Zeff

Hey guys, I dynoed my car after installing my new k27/6. While the car was down I did the cv/venturi delete, fabspeed dp, head refresh, widefire gasket, header/crossover/dp wrap and turbo blanket.

The other mods on the car include:
Mtune
tial wg
lr mbc
test pipe

18psi pump gas


Peak run


Old 26/8 runs


Something's up since the spool is extremely slow and I didn't make any more power than my 26/8.

I'm trying to borrow a compressor to test all the vacuum lines, but I still pull 18hg at warm idle and 22+ on deceleration.

I also need to check the header/crossover for any leaks, but I know the parts were filled with water to check for cracks before they were wrapped... So maybe a crush ring isn't sealing.

The dyno operator said the car felt like timing was pulled. I spoke to Josh/Rogue and some other Mtune users about timing and I decided to check the knock sensor since some threads here mentioned a constant -6degree timing pull if the sensor isn't working. The sensor resistance checked good, but upon reinstall I noticed a cut in the wiring before the sensor plug. I couldn't salvage the plug and I've got a new one ordered.

I took the car out for a spin with the knock sensor disconnected and it felt the same so I'm hoping that is the only issue. Can anyone tell me which side of the knock sensor is power and ground?

Also any other suggestions if power is still down after I get the new sensor plug installed?

Thanks to all that have already helped and for any further suggestions.

dillon410021

what psi was the dyno at

Adonay

It says 18.

No mather how many modifications you put ont the car you have to make sure you have not got any leaks (vac,exhaust) You may also be chasing electric issues i am sure there is something somewere thats not right.

Seattle944

I would bet it's a vac leak. LR has the diagrams if you need them.

refresh951

For reference, here is the thread with his previous dyno run:

https://rennlist.com/forums/944-turb...rogue-maf.html

Spool is worse, A/F is high, something is not right. Crossover leak?

Definitely pressure test for vacuum leaks, double check wastegate control plumbing, and check for exhaust/crossover leaks.

Scott H

Did you use new crush rings when you put the new turbo on? If not, I'd start there.

Zeff

I used the lr diagrams and I'm building one of those PVC testers to check all my lines.

Zeff

That's where I'm not 100% I wasn't there when that part of the install went down. My hg kit had new ones and my friend said he used them. I'm waiting on my roommate so I can verify.

alxdgr8

Sounds like a vac leak, definitely test it.
I was also going to recommend checking the cat/test pipe to see if it's collapsed, but it looks like you don't have stock anymore so that shouldn't be it.
Maybe mess around with the MBC too. What psi spring is in the Tial?

Black51

Definitely check for leaks. If I'm reading it correctly, the AFR on the old runs are extremely high. Seems like there was an issue before doing all this work.

refresh951

A/F looks good before the new mods. The old runs with the k26/8 look pretty normal to me. Now they show high. A pre-sensor exhaust leak would show as a lean condition.

black944 turbo

Zeff, I have a boost tester if you make to Charlotte area.

zeusrotty

Get an LS2

Bri Bro

You are climbing up to 13 AFR at higher RPM...That isn't good.

The knock sensor is a Pizo element (like a mic) so it does NOT have a polarity. You do need to torque them correctly and make sure the mounting surface is flat and clean, no washers. Also make sure that the connecting cable does not vibrate or flop around, that can effect the sensor. Lots of Bosch ECU units used the same knock sensor, Volvo 240 and Saab 900 to name a few.

zerMATT951

Talk to Joshua about plug temps and gaps too. I was indicating lean at high RPM's and Josh suggested one-step colder plugs, gapped at 022". When I made the change, my AFR's came down any power came back (butt dyno only).