Td4 Fuel Pressure Problem... HELP!

Hi folks...

I've posted on here before regarding my '03 Freelander 2.0 Td4 manual, but this is a fresh problem and has me baffled :S The car was running fine until a week or so ago. I bought a tuning box from Ebay (read around all different ones before I made the decision as to which to go for - feedback was all great etc.) and the difference was unreal. Far more power from low revs right to the red line. It was also easier on the juice. In line with the instructions, I increased the box by 1 notch at a time. I also disconnected the small hose from the EGR valve and cleaned inside it. Next day all was fine and I was still increasing it it every few hours (only a few notches through the 2 days - I hadn't reached maximum yet). Then when I was driving, the engine management light came on.. Few seconds later I had no power... Few seconds after that the engine died. Wouldn't start again after that. Would turn, but not fire. Disconnected and removed the tuning box in case this was the cause of the problem, but no joy. Got the car towed home. Then towed it to a mechanic the next day. It started when being towed, but not as much power as it should have. However later the engine management light came on and after pulling in, the car wouldn't start. Got it towed home again and it started on the rope again, but died again shortly after. Put £5 diesel in (even though it was between the empty and quarter mark) just incase the fuel guage was innaccurate. Then when towing it back from the garage, it started on the rope and we were able to drive it home (about 5 miles), though very little power. When we got home, it would start on the key OK and the engine management light went out.

When we went to bring the car to the mechanic the next day, it wouldn't start, so we towed it to the mechanic. It isn't far from us, so we didn't try to start it on the rope and thought it was better for the mechanic to see it dead anyway. The mechanic read diagnostic codes from the car and it showed Low Fuel Pressure and after further inspection they said it wasn't the fuel pump in the wheel arch - they were confident that fuel was getting to the engine bay OK. They replaced a small rubber seal on the injector pump and the car ran fine for 10-20 miles, then same as before, engine managment light etc, so they told me the injector pump needed replaced.

I sourced one from a breaker on Ebay from a Rover 75 and got the pump replaced on the car. Car ran for about 3 minutes then died again. It starts on the rope now when you put it in gear, but as soon as you put the clutch in, it dies. The mechanic thinks the pump might be faulty, but I don't think that's what it is.

I've read several threads on forums on the net about other similar issues and I want to try the injector leak test (even though the injectors were replaced less than a year ago), but I'm not sure how to go about this. Can anyone point me in the direction of a guide or pictures?

I disconnected the green fuel pressure sensor connector at the end of the rail (This is where I had the tuning box plugged in, but removed it as soon as the problem 1st ocurred in case that was the fault) because someone else said their car started after they disconnected this connector, but still no joy.

Is it possible the tuning box could of caused the fuel pressure sensor to malfunction or break? I read someone else's post about the voltages the sensor should be at, so I'll test this tomorrow and hope this sheds some light.

Any help or advice would be greatly appreciated!
Cheers.

UPDATE: I've been reading more posts regarding a leak off test, I realise I forgot to mention something... When the car first broke down, I pulled the rear seats forward and moved the carpet and cover from the top of the tank (I thought that's where the fuel pump was) and a mechanic friend took the fuel lines of and I flicked the ignition to position 2 (lights on, but not starting the engine) and off again and loads of diesel came back the fuel OUT line. I'm now thinking this could be caused my a faulty injector sending lots of diesel back to the tank?? There was lots of pressure in that line as the mechanic couldn't keep his finger over the end of the fuel line when I flicked the ignition to position 2 for 1 second. Definately want to do a leak off test tomorrow after work (If I can find a guide for how to do it).

Have you replace the fuel filter and checked the engine bay LP pump?

You say you have replaced the LP pump from a breakers?

Each time you adjusted the tuning module, did you turn it off first? I'm wondering if the changes have upset the ECU. I think it 'memorises' your driving style and might have got confused in the operation of injectors.... could be talking BS too :s

"I disconnected the green fuel pressure sensor connector at the end of the rail (This is where I had the tuning box plugged in, but removed it as soon as the problem 1st ocurred in case that was the fault"

The 'tuning box' changes the voltage signal from the high pressure sensor which causes the ECU to believe that the fuel pressure is low, the ECU increases fuel pressure to higher levels than normal, to begin with the engine performance improves until eventually somewhere in the system a weak link fails.

