Var­i­ous ques­tions

Car Mechanics (UK) - - Help! -

I work for the NHS in men­tal health and have re­cently been asked to sup­port a client who is very ex­pe­ri­enced in work­ing on cars and is used to dis­man­tling en­gines, chang­ing head gas­kets, etc. He re­cently bought a 2002 VW Lupo 1.7 SDI on ebay with bro­ken coil springs and rusted front brakes. There are a few ar­eas where we need some ad­vice: 1) The ‘Check En­gine’ light is not il­lu­mi­nat­ing when the ig­ni­tion is switched on, but when you di­rect a torch onto the dash­board you can clearly see the ‘Check En­gine’ icon. Should the en­gine light on this model il­lu­mi­nate upon switch­ing on the ig­ni­tion? 2) The EGR valve seems to be dis­con­nected. Is there a rea­son

for this and why is there a ‘cut’ pipe con­nected to it? 3) What are the torque set­tings for the front brake caliper bolts? There are two Torx bolts, a longer up­per one and shorter lower one; we re­newed them both with a set from Euro Car Parts sup­plied with a rub­ber rings and grease. 4. Even af­ter chang­ing the front brakes, the brakes feel very weak.

Is this nor­mal for this model or should we sus­pect a fault? 5. When we changed the fuel fil­ter, we clamped the fuel pipes and filled the fil­ter with fresh diesel, mak­ing sure it was full to the top to min­imise the pos­si­bil­ity of an air-lock in the sys­tem. Hav­ing al­ready warmed up the en­gine be­fore the fil­ter change, we then ran the en­gine at 2500-3000rpm for a pe­riod of time, but air bub­bles were still present in the trans­par­ent pipe be­tween the fil­ter and fuel pump. We re­newed the seals at the fuel con­nec­tion where some cheap clips were present and the pipes at this con­nec­tion were left un­done and the seals changed with the pipes undis­turbed. The re­main­ing two pipes are se­cured with same type of clip – al­though they are not loose, we were able to turn them round on their axis af­ter re­in­stalling the clips, so I’m not sure if they were tight enough. Should we re­place the clips on the fuel fil­ter or should we fol­low some spe­cial pro­ce­dure to bleed the air from the sys­tem? Us­ing a ba­sic scan­ning tool, it shows no er­ror codes.

Yes, the EML should il­lu­mi­nate when the ig­ni­tion is switched on. I sus­pect the bulb has been re­moved to cover the fact that the EGR valve has been dis­con­nected. First, re­move the dash­board and see if the bulb is blown or miss­ing. It is strange that no codes are show­ing on your scanner, but this may be a com­pat­i­bil­ity is­sue, as Eobd-com­pli­ance didn’t come into force on diesels un­til 2004.

The EGR valve should be bolted to the in­let man­i­fold and the pipe should go down to the ex­haust man­i­fold. The EGR is op­er­ated by a vac­uum pipe from the EGR con­trol valve on the bulk­head. From your de­scrip­tion, it sounds as though the pipe has been dis­con­nected and prob­a­bly blanked off. This is con­firmed in the photo you sup­plied.

The torque set­tings for both caliper bolts is 25Nm. It is dif­fi­cult to com­ment on the feel of the brakes, but pro­vided the vac­uum pump is op­er­at­ing and the brake pedal is nei­ther rock solid or spongy, this may be the stan­dard feel of the brakes. A good test would be to ask your lo­cal MOT sta­tion to check them on a rolling road; this will give a bet­ter idea of the ef­fort be­ing ap­plied and the bal­ance of the sys­tem.

Pro­vided the en­gine starts and runs OK, I would sim­ply re­place the clips. An air leak into the fuel sys­tem will nor­mally re­sult in poor start­ing and pro­duce black smoke while driv­ing. Some vis­i­ble air bub­bles in the pipes does not nec­es­sar­ily in­di­cate a se­ri­ous prob­lem. If there are no run­ning prob­lems, the sys­tem should purge it­self over time.

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