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914World.com _ 914World Garage _ Fuel consumption up

Posted by: redshift Nov 28 2003, 08:02 AM

I am using around 20% more fuel than a nicely tuned version of the same rig.

I just changed out my TPS, and I calibrated with a digital (jeesu!) meter. Let me say that *isn't* the way to go, prolly.

Is there a possibility that the TPS is on the idle switch, but just (high) out enough to enrich the mixture that much?

I'm having a ball working on my own car, and I am getting better results than the local mechanics, I only have one kind of car to deal with, and I love that kind of car. I owe so much to the people who have BTDT.

Thanks, as always.

Miles

Posted by: garyh Nov 28 2003, 11:57 AM

What are you comparing your mileage against?

I've seen a 20% variation due to driving style.

I've seen a 10% variation due to seasonal fuels.

Different size tires can make an appearant 10% change.

Need more data....

Posted by: redshift Nov 28 2003, 12:09 PM

I'm comparing it to my normal driving habits.

The only thing I can think of is that I need an analog meter to check my TPS calibration, the digital meter I have is very fast, and I may have adjusted it improperly.

M

Posted by: need4speed Nov 28 2003, 12:14 PM

I've seen wheel alignment/balance/tire pressure account for 10%.

Bad spark plugs, weak ignition coil, old spark-plug wires, incorrect dwell, loose valves, etc.

Posted by: redshift Nov 28 2003, 12:29 PM

Welp, all that's good.

I guess I'll just take more money when I go driving.

M

Posted by: Qarl Nov 28 2003, 03:11 PM

How many "miles" on the new engine? It will take a while until the engine is broken in and your fuel consumption normalizes.

Also, your right rear brake light is on, causing a drain on your electrical system, which is subsequently causing your alternator to work overtime, thus increasing load on the engine and increasing fuel consumption.

Maybe you're just getting fat and putting the engine under load. That... or you've been picking up some heavy Georgia girls at the oyster bar down by the waterfront!

Quit making those late night Krispy Kreme runs!!!!

Posted by: rhodyguy Nov 28 2003, 04:47 PM

miles, remembering a few threads of yours with regards to driving habits, ie slight loss of high top end, the reference to driving fast on public roads(the drifting thread), i suggest the following for a DRAMATIC INCREASE in your mileage!!! take your foot out of the gas a bit. drive like a regular mope for one tank full. then get back to us. lol.

kevin

Posted by: redshift Nov 28 2003, 09:07 PM

I'm a whale, and I drive too fast...

NOT HELPING!

I bought an analog multi-tester today, I am going to redo the TPS calibration for a start, this digital thingy has been a headache since day one, the slow mode is still about 10x too fast for what you'd think you need, more of a bench tester, not so good for iffy connection sniffing, nor calibration of anything.

People look at you when you pull away from a redlight in a 914 like you are trying to race everyone.... dood, I am just trying to get to second gear...

M

Posted by: anthony Nov 29 2003, 11:58 AM

One thing I've noticed is that how you top off the gas tank makes a huge difference in the mileage reading. It could also be a fuel leak.

Posted by: nebreitling Nov 29 2003, 11:50 PM

i've spent numerous hours repeatedly calibrating my TPS with a digital multimeter. took a few tries to get it right

what i found was that the TPS needed to be rotated not 1, but 3 hash marks Clockwise (after reading 0 ohms) before it would run correctly. just setting it 1 mark CW made it run real lean, popping on decel, etc. since then, the MPS has been reset correctly (it was leaning), so i think i might redo the TPS and see what i get -- maybe one mark is okay now ???

nathan

Posted by: redshift Nov 30 2003, 01:37 AM

Ah! We are on the same page, possibly chasing the same tail.

At this point, I am rich at most settings. I was stomping it today to get some clues, and I smelled some unburned fuel, not enough to smoke out the exhaust even.

I have someone locally that can calibrate my MPS, and I think Tuesday or so, I will do just that.

Thanks goys, and stay up on this with me Nathan, I'll let you know what goes on with mine.

M

Posted by: nebreitling Nov 30 2003, 11:48 AM

well, i'm chasing something....

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