A 'live data' analysis might be the quickest/cheapest way to diagnose this problem.

I dont think it will be an injector problem but have done this test twice now.

Just cut a small piece of about 12mm square from an old inner tube (or any softish rubber will do) and placed it on top of the injector. Remove the clip and connector and press it down on to the rubber. This is sufficient to stop the return flow in the pipe from leaking. Get an assistant to turn the key for about 5 seconds is enough to see if there is leakage from the top of the injector. Job done in 15mins but a bit longer to change the injector!

Would you care to tell us the maker of the box?

The seller of the tuning box was called MRMCBUK on Ebay. I emailed him about it and he says the most probable cause will be the connectors that connect to the fuel pressure sensor (maybe a lef broken or something) so I'll double check this later.

I did the leak off test today. I clamped the hose just before it meets the 1st injector, then I started with the left hand most injector (If looking from the front of the car into the engine bay). I disconnected the metal clip and the hose on top of the injector and turned the ign on. No fuel coming out the injector, but the return pipe was dripping as if some diesel was leaking from another injector. I continued along the injectors and the last 1 (the one at the end of the hose) seems to be leaking fuel. I took the hose off all the injectors to be sure, turned the ign on and watched the injectors. The 1st 3 were the same - no fuel coming out, but the last 1 filled the little silver ring that the hose connects to and when I wiped the fuel away, it was filled again almost instantly. Fuel wasn't shooting out, but it was different to the others. Could this be my problem as to why the car won't start? Faulty injector? Or would this just cause the car to run bad?

@ Mick - I have bought a replacement fuel filter, but haven't got it replaced yet. Where's the LP pump in the engine bay? I'm assuming LP means low pressure by the way.

@ Skynet - If LP means Low Pressure, then no, it was the high pressure Bosch pump that was replaced from a breaker (The expensive pump - LR quoted me £1060 +VAT for a new one!). And yes I turned the engine off each time I adjusted the tuning box. I tried to re-set the ECU in case this would fix the problem. I read somewhere that to re-set the ECU, you should disconnect the ground from the battery for 10 seconds or so, so I did this today.

Also, when the ign is on, you can hear something flowing somwhere in the engine bay, but I'm not sure where it's coming from.

there is only one fuel pump from 2003 onwards in the rear wheel arch.
If your injector is leaking back as fast as you say, that will probably the reason for the non starting, however once the engine fires then normally it causes no problems.
We have had the problem of misfire stalling, due to the plug to the common rail pressure switch(the one you have disconected) not making a proper contact, the plug looked fine and we scratched our heads with this fault, untill i remembered reading a bulitin from LR which mentioned the problem. We fit a new plug, you have to splice it into the loom, and bingo problem gone, Hope this may give you a pointer to the fault

Ok, tomorrow I'm going to use my Multimeter to test the Fuel Pressure sensor/connector. I'll take readings from the other side of the connector to see if the connector is faulty or not. Which of the 3 wires should I take the reading from and what should the typical voltages be?

Also, if it was an injector causing the problem... Should the car fire up if I disconnect the leak back hose from the top of the injector that I suspect is faulty?

I can't understand why the car started and ran fine for a few minutes after the injector pump was replaced. With the original pump on (before replacement was fitted), a mechanic changed the small rubber seal inside the pump (a small rubber ring) and the car started up and ran for several miles before it died again. When it died I think it broke that small rubber seal again, which is when the mechanic said it was the injector pump that needed replaced. What else could cause this small rubber seal to break if it's not the pump? I'm assuming that's what's happened with this replacement pump - it ran for a few minutes then broke that rubber seal (although I never thought to ask the mechanic to check for this at the time). Is there a name for this rubber seal and is it easy to replace DIY, or would I need to take it back to the mechanic to get him to replace this rubber seal?

