P38 2.5 Inj Pump modulation issue.

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Mark Piercy said:
Reading this lot, mine sits above 750 rpm, ive read the mg/str at 8 with my none nano and it goes like a demon.(not complaining)..
I dug the history from the last owner and it had a stage 2 tune up with a bigger intercooler. What bhp is the stage one?
This cost the owner £1200 in 2005!! I also discovered that dropping it into 3rd allows it to go into lockup in 3rd after a certain speed and goes very nicely when you drop the pedal.
Not abused as i quite like the drivetrain working in its current state. Anyhoo, mines up next for chains and tensioners when any bugger is ready??!!!;)
I really do love my bus, its absolutely ace.



Got my soppy coat..... :oops:
Click to expand...

Normal idle is 750 rpm plus or minus 50 rpm. The engine being chipped should not alter that.
 
wammers said:
Normal idle is 750 rpm plus or minus 50 rpm. The engine being chipped should not alter that.
Click to expand...
I know Tony, when i did the cap seals on the fip i hadn't quite got them in the exact place. Without the help of a more dedicated software i wasn't willing to start faffing about and running the risk of maybe damaging a seal in the process. So, i got it at that point, with luck I'll say and left it there...
It would be nice to have it put correct though.;)
 
Mark Piercy said:
I know Tony, when i did the cap seals on the fip i hadn't quite got them in the exact place. Without the help of a more dedicated software i wasn't willing to start faffing about and running the risk of maybe damaging a seal in the process. So, i got it at that point, with luck I'll say and left it there...
It would be nice to have it put correct though.;)
Click to expand...

Big expensive calibration machines do that Mark. ;)
 
Mark Piercy said:
Reading this lot, mine sits above 750 rpm, ive read the mg/str at 8 with my none nano and it goes like a demon.(not complaining)..
I dug the history from the last owner and it had a stage 2 tune up with a bigger intercooler. What bhp is the stage one?
This cost the owner £1200 in 2005!! I also discovered that dropping it into 3rd allows it to go into lockup in 3rd after a certain speed and goes very nicely when you drop the pedal.
Not abused as i quite like the drivetrain working in its current state. Anyhoo, mines up next for chains and tensioners when any bugger is ready??!!!;)
I really do love my bus, its absolutely ace.



Got my soppy coat..... :oops:
Click to expand...
Well as you aren't too far away when we're over there we could do both of ours when the weathers nice next year as mine is due a head gasket change, so might as well factor in chains & sprockets, static timing and then do the job on both properly. I have a timing kit :D what I don't have is 4 hands and the experience hahaha

And I can bring the wine
And I have huge barns for storage if you need anything under cover for any length of time:)
 
Mukiwa said:
Well as you aren't too far away when we're over there we could do both of ours when the weathers nice next year as mine is due a head gasket change, so might as well factor in chains & sprockets, static timing and then do the job on both properly. I have a timing kit :D what I don't have is 4 hands and the experience hahaha

And I can bring the wine
And I have huge barns for storage if you need anything under cover for any length of time:)
Click to expand...
Cheers for the offer mate, I replaced the head,timing chains and sprockets earlier in the year. Not a hard job if you follow Rave to the letter. Mind you I have had too many years on the tools
 
wammers said:
If they have never done this job before they must follow the correct procedure for pin location and timing set up using a DTI. There are two timing pips, one 40 degrees before the TDC pin hole and one 20 degrees after it. It is easy to get hung on one of those which will put static miles out. With the pin correctly inserted the engine should be immovable in either direction. The pump is set to 0.9 mm cam lift after having followed correct procedure for zeroing DTI and then inserting timing pin.
Click to expand...
I've just been to garage and witnessed them re-timing the pump as per RAVE at .9mm. They had the rocker cover off to verify the cam position. They had paint marks left from before this retime. The paint marks showed it being in the same place as previous. They also said that they had tried moving the pump to various positions but that the modulation never moved off 4%. We then took the ECU out and put it into another P38 (plugged in diagnostics to reset) and it ran OK. The ECU from the running P38 will be put into the car that's got the 4% modulation just to rule that out. The manifold is being put back on now - but they don't expect any change from the 4% modulation. Would this point to a wiring break? Really wondering where to go next....
 
