HELP! It chews heaps of fuel....

W

wagon

Well-known member
My Alloy head, EEC-IV efi crossflow (it is an XE motor with XF injection) goes very well but it chews heaps of fuel (typically 18L/100km, town cycle). I have advanced the cam timing 6 degrees and the ignition timing is 16 deg (base, spout disconnected). The motor has a ported head, dual outlet extractors and a near enough to standard cam. A recent 'inspection' and emissions test by Qld Transport gave 0.6% CO and 70ppm Hydrocarbon at idle. My wife drives it mostly, and it does a lot of short ~5km trips. The spark plugs run very clean. The car is automatic and is a wagon. I only use premium unleaded fuel (or better).

Any ideas? Am I expecting too much? Would dumping the clutch fan for an electric item help much?

Thank you in advance,

Kendall
 
Yep, expecting too much, my friend! Best cars were the XD 1-bb and XE 2-bbl autos sedans, 16 to 13 liters per 100 km, or 20 to 22 mpg was common.

Here's the drill.

EFI looses about 2 to 3 L/100 km (0.7 to 1.0mpg). The stock 34 Weber 2-bbl is very, very efficient intake system, and the EFI is timed for maximum torque everywhere. There is nothing that can be done unless the air vane sensor is removed, which will help a lot. This requires all of the MPI EEC hardware from an EA 3-speed auto.

The auto is a dead loss for fuel economy becasue the stock converter and kickdown conspire against the power getting to the rear wheels. The action plan is to spend 50 bucks and get the kicdown cable set-up via a auto tranny technician.

The car is very, very heavy, about 1595 kilos or more, or 3500 odd pounds. Fuel tank is steel, not plastic as in the sedans. The 5 " longer wheel base and all that metal, those extra doors, make it about 150 kilos heavier than an XF seadn.

The diff was 2.77:1 standard, I doubt there is a 2.92:1 diff there. If you fit the 3.23, it will be more economical around the urban tour.

Lastly, the high swirl head isn't there, so it can't run 37 to 41 degrees of advance when its not pinking. The unleaded 86 to 88 XF EFI is smarter than the leaded 85, and all XF's had bigger valves and better fuel economy features than the XE's did. Cam was timed up too, so the EFI had heaps more low end torque. Your 'Mrs' will be using large throttle openings.


My LPG XE did 25 liters per 100 km/h in hilly Dunedin on short hauls, but did 13 liters per 100 km on the open road. Hills kill economy.
 
Thanks xtaxi!! I was hoping for a magical fix, maybe wave a dead chicken around the car 12 times anticlockwise on a full moon or something... The car does have a 2.92:1 diff (out of a ZJ 302V8 Fairlane). Do you think an electric fan may help a bit?? Also, have you seen a EFI crossflow converted to EA efi?? There is not that much difference in the wiring (change the whole efi harness!!), does it work OK?? Maybe I could confiscate the lady's lead boots....

Kendall.
 
Kendall,
Two things that are crucial to fuel economy with a fuel injected engine is the engine operating range/engine temperature sensor and the oxygen sensor.
The engine must be operating in the correct temperature range. Fuel injection systems are temperature compensating. So if the engine is cold, more fuel is injected to ensure smooth operation.
Conversely, if the engine is at operating temperature but the computor is told it is too cold. Then more fuel will be used, in the belief that the engine has not yet achieved operating temperature.
All the ford fuel injection systems are very temperature dependent.
Second is the oxy seneor. Although just a trimmer in the scheme of fuel injection. It is crucial to efficient operation.Your system is an XF system in an XE? Check that it does have the Oxygen sensor in the exhaust manifold/extractors!
This operates by leaning off and richening the engine as it operates. Once satisfactory operating temperature of the unit and the engine is achieved.
This is also reffered to as "closed loop operation". This type of operation is also required by engines that operate with a catalytic converter in the system. Excess of fuel for an extended period of time kills cats.
May be a trip to the mechanics to check if these are operating correctly would help? If you can grab a digital multi meter I can give you some information on checking for correct operation
Noel
 
Backlash, thank you for your thoughts! Unfortunately, the XF EFI system (ULP) has no oxygen sensor!!! I have thuought about putting in a hotter thermostat (the car has a big 3 core radiator, shouldn't get TOO hot...). I was talking to some 'learned' gentlemen in the efi ecu repair industry, they think the EA system may cook my motor (lean outs???) ; also, I'm told EA motors run 97degree thermostats : 20 hotter than my XE. XTAXI, do you know how similar the ignition timing on an EA is to an XF? I think if I can get the fueling about right the ignition timing is the only other issue. Hooking up the EA sytem should be dead easy ; the vane lining up with the rotor in the dissy has to be made smaller and a couple of wires in the harness need to be added/moved. I wonder....
 
Know anyone selling a Wolf 3D?

I reckon, get an O2 sensor installed in your exhaust, pull off the vane meter, wire up the sensor inputs, then dyno tune to get the fuel and spark curves right.. enjoy a boost in power from getting rid of the vane meter, and get some lean cruise kays in..

Has your block got a knock sensor?
 
Yes, it does have a knock sensor! Trouble is, money is short at the moment (always!!) and a EA system with new oxygen sensor could be done for under $200!
 
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