hi, i've got a seat ibiza cupra 1.8 turbo and im having some trouble with the boost, after spending nearly two grand trying to fix it, im on the verge of selling it, right the main problem is that the car is only boosting to 6psi when its been mapped to 23psi, and when im stationary an you give it a rev, it miss fires about 3000 rpm, and stinks of petty, these are some of the parts i have replace upto now, map, maf, n75, 4 coil packs, 4 spark plugs, brand new k03s turbo, lambar sensor, all the boost and vac pipes, could someone please help me, because im baffled
boost problem
- Thread starter 16vsean
- Start date
diverter valve???? its got a forge 007 recon valve which works fine and yes ive checked and doulble checked all the pipes an clamps
since you didnt mentioned it in the original post.....so i suggested it, i know, its obvious the dv is the one to check first.
I had this problem on my mk4 golf, but mine wasnt as bad as 6psi, mine was 12psi but had been mapped to around 20psi, I never found the problem and ended up selling it.
have you checked the continuity of the wires from the n75 back to the ecu? no fault codes for it being open circ?
does it click on an actuator test on the diagnostics? if it doesnt and everthing else checks out ok you might have a driver fault in the ecu?
if you run a one of these 1.8t cars with the n75 unplugged 3-6 psi is all the boost you'll get, as the pressure the turbo produces is being fed straight to the actuator on the turbo. as the default position lets any boost pressure straight thru. i find that more than a coincedence if yours is "working".
another way to check this is to get a pipe clamp and physically clamp off the pipe to the actuator. if it now boost above this 6psi you know your on to something. dont drive it far or hard like this........ you'll bend the conrods!
does it click on an actuator test on the diagnostics? if it doesnt and everthing else checks out ok you might have a driver fault in the ecu?
if you run a one of these 1.8t cars with the n75 unplugged 3-6 psi is all the boost you'll get, as the pressure the turbo produces is being fed straight to the actuator on the turbo. as the default position lets any boost pressure straight thru. i find that more than a coincedence if yours is "working".
another way to check this is to get a pipe clamp and physically clamp off the pipe to the actuator. if it now boost above this 6psi you know your on to something. dont drive it far or hard like this........ you'll bend the conrods!
Last edited:
took it to a local garage to day to get it pluged in, its coming up with 3 faults, no 2nd lamba reading, but thats been mapped out, needs a new throttle pedal, and the main one is, low boost input-circut A, does any one nno what that is??????
best thing is to get rid of any fault codes then work from there. Its obviously running at actuator pressure, maybe because your N75 isnt working properly, or the ecu if being thrown into limpmode which will limit the boost right down, lots of faults can cause that, like boost leaks, or other errors. Take it to a Vag specilaist, which you should have dont in the first place, and stop just throwing parts at it.