TD5 90 won't start low fuel pressure

Hi all,
This is probably not the 1st time someone has mentioned this but my 1998 td5 70k won't start. It's cranks fine but just won't start. Apologies for the repeat in topic. I've been diagnosing the fault for ages to no avail. Firstly, I plugged in my nanocom and no faults recorded, which suggests a fuel problem.
Before I bought a fuel pressure tester gauge I took out the old fuel pump has it was a bit noisy and replaced it with an aftermarket one. From experience changing the fuel pump normally does the trick. I performed the normal purging procedure. Ignition on leave for 3 mins until fuel pump cuts out, ignition off and back on and repeat process for like 6 times. Because my td5 is an early one the press throttle down fives and wait for MIL light to flash does not apply. Still won't start but it does seem to want to. So I thought Id change the injector seals and washers with aftermarket ones. I also changed the crank position sensor. I've had experience changing the seals successfully on previous jobs. Still won't start on this TD5. Changed the fuel filter and the tiny air bleed filter in the filter housing. Bought a new battery too.
So then I decided to buy a fuel pressure tester kit and actually measure the pressure. I put together a t piece setup with my gauge and connected one end to the high pressure feed that goes to the regulator and the other end to the inlet of the regulator. Ignition on and I get 3.8bar.
I then connected my inline setup to the fuel return line before the fuel cooler and I get 1.5 bar.
I then connected the gauge to the fuel return line after the fuel cooler and again 1.5bar.
Everytime I turn the ignition on the pump squeals for a few seconds before settling down. To me suggests I have trapped air and air is getting into the fuel system.
Oil levels are fine and do not rise when cranking. So that indicates the injector seals are OK.
I've checked the fuel pipes for leaks and cannot see anything.
So lastly I recently changed the fpr and I measured the fuel pressure at the return line and got 3.5bar so I thought good it was the fpr. Then the next day I thought I'd measure it again to be sure and for some reason it measured 1.5bar again.
I'm at a lost. I've probably got a duff new pump. Fuel in tank is pass the half way mark. Red ECU plug is dry and no oil. Relays seem fine and fuses. The fuel inertia switch is fine.
Any help and suggestions would be much appreciated.

YB82 said:

To me suggests I have trapped air and air is getting into the fuel system

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Have you checked the fuel filter head/housing? Appreciate youve been in that area changing the filter and what not but they're only aluminium and get a load of ****e due to where they are. Go really porous, corrode and lose the seal between the housing and copper washers. Not sure if this would draw air in I'm no expert but maybe worth a look?
This was mine when I changed it. No starting issues but was dripping diesel on the road

aftermarket pumps arent recommended ,neither are the injector washers and o rings, id be thinking of getting an oe pump

That was going to be the next thing on my list. I couldn't see any fuel leaks there. I know they are prone to cracks. I'll give it a good looking over tomorrow

jamesmartin said:

aftermarket pumps arent recommended ,neither are the injector washers and o rings, id be thinking of getting an oe pump

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Yeah that's what I thought but have fitted them in the past without any issues so thought I'd do the same. I fitted a new aftermarket pump in another landy recently without any issues.
So confused. Think I'll bite the bullet and get a decent pump and washers. Are Bearmach ones good enough or go for the more expensive VDO? I'm not even sure if a new pump would actually fix the problem.

i only fit oe ,bearmach do an oe one i believe, ive know quite a few cheap pumps either fail or not start, but you cant know 100% its at fault

jamesmartin said:

i only fit oe ,bearmach do an oe one i believe, ive know quite a few cheap pumps either fail or not start, but you cant know 100% its at fault

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Maybe I got lucky with the other cheap pump. One thing for sure I know that this pump has one of the tabs broken where the compression springs sits. I doubt that would cause any issues or let air in as it's secured by the locking clamping ring.
Think new pump it is then.
Thanks for the advice.

YB82 said:

Maybe I got lucky with the other cheap pump. One thing for sure I know that this pump has one of the tabs broken where the compression springs sits. I doubt that would cause any issues or let air in as it's secured by the locking clamping ring.
Think new pump it is then.
Thanks for the advice.

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you cant guarantee that is the issue ,but after checking the obvious its a known problem

3.8 bar should be enough to start the engine. Don't worry about the lower pressure on the return line, that's just to get it back into the tank, so you'd expect that to be at low pressure. Yes, of course a decent OEM fuel pump is a good investment but probably isn't the problem in your case.

When I've had this problem, it has turned out to be oil in the injector loom (one occasion), and an ECU fault (one occasion). On another occasion it turned out to be a combination of ECU, main engine loom and an immobiliser fault all at once. Another thing that can cause this kind of problem is the crank position sensor. If it fails the engine will turn over but not start. Or the electromagetic interference from the starter interferes with it. When the engine is turning over, can you see an RPM reading on the Nanocom? Mine's about 260 rpm or so. If you can see that it suggests the crank position sensor and the starter are OK. If the car will start if you tow it or roll it down a hill but not with the starter, then this suggests the starter motor is causing a lot of interference. There are a variety of ECU faults and wiring loom faults that don't show up on the Nanocom but which will disable the car. Another thing to check is that the injectors are actually getting a signal. This is a little beyond the average amateur toolkit and needs things like oscilloscopes, but if you put the probes of a digital multimeter in one of the plugs of the injector loom you can see the readout 'kick' in time with the pulses, whereas when the ECU's dead you can't. Or at least that's what I've noticed on mine.

