Stock boost gauge vs aftermarket....

[90CherryTSI]

Not sure where i should begin to look for this so I'm going to fish for some ideas. The stock gauge recently started jumping up to around 12 lbs while my aftermarket sits at 3. Well then the car jerks and it feels like fuel cut. My question is this - can the stock boost gauge reading to much boost tell it to hit fuel cut or do I really have a boost leak somewhere? I'm about to replace all the vac tubing with normal stuff b/c the silicone crap I had started getting really hard and may have cracked in a place or two. I guess the main question is can the stock boost gauge reading like that tell it to hit fuel cut even though is NOT true fuel cut and just a faulty signal? Where does the stock gauge get its reading from?

Thanks tuners.
Matt

 

[oldman]

First of all, how do you define fuel cut? Do you know the difference between sputtering and fuel cut?

The stock gauge get it's signal from the ecu which estimates/calculates boost pressure using readings from it's other sensors like maf reading and such. You were on the right track about boost leak, probably a big one if you are sputtering or hitting fuel cut (which I question) at 3psi.

 

[90CherryTSI]

not just putt putt putttt. If I keep the boost at 2 PSI on MY gauge the car reads 10+ and it will sometimes accelerate ok. If it tries to go over 3 PSI on my gauge, hits a wall and won't go. I've had fuel cut before and this is fuel cut. I WISH it was just sputtering.

 

[project_tsi]

how do you have your aftermarket guage hooked up? is it Teed into the fuel pressure regulator?

 

[a_scobel]

not just putt putt putttt. If I keep the boost at 2 PSI on MY gauge the car reads 10+ and it will sometimes accelerate ok. If it tries to go over 3 PSI on my gauge, hits a wall and won't go. I've had fuel cut before and this is fuel cut. I WISH it was just sputtering.

Only time I've ever experienced that 'hit a wall' feeling is when the couplings on my intercooler piping come loose. I'd boost leak test first, so you can rule the boost leak theory out.

I can't even remember the last time I've paid my stocky any attention since I bought an aftermarket gauge.

 

[90CherryTSI]

and then through my water injection solenoids. There is NO way at 25% throttle I'm at 12 lbs though which is weird because the stock gauge shows that. When I try to go wide open of course it hits fuel cut very quickly but the gauge in car reads 12 again and the aftermarket hits 3-4 and boom. It's an aftermarket FPR and it reads 28 which makes me believe that it's not the aftermarket gauge but I can't be sure since I can't look at it while under boost etc.

 

[90CherryTSI]

I heard that but since the difference was SO obvious that's why I mentioned it in case it's all related somehow. I've seen my stock gauge off a couple lbs but 10?

 

[oldman]

Boost leak test first and go from there.