Thread: lets do this in reverse .....

ggggrrrr

Hesitation under load eg starving for fuel as I said fuel should pump at 31psi


Mrs hh

what type of engine in the vehicle?

generally without also hooking up and doing some elimination work no, there is no set of symptoms that can only be a faulty fuel pump.

a quick example.

a fuel pump thats not delivering fuel to the engine could be a perfectly fine fuel pump thats being let down by

a faulty earth lead
a faulty relay
a faulty switch
a blown fuse.
a blocked or cracked pickup
A blocked filter
a blocked fuel line.


An engine that wont start could be the fuel pump or it could be no spark no air getting to the engine

if you want to get into rough running theres lots of other things that come into it then.


fill in the This

my engine is doing this I suspect its the fuel pump how do i check for that?

and theres a more definitave set of answers available.

if your engine wont start at all crack a fuel line and see if the pump pumps if it doesnt check all the other things I mentioned earlier (volts + amps available to the pump and it can flow fuel) and if its got clean lines and volts coming in then its the pump.

if its starving for fuel (assuming the fuel isnt contaminated) then while its running crack a fuel line and see what comes out if the flow is erratic then its the pump or the fuel pressure regulator. remove the supply line from the filter and using a rubber stopper try to hold back the pressure. Idealy you T piece it and use a pressure gauge to work out whats happening.


Hope that helps.

Originally Posted by Blknight.aus

what type of engine in the vehicle?

generally without also hooking up and doing some elimination work no, there is no set of symptoms that can only be a faulty fuel pump.

a quick example.

a fuel pump thats not delivering fuel to the engine could be a perfectly fine fuel pump thats being let down by

a faulty earth lead
a faulty relay
a faulty switch
a blown fuse.
a blocked or cracked pickup
A blocked filter
a blocked fuel line.


An engine that wont start could be the fuel pump or it could be no spark no air getting to the engine

if you want to get into rough running theres lots of other things that come into it then.


fill in the This

my engine is doing this I suspect its the fuel pump how do i check for that?

and theres a more definitave set of answers available.

if your engine wont start at all crack a fuel line and see if the pump pumps if it doesnt check all the other things I mentioned earlier (volts + amps available to the pump and it can flow fuel) and if its got clean lines and volts coming in then its the pump.

if its starving for fuel (assuming the fuel isnt contaminated) then while its running crack a fuel line and see what comes out if the flow is erratic then its the pump or the fuel pressure regulator. remove the supply line from the filter and using a rubber stopper try to hold back the pressure. Idealy you T piece it and use a pressure gauge to work out whats happening.


Hope that helps.

as I have said Matt bring it down and it will be fixed

cheers

Mrs hh

Originally Posted by Blknight.aus

what type of engine in the vehicle?

generally without also hooking up and doing some elimination work no, there is no set of symptoms that can only be a faulty fuel pump.

a quick example.

a fuel pump thats not delivering fuel to the engine could be a perfectly fine fuel pump thats being let down by

a faulty earth lead
a faulty relay
a faulty switch
a blown fuse.
a blocked or cracked pickup
A blocked filter
a blocked fuel line.


An engine that wont start could be the fuel pump or it could be no spark no air getting to the engine

if you want to get into rough running theres lots of other things that come into it then.


fill in the This

my engine is doing this I suspect its the fuel pump how do i check for that?

and theres a more definitave set of answers available.

if your engine wont start at all crack a fuel line and see if the pump pumps if it doesnt check all the other things I mentioned earlier (volts + amps available to the pump and it can flow fuel) and if its got clean lines and volts coming in then its the pump.

if its starving for fuel (assuming the fuel isnt contaminated) then while its running crack a fuel line and see what comes out if the flow is erratic then its the pump or the fuel pressure regulator. remove the supply line from the filter and using a rubber stopper try to hold back the pressure. Idealy you T piece it and use a pressure gauge to work out whats happening.


