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  #16  
Old 06-08-2006, 06:15 PM
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300cd, come on over to our thread. Timing injection pumps with milli volt method. You might be interested. Perhaps good for a laugh. Lots of potential applications. Almost unlimited in some ways. We are just getting started. Talk about stooping to unethical means to steal participants.

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  #17  
Old 06-09-2006, 12:31 PM
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Guide/Interpreter needed

OK, so before I get started I am on the low end of the curve when it comes to electronics...but here she goes


I have a digital multimeter and attempted to test the millivolts through the glow plug harness. I set the gague on the 2000m setting within the DCV section...Clylinder 1: -005 Cyl 2: -014 Cyl 3: -005 Cyl 4: -015 Cyl 5 -006


OK, so am I way of base in my test? If not, what does this mean? As the car idled a consistent plume of white smoke came from the exhaust.

I changed the fuel lines to and from the tank. No significant change.

I am leaning toward injectors, but would love some help here.


Thanks
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  #18  
Old 06-09-2006, 12:53 PM
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Danok, the rack damper pin is on the back side of the IP toward the bottom. The correct way to adjust it is to unscrew it (first loosen the lock nut) with engine warm and idling until the engine starts to shake, then screw it back in a little bit just enough to stop the engine from shaking and tighten it right there. But this may not be your problem. I'd try some Diesel Purge or a good fuel additive first, like a whole bottle of Redline DFC. Also, have the valves ever been adjusted? What's your idle at? Does it have a rough idle only when cold or all the time? More information would certainly help in the diagnosis.
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  #19  
Old 06-09-2006, 01:27 PM
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reply

Idle is rough all the time warm or cold. It is idling about 6,000-6,500 rpm.

Valves were adjusted in the last year by a MB mechanic.
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  #20  
Old 06-09-2006, 01:32 PM
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A knowledge of electronics is not required really. Would you check your meter to make sure you were measuring milli volts and not milli amps. Usually the milli volt scale is 200-300 milli volts.. Most digital meters have a 2000 milli amp scale. Using milli amps will give you readings as well but they are not useful. You might have been measuring milli amps. All meters do not have a milli volt scale. I will try to check your thread at frequent intervals. Let us know. What you should have read is probably 4 glow plugs with a simular voltage and perhaps one extremely different. Then you would have looked further into why that cylinder was different. A good start would have been to trade the position of two injectors and see if the problem moved. Then you would have known your fault. Your readings are so erratic on that engine about the only thing that could cause them would be a mixed glow plug set with unusual output or perhaps a partially starving injection pump. Far more likely is the use of the wrong scale on your meter. If those readings were true I would almost suspect the engine could not run to give them to you. Example of expected readings. 10.5 mv 9.8 mv 10.1 mv etc. There would be a decimal in the readings on your meter just before the last didgit. If your meter does not have the right scale try to borrow one perhaps from a friend. It gets easier with experience and you might as well master it now as it is the best thing in sight for us over the long haul. Good try by the way it shows an open mind. Just wrong scale perhaps.
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  #21  
Old 06-09-2006, 02:07 PM
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I am not understanding the novella you've started over there. I've never adjusted the IP timing (I've only had the car for a year), but I understand the basics of adjusting it, sort of. To advance, the whole IP goes toward the engine, to retard, you pull it away.

Are you adjusting one injector at a time, or what or what is going on? I am totally lost here. You're measuring the heat in one cylinder compared to another, then adjusting them all? How do they get more uniform if they are all being adjusted together? How do you know what you want to achieve?

