I know it's not a mk5 Golf GTI but it's a TFSI , different badge , same sh1t
Mates got a 2008 Audi S3 8P. (BHZ) It's meant to be a stage 2 car but when you log the airflow g/s and do the calculation to the bhp, it comes out about 260bhp (it should be well North of 300bhp)
It's had a fair bit of maintenance in the time he's had it - carbon clean with manifold off, injectors serviced, timing checked both ends. Fuel filter new. Cam follower bucket that drives the high pressure fuel pump was changed Intercooler was leaking out of those stupid spring clip fittings so he's fitted an aftermarket APR intercooler to fix that.
All that's been done and it's no more powerful Sad if you log 115 boost pressure, it spikes to 2300mbar and holds just about a bar. (No wonder it's showing stock power) all the way through him owning it i've wondered if it had a weak turbo actuator.
Next thing was try another map so he's been in touch with Chris at Tuning Technics in London who has sent him a few maps to try with varying differences in boost pressure etc. Chris asked him to log fuel pressure and sure enough block 230 shows the ECU demanding 120bar and when on hard accel. the actual pressure drops right down to 35bar in some cases! When it does that the lambda control tries to add fuel but it can only try to add 25% when it drops to that low pressure it hiccups and goes into limp mode momentarily.
The low pressure readings seem to stay around 5 bar. So, we are wondering if it's a high pressure fuel pump failing or the low pressure in tank pump not being able to keep up with demand. Any ideas to this rambling?
