Go Back   The 75 and ZT Owners Club Forums > The 75 and ZT Owners Club Forums > Technical Help Forum
Register FAQ Image Gallery Members List Calendar Mark Forums Read
Notices

Reply
 
Thread Tools Display Modes
Old 16th November 2020, 12:40   #11
clf
This is my second home
 
clf's Avatar
 
MG ZT CDTi

Join Date: Jan 2014
Location: carrick
Posts: 7,859
Thanks: 3,494
Thanked 2,657 Times in 1,973 Posts
Default

Quote:
Originally Posted by ardvark View Post
Took fuel filter off and filled it with Redex, ran engine for 30 seconds and left it over night. This morning car started no problem but once warmed up it started playing up again. Cutting out at junctions and when slowing down. Starts straight away but still a pain.
Any ideas please?
Redex in the fuel filter did nothing for my injectors. I did check using the live data from TOAF, with a before and after. There was no change at all after 24 hours of soaking.

I did and still do get results from Forte injector cleaner (fill filter, start and run for 30 seconds, then leave over night, completed with an italian tune up).

The first time I used the Forte, the difference was more marked than subsequent services, however there is still a slight improvement after each use.

I am not sure this will fix your issue, it certainly wont do any harm. If the injectors are so bad to cut the engine when it idles, I would have expected them to be lumpy on the move.
__________________


It is not gloss primer .............. it is duct tape silver!
clf is offline   Reply With Quote
Old 16th November 2020, 13:09   #12
ardvark
Al
 
ardvark's Avatar
 
75 CDTI Tourer Auto

Join Date: Mar 2009
Location: Studley
Posts: 1,455
Thanks: 1
Thanked 69 Times in 48 Posts
Default

Maf is unplugged and when the engine cuts out the oil light comes on but goes out when I start the engine.
__________________
ARDVARK
ardvark is offline   Reply With Quote
Old 16th November 2020, 13:22   #13
Mike Noc
This is my second home
 
Mike Noc's Avatar
 
Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4.

Join Date: Jul 2009
Location: Hampshire
Posts: 11,531
Thanks: 3,470
Thanked 3,119 Times in 2,247 Posts
Default

If it was me I'd carry out a leak back test on the injectors next.
Mike Noc is offline   Reply With Quote
Old 16th November 2020, 13:31   #14
ardvark
Al
 
ardvark's Avatar
 
75 CDTI Tourer Auto

Join Date: Mar 2009
Location: Studley
Posts: 1,455
Thanks: 1
Thanked 69 Times in 48 Posts
Default

How do we do that?
__________________
ARDVARK
ardvark is offline   Reply With Quote
Old 16th November 2020, 15:33   #15
ardvark
Al
 
ardvark's Avatar
 
75 CDTI Tourer Auto

Join Date: Mar 2009
Location: Studley
Posts: 1,455
Thanks: 1
Thanked 69 Times in 48 Posts
Default

Another question. If a T4 was plugged into the car would it tell me what's wrong?
__________________
ARDVARK
ardvark is offline   Reply With Quote
Old 16th November 2020, 21:29   #16
Mike Noc
This is my second home
 
Mike Noc's Avatar
 
Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4.

Join Date: Jul 2009
Location: Hampshire
Posts: 11,531
Thanks: 3,470
Thanked 3,119 Times in 2,247 Posts
Default

Quote:
Originally Posted by ardvark View Post
How do we do that?

You check the amount of fuel leaking back from each injector running the engine at idle. Disconnect the leakback pipes and blank off the open end back to the return circuit or fuel will spill out from the HP pump return. I knocked up this GhettoTech version to measure the amount of leakback, but I think you can buy kits cheaply enough these days on The Bay. You can see the return pipe is clamped to the left of the picture.





Quote:
Originally Posted by ardvark View Post
Another question. If a T4 was plugged into the car would it tell me what's wrong?

In all probability yes, and if it doesn't it will at least help point you in the right direction as you can see LP and HP fuel pressures and other live data and also read any fault codes.

T4 doesn't measure injector leakback as such, but it can show you the compensation figures the ECM uses to ensure an even idle. It knows the amount of bang you get for your buck from each injector as it measures the speed of the crankshaft after each injection of fuel, and if there is excessive leakback the ECM compensates by increasing the injection duration on that injector.






.

Last edited by Mike Noc; 17th November 2020 at 07:26..
Mike Noc is offline   Reply With Quote
Old 16th November 2020, 21:35   #17
COLVERT
This is my second home
 
R75 Saloon.

Join Date: Feb 2009
Location: France/or Devon.
Posts: 14,003
Thanks: 3,851
Thanked 2,167 Times in 1,816 Posts
Default

Quote:
Originally Posted by ardvark View Post
How do we do that?
The leak-back test is explained in the --How-TOs.

Putting injector cleaner in the fuel tank might take a while to clean the injector spray holes if they've been partially blocked for some time. Even in the fuel filter, as you have tried, might not be long enough to do a good cleaning job.

Several weeks of driving could give you the results you are looking for.
COLVERT is offline   Reply With Quote
Old 21st November 2020, 17:07   #18
ardvark
Al
 
ardvark's Avatar
 
75 CDTI Tourer Auto

Join Date: Mar 2009
Location: Studley
Posts: 1,455
Thanks: 1
Thanked 69 Times in 48 Posts
Default

Update to who may be interested.
The car would start no problem.
When driving at low revs it would feel as though it was misfiring on one cylinder.
I know it's a diesel but that's the feeling I had.
After doing the things I said it was still the same.
So after work I opened the bonnet and disconnected and reconnected every connector I could find several times.
Injectors, Fuel Pump just to name a few.
Car started no problem as normal BUT this time when pulling away no coughing or spluttering.
Went for a quick drive with no problems at all.
Thank - - - - for that I thought.
Tip to members if I may.
If you get stuck of something like I did, try disconnecting and reconnecting connectors. It could be as simple as that.
Took me a week of rubbish driving to work and back to sus that one.
__________________
ARDVARK
ardvark is offline   Reply With Quote
Old 22nd November 2020, 11:04   #19
ardvark
Al
 
ardvark's Avatar
 
75 CDTI Tourer Auto

Join Date: Mar 2009
Location: Studley
Posts: 1,455
Thanks: 1
Thanked 69 Times in 48 Posts
Default

Me and my mouth. Car is playing up worst than before on the way to work. 😞
__________________
ARDVARK
ardvark is offline   Reply With Quote
Old 22nd November 2020, 11:10   #20
Alf Best
Avid contributor
 
MG-ZTT

Join Date: Oct 2020
Location: Cullercoats
Posts: 117
Thanks: 81
Thanked 69 Times in 47 Posts
Default

Quote:
Originally Posted by ardvark View Post
Me and my mouth. Car is playing up worst than before on the way to work. 😞
I wonder if your injector wiring loom is damaged?, the reason I say this as I had a misfire which turned out to be a broken wire making intermittent contact where the wiring connects to the injector.


Diagnosis wise, I wiggled each cable in turn with the car running until I induced the fault, the wire looked okay, but when checked it was green where crimped to the contact.


Worth looking at, costs nothing but a few minutes of your time


Alf
Alf Best is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 16:36.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright © 2006-2023, The Rover 75 & MG ZT Owners Club Ltd