Engine Fuel Pressure, useful, how do I measure it?

[Portofino]

I'd be looking for a blank on the filter housing measuring before filter... That way a pressure increase will show if filter is blocked or blocking... Post filter won't show much I wouldn't have thought. You only have one channel?

Steve

What are we discussing here ?
As per post #1 or Vac. Gauges?
like theses off the self?

 

[MapisM]

A. between Separs and liftpump: measure vacuum, checking condition of Separs

V, for this specific purpose, you might consider the following OEM Separ accessory.
Just click on the image for further details.

 

[sorabain]

 

[Assassin]

Have you ever seen that actually fitted to any marine engine?
Far from pretending to have seen them all, but definitely quite a few, and I never came across anything like that.
Regardless, I'm not sure I would want any kind of sensor in between the HP pump and any (let alone every!) injector.
Reasoning being, only what you don't have never breaks...

Yes, marine engines, industrial engines, heavy automotive engines, agricultural engines and many heavy engine fitters carry them in some form in their vans.

 

[Assassin]

Not strictly true as the lift pump is before the on engine filter generally (I think??) So the lift pump to filter / injector pump is under low pressure from the lift pump and if tank is high, then it will be under head pressure continuously when not pumping.

Between lift and bulk filter (closest to tank) it will be under vacuum when running, which is great to monitor as it indicates filter trouble, as would an increase in pressure on the post lift pump side indicate on engine filter issues

Steve

Read my post again, it says IT DEPENDS UPON LAYOUT.

 

[Assassin]

Basically only fit any kind of sensor to a system whereby if the said sensor fails for what ever reason it’s isnt gonna end up mission critical .
I wouldn’t mess .....interfere with the existing fuel lines, chopping and adding bits in ........If it can go wrong it will .

Its a pressure sensor and the only thing to go wrong is to lose the pressure reading, these do not impede the flow.

 

[Assassin]

thanks guys, to sum it all up:

My IVECOs layout is that I have Separ prefilters/waterseparators -> liftpump -> main engine mounted filters -> highpressure pump -> injectors. FWIW, lift/highpressure pumps are in one Bosch assembly, just a copper pipe leaving going halfway round the block to the two filters and back to the highpressure part.

so my options are:

A. between Separs and liftpump: measure vacuum, checking condition of Separs
B. between liftpump and main engine filters: measure fuel pressure and combined condition of Separs and lift pump
C. between main engine filters and high pressure pump: measure fuel pressure and combined condition of all filters and agility of lift pump
D. highpressure side, is not an option IMO

Seems that IF I decide to go ahead, I should tap somewhere along the C route.
I guess this pressure (say 25psi or there abouts) stays put with the engine off and turning the key to on position even before cranking you have an idea of potential fuel leaks and any need for bleeding the circuit.

cheers

V.

Thanks for clarifying your layout Vaz, so you want line pressure after the filters and before the HP pump!!! I suggest putting in a T piece between the line and HP pump and fit this to the pump end and not the filter end, you simply screw a pressure guage in and you can see ecxactly what pressure your HP pump is receiving, these are fairly standard components for Bosch pumps on industrial engines and can be sourced from Bosch with a choice of threads for the guage to screw into and I suggest 1/4" BSP. Bosch prefer to sell you their guage and they are expensive, you can source them for fuel almost anywhere for much lower prices.

 

[Portofino]

Its a pressure sensor and the only thing to go wrong is to lose the pressure reading, these do not impede the flow.

“ for what ever reason “ inc leaky unions and the thing itself seeping .......
Depending on where add another layer to prove out if air is suspected of entering or on the other side insufficient pressure .

Just seems counterintuitive to hack up your own fuel lines on the engine around the pump .
I mean to be sure of not getting swarf in you would have to totally remove said pipe and thoroughly rinse it out / compress air it through etc .

Fitting a new lid + OEM vac gauge on a remote filter housing is acceptable in my book .

 

[MapisM]

many heavy engine fitters carry them in some form in their vans.

I take your word for that, but my question was different: did you actually come across any pleasure boats whose engines had such HP sensors installed?
And on EACH injector (therefore, also with some instrument capable to handle such multiple parameters)?
Just curious.

 

[Assassin]

Mapis, nobody mentioned having them to each injector, they only install ONE on ONE injector and this is to measure the pressure to the injector, and as the OP has clarified he wants line pressure the point is moot now.

It only measures the pipe pressure from the pump to injector and the actual installation depends on which type is fitted, you only need a maximum of four wires to them and obviously live and neutral and the two signal wires to the reader, therefore no parameters are necessary.
Yes, currently I know of 4 marine engines with them fitted, 2 were fitted by the engine manufacturers for long term testing of a potential arising problem and 2 others fitted to engines with distributor pumps fitted which are known to lose injection pump pressure with age.

Porto, there are two types, the manufactured combined unit which comes installed in the pipe which is a straight bolt in replacement and has no other fittings other then the two unions on the ends of the pipes so there is no more chance of it leaking than your standard pipe if they do them for your specific engine; or the bolt in type which does have an additional union and requires the unit fitting to either the injection pump outlet OR directly onto the engine. There is no hacking unless you are an absolute bodger and you remove the existing pipe and shorten it back to compensate for the lost length and cut it using the correct tool and flare it using the correct tool. Sometimes I think you are being deliberately obtuse.
So, what your clear play on words is saying is that you undo one end of the pipe, cut it with a knife and fork with a hatchet for difficult bits, then flare it using a peening hammer and hope it fits, it says more about your lack of abilities than anything else, how many injector pipes have you fitted, and how many have you made?