No power a4 b7 tdi

[Joe101]

Hello all

Just brought myself an a4 b7 tdi with a blb engine, just sold my b8 avant as the extra cash is going towards a house. Picked the b7 cheap, took it for a quick drive around the block (silly me, only car I've ever done a quick test drive on)

Long story short, the car has no power at all. Very flat, no power, as if turbo isn't working at all, can't pull the skin off a rice pudding. Dip the clutch, revs fine and freely, takes about 2miles to get to 70 on a straight road, slows down going up a hill. No engine management light on, but will plug it in when I get home and check codes on vcds, going to try unplug the maf sensor and see if it goes anybetter on the way home. Not sure when the fuel filter was last done so will get one and stick it on, just looked through the service history again and found egr issue, garage blanked egr off but no mention of it being coded out and no engine management light on so? Can't hear the turbo boosting or kicking in, so will try check vaccum and n75? Any other ideas will be greatly appreciated. Was just going to stick a cambelt on it and run it around for a year or two. But depending on this issue It might be getting shipped out. Will update regarding maf and vcds later on

 

[desertstorm]

Well you now know why it was cheap. MAF unplug, Code read and checking for boost leaks in the hoses are where you start. After that there are many things that can be wrong with these engines. Certainly not one of VAG's better powerplants.

 

[Joe101]

Maf u plugged didn't seem to make a difference, just tried driving home with it unplugged, seemed better for about 1-2 mins, drive about more normally. But after that, it was back to 0-70mph in 3-5 business days

Only had 5 codes on engine via vcds, P0671 - p0674, glowplug electrical fault, and p1601, relay for supply voltage terminal 30 (j317) assuming the relay fault could be causing glowplug fault codes?

Got measuring blocks on maf sensor on group 010, mass air flow actual, specified idle, 180-300mg/str, measured at around 350mg/str. Just over tolerance reads upto about 950mg/str at full load when driving, limit 900-1200, I'm happy that the maff is working. It seems that when it's cold, for the first minute or 2, it seems OK. After that, it's done it 3 times now, in 3rd gear, 3000 - 3200rpm, under decent load, it just cuts power, then in a limp mode as such, no lights on dash, no extra fault codes. How is best to test actuator vacuum, assuming if your getting thr correct pressures that the n75 is working correctly?

 

[tr7]

What's it like driving up hill?

Sounds like my old BLB before it couldn't drive up an underground car park ramp. It was the EGR and Cooler completely blocked. Car made absolutely no power. I ended up having mine replaced, but if you've the time they can be removed and cleaned out.

 

[Joe101]

Hi bud, as mentioned above it has been blanked off, got some old service history saying that a garage has blanked it off and it recommends replacement. For what reason I don't know, also don't think it's been mapped out as no I for suggesting it has. No engine management light either. It could be that, I'm going to strip it out when I get chance and see what's going on. I'm going to removed the blanking plate and see what happens, go from there

 

[Pie-eyedpiper]

I realise you didn't have a fault code for it, but do you know the condition of your turbo? Sounds like your vanes could be sticking with carbon and throwing you into limp mode above 3k rpm.
It's an easy job to clean if your layout is like a BRE, but best to remove the EGR valve and cooler completely.