Today I went out to test Paddy's cold start issue and what a lovely frosty / misty / cold morning it was here in Canberra. Jumped in and cycled the glow plugs twice then kicked it the guts. Engine as usual started with no problems, I revved it to 1200 rpm. She started to run lumpy almost immediately, and just had time to race round and prime.
It then occurred to me when I was replacing the fuel hoses on the tank end I actually did not bleed the fuel system of air, simply primed it - Whoopsie another cold morning test wasted.
But soldiering on, I had read on the POCUK forum the following thread " Injector Pump " indicating another couple of possible causes regarding fuel tank end:
- Fuel vapour check value /breather blockage - (Vacuum in a tank (because its not breathing) will draw fuel back out of the fuel system if there is ANY slight air leak on the pipework connections)
- The fuel pickup pipes in the tank have been known to have an issue where the top end of the inner pickup pipes corrode and can allow air to be sucked in. Or the pickup mesh / filter is blocked or dirty. POCUK Thread - "Pajero cuts out when cold"
12. So this morning having just bled the air out of the fuel system, knowing that I want to keep testing down to 1 thing at a time but at the same time not to waste another Cold Start. So I decided to look for the Fuel Vapour Check Valve. After a little looking I found the little bugger located behind a protection guard plate / cover at the rear passenger wheel arch.
After removing the mud flap (2 x 10mm, 1 x 11mm screws) and the protective metal plate (3 x 10mm screws) I found a fairly dirty looking object:
After inspecting the exposed (Atmosphere) end of the breather pipes it had mud caked outside and inside, nearly blocking the pipe, but from what I could see not blocking it totally.
After undoing the 12mm bolt that held the filter on the chassis, I then proceeded to remove the the hose clamp and hose of the pipe on the top of the tank as you can see in the above photo.
When I took the atmosphere end pipe of the valve, I blew through it with some resistance (not totally block) but then dirt shot out and the resistance was less and it was easy to blow through the hose. I tapped the hose several times to clean it out and to be sure ran water through it and dried it off.
I then moved onto the hose between the tank and the valve, when I blew through this hose, it was free of any obstruction and fairly clean.
Now the check valve itself, the next photo show what it looks like after you clean the dirt and mud of it. I was able to find the Part Number on the side of the filter: MB925886 and after a search on the web I found the matching description - "Checkvalve, fuel vapor control".
As you can see in the above photo of the fuel vapor check valve, there is an "arrow" which indicates the flow / install direction. In this case the arrow points away from the tank hence the vapor flow from tank out to atmosphere and allow air back in if required.
No sure of what test to perform on this valve, I simply blew into the end from the tank and with a little air nothing, then slight increase in pressure the valve opens. Blowing from the over end (atmosphere) I could blow easily with no obstruction.
So all appears to be correct, I put it together again and well have to see how it goes tomorrow morning.
That it for today fella's......
Mark
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