Mysterious Engine Trouble...knocking and power loss.
Aug 14, 2009, 07:34 AM
#61
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Did you try replacing the MAF yet? You said you found another local X who would let you borrow some parts to test... seems worth the hassle if you didn't try it yet. How is your EGT reading (err...nvm unless you installed an EGT sensor)? I was thinking LTFTs as well... might be worth double checking, especially if its outside +- 5%
Aug 14, 2009, 11:04 AM
#65
Its probably fueled that way for a margin of safety against the unexplainable knock.
His tuner is Bryan at GST (formerly Razorlab), who is easily one of the best ECUflash tuners in the Evo community. He knows exactly what he's doing, there is not an issue with the shop's equipment either, I'm sure of it.
It is simply an issue with this specific car that needs to be discovered and sorted out.
His tuner is Bryan at GST (formerly Razorlab), who is easily one of the best ECUflash tuners in the Evo community. He knows exactly what he's doing, there is not an issue with the shop's equipment either, I'm sure of it.
It is simply an issue with this specific car that needs to be discovered and sorted out.
The theory of the car being in some sort of limp mode seems very plausible up until there is usually a SES light activated when that happens. It's quite amazing how much the ECU can restrict you though, when I triggered an airflow too low code the other day after making too many changes to my tables and I was flooring it and could barely get any boost. Mind you this is with a MBC so it managed to restrict boost through throttle reduction and/or timing retard. I'm almost curious enough to trigger it on purpose so I can see exactly how it's doing that so effectively.
Aug 14, 2009, 11:34 AM
#66
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^Is that the P1235 code, if so I triggered it on some of my runs down the 1/4 and my traps dropped from 116 -117 to about 113. So the reduction of timing is quite possible.
Aug 14, 2009, 01:39 PM
#67
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I agree that Bryan at GST has likely looked at all the angles from the tune itself, but I had to cover all the bases.
The theory of the car being in some sort of limp mode seems very plausible up until there is usually a SES light activated when that happens. It's quite amazing how much the ECU can restrict you though, when I triggered an airflow too low code the other day after making too many changes to my tables and I was flooring it and could barely get any boost. Mind you this is with a MBC so it managed to restrict boost through throttle reduction and/or timing retard. I'm almost curious enough to trigger it on purpose so I can see exactly how it's doing that so effectively.
The theory of the car being in some sort of limp mode seems very plausible up until there is usually a SES light activated when that happens. It's quite amazing how much the ECU can restrict you though, when I triggered an airflow too low code the other day after making too many changes to my tables and I was flooring it and could barely get any boost. Mind you this is with a MBC so it managed to restrict boost through throttle reduction and/or timing retard. I'm almost curious enough to trigger it on purpose so I can see exactly how it's doing that so effectively.
I agree about the SES light not coming on...but it may be one of those passive safeguards that doesn't necessarily throw a code...it just does what it's supposed to do...limit power.
Aug 19, 2009, 11:09 AM
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So over the past couple of days I've gotten a couple of PMs from people who have found that they are having this knocking issue...interesting.
Trying out the race gas next week, no time to make it to GST this week.
Trying out the race gas next week, no time to make it to GST this week.
Aug 27, 2009, 01:00 PM
#74
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At this point, we're really just trying to isolate what the problem is. After 3 months we still don't know what to fix.
Aug 27, 2009, 01:45 PM
#75
Maybe just switch to E85 and add a meth injection setup to mask the stupid issue until it fails enough to finally expose what the real problem is. 
Hopefully the 100 octane test will let you verify what it isn't and help you focus your efforts on what the possible reasons really are. You may want to try using the airflow and torque disable mods to just take those flow limit tables out of the picture all together.
Hopefully the 100 octane test will let you verify what it isn't and help you focus your efforts on what the possible reasons really are. You may want to try using the airflow and torque disable mods to just take those flow limit tables out of the picture all together.