Extremely Lean at high rpms???
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From: Birmingham, AL
Extremely Lean at high rpms??? OK, I was at the track recently and after making a few passes I reviewed my logs. Right now, I am running in OL and I've tried this in SD and also with the MAF enabled. My LC-1 reads nice and rich at 12.5-12.8:1 but at around 5300 rpms, the air/fuel shoots up to 21.3 and I have no clue why. It doesn't feel like its losing a lot of power or dropping off. I'm not real sure what to think of this. I thought if the wideband sensor was going out, it would cause a code. It's strange that it's doing it on every WOT run and RIGHT at 5300 rpms. There is no knock above those rpms either. I'm kinda at a loss here. Any help is greatly appreciated. I don't know where to start. The plugs are gapped at .053 I think and the plugs and wires are new. I'm making 400 rwhp with bolt-ons and a cam.
The know it all's know it all
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thats not near enough power to max out a set of 28's.id suspect fuel pump issues. Check rail pressure with it during a pull either that or its lossing ignition.
Edit:
On second thought what type of valve trian you running ? could be valve float.
Edit:
On second thought what type of valve trian you running ? could be valve float.
Last edited by CollinsAutomotive; Nov 6, 2006 at 08:38 PM.
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Originally Posted by RedHardSupra
yea it is, i hit 109% idc on 26.4s while putting down about 360rwhp
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From: Birmingham, AL
I'm using the stock injectors and the car's an '02. Thanks for the input so far. Someone told me it couldn't be an ignition problem because it wouldn't show up as extremely lean due to the extra unburned fuel as well. It just goes straight to 21.3 with ONE cell of 16 before shooting up that high. But there is no knock. I don't understand. I may get some dyno time and a gauge to measure the pressure at the rail.
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The know it all's know it all
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Originally Posted by WS6 GreeN
I'm using the stock injectors and the car's an '02. Thanks for the input so far. Someone told me it couldn't be an ignition problem because it wouldn't show up as extremely lean due to the extra unburned fuel as well. It just goes straight to 21.3 with ONE cell of 16 before shooting up that high. But there is no knock. I don't understand. I may get some dyno time and a gauge to measure the pressure at the rail.
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From: Birmingham, AL
So how do I track this misfiring cylinder? I've got a log set up for misfires but what should I look for? What is normal for my cam? If one cylinder is showing twice as many as the rest is that a good sign? Should I decrease the gap on the spark plugs? Replace coil packs? Wires? Fuel pump? lol
Fuel filter?
What is injector pulse width doing when this happens?
Have you taken and converted this to injector duty?
Or maybe your tool will display it straight, I recall this
as a "sensor" item in HPTuners I think.
Putting a pressure gauge to the rail for a pull, would
answer a lot of questions.
What is injector pulse width doing when this happens?
Have you taken and converted this to injector duty?
Or maybe your tool will display it straight, I recall this
as a "sensor" item in HPTuners I think.
Putting a pressure gauge to the rail for a pull, would
answer a lot of questions.
Thread Starter
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From: Birmingham, AL
Jimmy, I'll take a look at the IPW when I get home. From what I remember, it wasn't doing anything strange. I also forgot to mention another important piece of info about all of this. Sometimes while cruising, the car whill just decide to go lean to 16:1 or a little leaner sometimes. If I rev the car up a few times, it will return to normal. Fuel filter's an easy change so I may do that. If the coil pack or plug is not firing, would that show a false lean condition? Someone clarify that for me. Thanks!
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From: Omaha, NE
If your WB is going that lean, monitor both factory O2s, if both show a lean condition, you have a fuel system problem, if only one shows lean, you have it narrowed down to four cylinders on one bank, if none show lean, it's your WB acting up.
