Hey all, I was having boosting problems a few weeks ago. After searching around the engine bay I had found the problem. What I had found was that the vacuum line from the boost controller to the wastegate was leaking air. I reclamped the hose and the boost stopped spiking. However, now I have a new problem where under boost my A/F drops down to 7.4, (I have an Innovate Wideband monitoring my car). Also, since I reconnected the vacuum line I notice that my car stumbles at idle and the A/F ratios go from 10.4 up to around 40 on my guage. I havn't changed anything in my car for two years now.

Current mods:
RnR downpipe
Thermal Research and Development exhaust
Warlboro 255 fuel pump
RnR Upper and Lower IC piping
Turbo XS boost controller
I had the car tuned at Turbotrix back in April of 05'.

I'm thinking that my fuel pump might not be cutting it anymore, but im not 100% sure. Also, I had changed my sparkplugs 4k miles ago with NGK7es. One other thing I notice is that I smell fuel when I'm at idle when it stumbles around.

Thanks for your time,
Josh.

 

After the car is warmed up are you still getting the wack readings or just on initial start up? Refering to the idle.

You said 7.4:1 under boost? I didnt know the Innovate WB read that low. That is obviously really rich. I cant imagine that it would even run like that.

 

7.4 is the lowest the guage will display. I dont know if it is actually reading that low. It does this when the car is warmed up. Another strange thing that I just realized now is that if i hold the throttle about halfway open the A/f will jump all around and sometimes the car will hicup.

Josh

 

do a boost leak test... fix all problems, and then see what happens. your obviously leaking something somewhere. from the sound of it it is huge too...

for example, a boost leak after the turbo compressor will cause the car to run lean when the intake manifold is in vacuum (part throttle... idle...). the reason being is the engine sucks air through the leak instead of through your MAF sensor. if the car thinks there is less air getting in then there really is, obviously it wont inject enough fuel. likewise when under boost. the compressed air releases out of the boost leak, causing the MAF to measure more air then is really getting into the engine. thus more fuel gets injected then needed, and it runs rich.

yours is a very severe case it sounds.

 

Alright, I thought I had found all my boost leaks, but apparently I havn't. Thanks for the advice, I will post what I found in a day or two.

Thanks again,
Josh