Lupo TDI not boosting (now fixed)

Gimme a clue where to start looking. Never had a diesel nor a turbo before.

It's got receipts for a new MAF and N75 valve a year ago.

Basically, it's as flat as a fart, no boost sensation or whistle at all.

 

Unplug the MAF. No diff and it could be worth finding another MAF to swap on.

Whip off the N75, wire it to a battery, blast brake cleaner through it, and switch it on off with the battery wire as you blast it. Brake cleaner may catch fire with the sparks, so avoid garage forecourts for this sort of on-the-fly testing malarkey (like I didn't ).

Swap an N75 if you can, since that didn't cure mine.

Then check capillary hoses from N75 to turbo and ECU to check they're not cracked, unplugged, blocked etc.

(experience from a TDi 1.9 Phisshat)

 

Obviously try to get VAG com or something similar on it. I had a fabia in once with a similar problem turned out to be a loose wire in the main ECU connector??

 

the idea behind taking off the N75 and cleaning it is to get rid of the oil and crud out of it that makes its way in there from the breather.

it therefore makes a lot of sense to clean/replace the vac hoses too (and the inlet pipes after the breather)

a boost leak can make it go into limp also. worth checking the EGR valve (they can get stuck open)

 

MAF and N75 are 10K old. can't be blocked already surely???

I had to fault codes, but forgot to save them.....one was definitely the cam trigger, and one was boost realted, and said somthing like "negative deflection" or somthing. will see if they come back.

hope it's not a new turbo job.

 

I killed a MAF in 1500 miles, just by not replacing a rubber band that held the airbox down - so worth not ruling it out.

It has no boost ie never builds? Rather than builds boost and drops it?

 

N75 could well be 10k miles old, but if the vac hoses were chocka full of crap when the new valve went on, they would have had crud flowing into them nearly instantly. stopping the crud getting into the intake system would cure the problem, fitting a new N75 is a temporary fix IMO

 

if you can get access to the turbo see if you can turn the inlet side to make sure its not sized

 

no boost at all. can't even hear it, let alone feel it.

will clean all the aforementioned stuff out and check the turbo.

 

In the absence of more info + codes I’d check the following .....


Roadtest and check for fault codes again, disconnect the vacuum pipe from the wastegate actuator and use a vacuum pump (or your peeeeenis pump) to check the operation of the actuator, even if the vain operating ring is partially sized the actuator rod will move but still not to the full extent. If the actuator works correctly (full extent and does not stick) then check the vacuum pipe to see if it’s rubber through, check all the vacuum pipes, check the operation of the boost control valve using Vag com, should hear a click with engine turned off, handy to connect a vacuum pump to the valve and then operate via Vag com to make sure pressure drops. All this assuming you get a good signal from the Maff.

 

nice one, cheers chaps.

can't do any testing tonight as she's gone to work in it. luckily it's not that far away...

there's no way i can use it in it's current state, it'd take me an hour and a half to get to work.

when looking at the mearusing blocks in vag com, manifold pressure was well below spec. I guess this just indicates there's no boost.

don't have a vaccum pump, would just sucking on the pipe create enough vaccuum?

 

Only a p0rn star could suck hard enough

 

Think about 20in, Hg vacuum to close actuator from memory, but my memory is cr@p so it’s not gospel

 

Phatty, come to Rochdale on this Saturday (the 22nd) and have an Upsolute re-map done on it for 220, then find your boost leak after, or come in your Mk4 and sell it to some Mk4 fanatic.

Daz, if you come i'll give you that Mars Bar I owe you otherwise i'll deliver it to your work but i'll have to eat 1/2 of it to cover fuel costs.

 

what's the point in having it remapped when the turbo does nothing! won't that make matters worse?

and how come it's so cheap?

hmmm. are you working all day saturday daz? i guess i could take it to get mapped and bring it down to borrow your pen1s pump

 

Off to roadtest a new shogun sport on sat morning, not sure on rest of day yet. If I’m at work I’ll bell you. No point in mapping it with the fault unless it’s just a generic map.

 

Anything less than a full mars bar will result in ve feedback

 

His pump will only do upto 1" in girth, and a bit less than that in length.

Its a generic map as part of a group buy, it replaces the factory map and will respond to further mods the same way a standard car does, it wont make it worse or better but one you get the boost sorted your lupo will be quicker and aparently more economical. I've got a boost leak on mine (17705 fault code) so I'm going to get some Forge/Samco silicone hoses and replace all the smaller vac lines.

It would be great to see you, I haven't had decent oral for ages.

 

I'll go to daz's first and bring the pump up then.

 

Only if you drop the pump off later, use it almost on a daily basis, invaluable tool