Diesel Non Starter 2000MY, Fuel Pump, Diagnostics

Lovel · 19th October 2009, 19:32

This question has been asked many times before, have just spent a couple of hours reviewing the posts on this subject, but am no further forward at this moment in time.

I have recently acquired a poorly 2000MY vehicle that does not show any fault codes via T4 diagnostics, I can feel that the in tank pump is running and also the UBP too, both pumps cutting out after about a minute or so with the ignition at position 2.
The fuel tank gauge indicates it is 1/2 full.

The vehicles previous owner took it to a ex MGR dealer to fault find. They could not locate the problem, the owner then gave up after spending so much money on it. Now I have ended up with it. The ex MGR dealer ran T4 diagnostics and tried a new UBP, but it made no difference, so they swapped back for the original.

I tried starting her on a little butane via the inlet manifold, she ran for a wee bit but would not rev and just cut out as soon as the butane supply was removed.

My question is could the in tank pump still run but not provide sufficient pressure? Maybe my next step is to obtain the Peugeot pump?

Departed · 19th October 2009, 21:03

Quote:

Originally Posted by Lovel

This question has been asked many times before, have just spent a couple of hours reviewing the posts on this subject, but am no further forward at this moment in time.

I have recently acquired a poorly 2000MY vehicle that does not show any fault codes via T4 diagnostics, I can feel that the in tank pump is running and also the UBP too, both pumps cutting out after about a minute or so with the ignition at position 2.
The fuel tank gauge indicates it is 1/2 full.

The vehicles previous owner took it to a ex MGR dealer to fault find. They could not locate the problem, the owner then gave up after spending so much money on it. Now I have ended up with it. The ex MGR dealer ran T4 diagnostics and tried a new UBP, but it made no difference, so they swapped back for the original.

I tried starting her on a little butane via the inlet manifold, she ran for a wee bit but would not rev and just cut out as soon as the butane supply was removed.

My question is could the in tank pump still run but not provide sufficient pressure? Maybe my next step is to obtain the Peugeot pump?

All the pressure comes from the high pressure pump, so unlikely.

Tim (Timbo P6) had a similar problem. We did get a fault code for low capacitor voltage but it cleared and didn't return, however it still wouldn't start.

The problem in the end was the ECU. Fixed by the ECU doctor.

There had been a minor water problem a long time before this, but it had dried out and was OK. It could have been related but we don't know what they actually fixed. We tried swapping capacitors before it was sent, but that didn't make any difference, so I suspect one of the other components in the injector drive circuit had been replaced.

Lovel · 19th October 2009, 22:04

Without the engine running the T4 indicates a reading 3.72 Bar on the low pressure pump/s side which in theory should be more than the minimum requirement of 1.7 Bar to avoid shutting down the engine.
Capacitor readings 0.8V for both, not sure what to read into this?

As a comparison against my healthy running Tourer with the engine running capacitor values of 79.1V and 29.0V and without engine running 0.8V & 29.0V.

I'll make contact with the ECU doctor as you advise.

Departed · 20th October 2009, 07:05

Quote:

Originally Posted by Lovel

Without the engine running the T4 indicates a reading 3.72 Bar on the low pressure pump/s side which in theory should be more than the minimum requirement of 1.7 Bar to avoid shutting down the engine.
Capacitor readings 0.8V for both, not sure what to read into this?

As a comparison against my healthy running Tourer with the engine running capacitor values of 79.1V and 29.0V and without engine running 0.8V & 29.0V.

I'll make contact with the ECU doctor as you advise.

My T1 suggested the capacitor values engine not running were different between manual and auto, though no idea why. On Tim's car, a manual, they were both supposed to be around 0.8v engine not running, but one was more like 6v. With engine running they both went high, but the 'odd' one dropped away much more quickly when the engine stopped.

I'll also say I got hold of an ECU, not sure if manual or auto, but it has only one capacitor inside. So I'm not sure you can read very much at all into the capacitor voltages.

Lovel · 20th October 2009, 07:30

Please excuse my lack of knowledge on the internal of the ECU but what function do the capacitors serve in the ECU. I understand how a capacitor works in principal, but would like to know how it interacts with the ECU.

The car I am working on is a 2000MY manual box, both capacitors reading 0.8v.

