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Gas mileage MPG
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vintageant  



Joined: 15 Apr 2016
Posts: 33
Location: Miami, Florida

PostPosted: Thu Sep 22, 2016 1:41 am    Post subject: Gas mileage MPG Reply with quote

As a 5 month first time 924S owner, I'm curious as to gas mileage expectation for these cars.
Car starts immediately and runs very well. 91k miles.
This past weekend on a >300 mile open road cruise, with AC on the whole time, mpg was 21.6. Around town it's been as low as 14.3, and the average for the 890 miles since I've owned is 17.1 mpg.
Seems low, especially compared to my 2003 Honda Accord with 192k miles, and similar size engine in a heavier car, which has returned 25.6 over the past 90k miles.
Thanks for your input
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New first time 1987 924S owner - April 2016
1970 VW 'Peking to Paris Rally' Beetle
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Paul  



Joined: 02 Nov 2002
Posts: 9317
Location: Southeast Wisconsin

PostPosted: Thu Sep 22, 2016 2:00 am    Post subject: Reply with quote

Is your tail pipe covered with black soot?
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White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
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vintageant  



Joined: 15 Apr 2016
Posts: 33
Location: Miami, Florida

PostPosted: Thu Sep 22, 2016 2:10 am    Post subject: Reply with quote

No, not really.
If it was running rich, how does one adjust mixture on FI?
I'm an old school carb guy!
Thanks!
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Paul  



Joined: 02 Nov 2002
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Location: Southeast Wisconsin

PostPosted: Thu Sep 22, 2016 3:58 am    Post subject: Reply with quote

Check 02 sensor for proper operation first.
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White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
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vintageant  



Joined: 15 Apr 2016
Posts: 33
Location: Miami, Florida

PostPosted: Thu Sep 22, 2016 4:10 am    Post subject: Reply with quote

Researching, I found this video:

https://www.youtube.com/watch?v=y1Cgn3dq__c

In addition to your O2 sensor suggestion, Throttle Valve Switch, Reference Sensor/Crank Position Sensor and Temp Sensor are also suggested.

Usually, I'd start with the cheapest.
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Paul  



Joined: 02 Nov 2002
Posts: 9317
Location: Southeast Wisconsin

PostPosted: Thu Sep 22, 2016 4:57 am    Post subject: Reply with quote

In my experience, if the car is idling and running smoothly and the O2 sensor is original equipment, it's the first thing to test.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
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vintageant  



Joined: 15 Apr 2016
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Location: Miami, Florida

PostPosted: Thu Sep 22, 2016 5:03 am    Post subject: Reply with quote

OK, thanks!
Please excuse my ignorance, but how does one test it? Or does one just replace?
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Paul  



Joined: 02 Nov 2002
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Location: Southeast Wisconsin

PostPosted: Thu Sep 22, 2016 5:21 am    Post subject: Reply with quote

Clarks garage is a site that has helped us all...

http://www.clarks-garage.com/shop-manual/fuel-18.htm

You can use the 3 pole O2 connector on the back of the head (passenger side).
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
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vintageant  



Joined: 15 Apr 2016
Posts: 33
Location: Miami, Florida

PostPosted: Thu Sep 22, 2016 5:57 am    Post subject: Reply with quote

Thanks!

There's a three prong male plug, with cap, mounted on the engine hoist bracket at the back of the head. nothing attached. It's the male side of this:

https://www.amazon.com/Bosch-13011-Oxygen-Sensor-Fitment/dp/B000BZG5OY

On the exhaust, I see two sensors. The forward larger has a wire ascending. The smaller, about 2" behind, looks like a wire or tube has been cut off.

Really appreciate your help!
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Paul  



Joined: 02 Nov 2002
Posts: 9317
Location: Southeast Wisconsin

PostPosted: Thu Sep 22, 2016 6:20 am    Post subject: Reply with quote

The 3 prong connector is for the O2 sensor. Correction that connector is empty on my car too.

The tube used to run up to the back of the head. Its purpose was to provide an easy place to check the mixture/emissions pre cat.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977


Last edited by Paul on Thu Sep 22, 2016 7:05 am; edited 1 time in total
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vintageant  



Joined: 15 Apr 2016
Posts: 33
Location: Miami, Florida

PostPosted: Thu Sep 22, 2016 6:32 am    Post subject: Reply with quote

So if there is nothing plugged into that 3 prong male plug, does that suggest the O2 sensor is disconnected?

I'll have to get the car up on ramps to get underneath and grab the wire attached to the sensor to see where it goes......
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Paul  



Joined: 02 Nov 2002
Posts: 9317
Location: Southeast Wisconsin

PostPosted: Thu Sep 22, 2016 6:35 am    Post subject: Reply with quote

I just put my car up on the lift and looked, the connector is actually on the other side of the head with the reference mark sensor connections.


_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
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vintageant  



Joined: 15 Apr 2016
Posts: 33
Location: Miami, Florida

PostPosted: Thu Sep 22, 2016 7:10 am    Post subject: Reply with quote

Is it one of the two connectors in a white plastic clip directly behind the aft branch of the intake manifold?
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Paul  



Joined: 02 Nov 2002
Posts: 9317
Location: Southeast Wisconsin

PostPosted: Thu Sep 22, 2016 7:24 am    Post subject: Reply with quote

Yes, but try testing it with the one on the lift point.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
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vintageant  



Joined: 15 Apr 2016
Posts: 33
Location: Miami, Florida

PostPosted: Thu Sep 22, 2016 7:40 am    Post subject: Reply with quote

How could I test that if the sensor in the exhaust is not connected to it? Surely the test is on the female connector?

I believe I'm going to order that new one from Amazon and just replace. I'll figure out if it's the one on the left or right of the photo you posted
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1970 VW 'Peking to Paris Rally' Beetle
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