markav8r said:
I've just been to garage and witnessed them re-timing the pump as per RAVE at .9mm. They had the rocker cover off to verify the cam position. They had paint marks left from before this retime. The paint marks showed it being in the same place as previous. They also said that they had tried moving the pump to various positions but that the modulation never moved off 4%. We then took the ECU out and put it into another P38 (plugged in diagnostics to reset) and it ran OK. The ECU from the running P38 will be put into the car that's got the 4% modulation just to rule that out. The manifold is being put back on now - but they don't expect any change from the 4% modulation. Would this point to a wiring break? Really wondering where to go next....
Click to expand...

If you get no luck look at the connection to the modulator valve (bottom rear of pump) two wires Red/white tracer and White. Make sure its plugged in. Make sure there is power to Red/white wire on socket from loom with ignition on engine running. White wire goes to engine ECU that grounds it as needed to operate modulation valve. With engine running you should be able to hear this buzzing using a stethoscope.
 
markav8r said:
I've just been to garage and witnessed them re-timing the pump as per RAVE at .9mm. They had the rocker cover off to verify the cam position. They had paint marks left from before this retime. The paint marks showed it being in the same place as previous. They also said that they had tried moving the pump to various positions but that the modulation never moved off 4%. We then took the ECU out and put it into another P38 (plugged in diagnostics to reset) and it ran OK. The ECU from the running P38 will be put into the car that's got the 4% modulation just to rule that out. The manifold is being put back on now - but they don't expect any change from the 4% modulation. Would this point to a wiring break? Really wondering where to go next....
Click to expand...

So, to recap so I can get my head around what is happening ...

Car was running fine but FIP was leaking.
FIP replaced and car won't run properly - cuts out.
Original FIP refurbed and swapped back in - car still won't run. Cuts out.
ECU taken out and placed in another car - other car runs fine.

So, the act of changing the pump f*cked something.

The modulation is from comparing point of injection from crank sensor with needle lift sensor in injector #4. Based on this value it either moves the control collar solenoid to fine tune the injection. Solenoid closed increases pressure and so the start of the injection at the needle will be advanced. Wammers seems to suggest that a wire has broken so no power to move the solenoid? Is that right?
 
Grrrrrr said:
So, to recap so I can get my head around what is happening ...

Car was running fine but FIP was leaking.
FIP replaced and car won't run properly - cuts out.
Original FIP refurbed and swapped back in - car still won't run. Cuts out.
ECU taken out and placed in another car - other car runs fine.

So, the act of changing the pump f*cked something.

The modulation is from comparing point of injection from crank sensor with needle lift sensor in injector #4. Based on this value it either moves the control collar solenoid to fine tune the injection. Solenoid closed increases pressure and so the start of the injection at the needle will be advanced. Wammers seems to suggest that a wire has broken so no power to move the solenoid? Is that right?
Click to expand...
Yes.
 
Grrrrrr said:
So, to recap so I can get my head around what is happening ...

Car was running fine but FIP was leaking.
FIP replaced and car won't run properly - cuts out.
Original FIP refurbed and swapped back in - car still won't run. Cuts out.
ECU taken out and placed in another car - other car runs fine.

So, the act of changing the pump f*cked something.

The modulation is from comparing point of injection from crank sensor with needle lift sensor in injector #4. Based on this value it either moves the control collar solenoid to fine tune the injection. Solenoid closed increases pressure and so the start of the injection at the needle will be advanced. Wammers seems to suggest that a wire has broken so no power to move the solenoid? Is that right?
Click to expand...

