OM617 Newbie - PeachParts Mercedes-Benz Forum

BenzHeartYota · #1 10-09-2014, 12:52 PM

Just recently picked up an '85 OM617 turbo out of the local salvage yard. I have been researching the engine swap into my Toyota pickup, so when I saw this complete engine still in the car I jumped at the chance to get it. The clock read 128,xxx miles so I figured it couldn't be too bad. I pulled it and jumped it while on the ground to make sure it was not seized up. Now it sits in my garage on the floor and I am lost. I have experience with diesel engines just no enough to give advice or know exactly what I am doing. That is the reason I brought my problem to the experts in search of some valuable information.

Right now I am just trying to get it started to see if it will run. Unfortunately I have had no such luck. What am I doing wrong?

The pos off the starter solenoid is attached to the pos on the battery via 2 gauge wire. I have another 2 gauge neg going from the starter housing to the neg on the battery. There is a second ground 6 gauge wire from the block to the neg battery. The glow plugs are still wired as they were in the car I just have some jumper wires plugged into the factory controller box with a single wire I touch the battery with to heat the plugs. I have the lift pump fuel line in a fuel can and the fuel return line in the same can. The lift pump works fine.

My steps to get it started:
#1 I used the lift pump until the fuel started returning to the can.

#2 I hit the glow plugs for about 15 seconds

#3 Then I started turning the engine over.( 1/2 throttle)

#4 There was a little smoke but not much and not even a stutter trying to start.

#5 I read to spray some WD-40 but no luck there either.

#6 I pulled the #5 fuel line from the injector and cranked the engine. There are slow fuel drips coming from the line while cranking. The #4 fuel line was the same way.

That is where I ran out of ideas. I don't know what else to do. I'm not even sure the engine is good. Is there something that I am missing? I really appreciate you reading my long and boring post.

oldsinner111 · #2 10-09-2014, 03:50 PM

you should get fuel,but maybe lift pump is shot.You can buy a cheaper electric pump to assist
Now it takes for ever without electric pump to get air out of lines.Make sure,the shut off switch gets vacuum

spdrun · #3 10-09-2014, 04:17 PM

Are you sure all five GPs are working? Did you check their resistances?

And actually, the shutoff switch does NOT need vacuum for the car to run, only to shut off. The default state of a OM616/OM617 is "on."

Skippy · #4 10-09-2014, 05:11 PM

2 ga wire sounds a little small. How fast is the starter turning the engine over?

interzonearts · #5 10-09-2014, 05:24 PM

It does take forever to get it started for the first time. I read somewhere that you can purge the air from the system faster when you replace the return fuel line banjo bolt that screws into the filter housing with a regular bolt.

HAVE FUN WITH THE PROJECT.

BenzHeartYota · #6 10-09-2014, 07:23 PM

I did a voltage check on all 5 GP's making sure that I was getting the same voltage through them that the battery has. all showing 12.81volts. the ones I did pull and check resistance were reading 0.8 ohms.

The 2 gauge wire is the same that was on the car when I pulled the engine. Before I was using 6 gauge and it was getting pretty hot and really slow to turn the starter. Now the 2 gauge wire does not seem to get hot just a little warm. The engine still turns over slower than I would imagine it should. I have a optima red top with 12 volts hooked to a charger with the start boost function and it does not seem to make a difference. I am going to try wiring a second battery and running 2 in parallel to see if it will make a difference.

I am going to try putting the bolt into the fuel filter return spot and see if that helps with fuel. I was also thinking that I could bypass the filter completely straight from the lift pump to the IP since I don't know what condition the filter is in. But at the same time I thought that fuel should come from the IP to the injectors at a higher pressure than a little drip.

I actually read a thread about turning up the IP and it said that there is oil that goes into the IP just under the ALDA. is that a possibility if it doesn't have any oil? Is the ALDA making it so there is no fuel since from my understanding that the ALDA controls fuel at low boost and considering I'm not making any boost while cranking...

junqueyardjim · #7 10-09-2014, 07:43 PM

Don't mess with the pump or the ALDA. I don't really understand your last question about "oil" in the pump. Anyway, forget that and concentrate on two things. Get all the air out of the system. If you are in a building, garage or whatever, try to hang up a bottle of fuel straight up above the engine. You will never run a quart through it, so it doesn't take much, but gravity will work wonders. Get that fuel up, and hand pump that pressure pump tell in "oinks" like a pig. Then make sure you have a hot battery with an excellent electrical hook up. Jumper cables won't do it. Anything less then a factory positive and with an equal ground is the only way to go. They can be real sullen starters if it has been laying around for a while. Don't use starting fluid!

spdrun · #8 10-09-2014, 07:48 PM

Older models (W115) had a separate oil supply stored in the pump. Newer (W123) cars have the pump oiled by the engine. Valid question, but not applicable to a W123.

mach4 · #9 10-09-2014, 08:26 PM

If you've got compression, fuel and glow, it should fire right up.

