1974 Mercedes o309 with OM314 fuel system troubleshooting and priming
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- เผยแพร่เมื่อ 14 ต.ค. 2024
- Now that we have the 1974 Mercedes o309 cranking we need to prime the fuel system.
After manually pumping the hand pump for quite some time I decided to have a look under the bus to inspect the fuel lines. Keep in mind that this bus has a different fuel tank than stock.
I found a frame mounted fuel pump and some fuel lines that have either been chewed through or dry rotted. I used a vacuum pump to pull some of the fuel through the line to make sure no large particles of debris were present that could damage the lift pump. I then replaced the line and connected the pump to 12 volt B+. We could hear the pump running and spotted a couple of leaks.
To purge the air from the injection pump you have to remove the 10mm headed bolt on the side of the injection pump and then manual pump the hand pump. Since we have the electric lift pump this process went slightly faster and the air was mostly purged before I removed the plug.
Now we can try starting this bus again. Vroom!! The bus now runs but didn’t have any oil pressure. 6 qts of oil later I now have oil on the dipstick. I thought I had oil before but it was just a stain on the dipstick. Started it up again and we have oil pressure.
Still no brakes and a weak clutch pedal but that wasn’t going to stop me from a quick test drive around the farm.
I believe the frame pump is a facet lift pump with a rubber mounting kit.
loads of RV fun ahead for that thing!
Congratulations Chad on getting the bus running. Push the throttle control in to stop the engine. No need to idle right down each time. If that fails then yeah, grab the accelerator pedal and lift it right up. They tend to get stuck now and then. 😂
I thought it was a strange design to have to screw the idle control in and out. I’m guessing it’s seized up. I will see if I can correct that. Thanks for the tip.
Went out and confirmed the throttle knob will neither push in or pull up. I may have to take it apart and lube it up to make it function again.
When it started up I had the biggest smile on my face! Success!!! The engine sounds great!
So far so good. I think the worrisome part is over and now I can put a little money into it.
That's going to be a fun project. (Like you have time for a new project, ha ha) But yes, I do love the idea of recycling your old RV components to this one.
As much as I would love to have it done this summer I doubt that will happen. I am hoping to have it road worthy and maybe build a rough interior for this season.
Thx for sharing ! Just bought a 408D that needs a bit of care after 2 years still, it runs and drives well but sometimes get out of breath. Primer pumps needs to be replaced, it looks it hasn't been spared over time, next mission for me. I learned a lot here and in previous vids, thanks again. Greetings from Belgium
I have the 3.8L OM314 in my 82” 407D and I recommend if it’s running the wet air filter system, fit a dry direct air filter to the intake and run the crank oil vapors onto an oil catch can, in getting over 30mpg driving at nice 55mph
Thanks for the tip.
It’s good to see how you got there. I already caught the teaser on the face book love this project. So cool!!!
Another great video in this series...thanks, Chad!
Ahh, I do remember this one!
Hi Brad, I have a 1976 0309 bus here in Australia and finding any owner operation manuals is proving difficult. You mentioned that you found something online, do you remember where? I havent ran it for 6 months or more and its being a bit difficult. The series parallel switch is damaged, the points on one end are burnt out so now it just chatters for a few seconds when trying to start and then the starter button stops working but wait a while and it will chatter again but only for a few seconds before dying again. When I first bought the bus three years back it would occasionally chatter when trying to start but eventually start so now it is totally broken. Thankyou in advance if you read this and can tell my the url. 👍
Here is a link to my google drive folder where I started collecting manuals for my O309
drive.google.com/drive/folders/11KzN41Be4F7LnhNXJflk9F2FsCrNo79n
@@ThePracticalMechanic Thank you sir, I searched for hours and couldnt find these, you are a super sleuth. 👍
❤❤❤ ineterc
Hey yo, wtf happened to the MB Bus? 2 years ago!?! Love this thing. I just got a Unimog and looking up vids on MB diesel engines. You still have it?
Can you adjust the pump on so it adds more fuel?
OM 314 Runs Every Time Man
this Model has a Mechanic Clutch not with oil Working snce 1977 the have become a clutch with hang pedals an brake oil
So I have just retro fitter a turbo to MY OM314 engine, got up to 8psi of boost as not to overload, but I can’t fathom from the manual to adjust the fuel to increase it slightly, have you Amy knowledge on this? How’s your van running now?
@@NomadicMechanic101 the project is at at standstill for me at the moment. The starter failed but at some point in the past someone welded the starter to the transmission and I haven’t had the time to grind the welds and remove it.