Recap correct, but since then needle lift injector, crank position sensor, temperature sensors have all been changed.
Also today the garage traced the wires from the plug on the harness pump and they appear unbroken to the fuse and also to the ECU plug.
The modulation appears to stay at 4% at idle and may go to 22% on a run.
They are going to look again at the Crank position sensor.
Maybe the modulation can be manually operated to test its function - applying 12v.... ?
 
markav8r said:
Recap correct, but since then needle lift injector, crank position sensor, temperature sensors have all been changed.
Also today the garage traced the wires from the plug on the harness pump and they appear unbroken to the fuse and also to the ECU plug.
The modulation appears to stay at 4% at idle and may go to 22% on a run.
They are going to look again at the Crank position sensor.
Maybe the modulation can be manually operated to test its function - applying 12v.... ?
Click to expand...
Tracing the wires is not the same as checking you have power on one and a signal on the other.
 
markav8r said:
Recap correct, but since then needle lift injector, crank position sensor, temperature sensors have all been changed.
Also today the garage traced the wires from the plug on the harness pump and they appear unbroken to the fuse and also to the ECU plug.
The modulation appears to stay at 4% at idle and may go to 22% on a run.
They are going to look again at the Crank position sensor.
Maybe the modulation can be manually operated to test its function - applying 12v.... ?
Click to expand...

If the modulation moves at all at higher engine speeds other than idle that would indicate either that the timing is still wrong or bad signals from number four injector.
 
wammers said:
If the modulation moves at all at higher engine speeds other than idle that would indicate either that the timing is still wrong or bad signals from number four injector.
Click to expand...

If you accelerate it will try to advance the injection, won't it? So if already advanced the modulation will go towards 50%? So what we'd expect to see if the collar isn't moving is modulation of 4% at idle (on his), increasing as you plant your foot and then as the revs level out and it reaches equilibrium on load it'll drop back to 4%. And then presumably when you let off the accelerator it'll try to drop but cannot go much below 4% and will cut out?
 
Grrrrrr said:
If you accelerate it will try to advance the injection, won't it? So if already advanced the modulation will go towards 50%? So what we'd expect to see if the collar isn't moving is modulation of 4% at idle (on his), increasing as you plant your foot and then as the revs level out and it reaches equilibrium on load it'll drop back to 4%. And then presumably when you let off the accelerator it'll try to drop but cannot go much below 4% and will cut out?
Click to expand...

What collar. modulation is about timing nothing to do with quantity collar.
 
Grrrrrr said:
So, to recap so I can get my head around what is happening ...

Car was running fine but FIP was leaking.
FIP replaced and car won't run properly - cuts out.
Original FIP refurbed and swapped back in - car still won't run. Cuts out.
ECU taken out and placed in another car - other car runs fine.

So, the act of changing the pump f*cked something.

The modulation is from comparing point of injection from crank sensor with needle lift sensor in injector #4. Based on this value it either moves the control collar solenoid to fine tune the injection. Solenoid closed increases pressure and so the start of the injection at the needle will be advanced. Wammers seems to suggest that a wire has broken so no power to move the solenoid? Is that right?
Click to expand...

Nothing to do with fuel control collar. You need someone who knows what he is doing to look at it. Your understanding of what goes on above is tits up and arse about face see post # 35.
 
If you have a problem stalling on overrun that is most certainly a quantity servo fault and that does control the fuel quantity collar. Nothing at all to do with timing. How are you getting modulation readings do you have a Nanocom?
 
Grrrrrr said:
Does the collar not adjust the pressure and that in turn the opening of the #4 injector and hence the timing of #4 and the modulation?
Click to expand...

No. The modulation valve adjust the internal fuel pressure against the timing device piston spring. See post #35.
 
wammers said:
If you have a problem stalling on overrun that is most certainly a quantity servo fault and that does control the fuel quantity collar. Nothing at all to do with timing. How are you getting modulation readings do you have a Nanocom?
Click to expand...

Given the OP is using a garage I imagine they're using some sort of generic reader.
 
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