'82 240D Unable to locate starting/running issue(s) help!

For discussing the modifications needed for diesel vehicles to run with 2 tank veggie oil conversions.

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'82 240D Unable to locate starting/running issue(s) help!

Postby svojoe » Wed Oct 06, 2010 6:35 pm

First I want to thank Sun-wizard for showing me this forum.

Second I want to say that this post is out of pure desperation! :)

Here is the situation in a nutshell, I have a 82 240D I have been using as my daily driver for a little over a year. It has a two tank WVO system I designed but I would like to leave wvo out of this equation as I am trying to get it stable and trouble shoot in diesel only for now. (it will make sense later!)

Car has 170k miles, Is a California car in otherwise good/great shape. About 4 months ago it started to require more effort to start. Eventually requiring a wiff of ether to kick over when it was cold, then requiring a wiff of ether to start no matter what (even when hot) towards the very end. It also developed another issue being that sometimes after starting it would have very poor throttle response unless restarted. Knowing something serious was up I started driving it less and only when absolutely necessary but I was unable to dig into it thus far because I am working two jobs and trying to finish up my off-grid home enough to be comfortable this winter.

After the ether start the car would appear to run fine, just a little more smoke than I like. I took a long trip of 1200 miles round trip in 48 hours to pick up my brother. Aside from some clogged veggie filters the car seemed to run okay. It died while idling while i was trying to park it at my place upon return. Lucky huh?!

After playing with it for a bit I realized it would only start while rolling it down a hill and poping the clutch. And when doing this it would not idle and run very rough with lots of smoke.

This was the beginning of my woes, I had assumed it was just time for some major maintenance and a major overhaul. So I dug into it over the last 4 days putting almost all my other responsibilities aside. Now four days later I stink like diesel and ether and feel defeated! It is exhibiting the 'exact' same issues it did before it took it apart.

Here is a run-down of what I did.


I purchased a compression tester, new injector nozzles and a glow plug reamer from mercedessource.

Here is the initial compression results.

cyl #1 120 first stroke, max 280 psi. (320 max psi with oil added)
cyl #3 160 first stroke, max 340 psi. (380 max psi with oil added)
cyl #4 100 first stroke, max 215 psi. (240max psi with oil added)
cyl #2 120 first stroke, max 305 psi. (300 max psi with oil added)

Pretty good except for cyl #4, The lack of major changes with oil tells me the rings may not be toast. I now did a valve adjustment and this was the results. (the valves appeared to be very tight across the board)

AFTER valve adjust:

cyl #1 175 first stroke, max 395 psi.
cyl #3 190 first stroke, max 410 psi.
cyl #4 100 first stroke, max 260 psi.
cyl #2 160 first stroke, max 360 psi.

Pretty good i think!!! With no oil added, I have a very weak cyl (#4) but its still in the 'fair' condition right?

I then rebuilt the injectors. I used Monark nozzles and pop tested them for spray pattern and pressures. They have good spray (making a diesel fuel 'fog') and here is my pop pressure results after shims.

cyl #1 1800psi (125 bar)
cyl #3 1750psi
cyl #4 1800psi
cyl #2 1780psi

Factory spec is said to be within 115-125bar, I went to the outer side of that hearing a little more pressure is good for WVO.

I replaced ALL fuel filters, And reamed the glow-plug holes which did contain a lot of carbon/build-up.

After all this work, I had expected it to start and run like a beast when I got the air out of the fuel system. However now I am in the same boat as before...

leaving it in diesel only to rule out any veggie issues, after a lot bleeding process I believe I was able to prime the pump and was able to get the motor to turn over and run for a bit on diesel. It died while I was trying to let it idle and would no longer start. Not even with ether. After a long attempt to re-check everything I gave up as I was loosing light fast and just rolled it down the hill again. It started... and ran terribly just like before.