I have some other ideas for the project anyways so I’ve just put the van aside for now.
I acquired a 1992 Isuzu NPR/NRR with a six cylinder turbo diesel. I may swap the powertrain over to the bus. This will give me more power and easier part availability. The engine is larger than the Mercedes 6 cylinder so quite a bit of fabrication would be required.
As for your question, I think the injection pump was different for the turbo models. I don’t know if you can adjust the pump to increase fuel delivery but there may be some excessive smoke until the turbo spools up. Most turbo charged diesels have a boost reference port on the injection pump that increases fuel as the boost increases but I don’t know if the MB pump has that option.
@@ThePracticalMechanic I don’t suppose you have a source for the fuel model pump set up? I had found, but no longer can, a video on the tear down of one. For now I put in larger jets which gives 1st and 2nd a noticeable improvement, 3rds gearing drops RPMs so not quite there with picking back up post gear change. Of course as boost increases its leaning off. I’m going to fit a electric fuel pump too. Wondering to add a direct jet to the intake to add more fuel as boost increases. A lot of trial and error but fun to try out different methods. Ultimately I know I’ll need to find a more modern turbocharged engine to retrofit, just as of now, not sure what engine & Trans would be easiest to install. Appreciate you getting back to me.
Will keep on the watch for updates of your project if you do replace the engine :)
Watching this video up till 7 minutes, I really wondered why you didn't cut & bend the metal part of the fuel line to get it in proper position /alignment to the feed-pump, secure it with a solid metal stay and then use as short as possible rubber tube to connect... ;-)
The metal line will need reformed for sure. This is how I purchased the bus. I think the electric lift pump was an afterthought by the previous owner. I will reform the line once I confirm my fuel tank situation. This fuel tank was added and the filler nozzle is in the rear wheel opening which will make it difficult to fill. Included with the bus was another brand new 36 gallon fuel tank so I may need to change the line routing to accommodate the second tank.
Thanks for watching and hopefully I will have time to rework the whole system in a future video.
Did you undo the 10'mm bleed nut on the main injection pump to bleed air out as you prime ?
great runner! and OM314 normally doesn't have glow plugs ;-)
Do they have cold start issues? This one has some sort of ether injection but I haven’t looked into filling the reservoir yet. If I have an issue with cold starts I may add a intake air heater.
@@ThePracticalMechanic with normal temperatures it shouldn't have any issues starting. With very deep freezing temperatures hot air in the intake helps yes. But I have also seen Iranians and Russians making small fires under the oil pan.
@@ThePracticalMechanic ether injection I have never heard of, sounds cool tho, probably helps. But originally it should have enough on it's own compression to start puttering away.
@@ThePracticalMechanic Yeah hence the 24V starter, some of these were sold in warm countries with just a 12V starter. Now since the engine doesn't have glow plugs (direct injection state-of-the-art!) you can safely use ether, to start in temperatures below -20C. It's in the manual, where they called it "Pilot start", using special Mercedes Benz canisters and the inlet you have on your bus.
@@lolilolplix are the canisters only available from Mercedes? It does have the pilot start system installed but I may have to adapt it for a more common canister if the original ones are unavailable.
To turn OM314 engine off, either pull out or push in the idle adjustment knob ( i cant remember which) OR pull the accelerator pedal all the way towards you. Let me know if these work for you.
When there will be a new video about the 0309?
I’ve been dying to work on it but workload at the shop has increased and I’m working 70-80hrs per week at the moment. I hoping things will settle down soon. There is so much I want/need to do on the bus.
Thanks for checking in and reminding me that I need to at least tinker with it from time to time.
Con cuantos voltios trabaja ese carro ? 12 v. O 24 voltios?
hello american brother. I am from Russia. I have o309 with OM314. I have the same problem.
i made autohouse
motorhome or mobile home
Sounds to me like it was converted to run on veg oil,
Could be. Unfortunately the starter has failed and was welded in place. I haven’t had the motivation to move forward with the bus as of yet. I just obtained an Isuzu NRR with turbo inline 6. I am going to take some measurements and see if a transplant is possible.
The previous owner of the van also has a factory 6 cylinder available but he hasn’t decided on a price.
@@ThePracticalMechanic hmm, i actually own a 69 mercedes, mine was converted to veg oil, and it seems has gummed up my injection pump my starter was also welded in and failed, so i had to put one in, cheapest one i found was on ab Marineservice... They starters go for about 1400-3000$ here in canada... Ouch...
v8- полный мусор