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Old 31st July 2022, 12:28   #11
Number 6
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Originally Posted by grivas View Post
Looking at the results of your FrenchMike tests, it looks to me that you are not getting the correct pressure from the HP pump, for the fuel to ignite. So I would be concentrating on the HP regulator seals/flange, I wouldn't be surprised if one of the sealing rings is had it.
Good luck.
It could well be the HP pump regulator, The only thing is when I had a similar/same problem it would start on Easy Start and keep running. So maybe it is linked to the HP pump but also something else
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Old 31st July 2022, 19:39   #12
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Thanks all for your help so far. Yesterday I ordered a set of replacement regulator seals as I thought they were inexpensive and worth a try.

Today I took the ECU out and had a look. I can't see any signs of previous water ingress and everything looks okay to me, bar one small area of oxidation that I'll carefully clean up.











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Old 4th August 2022, 20:08   #13
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Quick update:

So I carefully cleaned the oxidised area on the ECU with electrical contact cleaner and a soft, clean brush and reinstalled it. I also replaced the seals on the regulator, although the old ones looked fine. Unfortunately no joy, it still won't start

I'm going to repeat FrenchMike's voltage tests just to make sure I'm looking in the right area. I'm also going to check the valve on the inlet to the HP pump as suggested here: https://www.mg-rover.org/threads/75-...p-pump.329789/

If that doesn't solve it, I think I'm going to replace the regulator (assuming the voltage tests still indicate a HP fuel issue). I don't like replacing parts without being certain, but I'm running out of options. I could try and locate a diagnostic computer but I don't know what information it'll be able to give me beyond the voltage tests.

I read on another post somewhere that it is possible to start the car with the HP sensor disconnected. I did this to try and eliminate it as a suspect and the car still wouldn't start, so I think the sensor is OK.

It's seems unlikely to me that the HP pump would catastrophically fail in such a way where the car ran fine one day, then wouldn't start the next.

It's possible that this is still an injector leak off issue as I never managed to confirm whether my results were normal or not, but they didn't seem that bad so I'm not convinced.
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Old 4th August 2022, 21:25   #14
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Go to the engine bay fusebox and lift it out, there is a blue connector block, with a thick yellow/red wire, clean that terminal with some contact cleaner, both ends then replace and try to start the car.

It was this very cable that caused me no end of trouble on my missus's zt, it too had been stood for a while and ran ok for a few weeks then died.
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Old 5th August 2022, 00:05   #15
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Quote:
Quote:
Originally Posted by Matt_75 View Post
Thanks all for your help so far. Yesterday I ordered a set of replacement regulator seals as I thought they were inexpensive and worth a try.

Today I took the ECU out and had a look. I can't see any signs of previous water ingress and everything looks okay to me, bar one small area of oxidation that I'll carefully clean up.











Hi Matt
What do the pins look like on the ECU any corrosion, brown or green residue ? there is a chance the ECU could be damaged T4 may let you know.
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Old 5th August 2022, 22:16   #16
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First of all, I want to thank everyone for their input. It's greatly appreciated!

I finally managed to find the issue and get the car to start and run today! It was a stuck check valve in the HP pump as mentioned in one of the forum posts I linked. I think having stood for 4 years, the fuel has gone a bit sticky and needs diluting with fresh diesel or draining from the tank.

To fix it, I removed the starter motor to get better access to the clamps holding the hose to the inlet of the pump. I removed the clamps and hose and inserted a clean punch into the inlet and found the valve to be stuck. I applied a bit of pressure and it came unstuck. I then pushed it a few times as initial movement wasn't very smooth but it soon improved.

I then put everything back together however one of the hose clamps was a weird design I've never come across before. It could be undone with a flat bladed screwdriver but needed a special tool to do it up. I replaced it with a regular fuel hose clamp borrowed from my '73 Triumph Dolomite as I didn't have anything else to hand!

For anyone trying to diagnose a similar issue, I'll leave some helpful links here:

Multimeter Tests for fuel pressure and cam sensor signal
https://www.the75andztclub.co.uk/for...ad.php?t=69308
https://www.the75andztclub.co.uk/for...d.php?t=109615

Additional info on pressure sensor voltage
https://www.mg-rover.org/threads/cdt...1/post-5027500

HP Pump Check Valve
https://www.mg-rover.org/threads/75-...p-pump.329789/
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