MY 1999p38 With the M51 BMW engine has developed a fault that when it s being revved it will get up to 2500 rpm and then hesitate and start to rev to 3500 rpm and the MIL light will come on.when my foot is lifted off the throttle it the revs will drop ton 2500 and then back to 3000 and then drop off again back to 2500 and surge again.
I have put my NANACOM on it and the live readings are the modulation is about 7% at idle and then goes up to 70% when the MIL light is on. I also have had one fault recorded that said timing solenoid out of expected range so i assume that is the problem. but i don't know where this solenoid is located as i lave left my RAVE disc back in Oz.
i rather fancy its embedded in the FIP somewhere and needs a diesel pump repair place to repair it.
If anyone (wammers ) know where it is the knowledge would much be appreciated
the no 4 injector is new and the ECU has had a known good one in it and different MAP and MAP has been tried the EGR disconnected Not using oil so not eating the sump oil the temperature sensors replaced with known working ones and the CPS been replaced
The car has been standing for 7 months but it had this problem before i laid it up and it started first hit of the button. The FIP has been timed with dial gauge but the modulation is way out from what it should be.

Quantity servo fault? It’s in the FIP

Usually accompanied by mil lamp coming on when lift off throttle. How old is your fuel filter?

I’d wait for Wammers.

Timing solenoid is at rear bottom of injection pump. With static timing correctly done modulation at idle warm should be between 45% and 55%. Modulation is checked ONLY at idle. As it will obviously change at higher RPMs due to internal fuel pressure increase.
Providing the solenoid is functioning 7% at idle warm would suggest static timing is too far advanced.

wammers said:

Timing solenoid is at rear bottom of injection pump. With static timing correctly done modulation at idle warm should be between 45% and 55%. Modulation is checked ONLY at idle. As it will obviously change at higher RPMs due to internal fuel pressure increase.
Providing the solenoid is functioning 7% at idle warm would suggest static timing is too far advanced.

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Isn't there a hole in the flywheel before the TDC one? If lift was checked in the preceding hole would it run and would modulation go up or down?

wammers said:

Timing solenoid is at rear bottom of injection pump. With static timing correctly done modulation at idle warm should be between 45% and 55%. Modulation is checked ONLY at idle. As it will obviously change at higher RPMs due to internal fuel pressure increase.
Providing the solenoid is functioning 7% at idle warm would suggest static timing is too far advanced.

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As i said I have checked the static timing both on No 1 and number six with a dial gague and the modulation at idle is 7% and remains at 7% untill the revs reach 2500 and then the MIL light comes on and the revs go up to 3500 and will not drop back and i have to switch the engine off to bring the revs down, and the only thing that live data shows is the modulation goes up to 75%. the engine starts first time and it will idle at 750 ,and does not play up untill the revs reach 2500. so i dont think its static timing thats the problem.

Can you see what the throttle pot is doing on the Nanocom?

This is the car that was never the same after leaving it with that garage?

ovalandrover said:

As i said I have checked the static timing both on No 1 and number six with a dial gague and the modulation at idle is 7% and remains at 7% untill the revs reach 2500 and then the MIL light comes on and the revs go up to 3500 and will not drop back and i have to switch the engine off to bring the revs down, and the only thing that live data shows is the modulation goes up to 75%. the engine starts first time and it will idle at 750 ,and does not play up untill the revs reach 2500. so i dont think its static timing thats the problem.

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If CPS is failing engine will rev to 2500 or so because the ECU relies on the number four injector to get it's RPM info. So instead of six pulses per revolution it only gets one pulse every two revolutions. If the number four injector and timing solenoid are sound static timing cannot be correct at 7% modulation at idle. It is far too advanced. Timing pin MUST be inserted in flywheel correctly so that the engine is locked solid in both directions. All this is taking the injection pump as not having been played with in any way.

Further to the above. When reading modulation look at the two values immediately above modulation readout. Injection set point degrees and injection actual degrees. At idle warm modulation should be between 45% and 55% and set point and actual should be no more than 0.5 degrees different. If they are vastly different, use a stethoscope and check that the modulation solenoid is buzzing. If it is not check wiring to it.

Update
I finally found time to investigate further and took of pump and sent to pump repair specialist and he found a part had fallen off somwhere in the internals that should have affected the internal
Refitted pump and same fault as before but i could not get any sensible static timing this time so in desperation i removed the front cover to check the basic chain timing. Remember this engine had been rebuilt twice by SIAN AUTOCENTER and has never een right since and all they wanted to do was throw new parts at and would not fix it so after about 2 months i took it off them.
anyway front cover off and what did i find the chain was 2 teeth out and the plastic guide was not secured in its position see photo.will fix back tomorrow aand time pump and hopefully will cure it.
will upate furthere tomorrow if i have time to reassemble.

Wow! Quality repairs.

ovalandrover said:

View attachment 191029 Update
I finally found time to investigate further and took of pump and sent to pump repair specialist and he found a part had fallen off somwhere in the internals that should have affected the internal
Refitted pump and same fault as before but i could not get any sensible static timing this time so in desperation i removed the front cover to check the basic chain timing. Remember this engine had been rebuilt twice by SIAN AUTOCENTER and has never een right since and all they wanted to do was throw new parts at and would not fix it so after about 2 months i took it off them.
anyway front cover off and what did i find the chain was 2 teeth out and the plastic guide was not secured in its position see photo.will fix back tomorrow aand time pump and hopefully will cure it.
will upate furthere tomorrow if i have time to reassemble.

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F*ck me. No wonder nothing made sense.