A minor and rare ignition idling problem...

[BongoBongo123]

Just for the record I have not had this for 3 weeks now. It only ever happens in the winter and oddly I think it has a relationship to the Bongo facing downhill when parked for more than 5 days.

Less than 5 days and it never happens.

The symptoms: I turn it over and it always starts but shortly after turning over it runs lumpy so I give it a slight gas and it clears and is then rock solid all the time.

I am beginning to think that the steep incline I park it on makes gravity draw the diesel away from the pump/engine. Is there any logic in this as if I'm park facing uphill this issue never occurs. (there's the answer I hear you say )

I have got new long glow plugs, not put in yet cause I now do not think it is the glow plugs as 98pct of the time I start with a smooth, stable and solid idle no trouble, only after it has been sitting a while and facing downhill does this occur. Just wondered if anyone else had any thoughts.

It is not at all a major issue as it does not even stall. I am just curious as to why this might be ocurring and can only think of gravity/leveling of cold thick diesel.

I started the engine at 1C a few days ago and it started perfect. It is just on this rare occasion it starts lumpy always after facing down.

Another thought is I wonder if the fuel outlet pipe from the tank (sucked out by the pump) is near the front or back of the tank and whether any detritus in the tank bottom (I assume the tank contents is drawn from the bottom by the fuel pump, surely it could only be?) could rest near the outlet after 5 days sitting and get drawn in and cause a lumpy initial turnover? That could be complete rubbish though I am not sure.

I am not familiar with where the pipe that sucks the fuel out is exactly but if it was at the front of the tank (facing forwards towards front of the Bongo) my detritus theory could have some mileage as this front facing part of the tank would collect detritus in the lower front edge of the tank when facing downhill.

Just thoughts but if anyone has any ideas that would be interesting. No stress as it is hardly a big problem more of an occasional head scratcher.

Odd.

[mikeonb4c]

Might there be a bit of gravity feed leakage of fuel from the tank, through the pump and into the chamber(s). If so this could be the reverse problem of an imperfect pump seal allowing air into the fuel line and causing starvation on start up?

[BongoBongo123]

It might be, I will live with it for now cause I won't be able to fix that anyway. Thanks for the suggestion Mike.

[mikeonb4c]

It might be, I will live with it for now cause I won't be able to fix that anyway. Thanks for the suggestion Mike.

I suppose the theory could be tested by parking it uphill for 5 days and seeing if it shows any sign of fuel starvation on startup

[BongoBongo123]

It might be, I will live with it for now cause I won't be able to fix that anyway. Thanks for the suggestion Mike.

I suppose the theory could be tested by parking it uphill for 5 days and seeing if it shows any sign of fuel starvation on startup

As mentioned it starts on the nose it just runs lumpy for 10-15 seconds and has on one occasion stalled through the lumpy idle immediately after start, if I give it slight bit of pedal it clears and runs fine from then on.

Not sure how we could know if it is just taking a little time for the pump to bring the thick cold fuel up the pipe against gravity or if it is due to a leak.

I am fairly convinced it is not glow plug related now due to the rarity and very quick clearing of the issue.

[mikeonb4c]

It might be, I will live with it for now cause I won't be able to fix that anyway. Thanks for the suggestion Mike.

I suppose the theory could be tested by parking it uphill for 5 days and seeing if it shows any sign of fuel starvation on startup

As mentioned it starts on the nose it just runs lumpy for 10-15 seconds and has on one occasion stalled through the lumpy idle immediately after start, if I give it slight bit of pedal it clears and runs fine from then on.

Not sure how we could know if it is just taking a little time for the pump to bring the thick cold fuel up the pipe against gravity or if it is due to a leak.

I am fairly convinced it is not glow plug related now due to the rarity and very quick clearing of the issue.

I meant park it on slope but facing uphill as opposed to facing downhill?

[wonkanoby]

when its cold is the cold start working

and raising throttle to around 1500 rpm

[BongoBongo123]

Sure I do that (park it upwards) and never have the issue. I was just wondering what the cause of the issue could be. Facing upwards is the best solution. But I like to switch it around so water never gets a chance to sit too long in any specific areas.

Hi Wonkanoby... yes it initially revs a little faster idle for around 45 seconds then drops down a few hundred revs by itself. I am generally mindful to try not to rev any engine too much from a really cold start like below 5C and wait 1-2 mins and gently pull away, it all reduces wear a little. This is why I love the Magnatec for winter as well. I think that glues itself a little better to the metal surfaces, well that is the theory anyway.

Here is an advert, basically:

https://www.youtube.com/watch?v=pzqI6qHEdoI

[Tony x]

We had a similar problem - the Bongo would start fine if used recently but not if left and, if parked nose up the problem was worse. It would start but not so readily and it would be lumpy for 2-3 seconds.
Problem was solved by cleaning out and servicing the diesel filler cap.

[BongoBongo123]

We had a similar problem - the Bongo would start fine if used recently but not if left and, if parked nose up the problem was worse. It would start but not so readily and it would be lumpy for 2-3 seconds.
Problem was solved by cleaning out and servicing the diesel filler cap.

Well that is interesting as I saw something about the diesel filler cap on here a few weeks back and took a snap of my diesel cap (but did not post it up) I could not see any holes to clean as such seemed like solid white plastic on the inside as far as I could see.... I read "put in hot water and washing up liquid" off the top of my head. Is this related to a breather hole?

I could not really see a hole.

I am all ears !

[cmm303]

We had a similar problem - the Bongo would start fine if used recently but not if left and, if parked nose up the problem was worse. It would start but not so readily and it would be lumpy for 2-3 seconds.
Problem was solved by cleaning out and servicing the diesel filler cap.

Well that is interesting as I saw something about the diesel filler cap on here a few weeks back and took a snap of my diesel cap (but did not post it up) I could not see any holes to clean as such seemed like solid white plastic on the inside as far as I could see.... I read "put in hot water and washing up liquid" off the top of my head. Is this related to a breather hole?

I could not really see a hole.

I am all ears !

remember same advice, you're not imagining it! It has a one-way valve to stop a vacuum building up in the tank.

[BongoBongo123]

Ok thanks, I must get it off and make a closer inspection. In fact I am pretty sure I can hear air releasing/pushing every now and then when I unscrew it, maybe that is working against the pump.

[Bob]

Yep, if the vent is blocked a vacuum will build up in the tank and stop the pump delivering fuel.

This is most likely the 'Sucking' sound you hear when releasing the cap.

If the tank is fairly empty (so fuel can't slop out) it might be worth a short run with the cap removed.

[mikeonb4c]

Yep, if the vent is blocked a vacuum will build up in the tank and stop the pump delivering fuel.

This is most likely the 'Sucking' sound you hear when releasing the cap.

If the tank is fairly empty (so fuel can't slop out) it might be worth a short run with the cap removed.

And its interesting that Tony's problem was worse when the Bongo was left parked facing uphill.

[Tony x]

You can rebuild the cap. I can't remember the ins and outs but you'll notice that the whitish bit that faces into the tank is spring loaded. I removed this and chopped the spring in half plus you separate the black part of the cap from the white bit. Air gets in at this joint and, if blocked, may be your problem. It all makes sense when dismantled.