1G Bone Stock DSM Hitting Fuel Cut @ 4500RPM

[radwoodtsi]

Hey all,

As the thread title says, I have a 92 TSi that is completely stock outside of a cat-back and high-flow(but still restrictive CA legal) cat

My mechanic removed the airbox to get to the radiator overflow tank to clean it off and inspect it. That's all fixed, everything back together.

Drove the car and it's hitting fuel cut at WOT/4500RPM.

Boost spikes to 14 PSI+(on stock gauge) and it hits a brick wall. Feels like someone punched you.

I checked all the vacuum lines and hoses. I found the intake boot was on but loose so I tightened up the clamp and its on there good now.

The ONLY thing I found was a missing clip on the air intake canister. Could that be causing that drastic air change to cause the MAF to freak?

It's going back Sunday because the mechanic is also a friend(and it happened after his work) but I want to arm him with any info.

To be clear, no boost leak test done and when i say stock I mean stock. No gauges, no MBC, nothing. We don't have a leak tester and in CA, we're in lockdown. Not much is open.

Would love advice.

 

[DevineAstral]

I will say I haven’t read all the reply’s at this point in time.(so please disregard if already mentioned or already checked out.) but could it possibly be one of the knock sensors.? The issue you’re having sounds similar to a friend of mine who’s knock sensors were about shot. (He had to do a TB job anyway, so he just replaced them while at it and vuah-la.! Just figured I’d throw it out there as it possibly could be a possibility,?

 

[radwoodtsi]

I will say I haven’t read all the reply’s at this point in time.(so please disregard if already mentioned or already checked out.) but could it possibly be one of the knock sensors.? The issue you’re having sounds similar to a friend of mine who’s knock sensors were about shot. (He had to do a TB job anyway, so he just replaced them while at it and vuah-la.! Just figured I’d throw it out there as it possibly could be a possibility,?

Thanks! Will look into.

A quick update: For the first time, I saw a CEL.I was on the freeway with the car and had to pass, WOT and max boost and it cut out, CEL came on.

 

[2gmitsueclipse]

Have you completed the suggested boost leak and wastegate tests? What were the results?

 

[radwoodtsi]

Have you completed the suggested boost leak and wastegate tests? What were the results?

I have not had the opportunity to do the boost leak test. I don't have a garage or a place to even build the tester.

I did order a tester and just got it.

Wastegate tested fine.

 

[2gmitsueclipse]

Wastegate tested fine.

What psi did the wastegate start to actuate?

The BLT tester works well with warm, soapy water in a spray bottle. If your not sure how to perform the test:

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I would caution going into boost until you have solved your issue.

 

[radwoodtsi]

For those counting, the culprit was an intake manifold gasket which is being replaced now!