Injection Pump Timing Mercedes , VW & pop tester

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Injection Pump Timing Mercedes , VW & pop tester

Postby omar » Sun May 03, 2009 10:32 am

Have you checked your timing? pop tested your injectors ? Spring is here now is the time!
good luck and have fun

The following page is a backup which was originally created by Richard Easley and Stu Ritter, all credit should be given as such. Most links on these pages are unfunctional.
Injection Pump Timing Adjustment for 617 Engines
The technical material for this FAQ (Frequently Asked Question) was provided by Jim Mahaffey of Georgia Institute of Technology (Georgia Tech) and other subscribers to the Mercedes-Benz Discussion List, was edited by Richard Easley of Baylor University, and is provided as a service to the subscribers of the Mercedes-Benz Discussion List.
After getting excellent advice on the Mercedes-Benz Discussion List regarding injection pump timing for the 617 diesel engine (turbocharged 5 cylinder), I thought that it would be helpful to write it up for the benefit of others as a "one-stop" message that incorporates everything into one post. This method of timing is ideal for the do-it-yourselfer because no tools are needed.
To receive similar quality tips as described below on a daily basis, consider subscribing to the Mercedes-Benz Discussion List, which is located at the following site:

Using the categories of mechanical ability from the Mercedes-Benz Discussion List <http>, you need to be at the level of "Medium Do-It-Yourselfer" at minimum. If you are below that level, you may want to provide these instructions for someone who is at the medium level or beyond.

Tools needed for injection pump timing
1. The procedure requires only a few do-it-yourself tools at Craftsman quality or above (we'll set the "floor" level on tools for do-it-yourselfer where Craftsman equals the minimum quality needed).
2. Floor jack and stands
3. 27 mm socket and long ratchet or breaker-length bar
4. Heavy duty prybar
5. 8 mm 1/4" drive socket with ratchet and long extension
6. 8 mm closed end wrench
7. 17 mm wrench
8. 13 mm combination wrench (See #13 below which provides an excellent tool for this particular procedure)
9. Small block of wood
10. High quality paper towels (Bounty or above)
11. An extra set of eyes to watch the #1 injection valve to determine timing
12. Your 1/2" drive ratcheting torque wrench will make an excellent long
ratchet for this job
13. If you have an Ace Hardware Store in your area, by all means buy a 13 mm Ace Professional Gear Wrench combination ratchet. This tool is open-ended at one end and has a "ratcheting" (literally) box end at the other end. It is a very well-made tool, yet it is also very slim, particularly on the box end. Smooth, high quality finish.
1. Assume cold engine
2. Remove the #1 injection line. [Don't take anything off of the injection pump except the injector pipe. If you even __think__ of removing anything else (e.g., the nuts that hold the valves to the top of the pump body), you will regret it!]
3. Jack up the front end and block it.
4. Pump the hand pump several times to build pressure.
5. With 27 mm socket and bar, turn the engine over at the crankshaft until you have gone through a compression stroke on #1 -- this will be noted by fuel coming out of the #1 open valve.
6. Roll the corner of a paper towel into a pointed end.
7. Twist and insert this into the #1 injection valve and remove all fuel.
8. Note that you'll have to repeat this 2 - 3 times to get all fuel out.
9. Turn the engine over by hand until you go through the exhaust stroke.
10. Turn the engine until you get within 40 degrees of TDC (TDC = stub on crankshaft pulley).
11. With your helper watching the injection valve closely, turn the crank as slow as possible by hand until the point where your helper first notices fuel "welling up" in the bottom of the injection valve. [It will be beneficial at this point to mark the "bottom" side of the pulley with chalk to inform you, underneath the car, that you are getting near the mark.
12. Note the degree of advance at the timing marks on the crankshaft pulley. The correct timing should be BTDC 24 degrees +/- 1 degree.
13. Advance is accomplished by swiveling the injection pump toward the engine at the top. Retard is the reverse.
14. If your timing is within one degree of 24 degrees, you are finished. If not, continue.
15. Pregnant pause. Still with me? -- then go to the next step.
16. If your timing is not within specs, you must first loosen the nuts that hold the injection pump in place. There are four, and three can be accessed topside.