I think what I need is a step-by-step DIY guide that tells exactly what to do and why. At this point, I think it would be better to pay the $250 to have it done than the $500 to have it fixed.
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  #22  
Old 06-09-2006, 03:07 PM
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On this thread all the information sought is what cylinder is abnormal if any. The findings do not mean you adjust anything. All we are looking for is the abnormal cylinder. An extremely different voltage from any cylinder indicates it is not operating properly like the rest. Hopefully caused by a bad injector for example. No adjustments expected or required. Once the cylinder is located changing injectors with an adjacent cylinder and the milli volt readings moving there as well would tell you that you have a bad injector. If the voltage remained the same after switching injectors next might be a compression check of that cylinder for example. But first you have to locate the cylinder with the expected lower voltage if any. This is the simplest application of this method. Yes there will be an operation manual at some stage. We are just getting into this approach. For what it's worth the voltage is indicating the heat being created in each individual cylinder. If you get an unusual voltage their will be a reason for it. When the milli volts readings are posted it becomes much easier to figure out what is perhaps happening. The last thing I would expect with the problem described is to have to adjust something. The use of this system is to find your actual problem accuratly rather than spending money or guessing. When you get your milli volt readings something should be indicated. What can it hurt to try? Has worked on problems much more serious than yours. Again with a problem like yours no adjustment of anything is indicated. Just something bad somewhere to be found.

Last edited by barry123400; 06-09-2006 at 03:21 PM.
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  #23  
Old 06-09-2006, 03:28 PM
John Holmes III
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Quote:
Originally Posted by danok
Idle is rough all the time warm or cold. It is idling about 6,000-6,500 rpm.

Valves were adjusted in the last year by a MB mechanic.

If it really does idle at 6,500 rpm it must be ready to throw a rod.


I take it you mean 600 to 650 rpm, which is way too low and will cause the symptoms you describe. The p/s and a/c will cause the engine to die at such low speeds with the transmission in gear. I would look at the linkage real close, before I messed with anything else.
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  #24  
Old 06-09-2006, 05:40 PM
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yes of course

Quote:
Originally Posted by John Holmes III
If it really does idle at 6,500 rpm it must be ready to throw a rod.


I take it you mean 600 to 650 rpm, which is way too low and will cause the symptoms you describe. The p/s and a/c will cause the engine to die at such low speeds with the transmission in gear. I would look at the linkage real close, before I messed with anything else.


I woke up earlier than normal this morning, as you can tell. Yeah, 600-650 rpm. What should it be at? The question I would have then is why would this happen suddenly, and what is the story with the smoke???
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  #25  
Old 06-09-2006, 06:01 PM
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If you step on the accelerator slightly and raise the RPM, does it smooth out? What about the smoke? If all is fine, then there's only two possibilities IMO. Either your idle is set too low, or your fuel tank screen is clogged and the engine is starving for fuel. It should idle around 750 RPM once it's warmed up.
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  #26  
Old 06-09-2006, 06:03 PM
John Holmes III
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This is just a shot in the dark, but the white smoke could be air in the fuel system. Which also might cause the low idle. Check the primer pump and rubber fuel lines for cracks and loose clamps. A clogged fuel tank strainer might also be the clulprit. Try reversing the inlet and return lines so you by pass the strainer to see if the problem goes away. Good luck.
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  #27  
Old 06-09-2006, 07:35 PM
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Try a New fuel Tank

Sort of... You can easily bypass your fuel tank. http://dieselgiant.com/runningcornoill.htm has an example of how to create a fuel tank under your hood. This would rule out (or in) a set of problems from the fuel filters back to the tank. Easy to do. Run diesel or purge, or ...
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  #28  
Old 06-10-2006, 11:24 AM
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Okay, so you can test the millivolts of each to make sure they are all uniform. That's all we're doing here. I see.
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  #29  
Old 06-11-2006, 11:52 AM
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Your statement is correct. If there is something wrong you will get a really strange reading from one of your glow plugs. Read them and post the results Will quickly indicate what if anything and where to look. The way it was done in the past was to loosen each injector line nut at the injector one at a time a little until the fuel seeps out and try to find the one that makes no difference when loosened to the engine if any. Both ways just show you where to look for the problem basically. Plus inform you what cylinder it is. Glad you are getting an understanding. Well worth learning in my opinion.
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  #30  
Old 06-11-2006, 12:11 PM
John Holmes III
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I still think the problem is in the fuel system before the ip(clog or air in lines), or a throttle linkage problem. On the side of the ip there is a large screw held by a locknut, this can be turned in to icrease idle speed, of course this won't fix a problem with the linkage that has broken or come loose.

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