Brown said:

3.8 bar should be enough to start the engine. Don't worry about the lower pressure on the return line, that's just to get it back into the tank, so you'd expect that to be at low pressure. Yes, of course a decent OEM fuel pump is a good investment but probably isn't the problem in your case.

When I've had this problem, it has turned out to be oil in the injector loom (one occasion), and an ECU fault (one occasion). On another occasion it turned out to be a combination of ECU, main engine loom and an immobiliser fault all at once. Another thing that can cause this kind of problem is the crank position sensor. If it fails the engine will turn over but not start. Or the electromagetic interference from the starter interferes with it. When the engine is turning over, can you see an RPM reading on the Nanocom? Mine's about 260 rpm or so. If you can see that it suggests the crank position sensor and the starter are OK. If the car will start if you tow it or roll it down a hill but not with the starter, then this suggests the starter motor is causing a lot of interference. There are a variety of ECU faults and wiring loom faults that don't show up on the Nanocom but which will disable the car. Another thing to check is that the injectors are actually getting a signal. This is a little beyond the average amateur toolkit and needs things like oscilloscopes, but if you put the probes of a digital multimeter in one of the plugs of the injector loom you can see the readout 'kick' in time with the pulses, whereas when the ECU's dead you can't. Or at least that's what I've noticed on mine.

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Hi Brown thanks for the reply. I have not checked the RPM reading. I will check that tonight when I'm back from work and let you know. I will also check the injector loom too when I get some free time.
Appreciate the advice.

Brown said:

3.8 bar should be enough to start the engine. Don't worry about the lower pressure on the return line, that's just to get it back into the tank, so you'd expect that to be at low pressure. Yes, of course a decent OEM fuel pump is a good investment but probably isn't the problem in your case.

When I've had this problem, it has turned out to be oil in the injector loom (one occasion), and an ECU fault (one occasion). On another occasion it turned out to be a combination of ECU, main engine loom and an immobiliser fault all at once. Another thing that can cause this kind of problem is the crank position sensor. If it fails the engine will turn over but not start. Or the electromagetic interference from the starter interferes with it. When the engine is turning over, can you see an RPM reading on the Nanocom? Mine's about 260 rpm or so. If you can see that it suggests the crank position sensor and the starter are OK. If the car will start if you tow it or roll it down a hill but not with the starter, then this suggests the starter motor is causing a lot of interference. There are a variety of ECU faults and wiring loom faults that don't show up on the Nanocom but which will disable the car. Another thing to check is that the injectors are actually getting a signal. This is a little beyond the average amateur toolkit and needs things like oscilloscopes, but if you put the probes of a digital multimeter in one of the plugs of the injector loom you can see the readout 'kick' in time with the pulses, whereas when the ECU's dead you can't. Or at least that's what I've noticed on mine.

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So I hooked up my nanocom and engine rpm speed is 180rpm not sure if that's good or not. Somehow I will have to try tow start it and see but space is pretty limited where I live

my nanocom has now picked up

INJECTOR 1 PEAK CHARGE SHORT, (LOGGED).
INJECTOR 2 PEAK CHARGE SHORT, (LOGGED).
INJECTOR 3 PEAK CHARGE SHORT, (LOGGED).
INJECTOR 4 PEAK CHARGE SHORT, (LOGGED).
INJECTOR 5 PEAK CHARGE SHORT, (LOGGED).
I'm assuming these are old faults as they are 'logged'.

YB82 said:

my nanocom has now picked up

INJECTOR 1 PEAK CHARGE SHORT, (LOGGED).
INJECTOR 2 PEAK CHARGE SHORT, (LOGGED).
INJECTOR 3 PEAK CHARGE SHORT, (LOGGED).
INJECTOR 4 PEAK CHARGE SHORT, (LOGGED).
INJECTOR 5 PEAK CHARGE SHORT, (LOGGED).
I'm assuming these are old faults as they are 'logged'.

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I had those on mine, just under a year ago, just refused to start completely, messed about with everything, then sent the ECU to be checked out, they said it was ok and when it came back it started up. But then it cut out a couple of times on me and the faults were there also top side switching error ( think that's right) I bought a second hand ECU and programmed it and it's been fine since.

