Order of fuel/injection performance work? - PeachParts Mercedes-Benz Forum

djburt · #1 07-06-2012, 03:34 PM

I bought my W116 '80 300SD Turbo Diesel about a month ago, drove it two hours home with no significant problem, and have been tinkering (rather, learning) on it ever since. I'm brand new to Mercedes, but am loving this car. It had set up for over a year, covered, then was traded for work to a mechanic, who sold it to me after replacing the battery, A/C compressor to an R34, and tires.

So far, related to the engine, I've changed the oil, replaced the fuel filters, upgraded the primer pump to the new black Bosch one, replaced the leaking return injector lines, used some Howes fuel additive for two tanks, replaced the broken air cleaner bracket and mounts, replaced a hose clamp on the turbo intake, and cleaned the air filter.

It's still got a fairly tough start and pretty rough idle, some white smoke out the tailpipe especially on starting, doesn't have the power that it should (I'm told) especially in first gear, and since it's at about 220,000 (odometer just stopped working as I expected it eventually would), I figured I'd replace the injectors or injector nozzles. I went with the nozzles only, since I couldn't afford all new injectors and wasn't sure I had the knowledge to clean the old nozzles. Went with the Monark nozzles at mercedes source (just stocked today, I've been waiting) since I do plan on using biodiesel in the future. I plan to pull injectors out next week and switch to these new nozzles and see what happens.

Now, I've read that my rough idle / power issue can be a number of things - bad injectors, needs valve adjustment, faulty injection pump, etc. I haven't had a valve adjustment or compression test yet, and didn't really plan on it before I did these nozzles. I also didn't run a diesel purge before I changed my fuel filters.

Should I wait to change the nozzles until I can take it in for a valve adjustment? Compression test? Should I still do the diesel purge even though I already changed the fuel filters? If so, should I change the filters again? Lastly, I don't have the space to store a pop tester...am I being naive to hope that they're calibrated close enough to install without additional testing, and if so what is the vital order of work for me/someone to do at this point?

Thanks in advance!

Diesel911 · #2 07-06-2012, 03:54 PM

Quote:

Originally Posted by djburt

I bought my W116 '80 300SD Turbo Diesel about a month ago, drove it two hours home with no significant problem, and have been tinkering (rather, learning) on it ever since. I'm brand new to Mercedes, but am loving this car. It had set up for over a year, covered, then was traded for work to a mechanic, who sold it to me after replacing the battery, A/C compressor to an R34, and tires.

So far, related to the engine, I've changed the oil, replaced the fuel filters, upgraded the primer pump to the new black Bosch one, replaced the leaking return injector lines, used some Howes fuel additive for two tanks, replaced the broken air cleaner bracket and mounts, replaced a hose clamp on the turbo intake, and cleaned the air filter.

It's still got a fairly tough start and pretty rough idle, some white smoke out the tailpipe especially on starting, doesn't have the power that it should (I'm told) especially in first gear, and since it's at about 220,000 (odometer just stopped working as I expected it eventually would), I figured I'd replace the injectors or injector nozzles. I went with the nozzles only, since I couldn't afford all new injectors and wasn't sure I had the knowledge to clean the old nozzles. Went with the Monark nozzles at mercedes source (just stocked today, I've been waiting) since I do plan on using biodiesel in the future. I plan to pull injectors out next week and switch to these new nozzles and see what happens.

Now, I've read that my rough idle / power issue can be a number of things - bad injectors, needs valve adjustment, faulty injection pump, etc. I haven't had a valve adjustment or compression test yet, and didn't really plan on it before I did these nozzles. I also didn't run a diesel purge before I changed my fuel filters.

Should I wait to change the nozzles until I can take it in for a valve adjustment? Compression test? Should I still do the diesel purge even though I already changed the fuel filters? If so, should I change the filters again? Lastly, I don't have the space to store a pop tester...am I being naive to hope that they're calibrated close enough to install without additional testing, and if so what is the vital order of work for me/someone to do at this point?

Thanks in advance!

Any time is a good time to adjust the Valves no need to wait and it is cheap to do.
If the Valves have not been adjusted for a long time after the Adjustment and you drive the Car around it is likely the Compression will go up a little and some have said to re-check the Valve adjustment. The reason is the deposits that were on the Valve get beaten and rubbed off due in part to the Valve Rotators; they sort or re-seat themselves.

When the Injectors are out is a good time to do the Compression Test; but, there is a Glow Plug Adapter but I haver read the 90 degree one is prone to breakage.

When you re-insall the Injectors new Heat Shields.

Just swapping the Nozzles might or might not help. After swapping Nozzles some have experienced leaks between the Upper and Lower parts of the Injector. This is due to dirt getting between the surfaces or from not lapping the precision surfaces.

What ever you do keep the 2 pieces of the Injector Nozzle with that Nozzle as they are mated together. It is also a good idea to work with only one Injector at a time so none of those parts get mixed either.

