Seems to be an odd one. I'd be putting a link across the fuel pump relay, so it's driven constantly. Then take for a test run to see if the fault goes away. If it's then ok, you'll be one step closer to solving it.
 
Thanks for ideas. No remap. Still suspect lp pump but all test figures are good. Was thinking of strapping pump relay but concerned in case shut down was safety protection. What I need is a functional spec for the ecu.....what causes pump shut off. May test with link but I am sure this will solve as pump relay is dropping when fault occurs.
 
Just a thought. Engine came from 2003 car. 2003 car has fuel pump relay in bonnet fusebox and pump in rear wheel arch. Mine has relay in passenger fusebox and pump under bonnet. Is there a difference in wiring and does the under bonnet relay with wheel arch pump arrangement still have a feed from the ecu to the relay coil? How does the rev limiter work? Is it crank sensor to ecu and then command at certain revs to command fuel cut off - could it be the crank sensor telling porkies? Speedo seems accurate though. I could live with it but MOT will be interesting when they try to rev the wotsits off it ! Will protect the engine though :)
Can anyone confirm LP fuel pressure at around 3500 rpm? Mine is 360 (whatever the icarsoft units are - no labelling). My other TD4 is 375 - could it be a critical threshold?
Next move will be to substitute LP pump and change filter. Pressure measurement should be via sensor at output of filter so should be o.k but I have been foiled by believing readings before !
 
Just found this post - it suggests that there is a 3,000 rpm limit when stationary.
https://www.landyzone.co.uk/land-rover/jatco-auto-box-is-this-true.231171/#post-2662547

Anyone know if this is definitely the case - maybe mine thinks it is stationary when it isn't ! If so what sensor says it is moving?
Does anyone know how the rev limiter works? Mine is definitely a cut in power to the fuel pump relay from the ECU when the 'fault' occurs. Beginning to think it may be linked to a fault here.
 
Think I'd try the lp fuel pump if not already changed before delving too deep. Sounds like fuel starvation, seem to remember that you must use either genuine or OE, I used OE and had no problem. Changed mine because it was free floating due to corrosion thanks to the build up of crap under the O/S/R wheel arch.
 
Thanks - pressure reading in icarsoft reader is o.k and isolating the LP sensor (so that it doesn't know the pressure and therefore won't act to protect the HP pump) does not solve problem. BUT if I can't find a genuine reason for the ECU cutting the fuel relay supply then I'll change fuel pump and filter.
 
andyfreelandy said:
Just found this post - it suggests that there is a 3,000 rpm limit when stationary.
https://www.landyzone.co.uk/land-rover/jatco-auto-box-is-this-true.231171/#post-2662547

Anyone know if this is definitely the case -
Click to expand...

If it was the case, the MOT tester couldn't do the govenor smoke test for the MOT.
Some more modern diesels do limit RPM while the brake is applied and the throttle pedal is floored, but not if just the throttle is floored, for the reason above.

Have you linked out the LP relay and tried that yet?
 
Ok so temp bypass of lp fuel pump relay contacts solves problem. But...obvs that bypasses the ecu and it's abilty to cut engine. Maybe the 'governer' is operating too low?? How does governer work, assume it is crank sensor and electronics? Thanks
 
andyfreelandy said:
Ok so temp bypass of lp fuel pump relay contacts solves problem.
Click to expand...
That narrows it down then.
andyfreelandy said:
But...obvs that bypasses the ecu and it's abilty to cut engine.
Click to expand...
Yes it does, but only so far as to kill the LP pump when the engine isn't running.

andyfreelandy said:
Maybe the 'governer' is operating too low??
Click to expand...
The governor isn't anything to do with the LP supply.
andyfreelandy said:
How does governer work, assume it is crank sensor and electronics?
Click to expand...
The max speed governor is part of the fueling map. This works by reducing injector throughput as the engine reaches the maximum speed, in the same way as a modern petrol engine does.

I'm curious as to why the EDC is killing the LP pump, when the LP rail pressure is correct. I'm thinking that maybe the EDC has some corruption in its map.
 
Thanks, I meant by 'the governer is operating too low' that maybe the thing that tells the EDC the engine speed (crank sensor) is lying? Although if the only 'cut the LP pump' feature is due to low pressure then it does sound like the EDC could be at fault. I think the fact that it was o.k prior to engine change makes me think 'incompatibility' somewhere rather than fault. I think the engine management module is coded to the security box so a swap not easy to do?
 
