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View Full Version : Detonation or Preignition..er sumpthin


Twisted Noodle
09-25-2009, 01:31 AM
I wasn't sure where to put his. I looked around and couldn't find the answer I was looking for. So please be gentle..

So I had a custom tune done to the SL back in May or June. I am running around 14.5 psi or so and have the CEL blink. I've noticed more frequently (since I've been down in Alabama) that on a few runs down an on- ramp onto the interstate I'll drop the hammer, let the car spin up to 4500 to 5000 rpms in 3rd and 4th before shifting the CEL starts flashing. I was thinking it was the brand of gas I was using so I started buying Shell or Chevron (the 2 major brands down here) and it is still happening.
Is it possible that I'm not letting the car warm up enough before running it? Some of the companies advertise "no Ethanol". Could that be a factor? Or possibly is my O2 sensor on its way out? It ran ok in NY with this happening only once in a while. I do get out of the throttle when I see the CEL flash. I'm afraid of punching holes in the pistons, because for the time being, the SL is my daily driver.
turbovanmanČ
09-25-2009, 02:36 AM
What/who's cal? what grade of gas? what engine mods?
Twisted Noodle
09-25-2009, 09:48 AM
It's a "Aries_Turbo" cal, I run the highest Octane I can find, usually 96+. I'm just running a home grown cold air with cone filter, 3" exhaust with no cat or muffler, everything else is pretty much stock. You know, nothing too extreme.
GLHNSLHT2
09-25-2009, 09:52 AM
stock i/c? If so it will heat soak in traffic. When I jump on it getting on an on ramp it'll detonate. I've got to let the i/c have plenty of high speed (above 40 at least) air before I think about romping on it. Good reason to upgrade to a FMIC
Twisted Noodle
09-25-2009, 10:03 AM
Yeah, and I have one I have just been hesitant to put it on the Lancer. Trying to find another car to build up.
Frank
09-25-2009, 10:12 AM
I wasn't sure where to put his. I looked around and couldn't find the answer I was looking for. So please be gentle..

So I had a custom tune done to the SL back in May or June. I am running around 14.5 psi or so and have the CEL blink. I've noticed more frequently (since I've been down in Alabama) that on a few runs down an on- ramp onto the interstate I'll drop the hammer, let the car spin up to 4500 to 5000 rpms in 3rd and 4th before shifting the CEL starts flashing. I was thinking it was the brand of gas I was using so I started buying Shell or Chevron (the 2 major brands down here) and it is still happening.
Is it possible that I'm not letting the car warm up enough before running it? Some of the companies advertise "no Ethanol". Could that be a factor? Or possibly is my O2 sensor on its way out? It ran ok in NY with this happening only once in a while. I do get out of the throttle when I see the CEL flash. I'm afraid of punching holes in the pistons, because for the time being, the SL is my daily driver.

How far into the throttle are you when this happens?
Twisted Noodle
09-25-2009, 10:39 AM
All the way Frank. Right to the floor.
mario03SRT
09-25-2009, 11:00 AM
What is your base timing set at? If it is in excess of 12 degrees try retarding it a bit and then see.

Also try looking at your plugs. Run it flat out, stop pull a plug or 2 and see what is the color of the elcetrode.

Also if you have a friend with a OTC Scanner do a pull or two and cross check the knock counts.

You should have no problem running 14.5 psi on good premium pump gas.

FYI,
Marion
puppet
09-25-2009, 11:08 AM
Could just be "noise". I'd do the plug check, as stated, to be sure.
bakes
09-25-2009, 12:51 PM
What heat range on the plugs you running?
have a egt and wide ban ? readings if so
turbovanmanČ
09-25-2009, 01:14 PM
5000 in 4th is loaded pretty good, I would take out some base timing, if the problem clears up, then Brian simply needs to take out timing for your setup. He probably has it for a good IC like Jay suggested. Every car is different.
Twisted Noodle
09-25-2009, 01:53 PM
We did quite a bit of tuning. The base timing is dead nuts at 12 degrees. He had his OTC scanner connected and we did 10 or 12 runs. It was getting knock and he took out a few degrees to get it perfect. I am wondering if it is a change in climate. Right now I am AT sea level or below where back in NY I was up a few hundred feet. Also the Humidity is a killer down here.. But thanks for the input I will do a couple runs and pull the plugs after each one.
badandy
09-25-2009, 02:52 PM
Do you have access to race gas? grab some if so and see what happens. If your light still flickers it's due to engine noise and have Brian take some sensitivity out of the knock sensor table. If no race gas bump initial timing down to 10 and replicate the situation.

