Hi all.

You guys seem to know more about this M51 engine since it is used in the P38 if im right? so although iv posted this on other site i thought id copy it here and see if i can get a little help.
Below is the post iv send on other sites.
Thanks for any help in advance.

I have a problem with my 325 TDS
It has the M51 engine, same as fitted to range rover and Vauxhaul omegas.

Basically i bought the car a few months back knowing it had a few problems.
First it wouldnt start to easily - Fixed with a proper engine earthing lead fitted.
Then had hot start problems - Fixed with electronic box from e-bay tricks car into thinking its cold when its hot so puts glow plugs on.

Now my on going problem is the noise the car makes... Its loud and sounds tappety but its not coming from the tappets as iv put my ear close to where they are and its not sounding like them, sounds more like its from in the inlet?? Its been to two Diesel specialists and they confirm its not the injectors. Only one has said it may be the injection pump, but they will not know this untill they take it out, but that will cost me a few hours labour.
What i have noticed though is that the injection pump has been moved either to retard it or fully advance it, and considering the car's looks have been modified, it looks like maybe some tuning box may have been fitted.
I think this because the injector with the needle life sensor has had its sensor wires spliced and repaired, so maybe someone has put something in here to modify the signal??

Any help on this issue will be much appreciated.
When driving at night there does appear to be quite a bit of smoke behind me, and when revved hard at standstill you do get a puff of BLACK smoke.
The car idling is a little erratic and if you are cruising in gear just touching the accelerator the car seems like its misfiring.
Maybe all to do with the timing and correct boost and fueling?
How do i test and set up all these? thanks?

The latest problem that has become a big issue now and is why my car is off the road, is that whilst driving the car decided to accelerate itself?? then when i dipped down the clutch the revs went to maximum, i had to fight with the pedal by pushing it back and forth quite a few times before the revs died down, then when i drove along again the same happened, which 1) was scary! and 2) very scary!! LoL
I thought the engine was about to explode by it revving so hard!

I then calmed it down, pulled over and switched off the ignition.
I was then towed home where it is still sat.
Iv started it a few times and revved it whilst its sat there and it seems ok, but im not risking taking it out just yet untill i can pinpoint the fault.

Any help and advice much much appreciated!
Cheers

Hi,
You need an oscilloscope to check the needle lift sensor waveform. Pump problem sounds likely down to the fuel quantity adjuster, which is inside the pump and a specialist job.

Nige

aj11r said:

Hi all.


.

BASICALLY i bought the car a few months back knowing it had a few problems.
First it wouldnt start to easily - Fixed with a proper engine earthing lead fitted.
Then had hot start problems - Fixed with electronic box from e-bay tricks car into thinking its cold when its hot so puts glow plugs on.

Now my on going problem is the noise the car makes... Its loud and sounds tappety but its not coming from the tappets as iv put my ear close to where they are and its not sounding like them, sounds more like its from in the inlet?? Its been to two Diesel specialists and they confirm its not the injectors. Only one has said it may be the injection pump, but they will not know this untill they take it out, but that will cost me a few hours labour.
What i have noticed though is that the injection pump has been moved either to retard it or fully advance it, and considering the car's looks have been modified, it looks like maybe some tuning box may have been fitted.
I think this because the injector with the needle life sensor has had its sensor wires spliced and repaired, so maybe someone has put something in here to modify the signal??

Any help on this issue will be much appreciated.
When driving at night there does appear to be quite a bit of smoke behind me, and when revved hard at standstill you do get a puff of BLACK smoke.
The car idling is a little erratic and if you are cruising in gear just touching the accelerator the car seems like its misfiring.
Maybe all to do with the timing and correct boost and fueling?
How do i test and set up all these? thanks?

The latest problem that has become a big issue now and is why my car is off the road, is that whilst driving the car decided to accelerate itself?? then when i dipped down the clutch the revs went to maximum, i had to fight with the pedal by pushing it back and forth quite a few times before the revs died down, then when i drove along again the same happened, which 1) was scary! and 2) very scary!! LoL
I thought the engine was about to explode by it revving so hard!

I then calmed it down, pulled over and switched off the ignition.
I was then towed home where it is still sat.
Iv started it a few times and revved it whilst its sat there and it seems ok, but im not risking taking it out just yet untill i can pinpoint the fault.

