Resolved 1G Boost issue or fuel issue?

[SeriozHenka]

Car in question is a 1990 Eagle Talon Tsi, COMPLETELY BONE STOCK.

Just did the tranny oil and valve cover gasket and during a test drive after finishing up when I would enter boost it would sometimes read 14 psi on the gauge, or sometimes not get past 7 psi. Sometimes when it got into boost I would also feel some chugging, followed by the boost bleeding off with the rpms climbing, no change in throttle given to the engine. I would think it was a boost leak but I can't fully tell as it's not consistent. Idle is perfectly fine, the chugging only happens when it enters boost.

Spark plugs and wires are brand new, There is no check engine light, and unless a misfire doesn't flag a check engine light I'm going to assume the engine is running perfectly fine. What leads me to believe it is a boost leak is the drop in boost with no drop in acceleration, I just can't tell if it actually is one because it's so inconsistent.
Thank you!

 

[SeriozHenka]

1990 Eagle Talon TSi AWD, bone stock

I just got done doing the valve cover gasket as well as a transmission flush, now whenever I drive the car when it hits boost it gets to about 8 psi and all of a sudden starts to chug or buck. It sometimes holds boost and sometimes doesn't. There's no check engine light or anything that turns on, it only does this under load while driving, doesn't matter what gear I'm in. It never did this before except after I did the valve cover gasket and the transmission fluid.

Spark plugs are brand new and so is the wiring, same with the timing belt. Other than that if I keep the car under 8 psi of boost it runs perfectly fine, it's only when I really slam it and it goes above that 8 psi threshold it begins to buck, but it still builds boost, sometimes it doesn't and it loses boost back down to the 8 psi mark.

This is basing the reading off the stock boost gauge. I tore the intake apart and looking for leaks or lose clamps and I couldn't find any at all, I even checked the BOV to see if the spring was getting stuck but no, its in perfect condition. Anyways any input for you guys would help me greatly.
Car has 85k miles btw.
Thank you!

 

[pauleyman]

1990 Eagle Talon TSi AWD, bone stock

I just got done doing the valve cover gasket as well as a transmission flush, now whenever I drive the car when it hits boost it gets to about 8 psi and all of a sudden starts to chug or buck.

Look at everything you touched during the aforementioned maintenance. Hoses, wires etc. Dollars to donuts you missed something. The stock gauge is a useless indicator. It's an excellent indicator of a leak if it's going up but a real boost gauge isn't.

 

[SeriozHenka]

Look at everything you touched during the aforementioned maintenance. Hoses, wires etc. Dollars to donuts you missed something. The stock gauge is a useless indicator. It's an excellent indicator of a leak if it's going up but a real boost gauge isn't.

I went through everything, every tube seal, every clamp, ever bolt, every vacuum line and intake related. I can still feel the turbo kick in up until it gets to a certain point, then it bucks, I can hear the turbo trying to upkeep with it but it jolts shoots forward, jolts, shoots forward, and only a little after the 7 psi mark

 

[19Eclipse90]

Did you run a boost leak test to verify your intake piping / tract is sealed?

 

[pauleyman]

I went through everything, every tube seal, every clamp, ever bolt, every vacuum line and intake related. I can still feel the turbo kick in up until it gets to a certain point, then it bucks, I can hear the turbo trying to upkeep with it but it jolts shoots forward, jolts, shoots forward, and only a little after the 7 psi mark

How do you know psi on a stock gauge?

Original owner??
Check the ecu. Doubt the original owner did it.

 

[SeriozHenka]

Did you run a boost leak test to verify your intake piping / tract is sealed?

Not yet, I'm going to run a smoke test soon, not sure when.

I

How do you know psi on a stock gauge?

I don't. I'm estimating hence why I said the 7 psi mark. The mark on the stock gauge. It's building boost because I can feel it, I just don't know how much. I can for sure stay under that mark according the gauge and theres no bucking, only after that make

 

[99dsmer4g63]

What exact spark plugs did you install? Brand and heat range? What gap did you install them at?

-Daniel

 

[SeriozHenka]

Car in question is a 1990 Eagle Talon Tsi, COMPLETELY BONE STOCK.

Just did the tranny oil and valve cover gasket and during a test drive after finishing up when I would enter boost it would sometimes read 14 psi on the gauge, or sometimes not get past 7 psi. Sometimes when it got into boost I would also feel some chugging, followed by the boost bleeding off with the rpms climbing, no change in throttle given to the engine. I would think it was a boost leak but I can't fully tell as it's not consistent. Idle is perfectly fine, the chugging only happens when it enters boost.

Spark plugs and wires are brand new, There is no check engine light, and unless a misfire doesn't flag a check engine light I'm going to assume the engine is running perfectly fine. What leads me to believe it is a boost leak is the drop in boost with no drop in acceleration, I just can't tell if it actually is one because it's so inconsistent.
Thank you!

Plug wire cracked, replaced the wires and it worked fine afterwords, thanks all for the help.