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  #1  
Old 07-02-2017, 09:55 AM
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Default OM617 question

I could really use your advice/ opinions on this OM617 set up . I'm completely new to this diesel thing and am starting this thread so as not to muddy up Everglass's thread on his build . I do plan on going to a lower gear ratio but would like to get this sorted out first
here is the problem .
this is a swap in a 1970 scout 800A.
700R4 trans, 208 transfer. 33/10.5x15 tiers
in first gear she has acceptable power . in 2nd it still accelerates . but in 3rd it falls flat . pushing the peddle down does nothing . its almost like I'm not getting enough fuel ?
I'm getting very low boost . I rebuilt the turbo and with the waste gate disconnected I can get around 4 to 5 lbs but not more . that's also in first gear . little to no boost in 2nd and nothing in 3rd .
now on top of that my EGR temps run right up to 1100 to 1200 within about a 1/4 mile "if that "
would low fuel pressure cause that ?
she runs wonderfully when not under load . I can red line the RPM at 4800 with no problem . It also starts right up on the first crank so I don't think my timing is off or have low compression or it wouldn't do either would it ? everything I have read on low compression diesels is that having to crank the engine over considerably is a warning sign of low compression .
originally I thought it was my gearing causing the issue or maybe to low of a torque converter stall.
however I'm reading that guys are running very low stall rates in the 15 to 1800 level in their jeeps with larger tiers in the 35 range " I'm running 32/10.5X15 "
as well as 3.73 gears which is what I have in my 800 . I'm also running a B&M TC with a 2000 stall . which I was told should stall in the 2300 to 2400 range with the OM617 ? was I given BS advice when I ordered it ???
I contacted Mercedes Diesel . they sell the adapters for the swap in Jeeps . all I can get from them is that it sounds like an issue with the engine . they wont go into detail as to what to check or look for .
I have not messed with the pump settings at all . I have turned up the ALDL . cleaned the banjo fitting and line to the ALDL
I have not advanced the timing . Now that leads me to a question on timing . do diesel engine advance timing like a gas engine does ?
if so could my issue be that my timing is off . not so far that is effects start up and performance not under load . yet advances out of time when under load ?
what about the lift pump ? could the lift pump go bad yet still provide enough pressure to give none load performance and not enough pressure to provide enough fuel when under load ?
Thus the reason for the EGR temps to climb so fast since there wouldn't be enough fuel to cool the cylinders ?
.
what would be your thoughts please ? I can deal with the 3.73 gear performance for the time being . but I would like to make sure that I'm not having other issues prior to sinking the money into gears ?
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  #2  
Old 07-02-2017, 12:21 PM
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May be a restriction in your fuel line, take a quart or so container and put the pump line into it under the hood, drive it and see if the same issue happens, if not, you know which direction to go. Which turbo do you have? The Garret T3 or the Tripple K K26?
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Old 07-02-2017, 05:51 PM
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its a T3
Ill try the fuel container thing . I put in new lines plus new tank and pickups. doesn't mean I didn't pinch something though .
would however the stock lift pump still not pull the fuel enough if it was going bad ?
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Old 07-02-2017, 07:03 PM
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If it still doesnt run right with the container, at least you have eliminated the fuel tank and lines as being the problem so you don't have to tear that all apart again. Someone on here, may have been Evenglass or Rucktard had a problem with the rubber hose they used in the tank collapsing or leaking. The original 800 fuel pick up should have been metal though since they didnt use in tank pumps back then. I have heard some people use a low pressure booster pump because theirs would'nt pick the fuel up. If with the container next to the engine, and the problem goes away, and you dont find any issues with the fuel pickup and delivery lines, you might try that.
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Old 07-02-2017, 07:23 PM
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will do thank you
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Old 07-03-2017, 10:40 PM
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That's alot to cover I'll try.
It could be lots of things but if I had to guess I'd say 95% chance it's your turbo. What you described is the normal function of a NA om617. Your EGTs are high because without boost the fuel doesn't burn as efficiently and it exits the exhuast while still burning.
Your gears are a little to high.
the tank fuel return needs to be equal to the intake.
The IP should have a punched hash mark to line-up, leave it lined up.
Remove your ALDA.
do you have an intake restriction?
is your TV cable the correct length and adjusted correctly?
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  #7  
Old 07-04-2017, 07:53 AM
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morning Everglass and thanks for the reply
*TV cable I believe is correct . shifting feels good .
*Intake restrictions . I had the intake off and cleaned out while the engine was out . *head looked good . good as to what I would find acceptable in a gas engine
*I have not removed the ALDA. I do have it turned up .
*have not messed with the IP at all . my knowledge base or confidence with the workings of a diesel isn't even close to being to the point I want to even go there just yet . as such I have change nothing concerning the IP . now this doesn't mean that the PO had not adjusted something .
* Fuel lines are the same in fact they are the original steel lines from the 300SD. I do however have rubber lines joining the main lines at the tank. I also have a rubber line that replaced where the in tank fuel pump set in the Isuzu tank .
* gearing I'm a wear of as to being somewhat to high . my plan was to change those out to 4.88.
*Turbo I rebuilt prior to swapping the engine . she spins good and free with very little to no side to side or up and down play . originally my thought was that there was an issue with the wastegate . so I pulled the turbo an lapped the wastegate vale seat to make sure it was sealing . still had low boost . so I pulled it again and tightened the adjustment nut as tight as I could thinking this would tell me if the spring had gotten weak . no real change . so I pulled the turbo to wastegate line and blocked it off . still no change . that's where I'm at now with the turbo . again not saying I'm not missing something. only that this is what I have done so far .


