Hi guys, last week I installed a modified 50mm ITB on my stock 2.0 16V ABF Golf 2 rallycross car, but I couldn't drive it because it wouldn't rev up. When I floor it, the car starts to pop and bang on a low rpm like launch control. But if I play with the throttle, I can rev it up, like giving 2 or 3 half pushes, then floor it, it revs up to the limit. It has 269ccm 1.8t injectors, 3 bar chinese fuel pressure regulator, stock throttle position sensor, stock ECU. One thing is I don't know if it's important or not, but I didn't put any vacuum line on the ECU. Sorry for my bad english, I am from Hungary. Thanks in advance.
Isn't the vacuum line supposed to tell the ECU to enrich fuel for acceleration? Or is that completely calculated from TPS signal steepness? I think so too, in anyway you won't get the power out that you are able to get with this big intake setup.
I put a vacuum line on the ECU from the ITB and it solved the problem, now I have proper idle and really good throttle response, and now the engine revs as it should. I will take the car to a dyno and test it with the stock intake manifold and the ITB to check if it is better with ITB or not. Thanks guys!
Ideally you want a Wideband fitted and datalogging before you attempt to drive that. As said above I'd expect it to be running massively lean as it stands now. Vacuum was you should take a line off all 4 and merge them together. Most Throttle Body setups run Alpha-n or blended Alpha-n (TPS based load).
