SR20DET - timing retarded with bad knock sensor ?!?

[boarderkingjk]

hi!
I just solved one problem, and a new one appeared...
the ignition timing of my sr20det does not work well.
idle speed is smooth at ~850 RPM with ign. set to 15°BTDC.
when I push the throttle the ign. is advanced to about 30-40 degree,
and the engine revs well.
but at 3000 -3500 rpm the engine starts to make anti- lag noises and generates no more RPM or power.

-> I think of a false ignition timing by the ecu -> retarded ign. at about 3000rpm -> anti lag sound and no power

so what could be the reason for this? a bad knock sensor maybe??
I checked all other parts... MAF, TPS, boost controller, wastegate, bov, etc.


please let me know what you think!
best regrds,

johannes

[SteveC200]

Sounds similar to when the AFM isnt connected or has died.

[boarderkingjk]

hi
its connected, and I cleaned it recently.
do you know any way to check if the AFM is working fine? (except with consult software)
and what would happen if the knock sensor is unplugged - on a working sr20det??

thanks johannes

[boarderkingjk]

I checked the AFM: 1,4V on idle between signal (white wire) and ground, ~2,5V at 3000 RPM
so it seems fine to me?!
When I go over 3000rpm it starts to misfire and the ignition is retarded more and more till 0° !!
Also checked the TPS again: 0,45V at around 800RPM

could a bad knock sensor be the problem?
absolutely no idea what to do/check next...

[martinb]

If you are checking the timing ,

What is the timing going to at this point?????

If its saying at least 25degs then it's a fuelling problem

[jib136]

ive got pretty much the same problem!

when i nail it the ignition timing hits 40 sometimes 44 on my power fc.

what could this mean? as it runs like shit.

[boarderkingjk]

timing is increased to somewhere over 25° I would say, but I have no dial to tell for sure...
then it gets decreased and jumpy, but always redarded!
@martinb:
Tell me more about the fueling problem! what could be the problem with fueling?
Everything seems like I have a h-dev stage 2 ecu, but I´m using standard injectors!!!!
It was sold to me as stage 1 ecu, and the engine ran well with it before I rebuilt it. So I do not know if this could be the problem..
@jib136:
is your timing 40° at 3000 rpm??? that seems pretty much for me^^

I have now two weeks ago bought an CONSULT device on ebay and will check the ecu for fault codes as soon as I have it.

[boarderkingjk]

HEY GREAT NEWS! (and bad news too)
We fixed the Problem! I finally brought the ecu to flash its fault codes (no. 26 for Boost sensor, and no. 34 for knock sensor) and cleared them. Installing a 1MOhm resistor cutting out the knock sensor and a self made voltage divider which makes the ecu reading 2V from its "Boost Sensor" made it flash the one and only code no.55...

Started up the engine, same problem as before... BUT I thought that the pantyhose-airfilter could make the ecu read wrong values, so I torn it off and recognized that the Turbo suction pipe with the MAF on its end was hanging loose in there, making a kink next to the turbo when the engine sucks more and more air (thats why it wont rev over 3000!!! An air restrictor!!!), so I took a cable tie and bound it up to the hotpipe...

Started again, let it warm up and it revved through... First drive, pulling very hard (OMG) to redline thanks to the new cams. I never felt that satisfied before...

BUT there is a but again... After a few minutes of die hard uphill racing and approximately 3 drifted corners, under full boost near to redline in 3rd gear, a huge "PLONK PING ping .." could be heard and the engine stalled...
A boost hose popped off, and I found a nut from somewhere else there in the engine bay was laying on the street... Looks like an exhaust nut but I had no time and no motivation to look up where it was coming loose. After connecting the boost hose it idled well with a little rattle at startup, but fortunately not from inside the engine...

So problem fixed! :S
Many thanks for your answers and all your efforts guys.