75 replies to this topic

[sharkcohen]

Hi guys, I'm stumped on this one. I just got a Predator for my 2010 R/T. The car is bone stock. 91 octane is in the tank, and I loaded the 91 octane canned tune with no modifications to it, and then took it on a mild 16 mile drive to work in traffic. Every time I just eased into the throttle I got "clackity clack", the unmistakable sound of pinging. I'm not talking WOT runs, just mild, normal driving in traffic on the freeway. I put the Predator on during that drive to check KR, and I was getting alot of knock sensor activity. I gave it a good half throttle and heard bad pinging and KR shot up 15 degrees, confirming what I was hearing.

After I got to work, I put the stock tune back in the car and took it for a drive during lunch. No KR at all. I drove it good and hard and even WOT, no KR. I'm totally stumped.

My current plan is to run this tank of 91 out and then fill up somewhere else, and then try again. I'm also going to hook the laptop up and do some datalogs that I can post. But I do not understand why I'm getting knock even just barely touching the throttle down below 2000 RPM with the canned tune.

The car is practically new, only 3000 miles on it. I've had no issues with it at all before trying the Predator, it runs like a dream.

I also have a thread going at the diablosport forum:

http://diablosport.c...ewtopic&t=27322

Any thoughts for this n00b?

[WORK IN PROGRESS]

Its probably bad gas. I would say do what You allready planed on and run the tank,then fill her up with different gas. If that dont work, Email Johan your logs and see what he says. When it comes to helping out,He is the man. I can pm you his email if you would like.

[sharkcohen]

Thanks WIP, I'll stay the course. It takes me a week to run a tank out, arg!!!

[Jay6spdRT]

I've used the canned 91 octane tune for thousands of miles and never had any issue. I always fill up with 93 octane unleaded. I don't know if that would make the difference here or not. Kinda doubt it because it sounds like a pretty severe problem especially since it's happening at only partial throttle or during moderate driving.


Any audible pinging is definitely bad for your engine - I would revert to the stock tune ASAP and get it figured out.

[Gnostic]

The gas around here is the same crap. I use the 93 gas with the 91 tune, 'cause our 91 gas is not quite as advertised. From what I've heard, this is pretty common.

[WORK IN PROGRESS]

Gnostic, on 12 February 2011 - 05:05 PM, said:

The gas around here is the same crap. I use the 93 gas with the 91 tune, 'cause our 91 gas is not quite as advertised. From what I've heard, this is pretty common.

Hey G, Whats common? Shity gas or It knocking on the 91 tune?

Thats My biggest fear is gatting a tank of shity gas, Does'nt go good with high boost.lol

[Jay6spdRT]

I dunno - I think it would have to be REALLY shitty gas to audibly ping/knock on the 91 CAI tune. I wonder if it's even 87 octane, let alone 91. That tune is pretty tame - its only 10-15 rwhp.

[Speedy]

If you want to send me a log of your car driving with the stock tune and another with the canned 91 I'll have a look and tell ya what I see.

I need to see a few pids like:

desired FA cyl 1
st kr
lt kr
knk sensor 1 (mvs)
knk sensor 2 (mvs)
actual spark cyl 1
Engine speed (rpm)
Throttle Position %

I don't need a half hour log either, just a couple minutes of each. On the 91 canned tune log, make sure the log shows the problem.

I always use Shell 93 in mine as well as my SC 4Runner. They're a top tier gasoline and have to maintain a cert to keep the designation. Never had any issues with their gas and I've used it exclusively for going on 4 years in my FI cars. It's the best I can get in my area. Wish we had Sunoco 94 though.

[gsochallenger]

[Plumkrazy]

speedy.. you should just get the software and start playing..

and mike... you just beat me out on the torco

[Speedy]

Plumkrazy, on 12 February 2011 - 06:33 PM, said:

speedy.. you should just get the software and start playing..

and mike... you just beat me out on the torco

Can't afford it man.

[gsochallenger]

sharkcohen where are you located?

[Gnostic]

WORK IN PROGRESS, on 12 February 2011 - 05:27 PM, said:

Hey G, Whats common? Shity gas or It knocking on the 91 tune?