My normal use car is a 2004MY manual box with the engine running capacitor values of 79.1V and 29.0V and without engine running 0.8V & 29.0V. Now I am a little more confused with the values though as it would suggest that my good car has faulty values but at least this one is running fine unlike the other that won't start??

Lovel · 21st October 2009, 11:35

Spoke to the very helpful ECU Doctor and mentioned my issue. ECU is now on it's way to him, I just hope there are no problems with a possible Royal mail strike pending.

If my ECU is found faulty the ECU Doc mentioned that in the process they remove chip/s from main board, bathe the circuit board in a fluid? and the board is also ultrasonically cleaned too before reassembly.

BigRuss · 21st October 2009, 12:48

Another one with a auto diesel ecu in a manual, seems like it's more common than thought.

Running voltages are supposed to be Manual box 79v nominal on both capacitors and Auto's 79V capacitor 1 and 29v capacitor 2.

Got to be some reason for manuals and auto to use different ecu's but it doesn't seem to affect running if the "wrong" one's fitted.

Russ

Lovel · 21st October 2009, 16:22

Quote:

Originally Posted by BigRuss

Another one with a auto diesel ecu in a manual, seems like it's more common than thought.

Running voltages are supposed to be Manual box 79v nominal on both capacitors and Auto's 79V capacitor 1 and 29v capacitor 2.

Got to be some reason for manuals and auto to use different ecu's but it doesn't seem to affect running if the "wrong" one's fitted.

Russ

Very interesting reading your response, maybe my car could be running even better if the correct spec capacitor was fitted

What function do the capacitors serve in the ECU?

Departed · 21st October 2009, 18:40

I'm not 100% sure, but I think it's like this.

The injector coil is an inductor. To get enough mechanical power out of it it has lots of windings so the inductance is high.

When you switch on the power to operate the injector, if you just put 12v on it it takes a long time to get enough current flowing to operate the injector. So I think the idea is that you apply a higher voltage pulse (around 70v) at first to get the current flowing more quickly.

This is different from other systems where the whole injection pulse is powered from a big capacitor like in the Land Rover TD5 engines that have a BIG capacitor (actually two I think) inside them.

The reaso I say it works like this is that the capacitor isn't big enough (enough farads) to do the same as the TD5 ones.

I also expected to see the rest of the inverter circuit to produce the voltage (step up) inside the ECU, but no sign of it. Again only a theory, but it looks like the voltage is produced by the spike generated when the injector coil is switched off. Clever idea if this is how it does work.

Lovel · 21st October 2009, 22:04

Quote:

Originally Posted by BigRuss

Another one with a auto diesel ecu in a manual, seems like it's more common than thought.

Running voltages are supposed to be Manual box 79v nominal on both capacitors and Auto's 79V capacitor 1 and 29v capacitor 2.

Got to be some reason for manuals and auto to use different ecu's but it doesn't seem to affect running if the "wrong" one's fitted.

Russ

Could the fact that my car has Cruise control fitted have anything to do with it?

19th October 2009, 19:32	#1
Lovel I really should get out more....... P6B, L550, Imp, F56, Commando Join Date: Nov 2006 Location: Aberdeenshire Posts: 2,886 Thanks: 352 Thanked 677 Times in 440 Posts	Diesel Non Starter 2000MY, Fuel Pump, Diagnostics This question has been asked many times before, have just spent a couple of hours reviewing the posts on this subject, but am no further forward at this moment in time. I have recently acquired a poorly 2000MY vehicle that does not show any fault codes via T4 diagnostics, I can feel that the in tank pump is running and also the UBP too, both pumps cutting out after about a minute or so with the ignition at position 2. The fuel tank gauge indicates it is 1/2 full. The vehicles previous owner took it to a ex MGR dealer to fault find. They could not locate the problem, the owner then gave up after spending so much money on it. Now I have ended up with it. The ex MGR dealer ran T4 diagnostics and tried a new UBP, but it made no difference, so they swapped back for the original. I tried starting her on a little butane via the inlet manifold, she ran for a wee bit but would not rev and just cut out as soon as the butane supply was removed. My question is could the in tank pump still run but not provide sufficient pressure? Maybe my next step is to obtain the Peugeot pump? Last edited by Lovel; 19th October 2009 at 19:37..

