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Join Date: Dec 2001
Location: SAN DIEGO
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Can a 3.2 Motronic engine run without the o2 sensor? Plus misc DME questions
So the manual says that the DME must have a oxygen sensor in order for it to work right? Well I bought a Euro 3.2 and I am getting around to putting it in a early car. The exhaust that came with the engine was a aftermaket stainless unit with a funny looking pipe in place of the cat. It had a hole for a O2 sensor but this hole was plugged. I found no O2 sensor on the engine anywhere.
I have since sold the exhaust and I am installing headers. I guess I need to buy a O2 sensor as well but can this engine run without one? Also does the Motronic have a CD ignition? There is no CD box on a Carerra is there? Anyone ever put a MSD on one of these engines? I don't think a MSD will help a 3.2 DME engine, the only reason I ask is my car is already setup with a MSD. Coil- is there anything special with a DME coil? My engine came without a coil. New ones are cheaper than earlier model 911 coils. Has anyone ever flipped the intake manifold? I am putting this in a 914-6. I saw a similar setup in a 914. The reason to put the manifold on backwards was to fit the air flow sensor in the car. I guess the only changes are the fuel injector plugs (cylinder specific). Anyone have any comments on this? Performance mods? I will have a header exhaust and sport muffler. was going to use some type of cone air filter but haven't found one yet (there are some on ebay for $8! look like crap though). I hear chips can be very dangerous because of the small rod bolts in the 3.2 and 3.6 engines. They guy in England who pulled my engine from a wrecked car sells a chip... he says his chip is safe because it raises the rev limiter by only 300RPM. Any comments on chips? I hear you can extrude hone the intake manifold to increase power. Anyone do this? What is the cost and performance gain? Any other things to do? Any suggestions on installing a 3.2 into a early car or a 914. I'm just trying to find out misc info, I have never owned a fuel injected engine, I'm excited but still learning. I greatly appriciate the help from you guys.
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11-24-2004, 10:49 AM
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Location: Galivants Ferry, SC
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Hint....only USA spec ( or the Rest-of-World spec car with *optional* catalyst) would require a cat to function....hence would require an O2 sensor.
Normal Euro spec ( without cat) does not use a cat, and therefore does not use an O2 sensor.... Make sense ? .... Wil
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Wil Ferch 85 Carrera ( gone, but not forgotten ) |
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11-24-2004, 11:02 AM
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ahhh ha, interesting. Trouble is most of the info available in the states is for the USA version. But I though a O2 sensor has nothing to do with a cat and more to do with air/fuel ratio.
Well if i don't need a O2 sensor then great, save me a couple bucks and drilling of the headers.
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11-24-2004, 11:11 AM
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No you don't need one. I'm running without one. It just makes the engine run a bit richer at idle and part throttle. Running an O2 sensor just forces the engine to run at a higher A/F ratio, that's all.
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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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11-24-2004, 03:43 PM
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The *only* reason for an O2 sensor is to keep the stoic air/fuel ratio correct for proper cat operation. A too rich or even possibly a too lean mixture will make the cat run hot toward meltdown. It has *everything* to do with cat operation.
Wil
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Wil Ferch 85 Carrera ( gone, but not forgotten ) |
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11-27-2004, 05:53 AM
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I was curious if you run without 02 sensor, would there be any adjustments made for a performance chip. (with or without 02 sens)? maybe Steve W. could chime in.
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David. 85 carrera euro |
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11-27-2004, 08:45 AM
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"The *only* reason for an O2 sensor is to keep the stoic air/fuel ratio correct for proper cat operation. A too rich or even possibly a too lean mixture will make the cat run hot toward meltdown. It has *everything* to do with cat operation." - Wil -
That's it! "I was curious if you run without 02 sensor, would there be any adjustments made for a performance chip. (with or without 02 sens)? maybe Steve W. could chime in." It depends on the chip, i.e. if it's programmed on the rich side then more probable CAT problems. Who know what's really done in performance chips (most won't really tell)? That's why you usually "roll the dice" when installing them. Also, the Bosch/Porsche Motronic ignition system is more than adequate and modifying it using MSD parts gains nothing & may result in problems.
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Have Fun Loren Systems Consulting Automotive Electronics '88 911 3.2 '04 GSXR1000 '01 Ducati 996 '03 BMW BCR - Gone Last edited by Lorenfb; 11-27-2004 at 10:02 AM.. |
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11-27-2004, 09:58 AM
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