pinging 1jzgte

[lojik]

Had the 1jz tuned, it did not ping while it was on the dyno or when I took it for a test drive afterwards. But I've since noticed it pings at high rpm and high boost. I went back to the tuner once, he was happy to help but his slight timing adjustment did not resolve the problem. So if I could fix this myself it would be better.

I've got a haltech running the engine, and have done a little logging of the problem. It shows up when I hit 5000+ rpm and the boost is around 10-12psi. With the current tune the ignition is at 14deg advance around this range.

I can lock ignition timing with the ecu, I have worked backwards down to around 4-6deg advance where it no longer pings. I would like to start playing with the ignition maps, but I'm not sure that the 4deg is indicative of other problems or thats just where it needs to be at that rev/boost range. Seems quite retarded to me.

Any suggestions would be good, its painful not being able to push the car!!!

[Draven]

did you try adding in a little more fuel to see if that could be causing the problem?

[jonra23]

What duty cycle your injectors running at?
What is your fuel pressure like?

regards
jon

[lojik]

Not yet. I'm new to all this tuning stuff.
I was under the impression pinging is normally due to an early spark.
I suppose it would make sense as the tune prior to this one was quite rich, and we've leaned it out a bit.
ta

[lojik]

Not sure about the duty cycle, I'll have a look tonight.
I was too focused on the ignition timing being the problem.
The fuel pressure 'should' be fine as it has a upgraded fuel pump.

[RONA]

Not yet. I'm new to all this tuning stuff.
I was under the impression pinging is normally due to an early spark.
I suppose it would make sense as the tune prior to this one was quite rich, and we've leaned it out a bit.
ta

I was told by my tuner that cars always run leaner on the street hence dyno tunes may seem a little rich, perhaps your tune on the dyno doesn't leave much room for it to lean out a touch on the street and thus its pinging.

[jonra23]

A lean mixture will burn much quicker and hotter than a rich mixture, also more prone to detonation.

regards
jon

[lojik]

Thanks for the help guys.
I've had a quick look at the maps I've got with me on the laptop.
The new tune has lower injector time around the problematic range.
eg. 5000rpm/10psi on the base fuel map 7.66 vs 8.34.
The difference between the two is pretty consistently .4 to .7 in those ranges.
I'll try the extra fuel when I get home tonight and see how I go.

[chris davey]

4deg advance at 10psi at 5000rpm is ridiculous! I run 22deg timing and 12:1 AFR's at that point.

By running such a retarded ignition, the burn will not be finished in time and cylinder pressures will not reach optimum. (If you fire it too early then it will increase cylinder pressures more than optimum) What sort of fuel are you using?

Do you know the AFR's?

[mrshin]

Stick a wideband up it's butt!

[lojik]

Dont got no wideband. Might invest in the future, but for now I just want to be able to drive the car without worrying about it detonating.

It was tuned at 12-12.5:1 and had a nice steady o2 reading.
Chris: yes I agree 4deg is retarded (no pun intended ) which is why I was asking if it was indicating something else was wrong.
Its running on and was tuned on BP ultimate.

[Draven]

intake temps? is your car running hot at all? these things will promote pinging as well

[lojik]

I added a bit of fuel to the problem areas this evening. I thought I'd fixed it but the pinging began again

Also did some logging and noticed my injector Duty Cycle is quite high at problem times. I did a run in second gear until it began to ping. Here is some data while it was pinging:

Ignition advance: 13.00
RPM: 4643
Injector DC: 93.7
Injector time: 9.257

I had a look through some earlier logs and I've found spots where the duty cycle hits 100% Not good. wtf is going on??

[Draven]

93 duty cycle?!?
fark me, 80 is ideal, anything above 90 means new injector time.

what sort of power are you making to max out those 440s?
might be time to invest in some bigger injectors.

And, of course, a retune to go with them

[lojik]

They are standard injectors afaik, "only" running at 270hp at the wheels. Something must be amiss.
I don't suppose dirty injectors would explain it.
If this turns out to be the issue, I'm going to be rather peeved. I mean whats the point of paying for a pro to do a tune if this kinda thing goes unnoticed?

/me throws some rep around