Any help and advice much much appreciated!
Cheers

Click to expand...

if that yer basic version am glad yer dint enlighten us with the full un abridged version

Is that one of them freelander thingies?

Might be worthwhile replacing the No 4 Injector, as sensor wires don't like to be cut and spliced, that might solve rough running/idling problems.

Having said that I couldn't see how it could cause the engine to rev to the limiter. Have you looked at the wiring to the ECU? There could be an errant signal from some dodgy soldering to the accelerator pedal signal.

hello,
I would say due to the tappe-tlike noise, that the FIP is too far advanced.
worn out diesels may rev up burning their own oil fumes; dangerous for you and your engine.
regards, korkut

Just a thought... the P38 uses a variable potentiometer on the accelerator pedal does the BMW 325? If it does and its faulty, e.g. sticking, giving wrong readings this could cause the engine to rev. Would explain why fighting the pedal a bit got the revs down again.

Thanks for all the replies, I will have to look into the FIP being fat too advanced - how would i re-adjust this?

Today I took my turbo off and apart as there was a lot of oil in the inlet, and intercooer. When i took the turbo apart i found the outer "o" ring was ok, but the shaft was a little wobbly and as a guess the shaft bearings have worn hence the leak. A performance specialist now has my turbo to check it over and give me a price for refurbing it.

That is a good point about the potentiometer, i will have to check on the OEM website and ask around at the bimmr forums.
Thanks

Update
I now have the turbo apart and am replacing the bearings and seals myself, you can get teh kit off ebay for £40

I am now in possesion of the valve timing set up procedure, just need to by the kit to lock things in place.

How do I go about adjusting the actual injection pump timing? Retarding and advancing etc..

Does the turbo have roller bearings? I thought it would have a hydrodynamic oil bearing hence the looseness.

Oil gunge in the intercooler hoses is not uncommon, in fact Land Rover state oil from the turbo like this is normal, even losing 500ml every 1000 miles or so iirc.

BMW 2.5 tds over revving

I too have a BMW 2.5 tds doing exactly as you describe. Have you solved it?

I've spent thousands on a 1997 with 200k on the clock and done the following (but still doesn't solve it):
One main BMW dealer, two Specialists and a number of diesel experts.
Diagnostic check showed no faults, Replaced Crank Sensor, Check ECU earths, ECU has been tested - no faults, Injection Pump been tested and reconditioned - no faults, Replaced ECU, Replaced EWS, waiting for FAB to come up with another idea.
This first happened 19th January, 2008 (happy birthday) and STILL trying to resolve it. Once FAB come back, this will be the last chance to get it to work, if not, then I will scrap it - Sports Tan Leather interior (saloon) and Z4 Alloys.
Any ideas, as I've posted this also on the BMW Owners Club - but no one knows.
We could compare notes outside of Forum if you wish.

Regards :crazy:

This job sounds a bit like a rollercoaster that has no brakes. The first check with this fault is the potentiometer on the foot pedal.

You can test the output with a cheap voltmeter. If the pedal is telling the engine I am on idle and you are travelling at 50mph imagine what noises you would get from an under fuel or over fuel situation. It would Knock its nuts off.

Pin 5 on the pedal – the grey and White wire. This is the idle switch. With everything connected and the ignition off check that this wire is open circuit.

Put the voltmeter earth lead to earth and the live on pin 5 and turn the meter to resistance or continuity. Is should show infinity or OL
It’s a simple on/off idle switch.
You can use a powered test lamp. If it doesn’t light up then that’s good. Now press the pedal half way and the probe should light up or your voltmeter should show continuity or very little resistance ie 0-12 ohms.

The next important wires are the pedal voltage supply, Earth and Signal wires.

Pin 2 Pink wire is the sensor supply voltage. With the ignition on this should read 5 volts.

Next is the Pedal earth. Now this doesn’t go directly to ground. It is a signal earth back to the Engine Ecu (Pin 13)

Measure it with resistance or continuity. A high resistance reading is bad. You will normally get a reading between 0 and 12 ohms. The higher the reading, the worse your problem. 0 ohms being a perfect earth. In reality you are always going to get about 0-9 ohms.
If you get a bad reading you need to check the earth cables from the engine ecu and the earth cables from the engine and battery also not forgetting the wire itself back to the ecu.
(Engine earth leads are the most common)

Next is the signal wire pin 1 White wire. With the ignition on and the pedal untouched, this will read approx 0.35-0.55 volts as you slowly press the pedal the reading will go up progressively usually to a maximum of 4-4.8 volts . This depends how the pedal is set.
Sometimes the track will wear out just off idle and you will see your meter reading drop out or show high readings.