The point about looking at the RPM on the Nanocom is to see if the ECU is getting a signal telling it the engine is going round, so it knows to activate the injectors. If you can see an rpm value when cranking it on the starter it tells you the crank position sensor is OK. Another thing that can happen is that the starter motor can generate a lot of electromagnetic 'noise' which interferes with the signal from the crank position sensor. The fact that you can see an rpm value suggests that's not a problem in your case. So that much tells us that the crank position sensor and the starter are not at fault. So I wouldn't bother trying to bump start it. It probably won't work and you'll just have a dead vehicle out in the middle of the road getting in everyone's way!

However, one experience I had was that a previous injector harness was giving me 'peak charge long' errors which seemed to be to do with oil getting in it. A new injector harness, and they went away.

Brown said:

The point about looking at the RPM on the Nanocom is to see if the ECU is getting a signal telling it the engine is going round, so it knows to activate the injectors. If you can see an rpm value when cranking it on the starter it tells you the crank position sensor is OK. Another thing that can happen is that the starter motor can generate a lot of electromagnetic 'noise' which interferes with the signal from the crank position sensor. The fact that you can see an rpm value suggests that's not a problem in your case. So that much tells us that the crank position sensor and the starter are not at fault. So I wouldn't bother trying to bump start it. It probably won't work and you'll just have a dead vehicle out in the middle of the road getting in everyone's way!

However, one experience I had was that a previous injector harness was giving me 'peak charge long' errors which seemed to be to do with oil getting in it. A new injector harness, and they went away.

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Thanks Brown I've learnt something new with regards to the starter motor and crank position sensor. I'm waiting for my new fuel pump to arrive and if that don't work I'll think of a new injector harness.
Do you think the ECU could be duff? I would have thought if I had the topside switch fault logged then yes but I don't. Don't want to fork out on a ecu only for it not to be the cause of the issue.

The ECU can fail whilst not showing any obvious errors on the Nanocom. I had one do this about three years ago. Everything showed up as you would expect, but it turned out it wasn't delivering any signal to the injectors. I also had the new ecu fail about a year ago and that was much more obvious. It wouldn't communicate with the Nanocom or AA man's kit, and wouldn't show a yellow engine check light or do the fuel purge process. I sent it to a firm that tests and repairs them and after spending £300 it was fine. I keep meaning to send them my old one and see if they can mend that, so I have a spare, but haven't found a month where I've got £300 left over! I've been busy building sheds so most of my pocket money has gone on cement and wood and roofing sheets. The other thing to note is that TD5 wiring looms are prone to deteriorate. The insulation on the wires cracks off or wears away with the vibration and the metal in the wires seems rather stiff and brittle. I'm not talking about the injector loom here, but the big red plug and black plug looms. It's a big job checking everything as there's a lot of dismantling to do and hundreds of wires to get out of the tape and corrugated tubing. This can give you all sorts of weird symptoms which are often intermittent and thus hard to diagnose.

So I sourced a Disco ECU NNN000120 connected it to my defender and read the faults. Nothing bad apart from a road speed missing which I've never seen before. Cleared the faults with my nanocom. I've also changed the ecu to non immobilised. I then recoded the injectors. Noticed the needle on the temperature gauge has shot to red even though it's cold but I know it's because of the disco ecu. Still won't start. Ive cranked and cranked and loads of white smoke.
Battery was at around 12.2v before cranking. It wants to start more than the previous MSB ecu I had. Also previously there was no smoke with my 'duff' ecu.
I can no longer hear air whirling in the fuel tank since I fitted the NNN ecu and did the purge 5 times pedal down procedure.
Any ideas why it won't start? Battery voltage too low? I did trickle charge the battery for a day and a half.
This td5 is giving me such a bloody headache. I'm moving house in 2 weeks time and was hoping it would have started.

Sounds like something is happening then. Something is getting into the cylinders. In my experience it takes at least a couple of complete purge cycles to get a good steady supply of fuel at the injectors so you might want to run it a few more times. If the battery voltage is 12.2v with everything off, what is it when the engine is turning over? TD5s are very fussy about getting a high voltage when the starter motor is turning too. If it drops into single figures it's unlikely that the engine will catch.
The other possibility is some problem of compatibility between the new ECU and the engine, and Discovery versus Defender, as this guy had http://www.web-rover.co.uk/my_td5.html?n=3

When I put the discovery ECU in my defender it fired up first turn of the key it had the reverse temperature gauge thing but stll worked.
I had the defender map on disk so i put it in with the nanacom and it ran fine.
When it refusing to start it would spin over give one cough as it was about to fire then it puffed out a cloud of grey smoke and that's it I put it down to a bit of diesel leaking past my old injectors and burning off in one puff.

raywin said:

When I put the discovery ECU in my defender it fired up first turn of the key it had the reverse temperature gauge thing but stll worked.
I had the defender map on disk so i put it in with the nanacom and it ran fine.
When it refusing to start it would spin over give one cough as it was about to fire then it puffed out a cloud of grey smoke and that's it I put it down to a bit of diesel leaking past my old injectors and burning off in one puff.

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One thing I didn't do is put a defender map on the NNN000120 ecu but I didnt think that would prevent it from firing up.

Also are you suggesting my injectors are shot?