I had frankly decided that the issue was gearing . however after having a couple beers by the fire a few weeks back with a fella who works at a diesel injection service we got on the subject of why I had not driven my scout to camp this year . I explained what was going on . My EGs really concerned him . when we got to the subject of power . his statement was that the om617 even if it was a non turbo should put out more power then the original IH 196 . thus should be acceptable if I had found that engine to be acceptable . though it would be alittle slower in reaching that power band . he recommended bring it down so they could look at it . however his company is about an hour away and right now I'm in the middle of a small block , wide axle , drive train swap in a fellas YJ . as such it will be a few weeks before I can get back to my scout . So in the main time I been using what little down time I have to try and learn as much as I can . after reading so many posts about the om617 in the jeeps I dropped a email off to the company I mentioned earlier . their reply was that it sounded like an engine issue . but they did not go into what to look for at all .
so I'm back to looking at specific areas to check and double check before I go into a gear swap since I know I'm having issues with boost and high EGs
I have not checked the timing . its still set to what ever it was in the 300SD.
I have adjusted the valves and ran a couple cans of diesel purge to clean things up . I also have replaced the fuel filter and oil filter. cleaned the boost line from the intake to the ALDA and as I said turned the ALDA up all the way .
she starts wonderfully. no cranking . just hit the glows , wait for them to kick off , turn the key and its running on the first turn .
so I'm going to isolate the fuel lines and tank as hillbilly suggested . Ill then pull the ALDA as you suggest and plug the intake as a start . If I end up running the scout down to the shop in Nampa I want to at least have a good list of information that I have done so as to not seem like a total neophyte LOL
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  #8  
Old 07-04-2017, 10:37 AM
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Don't listen to the Cummins guys regarding EGTs.....
Per Mercedes FSM. 1250*F continuous, as in forever. 1450*F for les then 5 seconds.
Here's why;
DI engines the piston is the combustion chamber. Since the chamber is in the piston when it gets hot it expands, when it expands the piston contact's the walls of the cylinder and you have a ruined engine. This can happen around 1200-1400*F depending.

IDI the pistons are flat and the combustion chamber is in the head. The head has alot of mass and can absorb alot of heat and can expand without bothering the piston.

When you hear people talking about high EGTs it has nothing to do with melting metal and everything to so with piston expansion. Most IDI factory VWs from the past ran 1300-1400*F continuous.
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  #9  
Old 07-05-2017, 09:35 PM
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Got to thinking, with the low boost, and it dropping with accelleration, you may have an intake gasket leaking, either at the turbo, or on the block. If it was a gas engine, you would be able to use WD 40 or carb cleaner to find it, but since a diesel doesnt really have any kind of vacuum to speak of, that will not work. You might try a soapy water solution in a spray bottle, idle up the engine where you have boost, then spray it on the gaskets. If you have a leak, it should bubble up. Just a thought. Like Evenglass said, it could be any multiple of problems. He has done a lot more research on this engine than I have.
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  #10  
Old 07-06-2017, 07:06 AM
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I didn't think a turbo should build boost unless under load ?
I pressurized the turbo with 15 psi prior to the first test run and found no leaks . will check again as soon as I get the scout back into the shop .
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