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> poor fuel mileage
melnyk
post Sep 8 2008, 09:42 PM
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ive been getting around 13-17 mpg. i have no fuel leaks anywhere and this thing was tuned up about 2,000 miles ago. anybody have anny suggestions. its a 1.7 with the stock FI.
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SGB
post Sep 8 2008, 10:12 PM
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QUOTE(melnyk @ Sep 8 2008, 10:42 PM) *

ive been getting around 13-17 mpg. i have no fuel leaks anywhere and this thing was tuned up about 2,000 miles ago. anybody have anny suggestions. its a 1.7 with the stock FI.


(IMG:style_emoticons/default/biggrin.gif)
I don't know because my car is not FI, but weberized. I just wanted to comment on the really great avatar. What is that from? I guess you'll get a bump at least....
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Dr. Roger
post Sep 8 2008, 11:21 PM
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13 to 17 MPG is what I get... but my engine is a 5.7 liter.

Yep, you've got something going on there. Not good.

Are all cylinders firing???
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Spoke
post Sep 8 2008, 11:25 PM
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Is it blowing smoke like it's running rich?

If the MPS is not working or there is no vacuum in the intake, the engine will run real rich and burn gobs of fuel.
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melnyk
post Sep 9 2008, 06:26 AM
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QUOTE(Spoke @ Sep 9 2008, 01:25 AM) *

Is it blowing smoke like it's running rich?

If the MPS is not working or there is no vacuum in the intake, the engine will run real rich and burn gobs of fuel.

ill chect this. its running fine its just a gas hog you can almost smell it in the exhaust.
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melnyk
post Sep 9 2008, 06:27 AM
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QUOTE(SGB @ Sep 9 2008, 12:12 AM) *

QUOTE(melnyk @ Sep 8 2008, 10:42 PM) *

ive been getting around 13-17 mpg. i have no fuel leaks anywhere and this thing was tuned up about 2,000 miles ago. anybody have anny suggestions. its a 1.7 with the stock FI.


(IMG:style_emoticons/default/biggrin.gif)
I don't know because my car is not FI, but weberized. I just wanted to comment on the really great avatar. What is that from? I guess you'll get a bump at least....

its the cover of the carcass - tools of the trade ep
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Mike Gilbert
post Sep 9 2008, 03:05 PM
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a 72 1.7 got 27 mpg when new...with f.i. my 72 with a carb gets less than 20 now...
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ArtechnikA
post Sep 9 2008, 05:00 PM
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QUOTE(melnyk @ Sep 9 2008, 08:26 AM) *

...its running fine its just a gas hog you can almost smell it in the exhaust.

Pick one.

if it's so rich you can smell it, it is not running fine.

Most fuel issues are actually ignition, so check for fresh plugs, points, plug wires, and point gap (dwell). When you have the plugs out you'll get an opportunity to check out what's going on inside. Trigger points have been known to bounce and double-shot injectors, especially if they're dirty.

A FI 914 oughtta be in the 30's and be clean at idle.

If it's not ignition, failed or failing MPS could be too-high pressure from a crimped or plugged return line or bad regulator - but you'll need a fuel pressure gauge rated to about 4 Bar to go finding that.
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TravisNeff
post Sep 9 2008, 05:13 PM
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I would do a compression check and find out how much vacuum you are drawing at idle.
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r_towle
post Sep 9 2008, 07:05 PM
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MY 72 1.7 with a million miles on it gets 32-35 mpg...

you got something wrong with the FI or ignition or both.

Rich
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orange914
post Sep 9 2008, 08:08 PM
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you may want to check if your fuel pressure holds... if it leaks down pull the injectors (cold start too) and check for leakage under pressure
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Mike Gilbert
post Sep 10 2008, 08:07 PM
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QUOTE(r_towle @ Sep 9 2008, 08:05 PM) *

MY 72 1.7 with a million miles on it gets 32-35 mpg...

you got something wrong with the FI or ignition or both.

Rich

what have you done to get such good milage?...27 mpg is the claimed porsche figures from the original brochure..i would be happy with 25mpg..
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melnyk
post Sep 14 2008, 05:17 PM
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ok so i got a chance to do a quick look and the vac line to the decel valve was disconnected and plugged off, the hose that tees off of the t/b. now the other line was hooked up to the plentum and still hooked to the valve while the other end of the valve was unhooked. this might have been the problem all the ignition points and trigger points, wires plugs(gap) cap and rotor all are in a very good to new shape. so i think this might have been my problem. ill keep it posted i didnt have a pressure gauge and i forgot to check the cyl head sensor, but at least i found something.
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TheCabinetmaker
post Sep 14 2008, 05:26 PM
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unplugged and capped decel line will not cause poor mileage. You need to look farther. You've already been told what to check, so do that first. Have you checked the dwell? timing? plug gap? What kinda mileage did it get before the tuneup?
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melnyk
post Sep 14 2008, 05:35 PM
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QUOTE(vsg914 @ Sep 14 2008, 07:26 PM) *

unplugged and capped decel line will not cause poor mileage. You need to look farther. You've already been told what to check, so do that first. Have you checked the dwell? timing? plug gap? What kinda mileage did it get before the tuneup?

i dont know the mileage beforehand the p.o did it but only one line was plugged to the valve the other was open to the atmosphere
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