17. Three of the nuts attach the IP to the engine toward the front (two topside and one below) and one is attached to a bracket at the rear (accessible topside). The Gear Wrench greatly, greatly simplifies loosening the pump.
18. The factory workshop manual illustrates the need to "bend" a 13 mm boxed end wrench 45 degrees to the left for use in adjusting the timing. You do not need to do this with the Gear Wrench. [Please note that this tool is not a toy, by the way.]
19. There are two ways to adjust the pump:
a. the Jeweler's method and
b. the Neanderthal method
Both methods yield equally good results, both have their own inherent levels of risk, but they each require significantly different amounts of time. I prefer the Neanderthal method because my risk/benefit analysis suggests that this method is less risky to me, yet more fun. I will thus describe the Neanderthal method and, in parentheses (e.g., [ ]), will describe the Jeweler's method, where applicable.
1. After loosening the four "holding" nuts, loosen (but do not remove) the remaining anti-vibration interconnections between the pipes. [Jeweler's method: remove all remaining injection pump lines.]
2. Using your judiciously-placed prybar, advance by pushing toward the engine with the injection pump. If advancing is not applicable to your timing, push from between engine and injection pump to retard. For advancing on the 123 chassis (300D), the area immediately under the steering adjusting bolt provided an excellent "prybase", with contact on the injection pump provided by the small block of wood. Please be certain that you do not put pressure on the ALDA unit on the top of the injection pump. If unsure what is meant by the ALDA unit, re-read paragraph on assumptions and discontinue process. [Jeweler's method: Same procedure, but less force is needed because of all lines removed.]
3. Please note that the movement of the injection pump with Neanderthal method is more difficult than Jeweler's method, since 4 of the lines are still attached. Why this method then, you might ask? Later, please. When moving the pump, it will seem as if the injection pump is not moving, but it is. The remaining lines are very stout and will be "springy" while adjusting -- look at them while adjusting, you'll see. Therefore, you need to hold the tension with the prybar and have someone tighten one of the front three mounting nuts for you to hold the new adjustment in place.
4. Recheck the timing, by first repeating steps 4 - 9. Readjust if necessary.
5. When the timing is complete, bend the #1 pipe so that the pipe attaches to the injector valve and injector with no force-fitting. It is critical that the line's nuts do not get cross-threaded. [Jeweler's method: rebend all remaining injection pump lines.)
6. Reattach the anti-vibration interconnections. Be careful to not overtighten them. You have now successfully completed injection pump timing for the 617 engine.
Contrasting the Neanderthal versus Jeweler's Method
Quicker, more macho, more fun, much less danger of cross-threading. Injection pipes will "set" in new found position over time.

Harder to move injection pump (4 lines remain). Potential threat of damaging injection pump (very minimal if prudent).


Easier to move pump (all lines are removed), Injection pipes are already "set" when manually bent.

Higher probability of cross-threading injection lines, less fun, messier (you have all 5 lines off spilling diesel fuel).
Please let me know if you complete this procedure successfully; it took a while to type this, and I'd appreciate knowing when each person has completed the repair! Please e-mail me at

Concluding Comments
Thanks go to Jim Mahaffey, Dan Penoff, Stu Ritter, and Bob Sanigar for their posts. Thanks particularly go to Jim Mahaffey for providing DIYers an alternative for a procedure that normally requires special tools inaccessible to most DIYers, yet still provides an accurate and methodical method of injection pump timing.

It should be noted that the Neanderthal method should not be associated with Jim Mahaffey in any way. For those of you who don't know, Jim is a "closet" "jeweler" -- having studied and repaired hundreds of Mercedes-Benz clocks and other electrical and electronic components over the years. As such, the Neanderthal method is a "technique" that any self-respecting "jeweler," even "closet" would probably find reprehensible. However, to paraphrase someone who shall remain nameless: . . . it (the Neanderthal method) is really the educated application of real brute force.

Back to Jim Mahaffey: I don't think that it's a stretch to say that he is probably one of the most knowledgeable individuals in the world regarding Mercedes-Benz clocks.
Jim's presentation at StarTech97 was a real treat for anyone in the audience.
For more Mercedes-Benz links, please go to the following site:
Mercedes-Benz Discussion List Home Page (
To receive similar quality tips as described above on a daily basis, consider subscribing to the Mercedes-Benz Discussion List, which is located at the following site:

DIY pop tester ... #860105721

Ok for you VW folks I found this at this link

here is something on timing a VW

Checking timing
Take out the plug (bolt) in the middle of the four delivery valves.
Insert dial gauge in hole. There's a special VW tool ($30) to hold it in place, but other solutions work also.
Turn engine against normal rotation until dial gauge stops moving (flat spot).
Turn engine forward to the TDC mark.
Read dial gauge.
The value you should see differs for different eingines and pumps. For the 1.9l TD AAZ engine its: .75 - .85mm Checking, .80 Setting.



> Anybody ever figure out what RB meant by "zero the dial gauge w/ a
> 1mm preload" - if you do, there's no way you'll even get close...

What they mean is, set the engine to TDC, and insert the dial gauge into
the pump. Continue to push the gauge in until it reads about 2 mm. Lock
the gauge in place, then rotate the dial face so the pointer is at zero.
You must have a gauge that has about 5 mm of travel, and reads to 0.01 mm.
These are not cheap, nor easy to find. (But neither is a dealer who will
take the time to do the job really well.)

The reason for the preload on the gauge is to ensure that the gauge contacts
the pump plunger continuously while you are moving the engine around.
Otherwise you will not be able to locate the start of injection point
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