Octane 91 causes SR to knock...eventually?

[dongoesby]

I remember seeing a topic like this before, but I couldn't find it anywhere.

So stock sr20 is meant to run oct 93 in japan, will 91 causes the motor to knock in some level with stock management?

my s14 sr20 is throwing a 34 knock code and I've used the 24-hour-battery-kill method to clear codes, and the 34 shows up again as soon as i started the engine. Clear the code again and made sure I got code 55, then started the engine, and I got 34 again.

I suppose the motor should run rich while cranking to start, which the stock ecu sends signal to dump more fuel while cranking. And more fuel at cranking means rich. Is it possible or how likely to get a knock signal from just starting the engine? Am I really receiving a knock signal or possibly bad sensor/wire?

[LayNLow]

Check your timing. Mine was off by a good bit, ran like a dog outta hell until it threw the code. My timing was advanced more than it would retard it for the knock. Therefore it threw a knock sensor code. Check your harness too. Make sure its plugged in and whatnot.

[dongoesby]

^^thanks that helps a lot!

the motor is stock and timing was never been touched. Fresh after the swap, the motor hitted 14psi a few times while adjusting the hks actuator, would that retarded the timing?

Isn't it suppose to have no knock while the timing was retarded?

[steve shadows]

Yes,

Exactly

Just as an FYI, 95% of the cars that come in for Dyno tunes where the owners think their timing is correct it is not, it is actually WAY off.

You must use a timiing light, loosen the CAS and remove the TPS sensor while the car is idling at operating temp (80-90C) to check the actual timing. Then rest it, tighten the cas back down and replace the tps plug.

[dongoesby]

Originally Posted by steve shadows

Yes,

Exactly

Just as an FYI, 95% of the cars that come in for Dyno tunes where the owners think their timing is correct it is not, it is actually WAY off.

You must use a timiing light, loosen the CAS and remove the TPS sensor while the car is idling at operating temp (80-90C) to check the actual timing. Then rest it, tighten the cas back down and replace the tps plug.

thanks Steve, I was thinking to send you a pm on this, but thinks for chiming in.

so when you say yes, which part does it referring to? Octane 91 causes knock, or there is suppose no knock when initial start, or the timing usually self adjusted by ecu?

[fliprayzin240sx]

Originally Posted by dongoesby

thanks Steve, I was thinking to send you a pm on this, but thinks for chiming in.

so when you say yes, which part does it referring to? Octane 91 causes knock, or there is suppose no knock when initial start, or the timing usually self adjusted by ecu?

He's agreeing that almost all SRs on the road have a fucked up base timing. Go ahead and check your timing, make sure its good to go.

[steve shadows]

precisely haha

[djcobra]

I hope you know how to hook up the timing gun on our SR motors... Otherwise you'll get an incorrect reading.

If you can find a 'loop line' on your coil harness place the timing gun there! If however, you have upgraded coils ie, Splitfire etc.. then you'll need to do it differently

Remove the 1st coil and place a high tension cable between the coil and the 1st spark plug (easily found at junk yards) or you can fab one up easy. Clamp your timing gun on to the high tension cable and the rest you know what to do.

Steve.

[dongoesby]

Update: I FIXED the problem (crossing finger i'm right!) Took off the knock sensor from my former well maintained KA and put it on since the sensor is the same. Checked the continuity of the wire from sensor to ECU. And they are good.

Then after I cleared the code on the ECU, I let the car idle for 10 mins. The car was idling so good!! What a difference! The rpm needle was dead stable at 900rpm w/out any movement! I'm so pleased and the code 34 is gone!

However, I have a code showing 54 now instead of 55. Later i found out that it is a A/T signal from the tranny. I'm using a auto S14 WE ecu, so it can not detect the auto tranny. Other than that, the car is running exceptional well. Drove it around, I definitely in love with it. I can't believe the knock code could make such a difference.

PS: I also added a sard fpr along with a walboro @35psi idle, the car now does ~29mpg on freeway

The next thing I'm going to do should be recheck the timing. And bring it to a Dyno!
I got 15deg last time by hook up a wire from se-r sr20 wire to #1 spark plug and coil to receive signal. But I forgot to loosen the CAS and TPS