Defender won't start - ECU replacement?

Hi all,

I've got a 1999 Defender TD5 110 Hard Top HD with 168k miles. Having previously been very reliable, it died whilst driving last week and now refuses to start. Occasionally it will but dies again within 1-5mins and then refuses to start again for a period of a day or two. Using Hawkeye it's logging "injector peak charge long" for all 5 injectors, and occasionally "injector open circuit" for all injector. I'm clearing the fault log after every (attempted) repair action but the peak charge long on all cyliners returns.

I've been through all the usual stuff but here's a list:
1. Cleaned oil from ECU plugs. Injector wiring loom was replaced when I put in a new short motor about 30k miles / 2yrs ago.
2. Replaced fuel pressure regulator and gasket, and cleaned the small inlet filter.
3. Replaced fuel pump and fuel filter. Fully purges the fuel system of air. I've got over half a tank of fuel.
4. Replaced crank position sensor, and repaired damaged wiring adjacent to the connector plug.
5. Swapped Main Relay with know good (unused) HRW relay and checked for correct operation.
6. Despite fuel pump running normally, checked and cleaned dirty contacts on fuel pump relay. Will replace anyway but working ok.
7. By now I'm suspecting the engine harness so metered out wires from ECU red plug to injector harness plug. Continuity good from end to end on each of the 7 cables, plus no cross continuity between each cable to all others (ie no apparent insulation breakdown). I plan to replace the harness anyway as it's got oil in it and looking a bit tired in places.
8. I'm now also down to suspecting the ECU. I have an MSB101170 fitted want to try another unit if possible before forking out for a new one. There's a NNN500020 from a 2003 Defender 90 available locally. Can I fit this to mine (obviously after programming immobiliser and injectors) or will the fuel mapping be different? I'm assuming I can't as this will be an ECU3 engine but mine is an EU2 version.

Failing that, has anyone in the Sussex / Surrey / Kent area got an MSB unit available to try / buy?

Anything else someone can suggest that I may have missed?

Many thanks!

Vaughn.

those fault codes are showing faulty injector loom at first sight

and

1. Cleaned oil from ECU plugs. Injector wiring loom was replaced when I put in a new short motor about 30k miles / 2yrs ago.

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what do you mean by that?... cos if there was oil in ECU plug recently the fact that the loom was replaced 30K miles ago it's irrelevant because you must replace it again, and leave the ECU alone untill you replace the engine harness too

if you'll get to the ECU replacement at the end the NNN must work and you can save the fuel map from yours and load it into the new one with nanocom

Thanks for the response.

I understand the rationale for pointing to the loom and as I say will be replacing it anyway. The ECU plugs and headers have been thoroughly cleaned out and are oil free now. The injector plug end of the engine loom was oil free anyway so the 'new' harness isn't leaking, so the oil is from the old oil injector harness that's just taken a while to work it's way along the loom.

If there was a break in the wires, or breakdown of the insulation causing shorting, it would show up in the metering I did. I'll be interested to see if the the loom does fix it and if so what the problem with the old one is.

I can't seem to get a new engine loom before Tuesday noew so will have to sit tight till then. Will post an update after it's done.

Also, thanks for the info re ECU fuel maps. I kind of wished I'd forked out for a Nanocom now instead of the Hawkeye.

Anyone near East Grinstead with a Nanocom?

the continuity test with ohmeter on the wires is not the most relevant in this case though cos it's an up to 80V pulsatory voltage on those wires and your multimeter has max 3V supply i presume... it's a strange thing you have there and it needs serious investigation... i dont have diagrams for defender but if you have check the earth points from where the ECU must get it's earth asnd also check if tere is powerfull earth coming into the ECU cos this one is very important as well...you can do that by connecting a 100W bulb between that earth pin at ECU and a live from battery... if the bulb will dim or not glow well it means the earth is weak... so you can check the wiring from injectors but you need a voltage generator to send 80V on each wire and check the outcome on that wire's other end and on the others near it...cos even if the ohmeter shows continuity and open circuit if the uinsulation is affected the 80V will get through it... you have to emulate somehow the real conditions

I understand what you're saying re voltages. I was going to retry the test using my electrical tester to run the insulation tests (can put 250v or even 500v along the disconnected cables) but it was just too bloody cold yesterday!

