Potential knocking at low rpms/crap fuel?

[Arcade_West]

Hi guys. I've got a BRZ with sprintex (innovate) 69mm pulley supercharger, tuned using ecutek.

It has been great up until i drove it the other day, and it started acting weirdly. I was going 85km/h in 6th gear [~2000 rpm], put my foot down, and got 0 power. no rpm increase, just tractor noises. Usually it may bog down a tiny bit, but it would always take off shortly after. It has also been hesitating occasionally when i put my foot down in any gear at low rpms, then it gains power back at about 3000-4000 rpm usually.

My guess is that its detecting knock, and the ecu is retarding the spark causing a lack of power. This has only started happening recently, and has been fine for 3-4 months before. Is it possible that I have just got a crappy batch of fuel, or would it more likely be the tune? Sorry if this has been posted in the wrong place.

Thanks

[steve99]

could be many things

log the ecu parameters when it occurrs and send it to tuner.

might be running rearly rich or load limits set incorrectly .

could be exhaust leak causing ecu to run engine rich

[Kodename47]

Without a log and an idea of what's happening then it'll be very hard to diagnose. Have there been any big changes in conditions? Also with this kit, try not to go WOT is a high gear at low RPM. It doesn't like it.

[Arcade_West]

Originally Posted by Kodename47

Without a log and an idea of what's happening then it'll be very hard to diagnose. Have there been any big changes in conditions? Also with this kit, try not to go WOT is a high gear at low RPM. It doesn't like it.

No real changes in condition, only thing that has changed recently is installing new wheels/tyres, however i was driving it for a couple of weeks with them and it was fine.

[D_Thissen]

These motors don't like a combination of high load (foot down) and low rpm (~2000). If you can, try to post some data logs, hopefully someone can help you out!

[DeliciousTuning]

This sounds like the infamous vacuum leak on the back of the supercharger. This is a pretty well known problem on these kits. The plastic fittings will loosen up over X amount of heat cycles and cause the car to run poorly at low rpm.

I would check those fittings to see if they are loose. If so you can either replace them with brass fittings or use plumbers tape to reseal them.

Cheers,
William Knose
Delicious Tuning

[Arcade_West]

Originally Posted by DeliciousTuning

This sounds like the infamous vacuum leak on the back of the supercharger. This is a pretty well known problem on these kits. The plastic fittings will loosen up over X amount of heat cycles and cause the car to run poorly at low rpm.

I would check those fittings to see if they are loose. If so you can either replace them with brass fittings or use plumbers tape to reseal them.

Cheers,
William Knose
Delicious Tuning

Cheers

Yeah my fittings have already been replaced with brass fittings. I have taken it back to the tuners a few times, and it is STILL knocking below 3500rpm. At bang on 3500rpm it liven sup again. The tuner has tried to say that its just the hot weather, but it even does it at ambient temps of like 20degC. Not really sure what to do from here :/

[steve99]

Originally Posted by Arcade_West

Cheers

Yeah my fittings have already been replaced with brass fittings. I have taken it back to the tuners a few times, and it is STILL knocking below 3500rpm. At bang on 3500rpm it liven sup again. The tuner has tried to say that its just the hot weather, but it even does it at ambient temps of like 20degC. Not really sure what to do from here :/

These engines are very swnsitive to crap fuel at low rpm medium to high load probably more ao with sc fited

Run the best fuel you can also try different brands of cuel some are much better than others

[86fun]

I seem to be having the same issue with my newly installed Edelbrock kit. Good tip about checking for leaks, I'll do extra searching on my setup for these knowing this could produce the same result we're experiencing. I've already tried two different sources of fuel. Curious to hear what fixes your Arcade!

[Arcade_West]

Originally Posted by 86fun

I seem to be having the same issue with my newly installed Edelbrock kit. Good tip about checking for leaks, I'll do extra searching on my setup for these knowing this could produce the same result we're experiencing. I've already tried two different sources of fuel. Curious to hear what fixes your Arcade!

I will let you know what the issue is when i find it haha

I have tried different fuels, and still get the same issue as well. I'm going to look at the bypass valve and other vac lines when I get the chance.