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Spark knock, no power.

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Old 07-02-2013, 08:04 AM   #1
99gt302
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Default Spark knock, no power.

Ok, so I have a 2007 Mustang Gt.

Mods: Hot Rod Cams, Pacesetter Long Tubes, JLT CAI (110mm)

I have a SCT canned tune, but I doubt that's the problem as it was fine before.

The car used to run fine, then one day the o2 sensor went out, I made some extensions and got one a little too short(still connected fine, just a little tight), so I'm thinking that it may have pulled out or something and causing the issue. However, there is no check engine light?

What are some other things to check for? I have replaced plugs & fuel filter.

Could it be bad Coil on Plugs?

I sodered my connections on the O2s.

When I am driving, it just feels like it has no power, and when I shift gears into like third it will spark knock for a second. Sometimes I hit the gas (moderate throttle) and i can feel it actually stop making power, like I am hitting the brake.

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Old 07-02-2013, 08:06 AM   #2
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Forgot to mention, it skips a little too when It is not warmed up.... overall just running horribly.
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Old 07-02-2013, 08:29 AM   #3
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Maybe fuel pump or you got some bad gas.
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Old 07-02-2013, 08:32 AM   #4
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^ No bad gas, been happening too long and I get gas from all around. How can I check fuel pump, I though about that too.
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Old 07-02-2013, 08:48 AM   #5
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Check the fuel pressure at the fuel rail.
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Old 07-03-2013, 09:08 AM   #6
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A data log by a good tuner will tell you if the O2s are working. If you have aftermarket coils, go back to stock. I would diagnose the problem to a particular spot before buying or throwing parts at it.
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Old 07-03-2013, 09:09 AM   #7
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Any engine codes?
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Old 07-03-2013, 11:26 AM   #8
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SCT canned tune can compensate for Hot Rod Cams, Pacesetter Long Tubes, JLT CAI (110mm)??

I always thought the generic preloaded tunes were only good for stock cars.
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Old 07-03-2013, 07:42 PM   #9
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Check for vacuum leaks in the air intake system, unmetered air might be causing the pinging. If your handheld tuner allows, you can remove some timing until you determine the issue.
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Old 07-17-2013, 02:31 PM   #10
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Today I drove the car and it is still acting up. After idle at a stop light and take off it pops through the intake, any suggestions
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Old 07-17-2013, 02:54 PM   #11
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Quote:
Originally Posted by red96v6 View Post
SCT canned tune can compensate for Hot Rod Cams, Pacesetter Long Tubes, JLT CAI (110mm)??

I always thought the generic preloaded tunes were only good for stock cars.
yeah, this was what I was thinking. I thought SCT canned tunes were only good for tune + CAI...?

I'd contact a good local tuner and just have the thing dynoed. Let them sort it out and give your car the power it deserve with those mods.
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Old 07-17-2013, 04:18 PM   #12
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The thing is , I drove the car with the sct tune and cams for 4 months with no backfiring or spark knock without a tune, so before I put it on a dyno and blow it up, I would like to fix the above issue.
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Old 07-18-2013, 12:00 PM   #13
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What have you checked? Any of the suggestions mentioned earlier in the thread? Air leaks on the intake side will cause mad problems. Fuel filter? Fuel pump? Fuel pressure? Plugs? Coils?
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Old 07-19-2013, 10:16 AM   #14
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New plugs, I did a smoke test, no leaks from anywhere. Fuel filter is new. Fuel pressure was around 40 @ idle.

I got a few o2 codes yesterday after driving in a heavy rain, I do have home made extenders on them for the headers. Can I unplug those and see how it does in open loop putting around to rule out o2?
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Old 07-19-2013, 10:18 AM   #15
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That would be a good place to check - funkiness from the O2s would cause issues I would think.
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Old 07-19-2013, 10:47 AM   #16
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Will I be alright to drive it without the front o2s plugged in and let it run off the stock table... my tune is the SCT 93 performance tune with jlt 110mm
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Old 07-19-2013, 01:18 PM   #17
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popping through the intake is a lean condition

get yourself a data logger and check to see what the hegos are doing and how much fuel correction is getting applied

your best bet for DIY tuning support is http://www.efidynotuning.com/forum
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Old 07-19-2013, 03:01 PM   #18
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would the o2 sensors cause the lean condition?
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Old 07-19-2013, 03:48 PM   #19
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Also forgot to mention that when the car is in open loop , it idles like a dream.... then when it switched to closed it started idling rough again.
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Old 07-19-2013, 03:48 PM
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