NefMoto

2000 s4, 85mm hitachi MAF, 52lb ev14 injectors, deutchworks pump, BW k04's, AWE gen2 IC's. Nothing underscaled, logs LOOK good (timing isn't representative, CF's are around 4-5 typically). Problem is, the car isn't fast. The best FATS we've gotten is 4.9.

0 misfires. 0 DTC's. AFR is 14.7 @ idle, WOT is 11.5-12. Fuel pressure has been verified, no leaks present (pressure tested @ 20psi, intake manifold smoke tested). Cam timing checked, and rechecked. Blocks 91-93 show good.

New BRK7e's gapped @ .028
Injectors, maf, and pump are BRAND new.

Compression test time.

really interested to find out the root cause, i know someone who is having the same issues with a different brand of car, but all engine management aspects look good with a lack of power

One thing worth noting, this car isn't responding to timing like it should. It's running 94 octane gas, but the timing tables that keep CF's sane are what I'd consider the norm for 91 octane fuel.

Just some stupid guesses: Knock sensors on their way out? Or any other sensor that does not cause a DTC yet but it still affects timing? EGT sensors? Your EGTs are reading a constant 1035C.

I had this problem for a LONG LONG time.. the car would tolerate 5-6 deg less timing than just about any other motor with the same tune, hw, and fuel.

Never could solve it. Compression good, leakdown good, cams good, even replaced knock sensors.

but... pulled the valvetrain not long ago and the machinist discovered everything looked great... except my valveguides were gone.

replaced those, dropped the CR a bit with head gaskets, and now it is making timing again.

CDATR, CDATS, CATR are all 00'd. TABGSS(2) are FF'd to prevent intervention just in case. Sensors are unplugged. I'm going to clean/properly torque the knock sensors and see if that has an impact. Also making sure nothing is hitting the body or vibrating in a way that could be interpreted as knock.


That's pretty much where it's at. The hardware is standard, the fuel is consistent. Similar configurations have allowed a significant amount more timing without issue, this car is just being stubborn.

Anything else jump out at you? The logs look good to me, I see no obvious issues, but I figured maybe I'm just too close to it and need an outside perspective.

Because everybody loves logs, here are the newest. More timing, FATS down to 4.78 (Still awful). CF's are meh. I increased timing a bit (still less than I'd normally run) just to see the results.

I'm hesitant to post the file in it's entirety as I'm sure it'll get flashed by someone at somepoint. I'll post any data requested, or share it privately.

Thanks for the insight guys.

And where is the wideband log?

wideband isn't logged, more of a visual thing. As of yet haven't figured out how (AEM). However, AFR is steady without fluctuation, it doesn't lean out, holds 11.5 throughout the run and richens up to 10.5@ redline.

Either the turbo hotsides are not what you think they are, your exhaust is clogged, heads have been machined incorrectly, cam timing is out or wrong cams used. Wrong spark plugs, etc.
Also, at 10.5 it gets really slow...

If you can't run timing it's deffo not the compression being bad, but rather something to do with backpressure or incorrect cam configuration.

Heads/cams are stock, 2000 s4. Never removed from the car. I understand that 10.5 is rich, but that's @ 7000rpm. There's nothing more in her, that's redline. Exhaust DOES have cats (albeit high flow cats), but will be gutted shortly. Plugs are brand new and appropriate for the application. I agree on the compression, if anything less compression would mean I could safely run more timing.

I feel as though I've exhausted the typical avenues here. For your consideration, blocks 91-93. Thanks guys,appreciate the input.

(http://i50.tinypic.com/mab3om.jpg)

Something is up with cyl4.

Knock voltages are very high compared to 2/5, which are usually the highest.

Probably want to pull the heads and eyeball cyl4

Too rich...lean that sucker out!

Disclaimer: haven't looked at the logs...conservative timing first, but not too retarded...lean out AFR, then start advancing timing again.

Get rid of the cats and set fuel normal :)

Compression test results:

Cylinder 4: 160
Cylinder 5: 150
Cylinder 6: 160

Other bank is more of the same. Waiting on the weather to improve before logging the revised fueling.

im going to have to agree with prj, the cats could be an issue, if you really want to test it a simple backpressure gauge from your local parts store in the o2 port will give you some insight

here is the type of gauge i typically use in the shop here

I understand what you're saying, but the cats are 2 months old. They're coming off on the next nice day, so we'll see.

It doesn't matter how old they are. If they are bog standard ceramic cats it's not gonna work, as they are gonna restrict too much.

maybe the flex colapsed due to high temps ? common issue after instal bad quality flex

Alright, I'm bumping this. Problem never really solved, sorta just put it on the back burner. I started logging cam changeover, and this is where it gets weird. I haven't touched it in the file, so the cams SHOULD be changing state. They're not. Never advancing. What's more, bank 2 starts to show deflection when you get closer to redline. Log attached, as well as a picture of the cam timing.

This is what I'm seeing:

(http://i41.tinypic.com/2zhdr9u.png)

This is what I'd expect to see:

(http://i44.tinypic.com/2u8kked.png)

What gives? Am I missing something? I verified all my NWS settings, and the creeping of bank two leads me to believe there's a mechanical problem. Any other parameters I should be logging?

Please don't yell at me about the ignition timing CF's, it's not finalized yet. Fueling is solid as a rock@ 11.5-11.9 throughout the entire rpm range, and FATS are down a bit (4.54 seconds, still slooowww for a full stage3). I'm really leaning towards hardware, but open to suggestions.

Thanks, as always.

What variable are you logging?

wnwi_w
wnwi2_w

what kind of hubs do those cars have? free floating VVT hubs? or are they locked when you do the timing belt?

i would think there would be codes for that?

in my situation one of the hubs was having hard time advancing and immediately threw a code?

What does fnwue look like?

Will log it first thing tomorrow morning. Any other variables I should go ahead and log that aren't considered standard? I've got the markp's template with wnwi/2_w loaded.

B_nwsa 0x00FD6A 16 bit 0x0080
B_nwsb 0x00FD6A 16 bit 0x0100

New logs with the nws variables added.

These logs show a CLEAR cam changeover, as hoped, but bank 2 is still deflecting.

When looking towards a mechanical issue, you had no mention of the oil pressure being verified. I had a cam chain tensioner with partially blocked oil port - but that caused a noise complaint.

could you have a boost leak only at high boost and when the engine is at operating temp?

Log snippet showing deflection of bank 2 camshaft. Definitely a mechanical issue there, but I doubt that's the entire problem.

(http://i44.tinypic.com/aufgwg.png)

I've seen and heard of these little bastards failing before their time causing issues. Is the one installed OE? The aftermarket tensioners suck.