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Discussion Starter · #1 ·
Ok, little back story here. Last November I bought a stock 2004 Volvo S60 R. Once I installed a boost gauge I found out it was only running 8 psi rather than the 14.5 psi. I replaced a few things and eventually narrowed it down to the TCV. After I swapped that out with the HD TCV from IPD the car ran perfect.

Fast forward a month from the repair. I did a custom exhaust, 3" turbo back with no cat.

Car runs great for another 2 months. Get into a minor fender bender and car goes to a trusted shop for repairs. I get the car back two weeks later.

Now the issue. I got the car back and it ran great the first day or two I had it back. One morning I go and start the car, go to get on the highway and it starts sputtering at WOT full boost. It no longer runs full boost.

I've tried everything I can think of. I've cleaned everything from the filter to every sensor the car has. The TCV is new and the BPS is new. The spark plugs have maybe 9k miles on them and are OEM plugs. I've checked every connection I can think of and everything looks fine. A month has gone by since then and in that time two of my ignition coils (first cylinder 4 and then cylinder 3) has blown and replaced. The car runs like normal for the first day and then starts the issue again. At WOT it will build boost just fine (sometimes it'll overshoot 14.5 and hit like 18 and then sputter) until it hits full or close to full boost, sputter and then drop the boost down to 6 or sometimes 10 psi.

I'm so at a loss here and really need help.

My mods so far are as follows:

Snabb turbo inlet w/ k&N filter
Snabb upper charge pipe
IPD HD TCV
Forge CBV
Catless 3" Turbo back exhaust

I do not have a tune yet.


I took some videos of the problem today. First and Third pull you can see it drop to 6 psi and I'm WOT the entire time. Second pull it drops to 10 psi.


Please I hope somebody can help me.
 

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Wastegate or boost leak. Definitely thoroughly check for the latter, especially if your car was apart for repairs.
 

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Discussion Starter · #3 ·
Wastegate or boost leak. Definitely thoroughly check for the latter, especially if your car was apart for repairs.
There's no boost leaks and the wastegate is fine. It wants to hit full boost but something is holding it back. If you listen to the video closely you can here it sputtering trying to continue boosting.
 

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Power stutter means you have more coils going bad most likely. Replace the ones you haven't yet and that's your best bet to make it go away.

Been there, done that. Spent months chasing down my power stutter thinking it was everything but a coil. Even the dealer couldn't figure what was up after hooking the car up to Vida so thank god I was finally able to.

What happens is boost goes up, causes spark gap voltage to go up, making the coil start failing. One cylinder dropping out makes you lose boost, boost goes down, spark can jump again so the cylinder comes back on line, boost goes back up, and the process repeats itself cauing a what feels like a stutter in power which also limits your boost when it occurs.
 

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Discussion Starter · #5 ·
Power stutter means you have more coils going bad most likely. Replace the ones you haven't yet and that's your best bet to make it go away.

Been there, done that. Spent months chasing down my power stutter thinking it was everything but a coil. Even the dealer couldn't figure what was up after hooking the car up to Vida so thank god I was finally able to.

What happens is boost goes up, causes spark gap voltage to go up, making the coil start failing. One cylinder dropping out makes you lose boost, boost goes down, spark can jump again so the cylinder comes back on line, boost goes back up, and the process repeats itself cauing a what feels like a stutter in power which also limits your boost when it occurs.
Looks like I'll be buying a few more coils tomorrow then. Hopefully I can find enough of them, the stores around here only seem to carry one at a time.
 

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Good luck. Like you I changed the first two that gave me trouble, and after that it was 3 at once since I realized I didn't want to deal with this again once I realized the first two were not that rare of an exception.
 
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