This doesn't make sense because i have a Red and DW 1000cc's and my spool is 13.1 am i the abnormality?

 

ok bit of an update:

1) redid the compression test (140, 130, 130, 140) so not too bad

2) ruled out bad gas as the problem, same brand different station, 1 week later = still knock

3) ruled out relay, I swapped a green one into the FP relay = still knock

So running out of things to rule out

If the fuel pump was die'ing, would it be this inconsistant? ie I can do 15 spool tests (2000 -> 4000rpm WOT) and only one will knock???

Tomorrow I plan to swap the HFC back to stock... see if my AFR's change at all

 

Some people have mentioned MIVEC. Have you tried logging intake and exhaust cam timing (either the target or the actual value)?

 

no i havn't tried logging - I know what the target is because its in the map

But what is your thinking here?

My problem is that a tune that has 0 knock, doesn't goto a tune that randomly knocks upto 30 just because you add a HFC...

Also my second issue is that adding 1 point to the fuel should have more affect than its having. Perhaps this is a symptom of the real problem - ie fuel supply issue?

I hope to borrow a fuel pump assy next week to see if my AFR's richen up.

 

I get the impression that the knock occurs regardless of AFR. Is that correct, or did I miss something?

If it is correct then, then there must be some aspect of the engine operating parameters that is changing. We routinely log AFR and timing, but we never log MIVEC because we've assumed its doing what's list in the MIVEC tables. However, are you sure that we've got all the relevant maps for MIVEC? There's quite a bit of new stuff in the Evo 10 ROM that we have yet to decipher. Anyhow, seems worth logging just to tick it off the list.

Another possibility is a failing or illperforming injector. Maybe an injector is going bad, or maybe its something like a failing resistor in the resistor pack.

 

hmm, I guess what we normally log (using supplied parameters in Evoscan) is target Mivec and not the actual. I'm interested in logging the actual, do you know what MUT address this would be?

 

I would highly doubt the pump. I don't think they typically fail that way, and they usually failed on the CT9A cars due to not being able to keep up with demand on big mods. Rare on the X.

My friend with the ring issue started with random knock. It depended how it vibrated or got picked up. It always happened on spool when the cylinder pressure suddenly ramped up a lot (boost onset). His got so bad eventually that it would throw 9 and 10 counts randomly at even 1500rpm pulling out of a parking lot.

My soultion to make it stop was to richen it... A lot, like almost back to stock fueling. In the end, the fuel seriously reduced the knocking, but the power was very much taken away. He started to hate the car, because his wife was not on board with serious mechanical surgery, so he traded it in on a 335i.

The problem with these issues is that none of them are the exact same.

I am still hopeful that your aftermarket parts could be an issue and you should try the stock cat. I guess if you investigate the pump and get no cure with that or a bad injector, you should try the stock cat and DP next. If none of those things work, I think its time to investigate the engine. Good luck, Tephra!

 

yeah well this car is beginning to **** me off.. after the relay swap and improved compression test i was like "yes... should be good to go", then hearing that awful noise my heart sank!

gonna swap the cat tomorrow...

might also take of the timing chain cover to make sure the cam timing marks line up (thats right isn't it? they need to point towards each other??

 

Don't waste your time looking at cam timing marks. If the chain is even remotely out of spec, the HUD will warn you.

 

Tephra, maybe it's time to look outside the box, literally. Could there be something loose around the engine that vibrates up against it to make false knocks? Maybe your exhaust is hitting that heat shield by the drive line? (My test pipe is straight and taps it every now and then.) Maybe you dropped a nut in the engine bay? (I know I have, never found it.) Or anything else that could make noise that the knock sensor is picking up.

 

yeah nothing is hitting as far as I can tell.

and a nut/bolt wouldn't make the noise I am hearing!

but yeah I know what u mean

 

ok I have swapped the HFC back to stock, and recalibrated my LC1 (free air FTW)

going to go for a drive in a little bit and hopefully it wont knock and my AFR's will be stinking rich

 

I have my fingers crossed, Tephra! Waiting to hear an update.

 

ok...

firstly - off boost driving with the stock cat is MUCH better, feels like more torque down low, dont need to rid the clutch as much to get going... - anyone want to explain that? back pressure good for low down tq??

secondly - I am looking at some WOT logs and they arn't that rich...

there seems to be a fairly wide variance in AFR depending on load - ie
235 = 11.0:1
245 = 10.7:1
both 3250 rpm...

HOWEVER the IPW does confirm that AFR's would be different (ie not same IPW)

What really gets me is this adding 1 FULL point of fuel to the map not really making much difference...

Maybe I should load up the stock fuel/timing maps and start tuning again from scratch, seems like a waste...

On the topic of knock, the max I saw was 3 KS, I only did 4 part-pulls thou, so ... it might still pop up later...



maybe this is just a ****house tune, thats probably more likely, rather than some super freaky bug with the car...

What worries me is IF it tune related and I don't change my tune then it will still knock - so WTF do I do?

 

I had similar problems with a HFC, I went with a test pipe and the knock went away. When I got my car initially tuned at a shop here in Japan, the shop told me that my HFC was causing problems and that stock would probably be even better........ The shop dropped my HFC and replaced it with their own HFC (Garage G/Force) and my output increased by around 30whp and the knock went away.

I believe some HFCs actually flow worse than stock......