Pin 1 White wire – Signal wire goes to Pin 37 Engine Ecu
Pin 2 Pink wire – Sensor supply voltage comes from Pin 33 Engine Ecu
Pin5 Grey /White- Idle Switch comes from Pin 25 Engine Ecu
Brown wire Sensor Earth to Engine Ecu pin 13

If you ever suffer from no top end speed the the pedal may be set wrong you can adjust it so the reading will go higher. Sometimes the rod to the sensor bends a little over time and poor topend is the result.

The Earth is the important one to check as this is the earth for the Boost pressure sensor, the Engine speed sensor and the Throttle position Sensor (The one we are testing)
Those 3 sensors are 3 of the most critical sensors for a happy running engine.
Or of course you can scrap all this and hook up Autologic or Rovacom and see the readings on screen.

You can see the Engine Ecu pins here: P38 Range Rover Diesel Engine Management (EDC)-P38 Range Rover
Hope this helps.

A note if you are using diagnostic kit: it may never see this running rough as a fault. Its a bit like the coolant sensor. on a hot sunny day the sensor may read -40 and the Engine would over fuel like crazy but from the engine ecu's point of view its not a fault. It just thinks it is in Siberia.

WOW mind blowing. Are you in business (MTeckUK) - I'm sure one of the Specialists went through the earths, a Bosch dealer as well, but you never know.
I'll have alook, but I'm no electronic wiz.
I notice you are in Hereford, guess thats lucky as I'm in Ludlow.
Would you help beyond this forum?

Pm me with your number or Give me a call. Its no problem. I will sort that out for you. Ludlow hey, just shows its good to talk. Lol
Cheers,
Mark

Hi Mark, thank you for your offer. I've sent you my details, but I have no way of contacting you direct (apart from forum). The car is now in the 'last chance saloon', and if not fixed will be scrapped.

Cheers, Anthony

Hi
Stumbled on this thread through the wonder of google. I can see it's been dormant but what the heck - will either have to get a Peake reader or scrap the car if there's nothing further I can do myself.

Engine : 2.5 tds on a 1996 BMW 325 tds se.

I experience a very similar (perhaps identical) problem with my car - at certain speed/gear/rev (usually around 29 MPH) combinations it starts accelerating itself, with my foot on or off the pedal. It can be controlled (sort of) by touching the accelerator pedal on-off-on-off repeatedly, seems to disengage whatever the ECU thinks should be happening. Braking at the same time is required to bring the speed down below the threshold, or it just engages again.

So I followed Mtechuk's steps above, testing with a multimeter. All pins checked out as expected except pin 5 (grey/white - but it's solid grey on my particular car). It's meant to be a switch - open circuit with the pedal up, closed circuit with it down.
With the multimeter earthed to the the chassis, pushing the pedal the circuit is closed for an instant, and then opens again. I think it should remain closed?
I sourced a replacement potentiometer, and I see the same behaviour.

The strange thing is, earthing through the footwell light, I see the expected behaviour - pushing the pedal, the circuit stays closed. I would have thought the footwell light would earth to the body as well.

Does anyone have any idea what's going on?

Cheers....

Follow up - got a Peake reader, but the code interface on the car refuses to work, gives an E10 error indicating it can't communicate.

Ah well, it's either going to the big dealership in the sky, or ebay!

aj11r said:

Update
I now have the turbo apart and am replacing the bearings and seals myself, you can get teh kit off ebay for £40

I am now in possesion of the valve timing set up procedure, just need to by the kit to lock things in place.

How do I go about adjusting the actual injection pump timing? Retarding and advancing etc..

Click to expand...

Be carefull, i had a customer who thought he could rebuild his, he did... then when tthe turbo was spinning at around 14,000 rpm it gave up, seals went, and ran on its own fuel... blew its brains out... so i had to go out and tow it home for him, The turbo has to be balanced