1975 240d w115 injection pump questions... - Page 2 - PeachParts Mercedes-Benz Forum

jack.stew48 · #16 01-17-2016, 04:00 PM

Quote:

Originally Posted by Govert

A torn membrane doesn't prevent starting. The governor spring and/or the lever on the pump if it is in the starting position will put the control rod in the full-load position.

You need a micrometer to replace the membrane (to measure the compensation path) and it is a bit fiddly to connect it to the control rod. It is easier in your case because the engine is not in the car.

It still is a bit strange that the engine will not start. Are you sure the engine wasn't damaged insofar that there is no compression, because of damaged valves for instance? Did you check the timing (put the camshaft on its mark, the crankshaft should be at TDC (mark TD on the crankshaft). A couple of degrees off is not so bad, but not more than 5º.

There are two bleed screws on this engine: one at the top of the fuel filter, one at the pump itself. After bleeding, you should hear a sizzling noise when you operate the hand pump (that is the fuel return line valve at the back of the pump opening).

It could also be that the injectors are stuck or rusted. That way no fuel will be injected.

Thanks for your reply,
I have checked the compression twice and my best set was (from 4-1, 4 being closest to the timing chain) 150, 120, 90, 150

i have done both the bleed screws just like you described, and adjusted he valves twice, second time to .008 intake, and .018 exhaust

what i have not one is check the timing (ill do that right now and report back) or test the injectors, i have loosened the top nut of the injector lines and checked for fuel, which there is fuel.

another thing i am noticing is extensive blowby from the breather opening, and also extensive white smoke from the exhaust, there's pretty much white smoke everywhere when im trying to start it..

also i will be getting a set of pencil style parallel glow plugs by the end of the week, to rule that out of equation

any suggestions help...

Govert · #17 01-17-2016, 04:19 PM

Quote:

Originally Posted by jack.stew48

Thanks for your reply,
I have checked the compression twice and my best set was (from 4-1, 4 being closest to the timing chain) 150, 120, 90, 150

Those are in psi? Testing compression on a cold engine tends to give low numbers, but those figures are really really low. The difference between the cylinders is quite big too. The lower limit on a warm engine is about 250 psi.

Quote:

i have done both the bleed screws just like you described, and adjusted he valves twice, second time to .008 intake, and .018 exhaust

I might have the conversion not right, but the valve clearance seems a bit high. The intake valve should be 0.10 mm, exhaust 0.30 mm. Converted to inches that is 0.004" and 0.012"

Quote:

another thing i am noticing is extensive blowby from the breather opening, and also extensive white smoke from the exhaust, there's pretty much white smoke everywhere when im trying to start it..

Blowby is “normal” for these engines, but it is not easy to know what you think is extensive. White smoke is unburnt diesel from a cold engine. That is an indication that diesel is injected into the engine.

Quote:

also i will be getting a set of pencil style parallel glow plugs by the end of the week, to rule that out of equation

any suggestions help...

The old glowers require about 20-30 seconds to warm. Have you measured the current flowing through the plugs? If one plug is not working, the whole system doesn't work. When the engine is in the car, the glow controller on the dashboard lowers the voltage a bit, so that the plugs aren't overloaded.

Quote:

alright, so ive got an intake

Is that an intake with a butterfly valve?

jack.stew48 · #18 01-17-2016, 04:27 PM

Quote:

Originally Posted by Govert

Those are in psi? Testing compression on a cold engine tends to give low numbers, but those figures are really really low. The difference between the cylinders is quite big too. The lower limit on a warm engine is about 250 psi.

I might have the conversion not right, but the valve clearance seems a bit high. The intake valve should be 0.10 mm, exhaust 0.30 mm. Converted to inches that is 0.004" and 0.012"

Blowby is “normal” for these engines, but it is not easy to know what you think is extensive. White smoke is unburnt diesel from a cold engine. That is an indication that diesel is injected into the engine.

The old glowers require about 20-30 seconds to warm. Have you measured the current flowing through the plugs? If one plug is not working, the whole system doesn't work. When the engine is in the car, the glow controller on the dashboard lowers the voltage a bit, so that the plugs aren't overloaded.

Is that an intake with a butterfly valve?

yes those are psi, i agree they are very low, but i dont have a great tester anyway, also since i was testing from the glow plug hole, rather than the injector hole, cylinder two (the lowest i believe) wasnt in perfectly straight, so that may be a little higher.

i have the valves above spec, because im not concerned about performance right now, i just want to make sure they are closing. as soon as it starts ill bring them down to spec. its a way of compensating for worn valves.

i have not measured the current in the plugs, but i tested them outside the engine and they all got hot. i want to replace them anyway, because im removing the pull started and want a reliable, manual, parallel glow plug circuit.

yes the intake has the throttle body with butterfly valve. ive got all the linkage from there over to the injection pump, and down to where it attaches to the pedal

Govert · #19 01-17-2016, 04:58 PM

Higher valve clearance also means that the engine has difficulty sucking in air.

jack.stew48 · #20 01-17-2016, 05:18 PM

Quote:

Originally Posted by Govert

Higher valve clearance also means that the engine has difficulty sucking in air.

do you recommend i tighten them back up? they are only .005 inch over spec each..

Govert · #21 01-17-2016, 05:39 PM

I don't think it will solve all your problems, but I tend to prefer adjusting to specs and to proceed from there. It makes diagnosing problems easier.

jack.stew48 · #22 01-17-2016, 05:57 PM

Quote:

Originally Posted by Govert

I don't think it will solve all your problems, but I tend to prefer adjusting to specs and to proceed from there. It makes diagnosing problems easier.

alright ill get it done. i was just giving it a shot and it almost fired, i think putting the upgraded glow plugs in will finally get it goin

Diesel911 · #23 01-17-2016, 06:06 PM

Quote:

Originally Posted by jack.stew48

alright, so ive got an intake, i put it on, out all the lincages together, hit the glow plugs, and she still wouldnt start... so i opened up the back of the njection pump to check the pnuematic governor and wah lah! its got a few tears in it.. my guess is these developed while then engine was sitting and then tore when i started fooling around with it. the line that goes to the intake looks free of oil and diesel so i dont think the gov burst while driving..

ive posted a few pics of the governor, any thoughts?

also any good place i could get a new one cheap... like really cheap

llll

There is I think 2 threads on replacing the Diaphragm. There is a Pin that lides out of it. You need to be careful of the arrangement of the Shims inside of where the pin is and the same with shims in other places.

mannys9130 · #24 01-18-2016, 01:00 AM

If those compression numbers are accurate, I don't think the engine will run at all. That is asking the engine to run at gasoline compression and less in some cylinders, and run on diesel. It will not auto ignite at those compression temperatures.