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Join Date: Mar 2002
Posts: 3,563
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Motronic: Popping & gurgling when off throttle?
Curious, what's the cause of the popping and gurgling noises out the exhaust when off throttle, or when the throttle is very slightly open?
I don't have my O2 sensor connected to the ECU, therefore the mixture at idle and part throttle is obviously much richer, so I'm assuming it's just excess fuel being dumped out into the exhaust, causing the popping?  OR, could it be a vacuum leak somewhere? I've noticed it also happens between gear changes, so perhaps excess fuel is being dumped out the exhaust past the turbo? Your thoughts?
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Merv '89 911 Turbo Cab Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition 
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10-02-2005, 04:31 AM
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Join Date: Aug 2004
Location: Andover, NY
Posts: 1,350
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I agree with you. Overly rich/being burnt in the exhaust. Hey it used to bother me too, but now it makes me think that I am driving a race car. The Ferrari F40 did this BAD out of the box and that is a pretty cool car for being italian
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Alexander '75 911S Targa '86 951 SOLD |
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10-02-2005, 05:36 AM
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Sounds like a small air leak in the exhaust system. If not get the tappet clearance checked . both assuming ign timing & mixture havent been altered.
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10-02-2005, 05:39 AM
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Make Bruins Great Again
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My car has a little of what you are describing: a byproduct of headers and open exhaust (no cat).
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-------------------------------------- Joe See Porsche run. Run, Porsche, Run: `87 911 Carrera |
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10-02-2005, 08:06 AM
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Join Date: Mar 2002
Posts: 3,563
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Hmmm, will just have to invest in a good torque wrench and re-torque the intake manifold and check valve clearances I guess
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Merv '89 911 Turbo Cab Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition
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10-02-2005, 03:04 PM
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Registered
Join Date: Jul 2002
Location: Sydney, Australia
Posts: 2,477
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merv
this is exactly what my kremer does - after a while you can play tunes...
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Cheers, Ryan 1969 911E (historic racer) 911ST replica (tarmac rally) |
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10-02-2005, 03:52 PM
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Join Date: Mar 2002
Posts: 3,563
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Quote:
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Merv '89 911 Turbo Cab Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition
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10-02-2005, 04:11 PM
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RETIRED
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Pops and back fires on decell are almost always exhuast leaks.
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1983/3.6, backdate to long hood 2012 ML350 3.0 Turbo Diesel |
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10-02-2005, 04:22 PM
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another round please
Join Date: Sep 2004
Location: Carmel In.
Posts: 4,452
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My 3.2 does the same thing. I checked all plug wires etc. and thought about changing them, but the cost is high. Where is the most prone-area for leaks?, so I can start there. I just put a new muffler on, but its tight. Thanks for any reply.
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Getting old is not for wimps. |
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10-02-2005, 06:30 PM
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RETIRED
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Fire up the motor...dip yer hands in water and pass them under the engine......feel for leaks.
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1983/3.6, backdate to long hood 2012 ML350 3.0 Turbo Diesel |
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10-02-2005, 07:11 PM
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Max
Da cab
