when to change diesel injectors?

[Mr Butter]

Hi,

I have 107k on the clock, and shes getting a bit smokey, not terrible yet, but new filter, oil and several injector treatments still havent cleaned things right up. MPG doesnt seem to get much better than 45 with 75% motorway work (although mostly at 70mph) . Haynes recommends changing at 90k, is this a good idea, or too much hassle?

[rigsby]

Wait till it fails MOT due to smoke. make sure air filter is clean , as this can make them smoke if it is blocked

[KenONeill]

:iagree: - There's no set mileage for changing injectors, so change the air filter, and if you or the MOT man aren't happy, then do the injectors. 45mpg for a diesel this sort of age running at 70 cough mph isn't too bad really.

[Mr Butter]

Thanks! Turns out you were right, I didnt bother changing the injectors but I did do something else... .

I remembered reading somewhere that VW diesel cyclinder intakes getting fouled up and causing a restriction. I took a look - they were about 10-15% blocked with oily crud - socleaned them out (FILTHY 'ORRIBLE JOB).

Once the remnants of solvent and crap (very smokey) had cleared she seemed to rev up nicely with no smoke even on full throttle. It seems the crankcase breather caused the problem, slowly depositing oily crap in the intake trumpets which carbonises in the heat...

Word of caution my car has no 'cat' section in the exhaust, so any particles that get blown through are no problem.

The irony is , after all that effort., turns out they didnt even test the emmisions and she passed (except for the towbar - no type approval sticker...) . I also averaged 51.9mpg on the last tank which is bloody amazing - although I have been trying out some 'hypermiling' techniques.... I always wondered why some people drive so slowly...

[Mr Butter]

oh yeah Ken , what do you mean 70 'cough'?? The only coughing going on was the poor ******** on scooters behind me (everyone else is in front!)!

[TeflonTom]

they don't test emissions on diesels anyway, they test for smoke levels

[Mr Butter]

:confused: OK OK... smoke emission levels then?

To clarify, the towbar issue is for a SPANISH test ("ITV" equiv. to an MOT in UK). Sorry for spreading confusion (you should try a Spanish ITV station - that is the definition of confusion - they dont even speak Spanish - its Catalan!).

[rigsby]

:confused: OK OK... smoke emission levels then?

To clarify, the towbar issue is for a SPANISH test ("ITV" equiv. to an MOT in UK). Sorry for spreading confusion (you should try a Spanish ITV station - that is the definition of confusion - they dont even speak Spanish - its Catalan!).

Thats nothing Channel 4 have been talking b0ll0x cr4p and **** for years

[KenONeill]

oh yeah Ken , what do you mean 70 'cough'?? The only coughing going on was the poor ******** on scooters behind me (everyone else is in front!)!

I was working on UK law, and indicating that 70 may be a pessimistic estimation of vehicle speed.

[Mr Butter]

Ken ,your spot on mate, the speed limit in Spain is 120kph, plus the local plod don't fine you up to 130. However no-one knows where there indicator controls are (roundabouts are insane) and being tailgated at 130kph is standard... they are all nuts. In my limited experience, the hotter the country the more interesting the driving.

Quite a few felly's still knocking around, alot of diesels of course. No rust issues so maybe they will be around forever! Ive seen 1997 diesels for sale at 2000 euros! Cheapest was on ebay.es at 1400. I will def be sprucing mine up when I get my spanish plates!!

Saw the New Fabia for advertised for less than 9500 Euros which seemed a good deal (but they put a big registration tax on, so it may not be the OTR price). Not that I could afford it anyway, being an immigrant!

[mutetourettes]

mm no idea whether there's a cat section in my exhaust (uk t-reg) but how would you or anyone recommend cleaning the intakes if there were? any ideas?

Mark

[Mr Butter]

OK , the safest way / best way would be to take the inlet manifold off and clean with solvents, brushes etc. I didnt bother and did it with a suitable (plastic) scraping tool , a powerful torch (to removed the carbon without it dropping into the inlet valves) , followed by solvent and a rag to clean up any residue I could get!

Perhaps someone else could comment on how necessary this as... Mine was pretty filthy and choked / coked up (4-5mm thick) so thus must have dome some good and cost next to nowt!

[Mr Butter]

Oh and there will probably be a 'cat' style particle filter in the exhaust (unless a previous owner removed it for some reason - mine cracked so I had it cut out replaced with a stainless steel section, so far so good for the last 10k miles). In theory the 'cat' heats up and burns of any soot and residue anyway, but I dont have the knowledge or experience to make any assurances!!

[mutetourettes]

so are you saying the crud accumulates in the inlet manifold trumpets which come off, or the actual intake tube holes in the cylinder head? I guess i could take off the manifold trumpets and clean them if i find a new gasket somewhere. I guess I'm a little worried that bits of crud might get impacted into the valve seats and whatnot if I couldn't get it all out of the way.

[KenONeill]

"crud" can accumulate anywhere after the feed for the positive crankcase ventilation system. It's most likely to start building up on the inside of bends, and around lumps and constrictions such as the inlet valve stems.