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Old 09-17-2007, 01:29 PM   #1
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Help! I think I'm running rich

As in fuel, Iím not that arrogant. I wanted to know if anyone here knows of any air/fuel gages available for the boxster. Also any ideas of safe ways too lean it out a little?

Thanks Ė Sock

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Old 09-17-2007, 01:53 PM   #2
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I would be suprised the car wouldn't throw a "check engine light" if that was the case. These cars are very sensative to emissions related issues and running too rich is certainly one of them.
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Old 09-17-2007, 01:55 PM   #3
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What makes you think it's running rich?
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Old 09-17-2007, 02:07 PM   #4
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Should have manetioned

Quote:
Originally Posted by racer_d
I would be suprised the car wouldn't throw a "check engine light" if that was the case. These cars are very sensative to emissions related issues and running too rich is certainly one of them.
I should have mentioned I have a moded car and it doesn't twrow codes because it's set up that way....However I waste a lot of gas so I wanted to lean it out for daily driving.
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Old 09-17-2007, 07:47 PM   #5
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Knowing specific mods would help in diagnosis.
Also, you still haven't told us why you think it's running rich other then poor gas milage.
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Old 09-17-2007, 10:45 PM   #6
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Ok so the reason I think it's running rich is because of the poor gas millage the way it sounds and carbon deposits on my tail pipe. Also I was told it would be running a little rich by the guys who did my engine swap. They said it would give me a better top end, as it would lean out at higher speeds. As for the mods well I have a 3.6 engine, ecu (don't know what kind), headers, de snorkel, just took out my K&N and I have no cats.
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Old 09-17-2007, 10:47 PM   #7
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One more thing .

It smells like it's running rich.
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Old 09-18-2007, 04:51 AM   #8
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Sounds like the shop did a partially half -assed job to me. These motors dont "run rich" in a 996, they shouldn't run rich in your boxster. Unless they have tried to re-map the timing or reprogram the A/F ratio, they should be able to control and set properly all settings electronically. Having a K&N (or not), No Cats and headers doesn't make a car run rich.

Secondly, if they claim its set up to run "rich" due to high rpm/high speed use and you find that this doesn't gel with your actual driving styles, why have it set up that way?
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Old 09-18-2007, 05:03 AM   #9
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To add to the above post, there shouldn't be any "set up to run rich so it turns lean at high RPM" or whatnot with a fuel injected vehicle. That used to be the way with Carburetors, but not so with EFI.

For anyone who has not tuned EFI, there is a very specific map that states "At X RPM and X throttle (or air flow or Manifold Air Pressure, depending on setup), put in X fuel." This means that if you wish to have it run lean @ 3000 RPM under light load it can be set that way while keeping you rich @ 5000 RPM under heavy load. There's no knob or anything that sets X amount of fuel to use across the entire range, each point on the map is individually set.

What I'm really going for here is that either it wasn't done right if it was a stock ECU swap, or the time was never really spent to tune the programmable ECU better.
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Old 09-18-2007, 05:07 AM   #10
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I guess it would help if I actually answered the question, sorry!

If you have a stock ECU/injectors and you're running rich, it most likely means that the ECU isn't hearing something from the emmissions/oxygen sensors and is putting in more fuel to compensate.

My guess is that you have a standalone or piggy-back fuel system, though, which means you would have to get readings from the oxygen sensors (or EGT), and tweak the fuel map to give you less fuel in the required areas. That will require a laptop and the software to interface into the fuel system, as well as some dyno time (for best results).

Cheers!
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Old 09-18-2007, 06:39 AM   #11
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Time for a dyno tune remap of your DME. It sounds like your mods have the DME confused so it doesn't know what to look for mixture wise. Find someone in your area who really knows how to do this. Preferably someone who tunes racing Porsches every day. There are lots of guys here on the west coast who do this. Certainly there is someone in your area. If you find a good one... it won't be cheap but the results will be excellent.
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Old 09-18-2007, 06:56 AM   #12
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How are you running a de-snorkled OEM intake box with a 3.6L? I thought all 996 engine swaps required a custom intake of some kind?
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Old 09-18-2007, 02:00 PM   #13
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Not a 3.6

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How are you running a de-snorkled OEM intake box with a 3.6L? I thought all 996 engine swaps required a custom intake of some kind?
I was told by the dealer it was a 3.6 engine however I think i just discovered it to be a 3.4......I looked at my engine number last night and did some searching last night. Based on what I found I have a 3.4. Hence why I posted a question about engine serial numbers. Mine starts with M96/0166W according to the site I found that's not a 3.6 but a 3.4
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Old 09-19-2007, 01:29 AM   #14
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You are probably right.

Quote:
Originally Posted by Wonko The Sane
I guess it would help if I actually answered the question, sorry!

If you have a stock ECU/injectors and you're running rich, it most likely means that the ECU isn't hearing something from the emmissions/oxygen sensors and is putting in more fuel to compensate.

My guess is that you have a standalone or piggy-back fuel system, though, which means you would have to get readings from the oxygen sensors (or EGT), and tweak the fuel map to give you less fuel in the required areas. That will require a laptop and the software to interface into the fuel system, as well as some dyno time (for best results).

Cheers!
When I first got the car the 02 sensors where disconnected, I ended up replacing them both and noticed better gas millage. It went from 17mpg highway to about 19mpg city. However I still think it's running a little rich. I'm in west Texas any ideas of where to go to have my car tuned?
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Old 09-20-2007, 09:07 PM   #15
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I can't help on the running rich/lean question but I would definitely make sure of which engine you have 3.4 or 3.6 because if you paid for a 3.6 swap and only got the 3.4 you got ripped off.
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Old 09-20-2007, 11:16 PM   #16
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It's a 3.4 L

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I can't help on the running rich/lean question but I would definitely make sure of which engine you have 3.4 or 3.6 because if you paid for a 3.6 swap and only got the 3.4 you got ripped off.
I used my engine serial number to determine it's a 3.4, thanks to some links I found and some that you guys suggested I look at. I'm pretty happy with it though, I suppose it's all the extra mods that help.

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