When was the last time you had the old engine up to 3,750 revs? I mentioned it earlier, but I seriously do not think I ever take my L series that high. You may have had the problem before and not known about it.

Chances are though that it is something that has been introduced with the change.

Have you checked the alternator? If it is throwing spikes or dips of power this could be confusing the EDC or relays. Mind you, it would probably have fried something by now.
 
If the problem wasn't there with the old engine, then it must have been introduced with the new one. What didn't you swap over from the old engine?
I can't imagine it being the crank sensor as you would see the rev counter would fall at the time of the problem. If however the rev counter does dip, then it could well be the crank sensor.
 
Some more testing tomorrow. Rev counter does drop, but largely as a result of cutting the fuel supply I think !
I'm beginning to wonder if the sensor loom (which I left on the donor engine) is slightly different to the pin outs on the EDC. Haynes shows a difference between 2001 and 2002 and some pins around the MAP sensor and the Crank Sensor seem interchanged ! Might be on to it....... Map sensor fault and revs problem would fit with this. Will be testing old loom vs new loom to see if there is any difference (esp in these areas).

As the donor engine ran fine I left all sensors are they were, fitted my refurb starter, new alternator and EGR bypass / Cyclone filter and left everything else as it was. So all donor car sensors. Have now changed MAP with no effect.
If the problem had been on the old car, as Nodge points out - Mr MOT man would have found it at rev the bo**ocks off time - even if I didn't ! Auto on kick down hits 3,750 rpm fairly easily.
 
Just checked with dealer for donor and my car engine harness. They are the identical part. So....looking for a fault now either with loom or crank sensor. Just done 300 motorway miles and it runs brilliantly!! Mild annoyance at the 'bug' in system!!
 
If you have access to an oscilloscope, you can see the crank sensor's waveform as you run the engine. You could even try a DMM on the crank sensor connection at the EDC to see if it drops off at the speed where the problem happens.
 
So.. Checked all wiring from crank sensor and MAP. All good. Applied ac meter to crank sensor and all seems to be without gaps. Smoothly moves from 1 v at about 1000 rpm to 3.5v at 3500 rpm and continues through fault condition with minor fluctuation as revs change. Bad news is that with fuel pump relay contacts bypassed fault occurs at higher revs!! About 4300 rpm. BUT with lp pump relay contacts bypassed to keep fuel pressure stable and by watching live data through the fault condition it is the Airflow that goes all over the place. I did change fuel filter as it was due anyway but no change. Theory now maybe hose collapse?? Would that tell EDC to cut fuel pump?? Need a 2 persons to check that so will test another day. It still occurs with MAF disconnected so maybe genuine air starvation. Great fault!!
 
4300 is approaching the govenor speed, so the EDC will reduce boost and fuel to give a "soft" reduction in output.
I'd not worry about it myself, but I don't often push mine up that high.
 
Still cuts at 3750 with ecu in control thou. I also have a strange obsession for finding faults!! Today I have eliminated everything! All result in same fault. Carried out the following and reinstated each in turn: Disconnnected turbo and removed all intercooler pipes so that it was breathing normally aspirated straight into manifold. Substituted injector loom. Dis both MAF and MAP together. Dis each injector in turn. Checked for stable voltage on battery. Checked earth connection with meter. Did all this while watching live data. Airflow is the one that gets hit during fault regardless of MAF being connected or not. So...thinking it is ecu acting early on rev limiter for some reason. No wonder similar fault on this forum was never concluded! Nothing left on engine to test unless all injectors give way at high revs? Thinking may substitute ecu and immob unit for another matched pair. Would the fact they are from a manual car make a difference? Wonder if they would still output to auto electronics or not? Anyone changed an ecu? Have got key chip from matched pair to use to access immobiliser. Otherwise I'll just tell MOT man that mine has the latest eco mod to make it greener and rev limit is set lower!!
 
Just reviewing my notes from tests on crank sensor. Can anyone confirm the resistance of the sensor when disconnected from car? I haven't changed mine yet but I have one measures 0.56 K ohm (known good one) and the one on the car with fault measures 0.68K ohm. Voltage measurement when engine running looks ok but I don't actually know what the output should be. Thanks
 
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