How To test the Diesel High-Pressure system - Page 9

Arctic · 24th March 2020, 07:50

Hi Pedro.
Please find a photo from T4 for comparison below, it may or may not help ?

1

Jules · 24th March 2020, 08:02

Yes pretty typical T4 data.

I assume that a single pump system as the low pressure figures are slightly higher?

Try turning the flash off next time

mauzao · 24th March 2020, 09:44

Quote:

Originally Posted by Jules

I assume so. We use T4
Those numbers are at 2770 rpm.

You'll have to convert BAR to kpa.

The low pressure stays pretty much constant at 350kpa but the high pressure will vary from 28,000kpa while cranking to start up to around 180,000 at higher revs.

What reason are you monitoring the pressures?

Thks Jules, lately my car was stalling a bit when accelerating, seems like some micro fuel cut or something like that, just noticed this in low rev, when turbo kicks in, no problem.
It start's at 1st, no problem starting...
MAF is a brand new one, original Bosch.
I wanted to check if was something related with fuel pressure...

Jules · 24th March 2020, 10:08

Do a fuel flow test 1st.

The output of the fuel filter should supply 2 ltrs per minute.
Test it into a can

mauzao · 24th March 2020, 14:38

Quote:

Originally Posted by Jules

Do a fuel flow test 1st.

The output of the fuel filter should supply 2 ltrs per minute.
Test it into a can

Can i test at the fuel filter entry, right after the UBP?
At the exit of the filter it's not easy to test, since it goes right to the High Pressure system, i guess...

Arctic · 25th March 2020, 08:21

[QUOTE]

Quote:

Originally Posted by Jules

Yes pretty typical T4 data.

I assume that a single pump system as the low pressure figures are slightly higher?

Try turning the flash off next time

[/QUOTE

]

HI Jules.
Hope you are keeping well in Wales my daughter is in Conwy.

Yes as opposed to one with the UBP below

1

Teranchelope · 15th October 2021, 11:54

Fuel filter output voltage must get to 4.0v before ecu allows start up. I installed a pressure regulator oon return pipe to tank to increase back pressure to compensate for loss due to any leakback. Works fine now.

Mike Noc · 31st October 2021, 09:34

Sounds more like you have masked an LP pressure fault rather than anything on the HP side. Given the pressure causing the leak back, you'd blow the return hoses off well before you restricted it.

24th March 2020, 07:50	#81
Arctic Give to Learn Freelander 2 Join Date: Aug 2010 Location: West Midlands Posts: 18,713 Thanks: 1,155 Thanked 6,407 Times in 3,874 Posts	Hi Pedro. Please find a photo from T4 for comparison below, it may or may not help ? 1 __________________ Arctic Givology Learn to Give Everything is Achievable ad altiora tendo. Check out our Nano meet dates http://www.midlandsnanomeets.co.uk/ http://www.the75andztclub.co.uk/index.php?thepage=howto " You do the work , we supply the expertise " Last edited by Arctic; 25th March 2020 at 08:06.. Reason: photo editing

24th March 2020, 08:02	#82
Jules This is my second home ZT 260 SE Twilight and 10 other 75 ZT's :O Join Date: Jan 2007 Location: Conwy NORTH WALES Posts: 11,094 Thanks: 512 Thanked 1,116 Times in 763 Posts	Yes pretty typical T4 data. I assume that a single pump system as the low pressure figures are slightly higher? Try turning the flash off next time __________________ [SIGPIC][/SIGPIC] Newbies do now!! 1. Plenum drains..all 3 or 4 year dependent 2. Cooling fan..All speeds functioning 3. Bonnet cable divider block

24th March 2020, 10:08	#84
Jules This is my second home ZT 260 SE Twilight and 10 other 75 ZT's :O Join Date: Jan 2007 Location: Conwy NORTH WALES Posts: 11,094 Thanks: 512 Thanked 1,116 Times in 763 Posts	Do a fuel flow test 1st. The output of the fuel filter should supply 2 ltrs per minute. Test it into a can __________________ [SIGPIC][/SIGPIC] Newbies do now!! 1. Plenum drains..all 3 or 4 year dependent 2. Cooling fan..All speeds functioning 3. Bonnet cable divider block

15th October 2021, 11:54	#87
Teranchelope Regular poster Rover 75 Facelift 54 plate saloon Join Date: Feb 2016 Location: Pulborough Posts: 70 Thanks: 15 Thanked 4 Times in 4 Posts	Fuel filter output voltage must get to 4.0v before ecu allows start up. I installed a pressure regulator oon return pipe to tank to increase back pressure to compensate for loss due to any leakback. Works fine now.

31st October 2021, 09:34	#88
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,548 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	Sounds more like you have masked an LP pressure fault rather than anything on the HP side. Given the pressure causing the leak back, you'd blow the return hoses off well before you restricted it.