Since it doesn't, I'd check those a little closer.

The very first thing to do is adjust the valves. Then try for a start.

If no joy, for very little you can get a compression test kit at Harbor Freight. Pull the injectors and test the compression - you should see 300-400psi. (There's more to the specs but that's fine for starting purposes). While you've got the injectors out, hit the glow plugs and visually confirm good glow for each cylinder.

It would be nice if you had a pop tester to confirm the injector pressure and pattern, but I'd think you could swing the lines a bit and hook up an injector or two at a time and turn the engine to visually check for flow and pattern. (Be very careful to keep your hands away from the spray pattern!!!)

You'll want to get new heat shields before you reinstall the injectors for good, but you can probably reuse the ones you've got just for testing purposes. (Read up on how to use a ball bearing to "retension" one temporarily )

The only other thing it could be is timing, but that's not likely at all unless someone has messed with it.

Always replace the primary and secondary fuel filters on an unknown engine before trying to start.

Good luck....sounds like a fun project!

vstech · #10 10-09-2014, 08:34 PM

Try again with the picture.

vstech · #11 10-09-2014, 08:37 PM

Factory has. #1or larger... To starter, and a VERY short ground cable connecting to the chassis likely #2 or so. Another braided cable connects to the block from the chassis...

I've found that the chassis to block cable gets loose and causes starter drain...

BenzHeartYota · #12 10-09-2014, 09:15 PM

Ok I did what you suggested mach4, I pulled the number 5 injector. I checked and the GP's are working fine. However with the #5 injector hooked up to the fuel line out of the head, I cranked the engine over and nothing. There is at least some compression in that cylinder because it blew what I guess is the heat shield out of the pre chamber. But again there was no fuel being sprayed from the injector. from what I could see down into the chamber, there didn't seem to be excessive carbon build up. even on the injector there didn't seem to be much. I would love to post a few pictures but still trying to figure that part of the posting out. I like the larger pictures actually on the post instead of the attached mini pics that never seem to load.

mach4 · #13 10-11-2014, 10:14 AM

Looks like your problem is fuel. It still could turn out to be compression but clearly not glow.

Need to start in order to diagnose the problem.

I assume you've changed out the filters so we can assume that fuel is getting to the lift pump.

If you were able to purge the air out of the filters we can probably assume the lift pump is OK. Are you visually able to confirm you're drawing fuel out of your temp fuel reservoir?

Next in line is the injector pump and we can for the moment assume it's working and at least verify that indirectly.

Attached to the injector pump is the shutoff valve. If that were stuck open that would prevent fuel from getting to the engine, but those normally fail in preventing shutdown.

Check for prime - Loosen all the injector lines at the injector, hold the throttle wide open and crank until you get fuel coming from the lines and running down the injector. Tighten the lines and try to start.

Which gets us to injectors. It would be best to pop test the injectors, but since we don't have that option available right now, I'd go back to the junk yard and grab a set. The possibility of sourcing two bad sets in a row is infinitesimally small. Swap in the new set and try again. While you're there grab an injector line to modify for a drip test.

If that doesn't work, proceed like you're going to do a "drip timing" on the engine. Don't worry about timing at this point, all we care about is fuel flow. Google drip timing or use the PP search function.

Report back and we'll refine things further.

For now, just upload your pictures to the site - I'll PM you later with how to make them appear inline in the post.

OM617YOTA · #14 10-11-2014, 11:45 AM

It sounds like you need to prime your fuel system a bit better.

You mentioned pushing the primer pump until you got fuel out of the return line. Was it just a dribble? You should have gotten a little fuel out, then lots of bubbly foamy fuel, which would then clear up with still more pumping, accompanied by a whistling or "oinking" from the pressure relief on the injection pump.

Next, crack open the injector lines at the IP and crank the engine while holding the throttle wide open. When you have fuel dribbling out, close the lines at the IP and open the lines at the injectors. Repeat cranking at WOT until you have fuel at the injectors.

Close the lines at the injectors, hit the glow plugs and crank her up. Should start within a couple rotations, might run a little rough for a couple minutes while the last bits of air are purged.

t walgamuth · #15 10-11-2014, 12:32 PM

If you just metered the glows they may still be bad. I like to pull them out and put the jumper directly on them. If they don't lite up really quickly they are bad.