20th October 2009, 07:30	#5
Lovel I really should get out more....... P6B, L550, Imp, F56, Commando Join Date: Nov 2006 Location: Aberdeenshire Posts: 2,886 Thanks: 352 Thanked 677 Times in 440 Posts	Please excuse my lack of knowledge on the internal of the ECU but what function do the capacitors serve in the ECU. I understand how a capacitor works in principal, but would like to know how it interacts with the ECU. The car I am working on is a 2000MY manual box, both capacitors reading 0.8v. My normal use car is a 2004MY manual box with the engine running capacitor values of 79.1V and 29.0V and without engine running 0.8V & 29.0V. Now I am a little more confused with the values though as it would suggest that my good car has faulty values but at least this one is running fine unlike the other that won't start?? Last edited by Lovel; 20th October 2009 at 07:36..

21st October 2009, 12:48	#7
BigRuss Premium Trader 75 CDT Tourer,2.5 Launch Saloon, Omipro MG/Rover (T4) Join Date: Jul 2007 Location: Liversedge, West Yorkshire Posts: 5,405 Thanks: 1,105 Thanked 1,340 Times in 661 Posts	Another one with a auto diesel ecu in a manual, seems like it's more common than thought. Running voltages are supposed to be Manual box 79v nominal on both capacitors and Auto's 79V capacitor 1 and 29v capacitor 2. Got to be some reason for manuals and auto to use different ecu's but it doesn't seem to affect running if the "wrong" one's fitted. Russ __________________ Replacement Key Service http://https://the75andztclub.co.uk/...d.php?t=244732 Full T4 Testbook diagnostics available. Diesel ECU repair and replacement. Options enabled or disabled as required. Diesel X-Power 135 and 160bhp, Rover 1.8T 150 to 160 MG 160 V6 to 177 upgrades available P.M. for details.

19th October 2009, 22:04	#3
Lovel I really should get out more....... P6B, L550, Imp, F56, Commando Join Date: Nov 2006 Location: Aberdeenshire Posts: 2,886 Thanks: 352 Thanked 677 Times in 440 Posts	Without the engine running the T4 indicates a reading 3.72 Bar on the low pressure pump/s side which in theory should be more than the minimum requirement of 1.7 Bar to avoid shutting down the engine. Capacitor readings 0.8V for both, not sure what to read into this? As a comparison against my healthy running Tourer with the engine running capacitor values of 79.1V and 29.0V and without engine running 0.8V & 29.0V. I'll make contact with the ECU doctor as you advise.

21st October 2009, 11:35	#6
Lovel I really should get out more....... P6B, L550, Imp, F56, Commando Join Date: Nov 2006 Location: Aberdeenshire Posts: 2,886 Thanks: 352 Thanked 677 Times in 440 Posts	Spoke to the very helpful ECU Doctor and mentioned my issue. ECU is now on it's way to him, I just hope there are no problems with a possible Royal mail strike pending. If my ECU is found faulty the ECU Doc mentioned that in the process they remove chip/s from main board, bathe the circuit board in a fluid? and the board is also ultrasonically cleaned too before reassembly.

21st October 2009, 18:40	#9
Departed Retired -- Join Date: Jan 2007 Location: -- Posts: 3,785 Thanks: 0 Thanked 4 Times in 4 Posts	I'm not 100% sure, but I think it's like this. The injector coil is an inductor. To get enough mechanical power out of it it has lots of windings so the inductance is high. When you switch on the power to operate the injector, if you just put 12v on it it takes a long time to get enough current flowing to operate the injector. So I think the idea is that you apply a higher voltage pulse (around 70v) at first to get the current flowing more quickly. This is different from other systems where the whole injection pulse is powered from a big capacitor like in the Land Rover TD5 engines that have a BIG capacitor (actually two I think) inside them. The reaso I say it works like this is that the capacitor isn't big enough (enough farads) to do the same as the TD5 ones. I also expected to see the rest of the inverter circuit to produce the voltage (step up) inside the ECU, but no sign of it. Again only a theory, but it looks like the voltage is produced by the spike generated when the injector coil is switched off. Clever idea if this is how it does work.