Fuel pumps

[Seanalf]

Hi all, friend of mine has a ZT saloon, 53 plate diesel and has the annoying float issue and Friday her car wouldn't start. I recommended chucking a few cans worth of diesel in to make sure she was above a quarter, did that and still nothing. One visit from the RAC (she'd had to go to work so didn't speak directly to him), he has said it's a HP fuel pump issue.

The ZT has the under bonnet and in tank pump, she thinks she can hear the whine of the in take priming, would I be correct in assuming it is a good shout to change the under bonnet pump first as that can still do some of the heavy lifting? I'm thinking this way as it's the easiest to do, once we know which one is fitted?

It's not battery, it doesn't seem to be crank as the rev needle comes up and I'm assuming the guy checked other things. Any thoughts?

[Mike Noc]

Does the engine oil light come on with key to position II as it should? First thing to check is the plenum drains to ensure the ECM hasn't gone for a swim.

[Seanalf]

Originally Posted by Mike Noc

Does the engine oil light come on with key to position II as it should? First thing to check is the plenum drains to ensure the ECM hasn't gone for a swim.

Yes, that's all been checked, car is behaving as it should, just not actually starting. Tried both keys as well, just in case it was a chip fail.

[tonytolle]

If the RAC chap is right ,you are looking in the wrong place ,he has said it's the HP pump ,not either of the electrical ones.

[Arctic]

Hi Sean.
Was the car running ok until this episode, and did she allow the diesel to get low, try tapping the under bonnet pump while someone tries to start the car, if it fires up see if it runs or not.

It could be the High pressure fuel pump regulator O-rings, if so they are only about £5.50 to £12.50 and an hour to fit.
https://www.ebay.co.uk/itm/225688542946



https://injectionpumps.co.uk/product...sch-cp1-pumps/

https://www.dmgrs.co.uk/products/rov...l-kit-cdt-cdti

https://www.buycarparts.co.uk/bosch/...RoCiy8QAvD_BwE

[Seanalf]

Originally Posted by Arctic

Hi Sean.
Was the car running ok until this episode, and did she allow the diesel to get low, try tapping the under bonnet pump while someone tries to start the car, if it fires up see if it runs or not.

It could be the High pressure fuel pump regulator O-rings, if so they are only about £5.50 to £12.50 and an hour to fit.
https://www.ebay.co.uk/itm/225688542946



https://injectionpumps.co.uk/product...sch-cp1-pumps/

https://www.dmgrs.co.uk/products/rov...l-kit-cdt-cdti

https://www.buycarparts.co.uk/bosch/...RoCiy8QAvD_BwE

Hi Artic. Car was running day before, she doesn't think so, but added 15 litres of fuel just in case, RAC geezer couldn't get it started. She thinks the in tank was running, could hear the hum.

I take it the fuel runs from in tank to under bonnet as low presssure, down to the HP one near the engine. Any pointers to anything that would help diagnose if it's that or one of the others?

He did mention the HP pump I think, so the seals might be a good shout. She didn't get sent a report, so not really sure what he did to be honest. I'm hoping she can get a mechanic out asap to have a proper look. Thanks bud

[Arctic]

Originally Posted by Seanalf

Hi Artic. Car was running day before, she doesn't think so, but added 15 litres of fuel just in case, RAC geezer couldn't get it started. She thinks the in tank was running, could hear the hum.

He did mention the HP pump I think, so the seals might be a good shout. She didn't get sent a report, so not really sure what he did to be honest. I'm hoping she can get a mechanic out asap to have a proper look. Thanks bud

Hi Sean.
Unplug the the electrical connector on the low pressure pump on top of the fuel filter, and see if will start then, only the connector not the fuel lines.
1

Also unplug the UBP connector and clean with some electrical cleaner, do the low pressure plug above too.
2

3

All eliminating jobs that cost nowt to try.

Same for the fuel rail plug.
4

5


HPFP regulator but try the above first before condemning the O-rings.
6

You will see the HPFP below the oil filter pot.
7

Are the plenums dry no water in them or has the ECU gone for a swim.

[Mike Noc]

If you disconnect the outlet pipe from the UBP where it enters the fuel filter and place it in a large jar then with key to position II you should get a good strong flow of fuel with no air in it into the jar for 30 seconds to a minute depending on the type of ECM fitted.
That would prove the LP fuel supply.

[Seanalf]

Originally Posted by Arctic

Hi Sean.
Unplug the the electrical connector on the low pressure pump on top of the fuel filter, and see if will start then, only the connector not the fuel lines.
1

Also unplug the UBP connector and clean with some electrical cleaner, do the low pressure plug above too.
2

3

All eliminating jobs that cost nowt to try.

Same for the fuel rail plug.
4

5


HPFP regulator but try the above first before condemning the O-rings.
6

You will see the HPFP below the oil filter pot.
7

Are the plenums dry no water in them or has the ECU gone for a swim.

Awesome, thanks. If they do that and it still doesn't start, then I rings. She's struggling to get anyone to look at the car down there, bit far for you bud, unless you fancy a day at the seaside?

No swimming as far as I'm aware.

[Seanalf]

Originally Posted by Mike Noc

If you disconnect the outlet pipe from the UBP where it enters the fuel filter and place it in a large jar then with key to position II you should get a good strong flow of fuel with no air in it into the jar for 30 seconds to a minute depending on the type of ECM fitted.
That would prove the LP fuel supply.

That's what I was thinking as a quick test first, thanks 👍