The only saving grace from this entire experience is that it feels as if it will have more power/throttle response when it is properly running. The downside is that after all this time/energy I still don't have a car and I feel like I'm going to get lung cancer from an entire day of diesel/kerosine and ether fumes :(


At this point I am starting to feel as if I am having some type of major fuel delivery issue that I can't pin point as it looks like it bleeds properly when I crack the injector lines...

*sigh*

I want to thank everyone in advance for any input/help you might have! I may need a new/rebuilt injection pump I think...... :(
svojoe
 
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Joined: Sun Oct 03, 2010 10:55 pm

Postby SunWizard » Wed Oct 06, 2010 7:04 pm

Hi and welcome to the forum. You are doing many of the right tests.
Yes that one cylinder is a problem but it should still run. Have you tested the glow plug resistance? They go bad often and can make it not start, and its an easy check with a digital meter. I think they should read ~ 1.2 ohms. New ones are cheap and easy to replace.

Another easy check is to put a fuel pressure gauge on it and be sure the lift pump is providing good pressure to the IP.

Ether may have caused damage its not needed with working glow plugs.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
SunWizard
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Postby svojoe » Thu Oct 07, 2010 10:04 pm

I'm not familiar with the check for the lift pump. How do you recomend I measure the pressure to make sure its healthy?

I have the ability to pressurize the veggie system, and during the road trip the car seemed to run better while on veggie with my fuel system pressurized to around 7-9psi.
svojoe
 
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Joined: Sun Oct 03, 2010 10:55 pm

Postby SunWizard » Thu Oct 07, 2010 10:14 pm

svojoe wrote:I'm not familiar with the check for the lift pump. How do you recomend I measure the pressure to make sure its healthy?

Put a pressure guage on a tee on any line after the lift pump, before the IP. Any oil pressure guage from any auto parts store, the 270 degree sweep ones are better to see the low pressure numbers. Its handy to tell if your filter is getting plugged, I look at my guage often.

You didn't answer about your glow plugs, that is the most important thing by far, and a very common problem.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
SunWizard
Site Admin
 
Posts: 1719
Joined: Mon Dec 11, 2006 2:53 pm
Location: N. Colorado

Postby svojoe » Fri Oct 08, 2010 8:29 pm

I think it is my injection pump. This is what I did tell me if my logic is sound.


I disconnected the lift pump from the Injection pump to check fuel flow. The hand primer pumped fuel in heavy volumes. When turning the motor over the lift pump pushed substantial amounts of fuel out of the line normally connected to the injection pump. Yes I changed both fuel filters before this test. Though I think the old ones had been in working order.

After this test I then disconnected the injectors from the IP. Then turned the steel hardlines around and hooked up 4 different injectors from another 240d to spray into the engine compartment on the other side of the IP. I then removed the glow-plugs so that there was no compression in the motor.

The idea here is that the motor and the IP would free-spin at near idle speeds without compression hopefully showing me the 4 injectors spraying a good atomized spray in time. This is with the vacuum line unhooked from the IP.

I had hoped to see the injectors spray a correct pattern however only one injector (cyl number 3) popped at all. I really don't understand it. I tried several variations but not a single other injector even leaked/dripped. This would explain why my motor wouldn't start...

When the injector lines are cracked they leak and or shoot a little pulse of fuel but when attached to the loose injector I get nothing. Suggesting that the Injection pump is not pushing enough strength to pop the injectors.

This would explain why even with working glow-plugs, and or ether starts have virtually no effect to help the engine start.


Is there anything additional I can do to diagnose or otherwise try to repair the injection pump beyond assuming I need a new one?
svojoe
 
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Joined: Sun Oct 03, 2010 10:55 pm

Postby SunWizard » Fri Oct 08, 2010 8:54 pm

svojoe wrote:I disconnected the lift pump from the Injection pump to check fuel flow. The hand primer pumped fuel in heavy volumes.

Pressure is more important than volume. Especially pressure after your filter, which is always a lower pressure than before. Or you could have an air leak, another common problem.
The idea here is that the motor and the IP would free-spin at near idle speeds without compression hopefully showing me the 4 injectors spraying a good atomized spray in time.

