Power loss on BJ70 (1 Viewer)

[mahid49]

Hey mudders.

So few months back I got my 3B engine overhauled. It was running like a beast just fine but since last few days I feel like it suddenly don't have the same pick up.

Accelarator reaponse feels delayed when i need quick boost in rock climbing

Take off is very slow but runs fine after that

When I try to climb even a small rock, it does not respond. Feels like engine in under heavy load or something. accelerator is sluggish
Revs fine on idle though


Engine mechanic says it could be bad diesel filter
Replaced diesel filter around 20k kilometers

Diesel pump mechanic says it could be pump issue


Forgot to mention that i have to prime it before starting in the morning. Diesel returns to the tank.

 

[Irish11]

Sounds like a fuel delivery issue to me. I would check the filter and lines. You might have air in the line as well. So I would try bleeding the system while you are at it.

 

[mahid49]

Sounds like a fuel delivery issue to me. I would check the filter and lines. You might have air in the line as well. So I would try bleeding the system while you are at it.

Thanks mate, can post the steps of bleeding the fuel system in sequenceplease.

 

[Irish11]

How to bleed fuel system video ( B, 2B, 3B and H Diesels ) - https://forum.ih8mud.com/threads/how-to-bleed-fuel-system-video-b-2b-3b-and-h-diesels.993795/

I used this process on mine to bleed it. Worked well. Helps to have two people. One to pump and one to crack the injectors. Also keep some rags handy. You are going to need a set of flare nut wrenches as well so you dont round off the nuts.

 

[Felde]

Combustion also needs air... Air filter is clean?

Forgot to mention that i have to prime it before starting in the morning. Diesel returns to the tank.

That rather indicates air in fuel line, causing the fuel to return to the tank when being parked and causing air being sucked in when running, causing poor performance.
Question is: How came it in? Could be a) residue from poor bleeding after a maintenance operation, or b) could be a leak.
Get a manual fuel/oil pump; this oversized syringe style...
Check on a) first:
Disconnect the fuel line rubber hose feeding into the Injection Pump (plug IP nipple) and connect the pump to the fuel line with a peace of clear PVC hose. Pull trough fuel and check for bubbles. Could well take about 2-3L before running bubble free! (This is why the little priming pump is useless on bleeding the main fuel line). Connect fuel line to IP again (without letting air in again / thump on it) and then bleed fuel filter: Actuate priming pump until it becomes hard, open bleeder (with PVC hose on into a container), check for bubbles. Close bleeder, priming pump again, open bleeder ... Repeat until priming pump gets hard within 2 actuations. Bleed IP to injectors as described in other threads. Do a test run again.

If issue persist, check for leaks (b).
Check IP and primer pump. Any leaks? If not
I would start from the tank and work my way trough the fuel line (including filter and sedimenter)
Start with the pickup pipe on the tank. The metal pipe bend on top is notorious to rust trough.
Disconnect the first rubber hose connected to the pickup pipe and the last rubber hose feeding into the Injection Pump.
Block one end and attach the syringe pump to the other end and apply some pressure by pumping a bit of diesel in. (Not too much, as these lines are normally not supposed to be pressurized). Have a drink and then inspect all line and rubber hose connections for leaks...
Only once pickup pipe, main fuel line, filter and sedimenter can be ruled out, I would take a closer look to the IP itself or the injectors..
Good luck Ralf

 

[mahid49]

Update:

So I went to the mechanic today.
He immediately noticed that small return pipe from injectors rail to pump was hardened up and moving freely even with the clamp on. So replaced that small pipe.

Also replaced the main rubber hoses to and from fuel tank, as the old ones were not good quality and prone to get hard over time causing leaks.

Replaced the diesel filter. It had quite a lot or debris probably because of running on low fuel in the tank. Also saw some water droblets in there which also played some part in power loss IMO.

Diesel was opened too much from the pump, so reduced it. Took a little test drive home and still feel some power and pickup issue. But I'll gradually increase the diesel from the pump 1 full thread on each test run until I find the perfect sweet spot.

If none of this work then I guess I need to get the injection pump redone as it may not be producing enough pressure.

Thanks for the help, will keep you posted on the outcome.