There should be plenty of info on what you plan to do in the links below.

DIY Repair Links
http://www.peachparts.com/shopforum/forumdisplay.php?f=82

http://www.peachparts.com/Wikka/DoItYourSelf

Diesel911 · #3 07-06-2012, 08:54 PM

I fogot to comment on something. When I first got my Car it was scary slow building up speed even when I put my Root into it.
Once moving it drove normal.
It turned out that Linkages to my Throttle were really Sloppy. I tightend some of them up and the Car worked as it is supposed to.
Also the Bell Crank on the Fire Wall that that is between the Pedal Linkage and the Throttle Linkage can wear out.

You need to consult the Factory Service Manual but each of the Linkage Rods has a specific length.

charmalu · #4 07-07-2012, 12:15 AM

80 SD is the first year with the EGR. So with the blow by oil fumes and the soot the egr dump into the manifold, it creates this sticky thick black tar like stuff. At the rear of the intake manifold (IM) there is a plastic boost line. remove the banjo bolt (12mm), it about 1 1/2 in long and hollow. If it gets plugged up, then there is no boost pressure signal to the ALDA (square thing on Injection pump (IP). If the ALDA doesn`t get the boost pressure from the IM, then the engine doesn`t get the full amount of fuel it needs.

Valve adjustments are pretty simple to do, just need 2 14mm wrenches that have a bend to them to clear the fuel injection lines. remove the fuel lines and then straight wrenches will work.

The MB wrenches are around $100, sometimes you can find used ones for a good price. taking the car to a shop one time will be the cost for a set of the wrenches. or do a search on valve adjusting wrenches, there are guys that have made their own.

Here is a link to valve adjustments etc....

Valve adjustment OM615, 616, 617 FYI.

Charlie

gastropodus · #5 07-07-2012, 01:29 AM

I'm no expert, and perhaps this will provoke a real expert to jump in on the discussion, but I think that just changing the nozzles without doing the pop test adjustments is going to lead to grief. What you're relying on when you do a swap like that is that the dimensions of the old and new parts are so similar that the pop pressure is going to stay consistent. First of all, most old assemblies probably aren't going to have consistent pop pressure across the board to start with due to wear, so at the very best you're going to perpetuate a non-optimum situation. At worst, and considerably more likely, you're going to end up with an injection system that runs rougher and less efficiently.

My .02.

Kurt

djburt · #6 07-09-2012, 10:59 AM

Thanks for everyone's replies.

I've read quite a bit more about valve adjustments, and though it sounds a little scary for a newbie to get inside the engine like that, it does seem like I should do that as well. I have a lot of reading to do before I'm ready to try that. I've also read quite a bit about the wrenches needed for the valve adjustment...I think I read that if I'm removing the injection assembly as well that I can use straight wrenches.

If that's correct, should I just do this all at once to make it easier? Or is it better to do the valve adjustment first, see how it's running, then do the injector rebuilds? It seems it might be better diagnostically to do it one at a time...

Lastly, as I don't have the money time or space to get into the pop testing right now, any idea what kind of a specialty shop could do that for me? The two mercedes shops I've called don't even do pop testing, they just replace the whole injector.

djburt · #7 07-09-2012, 12:14 PM

Quote:

Originally Posted by charmalu

80 SD is the first year with the EGR. So with the blow by oil fumes and the soot the egr dump into the manifold, it creates this sticky thick black tar like stuff. At the rear of the intake manifold (IM) there is a plastic boost line. remove the banjo bolt (12mm), it about 1 1/2 in long and hollow. If it gets plugged up, then there is no boost pressure signal to the ALDA (square thing on Injection pump (IP). If the ALDA doesn`t get the boost pressure from the IM, then the engine doesn`t get the full amount of fuel it needs.

I checked that banjo bolt, and it's completely clear. But this did lead me to read up on the ALDA and find all the proponents of removing it entirely / replacing it / etc. I'll be interested to see how much improvement in power I get after the valve adjustment / new injector nozzles. If it's still as sluggish as it is, I may consider replacing or removing that next.

djburt · #8 07-09-2012, 04:11 PM

Quote:

Originally Posted by Diesel911

I fogot to comment on something. When I first got my Car it was scary slow building up speed even when I put my Root into it.
Once moving it drove normal.
It turned out that Linkages to my Throttle were really Sloppy. I tightend some of them up and the Car worked as it is supposed to.
Also the Bell Crank on the Fire Wall that that is between the Pedal Linkage and the Throttle Linkage can wear out.

You need to consult the Factory Service Manual but each of the Linkage Rods has a specific length.

Hmm, I can't seem to find a good thread on adjusting the throttle linkages...or at least not for my 116. Anyone have any tips (or know of a good thread?)?