Thats My biggest fear is gatting a tank of shity gas, Does'nt go good with high boost.lol

Well, both, I guess. Maybe too strong to call it shitty gas, just a lower octane than advertised. So it causes knock, which is how I found out that I needed to go with the "93" octane. It's probably actually only 91, so the 91 tune works with it. But the "91" octane around here is probably 89, so it knocks. This is Shell gasoline, btw, and I've run tests to find out that Shell's gas is no better in this situation than my local Sheetz's gas (Sheetz is a convenience store chain popular in this part of the country).

With high boost, though, you're in a custom tune anyway, and have no use for the canned tune.

[Speedy]

Gnostic, on 12 February 2011 - 09:24 PM, said:

Well, both, I guess. Maybe too strong to call it shitty gas, just a lower octane than advertised. So it causes knock, which is how I found out that I needed to go with the "93" octane. It's probably actually only 91, so the 91 tune works with it. But the "91" octane around here is probably 89, so it knocks. This is Shell gasoline, btw, and I've run tests to find out that Shell's gas is no better in this situation than my local Sheetz's gas (Sheetz is a convenience store chain popular in this part of the country).

With high boost, though, you're in a custom tune anyway, and have no use for the canned tune.

How did you test the fuel? I wouldn't mind sending some samples off to see what I see with my local stuff.

[sharkcohen]

Speedy, on 12 February 2011 - 06:12 PM, said:

If you want to send me a log of your car driving with the stock tune and another with the canned 91 I'll have a look and tell ya what I see.

I need to see a few pids like:

desired FA cyl 1
st kr
lt kr
knk sensor 1 (mvs)
knk sensor 2 (mvs)
actual spark cyl 1
Engine speed (rpm)
Throttle Position %

I don't need a half hour log either, just a couple minutes of each. On the 91 canned tune log, make sure the log shows the problem.

I always use Shell 93 in mine as well as my SC 4Runner. They're a top tier gasoline and have to maintain a cert to keep the designation. Never had any issues with their gas and I've used it exclusively for going on 4 years in my FI cars. It's the best I can get in my area. Wish we had Sunoco 94 though.

Thanks Speedy. I'll generate some logs on my next fill up. I really don't want to run the 91 octane tune on this tank full again, the knock was bad. Hopefully, with the next fill up things will be fine and I won't even need to post up some logs.

Unfortunately, I'm in CA, so the best I can get is 91. I was thinking Chevron this time around.

gsochallenger, on 12 February 2011 - 06:15 PM, said:

LMFAO!!!

gsochallenger, on 12 February 2011 - 07:27 PM, said:

sharkcohen where are you located?

I'm in CA bro.

Hey guys, thanks for all the responses!

[WORK IN PROGRESS]

Tru but oct is oct. If im tuned for 92, I HAVE TO HAVE 92 PERIOD, If its off alittle bigger bader things happen more then a stock car. I think I did find a station that sells 94oct tho. I'll have to go check tomarro.

[Speedy]

WORK IN PROGRESS, on 12 February 2011 - 09:32 PM, said:

Tru but oct is oct. If im tuned for 92, I HAVE TO HAVE 92 PERIOD, If its off alittle bigger bader things happen more then a stock car. I think I did find a station that sells 94oct tho. I'll have to go check tomarro.

<br><br>Your tuner should build some safeties in to the tune. For example, when it's hotter out my car runs less timing than when it's colder. Same thing for bad gas. So you get a tank of bad fuel, it knocks and the sensors pull timing. The car won't run as well but atleast the motor is safe.

[Gnostic]

Speedy, on 12 February 2011 - 09:27 PM, said:

How did you test the fuel? I wouldn't mind sending some samples off to see what I see with my local stuff.

I just mean that I ran some logs with the Shell 91, then with their 93, then with the Sheetz 91 and 93 (all of this with the canned 91 tune). As far as knock, the two brands were about the same. With 91 octane, they both showed a good deal of short-term knock, especially at shift points. The Shell 91, in fact, even showed some long-term knock. With the 93 octane from both places, there was no more long-term, and just a couple instances of mild short-term (not so much that I can't live with it).

[lakersfan7272]

The canned tunes I've tried have never given me anything worthwhile as reported by Trinity + TT Dyno. 93 octane is even worse because the gas around here is not very good and the car just ends up performing worse because of timing pull.

[sharkcohen]

Man, still have a quarter tank to go!