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Thread: Detonation at 2000rpm only

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Posts: 1-10 of 18
2013-01-27 10:23:49
#1
Detonation at 2000rpm only
So, in the last week I altered the tune on my SR20VE N15 (20V bottom end, 16VE head, 11:1 comp). Gave it a bit more down low and a bit more up top. Feels really good now and not as gutless.
Anyhoo, I only increased my 1600-2000rpm timing from 10 degrees to 12. Which is bugger all. In any case I added a little more fuel to compensate.

Now, the issue is that it will ping at exactly 2000 rpm and literally nowhere else. And it will do it with minimal load, just any increase in gradient will do it. It's also regardless of ambient air temperature, at night, early morning, midday sun, whatever. It will do it.
And then it won't. If I pull up at lights and turn the car off and then back on again, pinging is impossible to induce let alone notice. Ringing it at 1800-2400rpm, nothing. No ping. Turn the car off at destination and come home and it's back! But still, only at 2k. If I downshift and get it above 2.5k it's no worries.

What do you think people? I'm thinking that my ecu may be getting a wee bit dodgy, I'm not sure what else it could be-surely can't be a fuel pump thing as it's rpm specific right?

For now I have turned the timing back to 11 degrees just incase that was the cause, but it just seems so odd to be able to be fixed by restarting the car.

Let me know what you think in any case guys, I look forward to your responses

Cheers, Dan.
2013-01-27 16:09:42
#2
rod bearing...
2013-01-28 02:18:10
#3
Not sure if serious?
2013-01-29 17:28:44
#4
Why don't you try retarding the timing at that rpm for the lighter loads??

When you say you added fuel, what are your afr's when it is knocking?

Walker
2013-01-29 17:35:37
#5
rod bearing... seriously
2013-01-29 20:58:59
#6
Dan make a map trace and see at what tp your pinging at. If ur twisting the dizzy then go back.
2013-01-30 09:08:06
#7
Originally Posted by Dudeman258
Why don't you try retarding the timing at that rpm for the lighter loads??

When you say you added fuel, what are your afr's when it is knocking?

Walker


Well it was already super retarded at 10 degrees, and is back there now and still pinging.
So it is now pinging at a point where it previously wasn't, with the same timing and more fuel!
Not sure on the afr's, I have an AEM wideband on the way from GregV however.

Originally Posted by BlueRB240
Dan make a map trace and see at what tp your pinging at. If ur twisting the dizzy then go back.


Nah no twisting of the dizzy here, that sucker is locked in at 15*.

I'll make a map trace and get back to you guys, really appreciate the responses too
2013-01-30 16:27:48
#8
you should use a timing light and see what its actualy doing at 2k. possible dizy going bad. i have seen some crazy stuff happen with bad dizzy.
2013-01-31 08:25:03
#9
The timing was set with a light for 15* at idle, not sure how I'd go about checking the car under load with a timing light...I don't really trust my handbrake.
Dizzy going bad is certainly a possibility, it is AFAIK 13 years old. Did get new o-rings a couple years ago though.

Here are the timing and fuel maps. The fuel maps are calculated by a random number thingy. Not really sure on the mechanics of it.
Notice the super conservative timing down low. Full throttle yields approximately "56-65" load cells.



2013-01-31 08:26:09
#10
Dunno why they are so blurry, that sucks, enlarge them and they are a bit better
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