Diesel knock or pinking,,then Bio Fuel?

Hi again folks... Sadly I'm reporting the same problem I experienced last year/winter.

On acceleration, from cold, the engine misfires and knocks very loudly and blows out black smoke. This happens for about 3/4 secs until speed has built up. I try and keep this to a minimum by using a very light throttle and until the engine gets to full temp,, were the misfire/pinking almost fully disappears.

I fitted 4 new injectors last summer, this cured the erratic running and misfires, but regrettably its back again now, and in this very cold weather, the pinking has returned!. Driving with a window open the engine sounds like it could seriously damage itself.

I read on another forum that a freebee owner cured his misfire by running on Bio diesel. He, as well as others, found that fuel treatments and potions don’t really cure or clean blocked injectors.

When the engine has reached full temp I also experience surging when using very light throttle settings..

I love my FL but the engine has been a real pain in the A##E.....

Has anyone used Bio fuel? And suggestions re pinking/diesel knock.

The diesel knock can definitely be reduced using millers fuel treatment.

It could be a faulty maf causing overfuelling and would explain the black smoke. Try running with it disconnected and see if the smoke is reduced.

You can't use bio in a td4...

Hi i had noise on a diesel once,and it was caused by water in fuel.

Thanks chaps,,, I run a RoverRon Mafam box.... Could be water and will try Millers.. Any diesel experts out there with an idea please?? My FL improved from misfire etc last summer after I replaced all the injectors.. But the misfire has slowly reapeared and now knocks so loadly it worries me............ But when the engine is hot the knock disapears but surges at very low speed.......

gmzez said:

Thanks chaps,,, I run a RoverRon Mafam box...

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Sounds like you have the mafam turned up too high.

You can still test with the maf/mafam wiring disconnected, this way the ecu ignores the maf output altogether and substitutes a default value. If the fault disappears you then know your looking in the right area.

Ron recommends a high setting on the mafam. Bcoz I changed the sensor for a Pierburgh sensor over the Bosch one,, However , I have tried all the settings from High to very low,, without any change,, The box also has a switch to allow the maf sensor to be turned off,, I've tried this but the car drives very poorly but still knocks.. Last summer I sent the Mafam box back to Ron who tested it and found no Fault... These are wonderful motors but the engine is driving me mad!!!!

But how does it drive with the maf physically disconnected? It doesn't matter what maf is fitted if it's disconnected and ecu uses default value.

It's just a way of eliminating that whole area as the cause of the overfuelling if the fault is still apparent when it's disconnected.

A certain amount of increased diesel knock is normal during cold starts but not to the point that it is accompanied by excessive black smoke.