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Old 03-11-2013, 09:07 AM   #1
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Default AFR spike during acceleration

Sometimes during a 3rd to 5th gear pull, I get a hiccup where it feels like the engine stalls for a very brief period. Sometimes this happens two or three times in a row over a one or two second period.

Attached is a log from this morning. Around 666 seconds, , I am in 3rd around 3800 RPM, I hit the gas and it starts to accelerate. PW spikes, followed by MAP and then I see RPMs dip and AFR spike for about two or three tenths. Then acceleration continues.

And ideas on why this might be happening and how can I correct it?

Thanks,
Travis
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AFR spike during acceleration-log_capture.jpg  
Attached Files
File Type: msl 2013-03-11_06.57.34 - Copy.msl (150.8 KB, 93 views)
File Type: msq travisb_20130311.msq (40.3 KB, 57 views)
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Old 03-11-2013, 09:26 AM   #2
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increase you MAPdot threshold to 80 kPa/sec.

Where are you running your map sensor line from?


also i think this issue was the boost cut set to 175kPa, it needs to be about 10kPa or so higher than what you spike to, cause the MS will cut fuel if it *thinks* you are goign to hit 175kPa, and I see you're spiking hard to 178kPa right before you junk goes whack.

Why does your boost control suck so bad, where is your wastegate getting its boost source? are you using a MBC.
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Old 03-11-2013, 09:50 AM   #3
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When you say "MAPdot threshold to 80 kPa/sec", are you referring to "Cut Decel Setpoint:(kPa)"? See attachment.

I believe MAP sensor is connected to one of the fittings on top of the manifold. It's been a year since I've thought about that.
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Old 03-11-2013, 09:57 AM   #4
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accel wizard.

you should tee off the FPR line and not use any nipples off the TB.
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Old 03-11-2013, 10:10 AM   #5
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Ok. I changed MAPdot threshold to 80 and over boost to 185.

The waste gate signal line is also on a TB nipple. I just got the parts to move it to the IC pipe last week.

MAP should be on FPR line? Fuel Pressure Regulator?

Thanks
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Old 03-11-2013, 10:16 AM   #6
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Quote:
Originally Posted by travisb View Post
MAP should be on FPR line? Fuel Pressure Regulator?
I looked at some pictures and I think I have already done that. I'll have to double check.
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Old 03-12-2013, 09:54 AM   #7
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Regarding the FPR connection, I'm not sure I have one. At least not like in the BEGi documentation. Perhaps the previous owner did not install it or installed it differently.

See the attached pictures. I've highlighted different vacuum lines around the intake manifold.

The red line is the waste gate signal line that I plan on moving to the IC pipe post IC.

The yellow goes to some valve connected to the igniter and the canister.

I'm not sure where the blue, green, and pink go.

Can someone tell me where the lines go or what they do? Please be nice.
Attached Thumbnails
AFR spike during acceleration-c360_2013-03-11-16-55-02-copy.jpg   AFR spike during acceleration-c360_2013-03-11-16-54-44-copy.jpg   AFR spike during acceleration-c360_2013-03-11-16-55-13-copy.jpg  
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Old 03-12-2013, 09:57 AM   #8
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Blue is the FPR line, and Pink is the MAP sensor line tee'd off of Blue back to your MS.


did increasing the boost cut limit fix the issue?
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Old 03-12-2013, 10:09 AM   #9
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I think it might have fixed it. I only got one brief attempt yesterday. So I'll try again when the weather is better.
Thanks!
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Old 03-12-2013, 12:16 PM   #10
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Keep us updated on if the issue where to arise again.
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Old 03-12-2013, 12:33 PM   #11
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No EAE, no care.
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