Shortsguy1 · #9 07-09-2012, 05:29 PM

This listing on ebay for valve adjustment wrenches is a VERY good buy, assuming the price stays about where it is right now.

Mercedes Benz Diesel Valve Adjusting Wrench Set | eBay

The individual valve wrenches sell for ~$35, and the third wrench (which some consider optional) is often way more than that. So if you can get all three for around $60, I would jump on it.

47dodge · #10 07-09-2012, 06:18 PM

Look for truck shops that will pop test the injectors,and or rebuild them. Might be better for it to be a diesel injection shop.

For now I would get the valves first, compresion test next, I like to know what the fuel pressure is, and also boost pressure. Once you have numbers then you have a better chance of seeing where the problem is.

djburt · #11 07-09-2012, 08:43 PM

Quote:

Originally Posted by Shortsguy1

This listing on ebay for valve adjustment wrenches is a VERY good buy, assuming the price stays about where it is right now.

Mercedes Benz Diesel Valve Adjusting Wrench Set | eBay

The individual valve wrenches sell for ~$35, and the third wrench (which some consider optional) is often way more than that. So if you can get all three for around $60, I would jump on it.

I saw that...but assuming you're supposed to change the valve cover gasket when you do a valve adjustment, it seems less expensive to get the set at diesel giant with the gasket for 86 bucks...or throw in the DVD too for 96.

What's that third "optional" wrench for anyway?

Shortsguy1 · #12 07-09-2012, 09:17 PM

With all due respects to our hosts at Fastlane, I found the best price for my valve cover gasket (68 220D, w115) was via my MB dealer. It was about half price of everywhere else I looked (less than $10). Strange that Genuine could cost less than aftermarket, but I guess it is bound to happen on occasion.

The third wrench somehow holds the spring from rotating (I think). I just got my first set of wrenches and haven't used them yet (a newbie). So someone else will have to chime in regarding usage of the third wrench. I do know that some have suggested in earlier threads that it is rare that you need the third wrench. Some use a screwdriver jammed in to achieve the same goal, but others strongly recommended against the screwdriver approach. Good luck.

ROLLGUY · #13 07-10-2012, 12:54 AM

Quote:

Originally Posted by Shortsguy1

The third wrench somehow holds the spring from rotating (I think). I just got my first set of wrenches and haven't used them yet (a newbie). So someone else will have to chime in regarding usage of the third wrench. I do know that some have suggested in earlier threads that it is rare that you need the third wrench. Some use a screwdriver jammed in to achieve the same goal, but others strongly recommended against the screwdriver approach. Good luck.

I only had the need for the third wrench once, but I just wedged one of my wrenches between the valve spring next to it. It worked just fine. I see no real need for the third (large) wrench. Also, I just bent one wrench (the lower [thin] wrench). I just use a long 14mm (un-bent) wrench for the top nut.

djburt · #14 07-10-2012, 09:18 AM

Piecing together your advice from this thread along with occasional wisdom from others...here's my plan.

ALDA removal (just to test and see what happens to low speed power) and reinstall.
Valve adjustment (soon as I get wrenches)
Diesel purge
Change fuel filters (again...I hate to do this cause I just changed them a month ago, but it seems like most recommend you change the filter after a purge, and it seems like most recommend you purge before changing out nozzles)
Compression test
Rebuild / pop test (hopefully can find diesel shop to do it) injectors with new nozzles and reinstall
Drive a smoother, easier starting, more powerful car. I hope.

Does this sound reasonable? Thanks again to everyone for your advice!

Diesel911 · #15 07-10-2012, 11:00 AM

Quote:

Originally Posted by Shortsguy1

With all due respects to our hosts at Fastlane, I found the best price for my valve cover gasket (68 220D, w115) was via my MB dealer. It was about half price of everywhere else I looked (less than $10). Strange that Genuine could cost less than aftermarket, but I guess it is bound to happen on occasion.

The third wrench somehow holds the spring from rotating (I think). I just got my first set of wrenches and haven't used them yet (a newbie). So someone else will have to chime in regarding usage of the third wrench. I do know that some have suggested in earlier threads that it is rare that you need the third wrench. Some use a screwdriver jammed in to achieve the same goal, but others strongly recommended against the screwdriver approach. Good luck.

Once you use the third Wrench to loosen the Nuts it seems like you don't need it any more (I had one Nut that was stuck).

However, if you buy a set of Hazet Valve Wrenches the complete set sells better if you ever have to sell them.

My original reason for buying a Hazet Valve Wrench set was that If I had the right Tools I was more likely to actually get out there and do the Valve adjustment when it needs to be done.

Since then I have acquired a set of Heyco Valve Wrenches and have even bent My own Wrenches (made from Tappet Wrenches, no welded Pipe on them). (Tool Junkie.)

If you make or buy a set of Valve Wrenches there is a clear benefit to you Car and Wallet.