I am increasingly having the triangle DSC light briefly come on when accelerating under partial throttle between 2 and 3,000 RPM. The DSC light doesn't stay on for long and the ABS light has never come on. Interestingly, there are no fault codes. I could be crazy, but sometimes I feel like the car is making less power compared to a few months ago after getting a new clutch/header/exhaust. Today, I was accelerating on an on-ramp and after shifting, about 5000 RPM, the throttle felt dead before the power kicked back in. No DSC light during this event.

My bypass valve was replaced earlier this year, and I recently had to install a cheapo Amazon wheel speed sensor since it was all I could get quickly after one cracked while replacing my front wheel bearings.

The cheap wheel speed sensor was my initial thought, but the lack of codes, RPM range, and lack of power on the highway today has me considering if it's a bypass valve issue. Any thoughts?

 

Do you have a oem style crank pulley? You can get this weird behaviour when the rubber core is separating.

 

Do you have ISTA and a laptop? It can often find a fault that will not throw the check engine light. Specifically for wheel speed sensors, it will log when the error occurred (in KM or miles) and on which wheel. I had nothing but issues with cheapo speed sensors, did some digging and its suggested that Delphi makes the OEM sensors. Ordered these and all my issues went away. But again i confirmed the issues with ISTA.

If you dont have ISTA, i highly recommend getting it. A spare laptop and 25$ cable go a long way. It has saved me from shot gunning repairs in the past

Best of luck!

 

It may not be your issue but- many years ago I encountered a similar phenomenon; 'Upon acceleration the DSC (triangle within a circle) light would come on. At the time I didn't notice any decrease in acceleration but come to find out the drive belt was slipping and finally let loose.
As LukasH had mentioned; the same can be said with regards to the OEM rubber core pulley beginning to fail.

Just a thought; based on my similar unfortunate experience.

 

Good point. Slipping belt could equal no/less supercharger drive which equals loss of power.

 

Good idea on the crank pulley or belt issue. I have an OEM crank pulley and tensioner, plus a correctly sized belt for a 15% SC pulley. All of that was installed earlier this year along with a rebuilt supercharger. I had the right wheel liner out last weekend installing a Vibra-technics upper motor mount, and while I wasn't focused on the crank pulley, I don't recall seeing anything out of the ordinary. I'll take a closer look at it in the next few days.

This morning I was driving and can say it definitely seems to happen most often when the engine is under high load, like lower RPM and higher gear. Something slipping seems like a very likely explanation.

As far as the lack of DSC codes, I was scanning with a Foxwell NT510 elite which seems to be able to scan the relevant modules, but an ISTA setup sounds like something I should still pursue.

 

As an aside, DSC initialization retards the timing which is the reason you feel a loss of power. I programmed my DSC to remain off at startup (unless I purposely turn in on) because I don't like letting the car decide how it performs with no input from the driver.

 

Maybe deactivate your DSC, take the car for a test drive with the same speed/load, and see if the power loss continues. The DSC would not affect the power and you might look harder at the crank pulley or belt as suspects.

 

+1 inpa could be a big help here. or other capable scanner

 

I took a glance at the crank pulley today and it looks fine? Edit: Or is it not fine and what looks like rubber flaking is the beginning of it starting to fail?



Tomorrow I'll drive it with the DSC turned off to see if that makes a difference. I assume if the issue of hesitation or power loss occurs only with DSC on, a wheel speed sensor issue is likely, and if it occurs when DSC is off, I need to look further into the belt/pulley theory.

 

i cant see the pulley causing a dsc code.

the wheel speed sensor is likely. they get dirty and fail to read. they fail even when not very dirty from what i gather

its a magnetic pulse sensor reading a pulse ring on the hub if i remember right

 

I drove the car fairly hard today with the DSC turned off and didn't have any events like before. Will order a Delphi sensor to replace the Amazon one and see how that goes. I'm still working on figuring out the best course of action for getting an ITSA setup.