Hope that helps.

mate thanks ....i have this thread disoc v8 sticking that explains all thats been going on and have tried all suggested (and thanks to all for the help its much appreciated ) ....as said By Mrs Ho Har ..its really leading back to the fuel pump at this stage but ..im a little reluctant to spend 250 after already spending 550 already on the off chance it might be the fuel pump ...so this was really an attempt to get some definitive reasoning on if i could narrow the symptoms to the cause rather than be guessing all the time ...

will try out what you have suggested and again thanks for the info

cheers

just read the thread.

it sounds like a culmination of several small things not being right...

Drop the tank and dismantle the fuel system, get the injectors cleaned professionally and give the rest of the system a birthday cleaning Then Id be checking

the fuel pressure in the rail while its actually misbehaving. in fuel injected engines bad running with increased fuel economy is almost always lean running caused by blocked filters and loss of pressure in the rail cutting back the fuel going into the cylinders.

once its started to run rough after that pull the plugs and check them to see what the engines doing while its misbehaving then check the conditions of your leads and the spark thats being thrown out.

Originally Posted by Blknight.aus

just read the thread.

it sounds like a culmination of several small things not being right...

Drop the tank and dismantle the fuel system, get the injectors cleaned professionally and give the rest of the system a birthday cleaning Then Id be checking

the fuel pressure in the rail while its actually misbehaving. in fuel injected engines bad running with increased fuel economy is almost always lean running caused by blocked filters and loss of pressure in the rail cutting back the fuel going into the cylinders.

once its started to run rough after that pull the plugs and check them to see what the engines doing while its misbehaving then check the conditions of your leads and the spark thats being thrown out.

Thanks again Blk...so in you estimation would as kindly suggested buy Mrs Ho Har the fuel pressure should run at around 31psi and if it isn't would this suggest a fading fuel pump ?...

and atm checking the plugs whilst it is playing up is going to be hard because its running fine at idol ...it seems to only play havoc whilst under load ...replaced fuel filter yesterday and there was a fare bit of really loose black soot floating about ...so i guess as you suggested i might pull it out and give it a good clean ...do we just flush it with fresh fuel or is there a type of cleaner to be used ..excusse the ignorance

cheers

no, it could be a blocked strainer, blocked fuel line any number of small things that relate to the fuel filter, given the description of the filter you changed If I had a vehicle turn up in that state Id be calling the owner and explaining that it would be a good idea to at least pull the pump, inspect the strainer, clean out all the fuel lines and have the injectors serviced. you could have 31 psi in the rail but if the injectors are blocked they wont inject the right amount of fuel.

as for the plugs thing, take it for a drive, get it all warmed up and make it misbehave for at least 10-15 minutes then shut it down immediately and check the plugs/leads/spark with the engine still warm.

I doubt that what your getting out of the filter is soot as thats an indicator of a sticking injector on a diesel thats letting combustion gasses back into the fuel system. It might be rubber or plastic particles from failing fuel line or the tank itself.

Originally Posted by Blknight.aus

no, it could be a blocked strainer, blocked fuel line any number of small things that relate to the fuel filter, given the description of the filter you changed If I had a vehicle turn up in that state Id be calling the owner and explaining that it would be a good idea to at least pull the pump, inspect the strainer, clean out all the fuel lines and have the injectors serviced. you could have 31 psi in the rail but if the injectors are blocked they wont inject the right amount of fuel.

as for the plugs thing, take it for a drive, get it all warmed up and make it misbehave for at least 10-15 minutes then shut it down immediately and check the plugs/leads/spark with the engine still warm.

I doubt that what your getting out of the filter is soot as thats an indicator of a sticking injector on a diesel thats letting combustion gasses back into the fuel system. It might be rubber or plastic particles from failing fuel line or the tank itself.

right thanks Blk...mate dropping the tank wont be a problem but do you have any things to be aware of in doing so

cheers