"Which of the 3 wires should I take the reading from and what should the typical voltages be?"

Connect multimeter between battery neg and blue/black cable (connector clean and pushed firmly onto HP sensor, you will have to probe into the connector)

Ign on (position 2) 0.5v approx
Engine idling 1.3v approx
3000 rpm 2.0v approx

"Should the car fire up if I disconnect the leak back hose from the top of the injector that I suspect is faulty?"

The leak back prevents starting because the injectors can't develop sufficient injection pressure so disconnecting won't help, previous posters have briefly crimped the return pipe whilst cranking and the engine has started, just be careful with possible fuel spray.

"When it died I think it broke that small rubber seal again, which is when the mechanic said it was the injector pump that needed replaced. What else could cause this small rubber seal to break "


Excessive high pressure?

Yes I figured it was higher pressure that was causing the seal to break, but I meant is there anything that would cause this to happen? Thanks for the other info Dan, I'm going to go out and take voltage readings from both the fuel pressure sensor connector and the cam sensor connector to see if either of these could be the cause of the fault. I can't actually get the car started at the minute though, so I'll only get readings with the ign on. I'll post my findings later.

I think the 'tuning box' has caused the high pressure to increase way beyond normal limits and the rubber seal has acted like a safety valve when it blew out. I imagine that the new seal has now also blown out.

Although you've taken off the 'tuning box' I think the HP pressure is still very high because the unit which controls HP pressure has been damaged. The unit which controls HP pressure (regulator) is screwed into the rear of the HP engine driven pump, it's basically a solenoid operated by the ECU.
If this unit has been overworked by the 'tuning box' it may now be siezed and unable to control pressure.

I thought this myself, but I've fitted a replacement pump and it ran ok for a few minutes before it died again.

I used a multimeter on the cam sensor... With the ign on, the connector on top of the engine block didn't give any readings from the 3 pins, but the connector that connects into this gave the following readings with the ign on:
Red/White wire - 9.7v
Yellow wire - 9.6v
Brown wire - 0.01v
Do these readings seem ok.

More interestingly, I disconnected the green plug connected to the fuel pressure sensor and with the ign on, none of the pins gave any reading, either on the sensor side, or on the green connector. Is it safe to assume the fuel pressure sensor is knackered? Is this easy to replace? Is it a matter of using a spanner to screw it off, then screw the new one on, or will a load of diesel shoot out when I screw it off?

Also, I have a friend with a Rover 75 with the same engine as the Td4. If I was to run his car and use 3 wires to connect his fuel pressure sensor connectors to the connector on mine, would this fool the ECU into thinking the pressure in my car was that of the Rover 75 and therefore get the car to start? Would this cause any damage to the Rover 75?

Thanks

Cam sensor harness voltage readings are about right, and the sensor itself would not give any readings whilst disconnected.

I wouldn't advise connecting the R75 to the TD4.

Regarding the green harness connector showing no voltages:

With ignition on you should find at least 5volts on white/yellow this is a reference voltage from the ECU, the others are signal return and earth return so generally don't show voltage when disconnected. Check this again and if no voltages are present then make sure the ECU multiplug is secure and the cables arent damaged.

Should the yellow/white wire in the green connector read 5 volts even when disconnected from the fuel pressure sensor? I'll check this when it stops raining outside.

Yes, with the ignition 'on', the ECU supplies 5v to many of the vehicle sensors and the returning signals are a proportion of that reference voltage this is how an ECU knows what's going on around the vehicle.

I see. If I'm still getting no reading, then I'll open the ECU box and check the connections etc., and test for the voltage of the other end of the yellow/white wire (the end in the ECU box) incase the cable has been damaged or something.

If you can prove that the three cables between the ECU and the HP pressure sensor are O.K and that the ECU is otherwise working normally i.e the low pressure pump runs briefly after turning on ignition and the MIL light illuminates briefly after ignition on then it may be that part of the ECU has suffered damage.