1979-1993 & 94 Conv [Subscribe to Daily Digest] |
I need some help tracking down the source of my terrible gas mileage. I have been averaging 14 MPG city. Here is the setup on my car:
'88 900 SPG
K&N filtercharger
SPG9 Stage 2 APC
oversize IC pipes
24# injectors
SPG9 Rising rate fpr set to 3.0 bar
SPG9 AID
2.5" cat-back stainless exhaust
Magnecore ignition wires
timing set to 20 degrees btdc
NGKBP7ES plugs gapped to .028"
AMM set to 390 ohm resistance btw terminals 3 & 6
Silicone vacuum lines - no known leaks
O2 sensor functions in normal range
idles great
steady 20 psi boost, up to 22 in 4th under load
relatively new bosch cap and rotor
a/f ratio gauge reads stoich to lean at idle, very lean at light cruising throttle, and very rich at wot. normal stoich range under moderate throttle. (it has it's own O2 sensor)
My Driving Habits:
I rarely drive more than a couple miles at a time to and from work so the engine hardly warms up (lots of snow here in Halifax, Nova Scotia). I smell unburnt gas when I start up in the morning. I have difficulty keeping my foot off the floor when given the opportunity.
However, the city mileage was around 22 MPG a couple months ago.
My suspicions:
I wonder if the timing and AID are somehow not functioning optimally. I wonder about an injector leak. (I did have leaks at both ends of the fuel rail but replaced the washers). I wonder about the fuel pressure regulator being faulty.
Can anyone offer any insight?
I am paying over $0.80/Litre (over $3/gallon) for fuel here and really would like to solve this. Is this the price of power?
Thanks
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