Can anyone help? I am a bit of a newbie to the scope and would like some advice the relationship between the frp sensor and injection events.I have attached 2 measurements one of the frp at startup, then idle, then roughly 2500 rpm, back to idle, engine switch off and pcm shutdown, and also one of number one injector. The vehicle in question hydro locked which I suspect was due to a defective injector but left it a few hours and it has been fine since and the injector compensation values are all within a range of 0.5 so nothing really to worry about just wondering what if anything the capture attached shows and if anyone would be so kind to explain what discrepancies I should look for in future?
Thanks in advance
How does that allow me to ascertain an issue? and how is the pressure over time calculated? i.e how long should it take to build pressure and how can I see if a specific injector is less efficient than the others?
Hello,
To see if an injector will have a lower efficiency than others you must use Techstream /Fuel injector cut and record the injected quantity , the rail pressure must be compared with the target to see how fast the injection system can adjust it.
Best regards
Hi Victor2K I have done that but cant see a deviation, I was on a course once with Frank Massey and he showed a test that as he revved the engine the trace showed the fuel pump building pressure and also the injectors using pressure but I cant seam to replicate it, how would I go about doing this? I believe the test I have done is the same I am just struggling to read the data.
If we are talking about the fuel equipment DENSO, namely it is used on TOYOTA, the deviation of the fuel pressure when the injector is triggered at idle is almost invisible.
You can see the pressure deviation only when the rpm increases when the SCV valve closes.
But this pulsation is not associated with the opening of the injector valve, but with the operation of the plungers in the high-pressure pump.
I think there are a number of questions that need some answering but there is of course a relationship between the rail pressure sensor and an injection event. Below is a capture I took from a machine that had a performance issue.
As you can see there is a slight drop in the rail pressure after each injection event and notice that repeatably every 6th injection event, the pressure doesn't drop as much. This indicates that something isn't right and combined with the crank math channel we can also see that there is a slight slowing down in the crankshaft. All this leads us to have enough evidence to relate the slowing of the crank to change in the rail pressure. Could this be an injector partially blocked? Still awaiting feedback at the moment but we can prove there is a relationship between the rail pressure, injection events and the crankshaft speed.
The biggest problem I see with the capture you have is the sample rate is very low. To increase this use the arrow on the right hand side of the circled box till it reads 1MS.
The increase in samples will give us more detail and hopefully start to pick out any anomalies.
Try a capture at first at idle and then if you have Techstream, activate the fuel leak test. This will max the fuel pump to increase the fuel pressure and will hopefully give you further definition in the rail pressure sensor waveform.
I hope this helps and please re-post your capture for us to see.
Hello,
You can have a faulty injector(is hard to find it at the begining,the crystal is shorted only sporadic(clear fault memory and will work for a few days)),use TSB EG-0130T-1215 for this,you can see it using a clampmeter only when the fault is present.
Also you can't see a good injection/rail pressure drop because of the common rail construction(description at page 167 in attached file).
Best regards
Hi Victor2K I have done that but cant see a deviation, I was on a course once with Frank Massey and he showed a test that as he revved the engine the trace showed the fuel pump building pressure and also the injectors using pressure but I cant seam to replicate it, how would I go about doing this? I believe the test I have done is the same I am just struggling to read the data.