It's just those long steep gradients that give me trouble. I'm afraid that I might just have to do a compression test even though I lack the signs other then loss of power. (If the compression is bad i'll drive her till the engine explodes and throw in a turbo motor)

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inkblotz
Posts: 8202

Re: 300GD Fuel tank....biting the $2,000 bullet?

Post#36 » Thu Oct 24, 2013 2:07 am

Can you post a pic of your engine compartment and close ups of its various components? IP area, injector area, Fuel in and out area.

Thanks
Mark

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Chris
Posts: 4549

Re: 300GD Fuel tank....biting the $2,000 bullet?

Post#37 » Thu Oct 24, 2013 8:16 am

Food for thought:
Injection pump timing plays a massive role in engine power, cold start-ability, idle smoothness and tailpipe emissions (grey smoke).

Possible causes for incorrect IP timing are:
-Stretched/old timing chain.
-Someone removed/replaced IP incorrectly.


As it happens, the last 2 G turbodiesel swaps I have done both had freshly "rebuilt" motors supplied by the customer, both had the IP off of the engine block for one reason or the other, and both had the IP incorrectly installed (advanced/retarded 1-2 teeth).

Any motor showing signs of having the IP removed has a huge likelihood of no longer being at factory IP timing specs (hard starting, smokey, shaky and slow).

Do you have any signs that your IP has ever been off of the cylinder head?
Visible from the top (near fuel filter) there are factory hash marks near the IP mounting flange (half on cyl head, half on IP), they should line up with each other.

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Flanker525
Posts: 1519

Re: 300GD Fuel tank....biting the $2,000 bullet?

Post#38 » Fri Oct 25, 2013 8:20 pm

Chris,

I haven't checked to see if my IP has ever been played with but you might be onto something so I will check on those markings later this week.

On a related note I was a bit quick to jump to the conclusion that the monarch nozzles didn't make a difference, they did, just not in the brtue force department. I took the truck to work today (30 miles of varied terrain) and what I did notice is that the engine now revs much more readily then before. Before I would shift into 4th right around 40 mph, on the ride today I could hold all gears for much longer then normal. (When Dude first drove my G I noticed out of habit he revved 1st gear very high because he was expecting more :oops: ) Right now i'm just happy that my efforts up until now have been producing some results.

User avatar
Flanker525
Posts: 1519

Re: 300GD Fuel tank....biting the $2,000 bullet?

Post#39 » Thu Apr 14, 2016 5:03 pm

Long time since an update on my power loss but i've been unbelievable busy with the new house.

I have made some improvements since my last post but nothing "amazing" has thus happened.

1. Brand new plastic fuel tank, sending unit and fuel lines. No real change in performance
2. I had the injection pump replaced with a spare unit that I had. There was an improvement in how the engine revved (Much more freely above 40mph)
3. It turned out that someone at some point had installed part of the throttle linkage backwards. I could get full stop on the IP but there was still play in the lines. Now the pedal is much tighter and I actually have a bit of "reserve" in the throttle

Now, seeing pictures like the one below.I decided to pull my intake off and check to see what was going on inside. (Lack of air could of course answer a lot of questions)
http://users.zhonka.net/zeitgeist/MB%20 ... 0valve.JPG

Annoyingly, this is what I found....nothing.

http://imgur.com/a/Fh2MU

I was really hoping to have found the issues source but alas my fight will continue. I'm still going to be leaving the intake to soak in a cleaner overnight to remove as much gunk as possible. I still have to get the exhaust manifold off but I ran into a snag (The underside on the flange is filled with excess weld metal so I can't hold the bottom nut alone and I don't know when I can get someone to help me) I was thinking about just leaving it but I have a new gasket to install and I want to check the 1 in 100,000 chance that there is a clog in the exhaust.

I might be coming down to throwing in the towel on this engine. The only 2 things left that I could think of are either a new timing chain or an IP rebuild (I MIGHT be able to do the first job but certainly not the 2nd) Worse comes to worse I do have a complete 617NA engine from Vadim which I could always swap in....once I find an engine hoist.
Location: NW Connecticut

2015 ML250
1991 350SDL
Formerly (1982 300GD Cabrio)

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vadimivanovich
Posts: 8643

Re: 300GD Fuel tank....biting the $2,000 bullet?

Post#40 » Thu Apr 14, 2016 7:15 pm

Flanker, do some research about timing chain stretch measurement, injection pump timing, and valve adjustment. These have to be nailed before you can hope for better results.
"The way you think is the way you live"

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