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Discussion Starter · #1 ·
My friend's T5 AWD s40 has been having issues that are more pronounced lately. When I scanned the car last week we found the following codes

-Misfires (Cylinder 1, 5, random)
-Turbo/Supercharger boost code (can't remember the specifics)
-Cat efficiency code due to 3'' DP--hoping to solve with a spacer

The car has around 70k miles. At what point do these cars need new plugs and/or coils? Are coils a common replacement like on VWs? I'm am sure this will resolve the misfire codes.

The Turbo/Supercharger boost code I am unsure of. The car has been running and boosting inconsistently.

Recent replacements include:

Elevate tune (installed June)
Evolve Intake manifold (Installed June)
Elevate Interooler (installed 8-19)
Elevate CBV (installed 8-19)

The problem has been there before and after the installation of all the mods above. Some pulls it feels excellent and others it feels okay, then falls on it's face like it's going into limp mode. Is there a typical cause to the code? I did some reading last night and saw that some people were replacing the MAP (Boost Control Sensor?)....


Any insight would be appreciated. I come from the VW world so I can only pinpoint common replacement area.
 

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If the boost is sporadic and seems uncontrolled it could be your TCV. They are prone to issues and will cause boost spikes throwing the car into limp mode due to over boosting. This will set a turbo control fault code in many cases and the misfire could be due to blowing out spark or improper mixture. With higher boost pressure I would recommend replacing ur CBV as well which isn't rated to handle that much pressure properly.

Oh and the factory coils on the P1's are pretty good. Maybe replaced one or two in comparison to the hundreds done on P2 Volvos.
 

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Check your plugs and regap them. I run a gap that is .004 tighter than stock (.026) currently, and typically change them 15k-30k depending on conditions. Though I will be using 1 step colder ngk iridium which are recommended for boost over 19psi when I finish my build. Fix one issue at a time and retest. Start with freebies first like checking and regapping plugs, cleaning the MAF, checking all previous installed items and work.
 

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i vote check plugs and tighten gap if anything iver stock tune. what psi tune?

Yep, sent from my rooted, rommed Galaxy Nexus....
 

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TCV and plugs. make sure you get the right length volvo oem plugs. I rec ipd becuase they are a good price and easy to deal with and you know its right. tasca or viva for the oem tcv. stay away from HD tcv's, they are bad news when they go and wont do much over a stocker
 

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Discussion Starter · #7 ·
If the boost is sporadic and seems uncontrolled it could be your TCV. They are prone to issues and will cause boost spikes throwing the car into limp mode due to over boosting. This will set a turbo control fault code in many cases and the misfire could be due to blowing out spark or improper mixture. With higher boost pressure I would recommend replacing ur CBV as well which isn't rated to handle that much pressure properly.
Thanks for the reply. On the highway the boost feels like it fluctuates constantly even while applying the same amount of throttle. Does this sound like a TCV issue? In WOT cases, some pulls feel great and most are just mediocre at best.

With 70k on the plugs, we're just going to replace them. If the misfires persist we will replace the coils.

The tune is made by Elevate, and I believe around 14-16 psi. Does that sounds correct? The car doesn't have a boost gauge so I have no way of knowing exactly what it's hitting.
 

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Plugs definitely, I would hold out on the coils. Most Volvo coils either work or don't, rarely if ever will they produce weak spark generally just none at all and would be a constant misfire.
 

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Discussion Starter · #9 ·
Thanks, owner ordered the MAP sensor and replacement CV boot that's torn today. We'll order the TCV tonight as well and grab some replacement plugs for Saturday. Hopefully we can do one by one and troubleshoot what the issue is.

VW coils are similar in their on/off function.

After buying new wheels, tires, intercooler, CBV, MAP sensor, plugs, CV boot, and TCV this month, the damn car better run and look better than it ever has before!
 

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I got an inner boot on the left front axle I need to do. Spent about two hours with every concoction of pry bar setup I could come up with and still couldn't get it free. I'll be buying the special tool looks like. Just shows what good 30k worth of tools does without the factory specific ones :facepalm:

Guess that's one perk to workin for the dealer, least now I can afford to buy em haha.
 

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Discussion Starter · #11 ·
Yeah should be a fun job. I usually just buy a whole new axle assembly and swap it out for easy.

I rode in the s40 tonight. It feels absolutely terrible at WOT. It barely pulls at all and feels like it might be holding only like 5lbs or something. It feels stronger on 1/2-3/4 throttle than it does at WOT. Boosting on the highway is inconsistent and it seems to go from vacuum to low boost without any throttle or load adjustments by the driver.

Also, when the car first cold starts, the throttle fluctuates for 10-15 seconds while it basically hunts for an idle, going in and out of boost and blowing off. I really hope we can solve these issues over the weekend. The car has been nothing but a PITA over the past few months and my friend is just about over it.
 

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Hmmm hunting idle is generally a vacuum leak.
 

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Gotcha, maybe more of an improper mixture issue such as a fuel problem like the FPS or PEM.
 

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by chance are you running a custom cone filter setup? for a minute i was running one and experienced some of the issues you state. beastlike when cold but boggy when engine bay got warm/hot. i switched back to stock box with Eurosport filter and all was better.
 

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Discussion Starter · #17 ·
by chance are you running a custom cone filter setup? for a minute i was running one and experienced some of the issues you state. beastlike when cold but boggy when engine bay got warm/hot. i switched back to stock box with Eurosport filter and all was better.
Yes, running an AEM dry flow I believe. I would consider that as part of the issue but the car had many if not all of the symptoms prior to installing the Elevate intake manifold and cone filter.
 

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FPS and TCV then do a relearn procdure by disc. batt and pulling fuses for a few min. i would bet my lunch it fixes your issues.
 

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It's super simple, I think there is a DIY posted in the sticky. Just DON'T forget to release the pressure in the rail prior to popping it off. One bolt holds it in on the side of the rail.

Someone found that a land rover part fit. Thread was pretty recent.
 
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