P1210 fuel pressure regulator fault

[darbuck]

I am not sure but I think it goes to the bsi. The corrosion could be why it blew I still don't know about the rating but as I say I'm not sure.. I am getting 2 ohms from connector to connector on all the temp sensor wiring and the regulator wiring. It's about a meter of sensor size wire.

[Rhothgar]

I’ve no idea where the BSI is on these relative to everything else. Not familiar with the C5 X7 at all.

I’ve had thought the resistance should be 0.1 - 0.2 Ohms with a good meter.

As a matter of interest, I keep meaning to ask, what software is that you are using which shows DCM3.4 or whatever in your screenshots with the fault codes please?

[darbuck]

Hi Roger,
It's in the same location as the MK1 very similar looking just more awkward to get to. Ok so resistance is a bit high which is why I was thinking bad earth.

The software is diagbox. Fancy lexia

I have Delphi software aswell.

[Rhothgar]

Hi Roger,
It's in the same location as the MK1 very similar looking just more awkward to get to. Ok so resistance is a bit high which is why I was thinking bad earth.

The software is diagbox. Fancy lexia

I have Delphi software aswell.

I've no idea where is on a Mark 1 either.

Unlikely to be bad earth.

I have Diagbox box but no fancy interface like that.

[darbuck]

It changes from old style Lexia to the diagbox interface on newer models. It's just smoother graphics. ECU is on left hand side of engine bay and BSI is behind glove box. Maybe it's Norma I don't know I will check with a different ohm meter see if it's different.

[darbuck]

Ok so just home the ohm meter when tested against itself has a resistance of 0.9 ohm's so it's off by that much at least. So I think I can stop worrying about it.

[darbuck]

I tried two garages on the way home and couldn't get a 3amp standard fuse. I have ordered off Amazon should be here tomorrow so I am going to put as much back together tonight as I can throw the fuse into it and hopefully It will run. If not I will have to go back to voltage Drop testing.

[darbuck]

Right put a new three amp fuse in hasn't blown so I think that much is sorted, unfortunately no improvement in the starting condition.
I tried turning it over while graphing the regulator. There is regulation and it goes from 8% key on engine off and if I knock off the key it goes to 59%. If I crank it it shoots up to 58% very slow to start. It says the regulator is regulated when I look for condition.

The battery Comms unit is back working so must have been the Fuse for that.so that's something.

Coolant temperature is 20C so I think that is ok.

Same fault codes regulator, and exhaust temperature sensor and glow plug relay.

I am beginning to think the ECU is bad on it given it keeps giving the short circuit/open circuit faults and I can't find a bad earth or faulty wiring.

[KennyW]

Darren,

Did you change the earth cables ?

Kenny

[darbuck]

Not yet waiting on new ones Kenny

[Rhothgar]

Damn! My earlier post didn’t post.

My mate said that it is most likely an earthing fault at the ECU or somewhere between.

As above, Darren.

To test if the earth from the regulator is an issue and this is a bit Heath Robinson, bypass the earth cable to the regulator and try and pretend to be the pulse width modulation.

Currently, this thing is getting up to 2000 bar pretty quickly so...

If you could have someone in the car whilst you are earthing the regulator as quickly as you can by holding the free end of a wire coming from regulator earth to say battery earth and dabbing it on and off the earth as quickly as you can to create a pulse manually, will it run any better? I'm not talking running perfectly but does it show an improvement?

The fastest a human can generally press something is about 6 x times a second if they are very fast. That equates to just over 16% which is where you need to be. Time yourself over a minute and work out the percentage. If you're 20 or 25% then the car would need a bit of throttle.

Of course, the only issue here is that it is earthing from time to time via its actual cable to get the 58% you report so it would be better if you can wheedle that wire out if you have any termination tools to remove terminals from connectors?

You could simply remove the end from the ECU side and use that BUT you'd have be be very careful not to damage the termination tapping it on an earth rapidly. You'd need to be gentle.

See! Told you it was Heath Robinson but if it determines if there is an improvement that may prove the ECU is faulty.

If the earth to the ECU was faulty, I feel sure that there would be many more faults and issues but you should try to rule that out first.

[darbuck]

Ok Roger I will try what you have suggested I cant disconnect on the ECU end but might be able to create a ground at the other end.like you I think it's the ECU, hopefully not but it looks more and more like it is.

[Rhothgar]

To be clear, you're not just earthing it. You are trying to replicate a pulse width modulation of 18%, on off on off on off very rapidly.

So ideally, you need to remove the earth wire from the regulator connector and plumb a new one in. Ideally, you need the same termination to the wire so it is secure on the regulator pin.

Here is a little video of what I mean. (Cannot upload MOV as I will add it to my OneDrive and then add a link here as soon as it's uploaded.

You would start doing this before the ignition is even switched on so the ECU might then prevent the regulator from opening too soon. Not sure whether they are fail open or closed but I imagine closed in reality. I imagine the earthing of the regulator is the open portion of the pulse ie full voltage and when you remove the earth it is essentially open circuit or open cycle so therefore it needs to be earthed for less time than it is not earthed.

Obviously you would want the other earth cables in place first. When are they due?

[darbuck]

They arrived today I believe so I will try and fit when I get home. I understand what you mean by pulsing it I will try and find a way to do it.You think the earth on the driver is stuck on essentially in the ECU then do you.

[darbuck]

If I cut the earth wire a couple of inches back from the the regulator would that not be the same as disconnecting it and pulse it from there.