Non lr question

[bblaze]

Mate has a nissan bus camper conversion, about 20 seater size with a 4 cyc deisel. It has what he believes is excisive fuel consumption (14mpg), blows a lot of black smoke when you give it a boot full (I have only seen it in the driveway) but he also states it has no power. Blows the same smoke with air cleaner pipe disconnected. Has any one played with these motor/fuel pumps.
cheers
blaze

[JDNSW]

I don't know anything about that particular engine, but if it is blowing a lot of black smoke and down on power, it indicates fuel is not being burnt. There are several likely reasons for this, and the first one you have checked by disconnecting the aircleaner to see if it is obstructed.

If it has a turbocharger, the problem could be either blockages in the piping from the turbo to the aircleaner, from the turbo to the aftercooler (if fitted), the aftercooler itself blocked, or the piping from the aftercooler to the intake manifold, or the turbo not working effectively due to damage or wear, or a stuck wastegate or problems with wastegate control if this is controlled. If no turbo, ignore this paragraph!

Other likely causes are - one or more injectors not atomising properly; One or more cylinder not firing because of too low compression(burnt valve/seat, broken rings, hole burnt in piston, leaking headgasket); engine labouring because of lack of lubrication or cooling.

Probably most likely cause apart from poor injector atomising is incorrect injection timing, or possibly incorrect valve clearances that affect the effective valve timing.

John

[justinc]

Mate has a nissan bus camper conversion, about 20 seater size with a 4 cyc deisel. It has what he believes is excisive fuel consumption (14mpg), blows a lot of black smoke when you give it a boot full (I have only seen it in the driveway) but he also states it has no power. Blows the same smoke with air cleaner pipe disconnected. Has any one played with these motor/fuel pumps.
cheers
blaze

Hi Rob,

Is it a jap import bus? or a 'local' one? Can you see if it has a rotary or inline pump? and is it turboed?
Sounds like someone has previously wound the pump up. Has this just become an issue?
JC

[bblaze]

Hi John
Should have added a bit more detail
Non Turbo
No misses and engine running smooth through entire rev range. My thoughts are someone has fiddled the pump and didnt know what they were doing (maybe that dosnt account for being down on power though). He hasnt used it much after buying and the previous owner reckoned he was getting 30mpg, looking at the size of the bus and weight I dont think that would ever be possible. I have sugested he take it to a fuel injection specialist to be checked.
I will keep you posted
cheers
blaze

[bblaze]

Hi Rob,

Is it a jap import bus? or a 'local' one? Can you see if it has a rotary or inline pump? and is it turboed?
Sounds like someone has previously wound the pump up. Has this just become an issue?
JC

Hi Jc
This guy gets a bit frustrated when talking about it, from what I can gather it has been like it ever since he has owned it. Dont believe it to be a jap import
cheers
blaze

[JDNSW]

Hi John
Should have added a bit more detail
Non Turbo
No misses and engine running smooth through entire rev range. My thoughts are someone has fiddled the pump and didnt know what they were doing (maybe that dosnt account for being down on power though). He hasnt used it much after buying and the previous owner reckoned he was getting 30mpg, looking at the size of the bus and weight I dont think that would ever be possible. I have sugested he take it to a fuel injection specialist to be checked.
I will keep you posted
cheers
blaze

Most likely problem then is incorrect timing, although it could be just tired injectors. Fiddling with the pump to overfuel would not explain the lack of power, although is the power really less than original - the whole setup could be pretty low powered to start with. 30mpg from the type of vehicle you describe seems pretty unlikely. Taking it to a specialist is almost certainly the best thing to do!

John

[Blknight.aus]

dirty injectors, the auto advancer is shot or the timings out (retarded) or the valves need adjustment.

I'll be shocked if he gets any 20 ish seater much over say 7ish KPL call it 19ish miles to the gallon and thats in ideal driving conditions.

realistically you can expect maybe 5kpl or 15ish MPG

we need more info, how old is it, and whats he comparing "no power" to, a ferrari?

[bblaze]

Most likely problem then is incorrect timing, although it could be just tired injectors. Fiddling with the pump to overfuel would not explain the lack of power, although is the power really less than original - the whole setup could be pretty low powered to start with. 30mpg from the type of vehicle you describe seems pretty unlikely. Taking it to a specialist is almost certainly the best thing to do!

John

My Thoughts on power are the same as yours John, I sugested to him that the previous owner got sick of the low power and someone has attempted to overfuel and there has been no power increase and extra fuel usage so they cut their losses and sold it then over stated the vehicle when selling. Try telling that to a disgruntled owner
cheers
blaze

[alien]

My Thoughts on power are the same as yours John, I sugested to him that the previous owner got sick of the low power and someone has attempted to overfuel and there has been no power increase and extra fuel usage so they cut their losses and sold it then over stated the vehicle when selling. Try telling that to a disgruntled owner
cheers
blaze

I agree with this to:o
Some of the 4cyl Nissans had a fuel filter in the lift pump, undo the fuel in line and it screws into the fitting,(not in the work shop manuals).
Usualy caused lack of power overcome with more right foot(and poor economy to match).
As stated do the tappets as some times the intakes get tight.
Also worth checking the timing of the fuel pump as they don't take to kindly to being advanced.

Cheers.