I have a hard time believing that one of Brian's cals truely detonates at 14.5 psi.
Twisted Noodle
09-25-2009, 03:33 PM
Oh I don't doubt his Cal. He was very conservative. Just enough to feel it in my hiney but not enough to worry about destruction. I was leaning towards a mech failure such as O2, or possibly climate.
badandy
09-25-2009, 03:42 PM
O2 wouldn't be it as if failure it simply goes full rich on the adaptives. Climate would only be possible if the timing curve was already close to begin with where you lived previously.

It's possible you are only experiencing a degree or two of timing retard. You will know once you put some race gas in.
turbo84voyager
09-25-2009, 05:03 PM
Try running a set of autolite racing plugs I believe its AR51's. I had a similar situation where I would get occasional CEL tuning my g-headed 2.5. I threw in a set of the AR51's ( much cooler than stock) and it stopped. The other advantage is the engine idled smoother.
turbovanmanČ
09-25-2009, 05:20 PM
Try running a set of autolite racing plugs I believe its AR51's. I had a similar situation where I would get occasional CEL tuning my g-headed 2.5. I threw in a set of the AR51's ( much cooler than stock) and it stopped. The other advantage is the engine idled smoother.

Or BR9ES or BR9EIX.
Twisted Noodle
09-25-2009, 06:32 PM
I hav champion coppers in there now. I can't remember the number but they are one heat range cooler than stock.
Twisted Noodle
09-25-2009, 07:32 PM
I think at one point I changed the gap to .025 because I thunk it was a prob earlier in the summer. I should probably change that back.
Twisted Noodle
09-27-2009, 02:02 AM
I bought some AR51's today gaped them to .035 and dropped 'em in. I have to say honestly the car pulled a lot harder with these in. Maybe it was the gap, maybe it was the plug but the car definitely ran stronger. However, it still had some knock in the higher R's in 4th.. Here are some pics of the plugs I pulled out. I don't think they look bad. Prolly hard to see them good in this pic. They are kind of reddish, is that from deposits or additives in the fuel??


http://i682.photobucket.com/albums/vv181/TwistedNoodle_1/misc002.jpg

http://i682.photobucket.com/albums/vv181/TwistedNoodle_1/misc001.jpg
mario03SRT
09-27-2009, 08:18 AM
I bought some AR51's today gaped them to .035 and dropped 'em in. I have to say honestly the car pulled a lot harder with these in. Maybe it was the gap, maybe it was the plug but the car definitely ran stronger. However, it still had some knock in the higher R's in 4th.. Here are some pics of the plugs I pulled out. I don't think they look bad. Prolly hard to see them good in this pic. They are kind of reddish, is that from deposits or additives in the fuel??


http://i682.photobucket.com/albums/vv181/TwistedNoodle_1/misc002.jpg

http://i682.photobucket.com/albums/vv181/TwistedNoodle_1/misc001.jpg

To me those look fine at least not looking lean for sure.
GLHNSLHT2
09-27-2009, 10:41 AM
I bought some AR51's today gaped them to .035 and dropped 'em in. I have to say honestly the car pulled a lot harder with these in. Maybe it was the gap, maybe it was the plug but the car definitely ran stronger.


Like those AR51's eh? :eyebrows:
Twisted Noodle
09-27-2009, 11:38 PM
I love them. For the first time I can feel the car "twist" under hard acceleration. It feels good. I never though plugs would give that kind of performance. I feel sort a ricerish saying a spark plug gave me horsepower... but it did. Or maybe it just "unlocked the potential".. lol

I wish it fixed my problem though. I am going to take out the intercooler and powerwash it. After washing the car I noticed 22 year of gook and grime built up on it. It can't be helping it's efficiency any. Maybe it will help. I ordered my chip burner so I am going to do some playing around with some tunes. Bucar is going to send me a revised program. I just need to get my hands on a wideband. so if anyone has one to sell to a guy that has a difficult time ponying up the 200+ for one on ebay.. hint hint, nudge nudge...lol

Does anyone know if the knock sensor pittles out after a few years.
Twisted Noodle
09-30-2009, 05:54 AM
So the problem is getting worse. It is getting colder out here at night so that takes the hot weather out of the equation. I'm going to put in my stock LM tomorrow and see if it duplicates the same problem. If it fixes it then... well, I dunno maybe my fuel pump isn't keeping up? Man I really need to get a wideband.