After a bit more research I also realise now that it's old engine oil, loaded with it's carbon desposits, that causes the ability to short out cables that have broken insulation in the loom. I can understand now why the oil in the loom is such a problem. I was trying to get my head round this detail because new, clean oil is an insulator, hence why they use it in transformers for example.

Anyway, I have a new loom AND new injector harness on order, due to arrive tomorrow (hopefully, snow permitting!). Just hope it's just that and not the ECU too....

BTW has anyone fitted a modded ECU from this guy on ebay?
Land Rover Discovery / Defender TD5 ECU with performance chip (msb) | eBay

Well, engine loom and injector harness fitted today - no change. Runs for a few mins then dies and won't restart. Still logging injector charge long on all injectors so I'm down to the ECU now. If that doesn't fix it then I think i'll torch the bloody thing - well, ok I probably won't but I'll be really ****ed....!

BTW, earth connection checked already and that's good - no corrosion and 0.2ohms resistance to battery negative.

did you check all the earths to ECU?... cos if it's an earth thing it'll burn the other ECU too

Yep, that's what I put on the last line of my previous post. Earth connection from ECU to frame good.
Got a guy coming with Autologic tester tomorrow evening to see what that box of tricks can see. In the meantime, I'm tracking down an ECU and hopefully my new Nanocom will arrive tomorrow (snow permitting) so I can code it up as well!

Think i need a stiff drink tonight...

I am having the same problem with my 2000 td5
I was wondering if the immobaliser could have something to do with it?

Whilst waiting checked the fuel filter housing for possible blockage of the non-return valve or air bleed valve. Don't have a non-return valve fitted but will fit one as this improves throttle response on initial startup. Air bleed valve 'looks' OK but will replace it anyway.

Man with Autologic arrived this evening and confirms it's almost certainly the ECU but wants to confirm fuel pressure is correct in the gallery so he'll be back tomorrow with his special pressure gauge to confirm it's at 4bar. If so, then ECU definitely the culprit. Secondhand one on it's way as is a shiney new Nanocom. so will get it flashed with the correct fuel maps ready to slot in...and VRROOMM...hopefully!

albesure said:

I am having the same problem with my 2000 td5
I was wondering if the immobaliser could have something to do with it?

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It's not one I have seen mentioned in the forums but there are contributors out there with far more expertise than me on these matters.

Well, the final instalment of this problem - I got the 'new' ECU, coded it up with an appropriate map with the new Nanocom Evolution and away she went without any further symptoms. So it was a defective ECU after all...

Thanks for help and suggestions, both in this thread and those gleaned from the numerous other threads on the same / similar topic.

a62vw said:

Well, the final instalment of this problem - I got the 'new' ECU, coded it up with an appropriate map with the new Nanocom Evolution and away she went without any further symptoms. So it was a defective ECU after all...

Thanks for help and suggestions, both in this thread and those gleaned from the numerous other threads on the same / similar topic.

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Perhaps I had better look at a new ECU

albesure said:

I am having the same problem with my 2000 td5
I was wondering if the immobaliser could have something to do with it?

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have you had the fault codes read with a LR diagnostic

robinfedup said:

im having the same problems with the td5 , did start for a while then died again , changed most of the stuff you men have done , checked earths etc now going to check out ecu's , if l try a discovery ecu will l need to remap this before it will work. if an ecu is disconnected from the loom for a certain length of time will it need reprogrammed again​

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as long as you disconnect the battery first u have no probs

Immobiliser

Have a looky here see if this rings a bell

Dont panic you wont need to take the dash apart only need to remove the fuse cover and release the fuse carrier.

http://www.landyzone.co.uk/lz/f50/wont-start-195696-5.html