Now i've looked again i see there are several capture's i though it was just one.
I know you have to back up waveform's with tests i was just saying on this engine it is a bit of a pain to manually test fuel pressure that was all, i'm not claiming to be an expert!
Fuel pumps are bad for going and usually make a loud whine before they fail all together that is why i asked about that but he hasn't replied yet!
Fuel pumps are bad for going and usually make a loud whine before they fail all together that is why i asked about that but he hasn't replied yet!
Yes i am aware of that !
i was just saying on this engine it is a bit of a pain to manually test fuel pressure that was all,
Pretty sure i could test the fuel pump without too much trouble.
The OP is not looking for a silver bullet, (or at least i don't think he is) it just looks to me like he is after an interpretation (bit of a nudge) of the captures he has got so he can go away & test/prove/learn.
Last edited by Robski on Wed Aug 07, 2013 6:49 pm, edited 1 time in total.
In the TD5 engine the high pressure side and low pressure side are both built into the in-tank pump are they not?
Why would you test low pressure when the high side is the more important one on this set up?
Most problem's i have had have been from a lack of high pressure from the pump or they fail all together and cause a non-start but also other faults cause a lack of go on these as well, will wait and see what Tim says though
Why would you test low pressure when the high side is the more important one on this set up?
I edited the post as i meant 'fuel' pump
So then ......... whats the spec for this pump, LP/HP side, where would you 'tap' in to test ?
What's the flow rate, how would you carry this test out ?
It is easy enough to back that current capture up with the rest of the 'KPI's' .
I think your find Robski is correct in the ability of testing the low side, although this system is not the easiest to plumb into it still has a test procedure. I think your find that on the TD5 it has a two stage system.. The fuel supply system the low pressure (first stage) feeds into the replaceable filter and has a spec of 0.75 Bar..
The Td5 has no fuel injection pump
The second stage fuel pump will draw fuel from the filter and pressurises it to 4 bar before supplying it to the engine at a rate of 180 litres per hour.
I can't remember off the top of my head as i haven't done one for a while but i'm sure it is 4.0 bar on the HP side but i'd have to check my LR tech info to be sure for the other figures.
To test HP side i tap in at fuel regulator at the back of the cylinder head and LP could be done at the fuel filter housing but have never needed to do that as like i say fault for me has always been on HP side.
I'm not sure on MAF now i have had another look i'd say there is a problem as it is peaking at almost 5v and in some of other captures it looks 'flat' but this is where being new to scoping is going to bite me as i'm not 100% sure and looking back i should of kept my mouth shut before saying it was 'ok' so i apologise.
Before having the scope i used to check live data for MAF and we stock Genuine units so could always try one if in doubt to be sure and if not put it back into stock.
Darren Cotton wrote:I think your find Robski is correct in the ability of testing the low side, although this system is not the easiest to plumb into it still has a test procedure. I think your find that on the TD5 it has a two stage system.. The fuel supply system the low pressure (first stage) feeds into the replaceable filter and has a spec of 0.75 Bar..
The Td5 has no fuel injection pump
The second stage fuel pump will draw fuel from the filter and pressurises it to 4 bar before supplying it to the engine at a rate of 180 litres per hour.
Darren
Bang on by my info.
although this system is not the easiest to plumb into it still has a test procedure
although this system is not the easiest to plumb into it still has a test procedure
No pain no gain.[/quote]
This is true... Also I only see one MAF capture and it takes 1.5 secs to peak... that seems a long time, could this be an effect... if the fuel is restricted are pressure is incorrect?
Darren
Last edited by Darren Cotton on Wed Aug 07, 2013 7:15 pm, edited 1 time in total.
Before having the scope i used to check live data for MAF and we stock Genuine units so could always try one if in doubt to be sure and if not put it back into stock.
AKA swoptronics.
To test HP side i tap in at fuel regulator at the back of the cylinder head and LP could be done at the fuel filter housing but have never needed to do that as like i say fault for me has always been on HP side.
Where does HP start ?
What about a restriction on the LP side (filter) ?
I'm not sure on MAF now i have had another look i'd say there is a problem as it is peaking at almost 5v and in some of other captures it looks 'flat' but this is where being new to scoping is going to bite me as i'm not 100% sure and looking back i should of kept my mouth shut before saying it was 'ok' so i apologise.
No worries.
Look at the wider picture !
could this be an effect.
The reason why i never mentioned the MAF in the first place & angled at the fuel system
Both your post's make a lot of sense and just show's the difference between someone with knowledge and someone without
I've been brought up by people who don't know anything about diagnostics, proper testing and it's hard to learn when they don't teach you or will not spend money for you to learn.
Working with Land Rover's a lot i was just trying to help but in the process i have dragged this way off topic.
To be fair i used to play parts darts and being young i didn't know any better and i just did what i was told but since getting more into diagnostics i know things have to be tested, proved with the right equipment, test plan etc to get the fix right first time!