burning a lot of fuel Options

[jsf322]

I've had my 914 now since mid January and I am just about through the second tank of gas. I put 126 miles on the car and I am down to just over 1/4 tank of fuel left. I did a quick 30 mile run on a full tank and refilled and found the car to be getting about 20mpg. It is a 1976 2.0 without an air pump or cat and just under 44K miles on the car. It has new plugs, wires, cap, and rotor. The plugs were black like it is running rich and it smells rich when it first starts. Also starting it is a little trouble. It starts right away, but stalls twice and then on the third try it will keep running if I keep the RPMs up for about 5-10 seconds and then let it idle. Idle is usually fairly consistent, but sometimes will vary between about 800 RPM and 1200RPM. I have not gotten to checking much more on the car since it has been too cold here in New York to do much. This is my first 914. I have ideas where to start but not certain. I will be having the valves adjusted by a local shop that does a lot of VW's and some Porsches in the next week or two. I do have some fuel leaking at the fuel filler cap, but I do not see enough that I think it would make a difference in the amount of fuel I use.

[bd1308]

as for the rough starting, check for vacuum leaks..I had two HUGE leaks in my intake manifold (the runners) where it connects to the cylinder head (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

http://members.rennlist.com/pbanders/

that is your bible. These cars arent hard to learn. It just takes some time. To me, I couldnt afford to send it out, and my parents, thinking I didnt know diddily about this car sent it to a mechanic for stupid stuff and racked up over 5000 dollars....

anywho, the rich running could be a bad manifold pressure sensor. Or could be 7986987658 other things, the bible has a checklist for certain problems.

Check it out

b

[brp914]

1. there is a mixture knob on the ecu - clockwise = rich

2. pressure sensor may have leak. pull hose and vacuum test it

3. temp sensor on 3-4 head may have too high resistance, or po may have put resistor in line with it. I dont want to quote real value, cuz I dont know it. *roughly* 1500 ohm cold, 300 hot

4. I've never seen it, but cold start valve could be stuck open, or it's thermo time sensor could be malfunctioning

5. I really dont want to mention ecu problem, cuz many blame it first, whereasr rarely do they fail. 305,000 miles on my '76 - no bad ecu's. good luck

[jsf322]

Thanks for the replies. The link that was given is pretty helpful as well as the other info. AS it warms up up here in New York over the next week I should be able to track the problem down. Thanks.

John

[lapuwali]

Note, too, that air-cooled engines frequently see a big difference in economy between winter and summer. They have to have cooling capacity for the hottest days, so they overcool on cold days and don't run nearly as efficiently. 10-15% is not uncommon.