Td4 leak back test
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guineafowl21
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How bad is it?
A leaky injector causes hard starting, so in theory a really bad one could cause the rail pressure to drop enough to prevent starting completely. It would have to be very leaky, though.
A leaky injector causes hard starting, so in theory a really bad one could cause the rail pressure to drop enough to prevent starting completely. It would have to be very leaky, though.
guineafowl21
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Replace the injector. It’s leaky enough to cause idle and running problems, even if it’s not the cause of the non-start.
Or you could try some injector cleaner, if you wish to spend £5 and feel like you’ve tried everything. In the 20 years or so of fixing cars for myself and other people, I’m yet to see a dose of this stuff make a difference, with my own eyes.
That said, experienced bods like Nodge68 on here swear by Comma Diesel Magic. Who am I to argue?
Or you could try some injector cleaner, if you wish to spend £5 and feel like you’ve tried everything. In the 20 years or so of fixing cars for myself and other people, I’m yet to see a dose of this stuff make a difference, with my own eyes.
That said, experienced bods like Nodge68 on here swear by Comma Diesel Magic. Who am I to argue?
Nodge68
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You could do worse than use my favourite Comma Diesel Magic!
It's definitely worthwhile doing that before replacing an easy sorted injector.
Injectors leak back because they're not sealing tight when they should. If this slight leak is due to dirt that is dissolved by the cleaner, then it'll probably rectify it's self. If the excess leak back is due to wear, then a cleaner won't cure that injector. However it'll clean the spray head of all the injectors, so improve fuel atomization and running as a result.
It's definitely worthwhile doing that before replacing an easy sorted injector.
Injectors leak back because they're not sealing tight when they should. If this slight leak is due to dirt that is dissolved by the cleaner, then it'll probably rectify it's self. If the excess leak back is due to wear, then a cleaner won't cure that injector. However it'll clean the spray head of all the injectors, so improve fuel atomization and running as a result.
guineafowl21
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My arse
My arse
My arse
Stop reading the bottle!
And Merry Christmas!
Nodge68
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Don't need to read the bottle as I've done before and after treatment visual checks. Not on a TD4 but on a standard, non common rail and PD injectors.
The stuff is good at what it does. Sure it's not going to repair worn injectors, but it sure does clean fouled ones.
Nodge68
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guineafowl21
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Photos! Including spray pattern.
Why is it always anecdotes? Why does it never work for me or anyone I help? Have I been a bad boy?
Why is it always anecdotes? Why does it never work for me or anyone I help? Have I been a bad boy?
guineafowl21
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Yep, I’ve heard it many times. But never seen it. A bit like ghost stories.You need to read this.
It wouldn’t have been the 200 mile trip, then?
Post hoc ergo propter hoc. The reason homeopathy is still practised.
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teddywood1
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I tried some turbo cleaner and what a load of rubbish and as I thought about it now correct me if I am wrong but what a turbo does is to force air into the engine NOT diesel so when I put this turbo cleaner in with a tank full of diesel how could it clean the turbo
Alibro
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We'll never know the real reason for 100% but perhaps the 200 mile trip would have fixed it and perhaps not. Maybe the injector cleaner helped to clean the dirt that was causing the problem. This was an issue that happened overnight so was almost certainly caused by dirt rather than wear and tear. In that situation something that helped dissolve the dirt will make the difference.Yep, I’ve heard it many times. But never seen it. A bit like ghost stories.
It wouldn’t have been the 200 mile trip, then?
Post hoc ergo propter hoc. The reason homeopathy is still practised.
Vorsprung durch technik
DevonGuy
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Quite fond of this stuff myself. SWMBO has a habit of slinging any old diesel into her Pug and it generally sorts it out with one bottle to a tankful. Have used it in my Td4 before I took advice and started using a better grade.
Arctic2
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Dont need to provide photos. Simple fact is that my no 3 injector wasnt functioning properly and it is now after running a bottle of injector cleaner through in 30l of fuel thats good enough for me!
Before replacing the injector I thought id try adding a 500ml bottle of Wynns Diesel clean extreme ://www.eurocarparts.com/ecp/p/car-accessories/engine-oils-and-car-fluids/car-additives/diesel-system-additives/?555770090&0&cc5_862&gclid=EAIaIQobChMI3If-4qal2AIV5pXtCh1cTADgEAQYASABEgJpHPD_BwE
and after a 200 mile run the injector is now functioning fine with no more shaking of the car at idle and no more white smoke at start up. So as far as im concerned it did what it was supposed to do perfectly and saved me the cost of a new injector. Wether you believe that or not is completely up to you but im more than happy with the result!
Also for the comment that it was likely to be the 200 mile trip rather than the cleaner. Id already been using the car which is actually my wifes on an 80 mile round trip commute each day for 3 days to try and clear it which included sustained high revs to try and clear it but it had made absolutely no difference until I added the cleaner.
I did stop about 70 miles into the 200 mile trip to see if there was any change and it had improved slightly but was still not running right. However by the end of the trip it was idling perfect with no more 'stumbling'. 2 days later now and still running great
Alibro
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I have to give this a try with both my Freelander and my recently acquired Zafira. Both a bit lumpy on startup and smoky for a few minutes.
Alibro
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Brilliant Elv. Thanks for clearing this up for us.
doogiescott
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doogiescott
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I wondered the same thing? Asked a local mechanic & was told that the fumes after fuel burning are what recirculated and help "dissolve" carbon deposits. I can't see how else it could but I also asked if a car had been put on a MOT gas analyser before and after stuff was added. Not that he knew. So, I had my exhaust gasses tested. Filled up with fuel & added a bottle. Quick 5 mile run & gasses retested ........ a bloody slight increase, but still well within MOT standards. Some things are a con, some are not. It's very hard to tell. Best of luck with your additives.
