05-27-2006, 11:25 AM
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#1
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Registered User
Join Date: Jul 2005
Location: usa
Posts: 10
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Stomp on it, and it chokes
Hi guys -
I have a 2kS 6spd. Sachs clutch, Advanced Flow Engineering intake conversion. When I step (hard) on the gas, the engine chokes and sometimes pops back through the intake. For example, if I want to pull out of a driveway ahead of approaching traffic, it means I have to get the revs up first, then ease out the clutch. Once I'm moving out, I'm OK.
What's causing this choke problem? 
BD.
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05-27-2006, 03:33 PM
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#2
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Registered User
Join Date: Jul 2005
Location: Denver
Posts: 740
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Quote:
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Originally Posted by BrianD.
Hi guys -
I have a 2kS 6spd. Sachs clutch, Advanced Flow Engineering intake conversion. When I step (hard) on the gas, the engine chokes and sometimes pops back through the intake. For example, if I want to pull out of a driveway ahead of approaching traffic, it means I have to get the revs up first, then ease out the clutch. Once I'm moving out, I'm OK.
What's causing this choke problem?
BD. |
Sounds like a clutch issue. Is this a new problem occuring long after your mods or have you had some work done that might give a clue? If you put in your clutch coming up to a stop at high revs does it want to die (kind of the reverse of your problem)? If so, I'd definately say clutch.
I'm sure you'll get more info from others on the board. Probably so much info that you'll actually hemorage from your eyes. Just remember, no matter what they say, I invented bubble wrap. Keep that in mind. I'm serious...
__________________
'06 Cayenne Turbo S, Beige Metallic/Tan
Ex - '99 Arctic Silver, Red Interior, Silver Top
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05-28-2006, 10:46 PM
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#3
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Registered User
Join Date: Jul 2005
Location: usa
Posts: 10
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Stomp on It ...
I bought the car with the modifications already done, there were other non-engine / trans things done. But the choking has occurred from the beginning.
I'm not inclined to think it has anything to do with the clutch. The car doesn't rev up when I peddle-in, only when I stomp on the gas in low RPM's.
I've heard the same thing happen in some of the old carb-top engines, and some early FI engines. Something like idle, and mid throttle accelerator switches to spit gas into the throttle body when the demand occurs.
I'm still in a quandry.
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05-29-2006, 05:36 AM
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#4
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Registered User
Join Date: Feb 2006
Location: Toronto Ontario
Posts: 291
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If it's backfiring through the intake it's a fueling or spark related problem. Chances are your MAF is bad but not throwing a code. Borrow one from somebody local and see if it fixes the problem. If so, then buy a new one.
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05-29-2006, 11:35 PM
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#5
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Registered User
Join Date: Jul 2005
Location: usa
Posts: 10
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Stomp on it, --- MAF Solution?
Your MAF solution sounds reasonable. I hadn't thought of that! But if it is the MAF, wouldn't the engine run like #%@ all the time, especially at idle speeds?
Oh! Come to think of it, when the aftermarket intake system was put on, mayhaps the MAF was banged around a bit. I'll have to check it like you said. If it is that, whoa!!! A whole new driving experience! Ya Wol.
TX.
BD
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06-12-2006, 04:26 PM
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#6
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Registered User
Join Date: Aug 2004
Location: Alta Loma, CA
Posts: 1,334
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Two other things come to mind:
1. Fuel pressure/starvation issue. What you are hearing is a lean pop.
2. The fly by wire throttle body may need to be calibrated. Anyone with a PSTII can do this for you.
I have seen 3-4 cars this year with fuel pump issues. They are hard to start sometimes and fall on their face when you jump on the loud pedal.
B
__________________
Engine Builds, Transmission Builds, Engine Conversions, Suspension Installs, Suspension Tuning, Driver Coaching, Data Acquisition, Video, SCCA/PCA/POC/NASA/GRAND AM/ALMS.
We have worked with amateur and professional drivers for over 26 years. In house machinist, In house fabrication. Our cars, our parts, our engines, our transmission's run nationwide at events every weekend. We work side by side with industry names developing parts.
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06-12-2006, 04:52 PM
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#7
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Registered User
Join Date: Jun 2004
Location: Des Moines, IA
Posts: 8,083
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Believe it or not, I had a Z3 that did this and it turned out to be a bad cat!
Weird but true. Remote but keep it in mind. My money is on the MAF.
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Rich Belloff
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06-12-2006, 05:10 PM
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#8
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Registered User
Join Date: Sep 2005
Location: Minneapolis/St. Paul, Minnesota, USA
Posts: 3,308
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Quote:
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Originally Posted by Brucelee
Believe it or not, I had a Z3 that did this and it turned out to be a bad cat!
Weird but true. Remote but keep it in mind. My money is on the MAF.
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Hi,
It's not so weird at all. The Ceramic Matrix inside the Cat gets brittle and can collapse restricting or completely blocking the exhaust. I had this happen once in my Esprit 25 mi. away from home. Had to limp it back at 15-20MPH. Jamming a metal rod inside the tailpipe loosened all the ceramic which then just fell out. It worked perfectly until the new Cat arrived...
Happy Motoring!... Jim'99
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06-12-2006, 05:39 PM
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#9
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Registered User
Join Date: Jun 2004
Location: Des Moines, IA
Posts: 8,083
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Quote:
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Originally Posted by MNBoxster
Hi,
It's not so weird at all. The Ceramic Matrix inside the Cat gets brittle and can collapse restricting or completely blocking the exhaust. I had this happen once in my Esprit 25 mi. away from home. Had to limp it back at 15-20MPH. Jamming a metal rod inside the tailpipe loosened all the ceramic which then just fell out. It worked perfectly until the new Cat arrived...
Happy Motoring!... Jim'99
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Interesting. Cars are more complex than ever, no?
__________________
Rich Belloff
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06-13-2006, 09:45 AM
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#10
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Registered User
Join Date: Aug 2004
Location: Alta Loma, CA
Posts: 1,334
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My crew cab tow vehicle just launched the cat and was running like crappola up until the point when it unloaded itself into the Flowmaster muffler..ha ha, pulled the muffer off and cleaned it of all the CAT material..
The Boxsters are worse. Everything after 98 or so has two CATS per side.. now you have 4 CATS that can unload into the muffler and clog it.
B
__________________
Engine Builds, Transmission Builds, Engine Conversions, Suspension Installs, Suspension Tuning, Driver Coaching, Data Acquisition, Video, SCCA/PCA/POC/NASA/GRAND AM/ALMS.
We have worked with amateur and professional drivers for over 26 years. In house machinist, In house fabrication. Our cars, our parts, our engines, our transmission's run nationwide at events every weekend. We work side by side with industry names developing parts.
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