I don't think you will get idle speed but it should be enough to get a spray. Did you let it crank for a while, then rest, then more, since it can take a good amount of cranking to get the air out of the lines? With the injectors in the engine were you getting any smoke after a while of cranking? Normally they get smokey after a minute or more of cranks without starting.
Is there anything additional I can do to diagnose or otherwise try to repair the injection pump beyond assuming I need a new one?

Not much for a hobbyist, an injection pump repair place can test it. But testing it (beyond what you did) probably costs enough that I would get another used one from a junkyard. You might get ideas if you post your recent test you did with the injectors off to the mercedes fanatics:
http://www.peachparts.com/shopforum/for ... y.php?f=15
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
SunWizard
Site Admin
 
Posts: 1719
Joined: Mon Dec 11, 2006 2:53 pm
Location: N. Colorado

Postby svojoe » Wed Oct 13, 2010 12:21 pm

The plot thickens! It RAN!!!

I had put it back together after opening up the top of the IP, bleed the system and with all new glow-plugs it started, It actually started easily! Idled strong and I let it run for about 10 minutes. Throttle response was solid. It actually ran really well! After all the work I got that nice diesel ping/knock sound of the motor back.

I noticed that I had left the vaccum line disconnected from the IP fuel shutoff valve. After I hooked it up, it started to run funny after a few minutes. Reving up and down wildly then eventually would no longer idle and shut off. I could not get it to restart.

This is the exact same issue it has ultimately been giving me the these past three weeks.

I took off the fuel shutoff valve and played with it, using a vaccum pump I could get it to work and it seemed not to be gummed up.

What gives? this is just a wild goose chase, but it felt so good to hear it run strong. And now I'm suspecting it is not my injection pump dying.?

what do I do from here? sheesh...
svojoe
 
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Joined: Sun Oct 03, 2010 10:55 pm

Postby SunWizard » Wed Oct 13, 2010 12:44 pm

That's good news! Good glow plugs are essential to these old mercedes. There should only be vacuum applied to the IP when you turn off the key. Put a gauge on it to be sure, if there is vacuum at other times, your switch in the steering column is bad. Leaving the vacuum disconnected would let you know if that's the problem if it starts running fine again.

It sounds like you could have an air leak which is very common. Find out by getting a cheap clear inline filter, start with it just before the IP and look for air, and moving it around can help you find where its coming from.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
SunWizard
Site Admin
 
Posts: 1719
Joined: Mon Dec 11, 2006 2:53 pm
Location: N. Colorado

Postby svojoe » Sun Oct 31, 2010 9:35 pm

This car is still down for the count, I'm actually so stuck I'm shelving it for a while... :( I'm starting to work on my 300D that is also broke instead as I think I can actually make head-way there as it runs great. I just need to replace the rear drivers lower control arm.

What is the difference between these 3 filter types?

http://www.jmesales.com/item/110125/Cim ... r-Kit.aspx

Why is the bio fuels version $10 more?

I have a vormax from a old plantdrive kit bought years ago. But I'm thinking about not putting that into my truck and putting this in, instead. AFTER a block of 4 PH8A type filters in parallel. So essentially I would have dumpster grease sitting hot in the tank, then it would make a single pass through 1 of the 4 13 micron filters than into one of these cimteks at 10 micron for a final polish before the IP in my Dodge RAM (cummins 12v) Since I will likely only have access to awful grease on the road.
svojoe
 
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Joined: Sun Oct 03, 2010 10:55 pm

Postby SunWizard » Sun Oct 31, 2010 9:49 pm

svojoe wrote:What is the difference between these 3 filter types?

Media and glue made for the different fuels. I use the diesel kind for my WVO.
Why is the biofuels version $10 more?

Probably special glue or coatings since biodiesel is a strong solvent. WVO is not.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
SunWizard
Site Admin
 
Posts: 1719
Joined: Mon Dec 11, 2006 2:53 pm
Location: N. Colorado


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