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Fuel mileage goes from 27 to 28.5 after service...
#1
My fuel mpg popped up to 28.5 after cleaning the throttle body, lashing the valves and installing new brake calipers.

I think if I did wheel bearings, I would go up over 29!

The results are from about 80% highway driving, AT Grabber tires and MT.

John
95 Geo Tracker, Build Date 1/95,16v, Fed, Cami, 4x4, MT, Headed for Grenada.
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#2
if the bearing are dragging they will not last very long, they will get hot then seize fast. bearing loaded like this ,are very unforgiving,damaged in any way.
the car gets max 30 mpg on real gas, in usa we have 10% ethanol and gets less.
28.5 is what i got, tuned to total max, at 60mph cruise, I have a MPG gauge and can see this in real time.
be happy the V6 gets 19mpg no matter what.

in closed loop mpg is max
there is a magic speed, for all cars in top gear, that gets you , max MPG> it's called the sweet spot.
seen here.
(not our car here , just to show it exists on all cars made)

see that 0.46 date point, this is IT.
http://www.fixkick.com/ECU/power-RPM-plot1.jpg

i use my MPG gauge to find it, it can vary with all options on car. 2dr/4dr, trans, 2wd, and tire sizes, and their drag ratings (rolling resist)
http://www.fixkick.com
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#3
There's still no product on the market like it. 28mpg plus with 4wd! Those jeeps are gas guzzlers. My niece gets 17 maybe on her 2 dr safari!

John
95 Geo Tracker, Build Date 1/95,16v, Fed, Cami, 4x4, MT, Headed for Grenada.
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#4
that is correct, Americans all want big engines. but then cry about, mpg.
no free lunch there.
and the jeep has 1700lbs more steel. CURB WEIGHT 3782.
http://www.fixkick.com
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#5
Fixkick,

Do you know if there is any relationship between compression and MPG? In other words, does MPG tell you anything about the health of the engine? Or, can a low compression engine still deliver good MPG readings?

John
95 Geo Tracker, Build Date 1/95,16v, Fed, Cami, 4x4, MT, Headed for Grenada.
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#6
sure,
the more compression the more power, but you will need higher octane fuel $$$ to do that.
in fact this is the cheapest way (parts only) way to get power. (milling head or thinner head gasket)
sure MPG tells you 2 things
the EFI has not gone nuts. (limphome or ?)
and then engine is healthy and efficient.
and brakes are not dragging
and tires are not flat.


low compression. good mpg
you must know that many colleges have taken cars and killed cylinders , to get more MPG, right, but can go to fast.
think like this,
what is the weight of the car.? that is 1st
then how fast you want to go.
the best MPG at that weight and that speed is an engine that has just exactly the perfect HP to do just that job.
this is why many new cars drop cylinders. (called VDE, variable displacement engines.)

there are many college made cars that have only 1 cyclinder and have school contests , all great fun .

and this, long ago VW made a car that got huge MPG, but what did they do, the got rid of all that weight.
real 84mpg
with a carb.
id bet i could get 100mpg, with EFI, now.

http://www.youtube.com/watch?v=9XUKOUbp_PA

how low can you go?
well that is a matter for EFI.
the 16v has no lower limit, but may get very unset below 150 PSI, (below here some where) but why worry that
we check compression if say one cylinder is low, say 140, and oil added dont bring it up, the valves are burnt.
burned valves is a death call, DOOM SOON...... pointless to worry why the efi is upset and if the intake valve burns , that sends a pressure wave back in to the induction
making them upset the the MAF to go nuts.
how low is not the issues. ever.
sure the EFI runs great when the rings are old and pressure drops a bit.

lets now play game 2, the 16v head, is say, brand new,.
and the rings are bad.
rings can fail 2 ways. (not counting oil control ring and its drains) "rings bad, or not seating to cylinder, the walls are bad,usually both"
(my first instructor in 1965 , had this really cool engine. a 1950 chevy I6, with
like 500,000 miles on it. (the naked car for training only)


he asked us, to get it started. grinning. (perfect carb. / spark,/ starter) perfect clean fresh fuel.
most guys could not. (expected)

the engine had rings, as thin as razor blades. compression was pathetic, say 80psi? (like a lawn mower)
we started it with ether. and with fast right foot could keep it running, the body was missing but had a seat on the frame and could drive it in our school field. (was a SLUG !)
why did he have us do that.
to learn how a low compression engine runs. it was gutless.
lessons to learn
1: yes, compression matters, if wrong, there may be serious doom going on, unless rings are paper thin, but they would snap if we over-rev'd it.
2: no matter how much spark and fuel you dumped to it, it was hopeless. (a turbo would cure, it or blow the rings to dust 'BOOM")

Compression is a spec, if not at spec, then something is wrong, and will get worse fast, say not setting valve lash and burning the valves up.
some times rings are bad due, to cooling system failure, and overheating them and the cylinders look like hell scored to death,. a hopeless engine. again. the can warp cylinders and round rings just hate square cylinders. 1/2 joking..

i bet your's is ok. it's only a 20 buck tool and 30min work. (wot , hot or warm, and cut fuel)
http://www.fixkick.com
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#7
Just drove the car back to Florida. 15 1/2 hours. It ran good other than the tad bit of rough idle which I haven't solved. I think it's egr or iac circuit or carbon deposits from EGR port cleaning jamming the valves. Or, could be a cracked hose somewhere I am just not seeing. I've given up for now trying to solve it. Car idled fine after getting it back together. It was only after a test drive that the IDLE went wonky on me. Only things that would have changed is EGR opening properly and maybe carbon deposits may have gotten into the valves?

I ran at 3500 rpm most of the way which gave me about 70mph. At 100% highway, I was getting a fantastic 29 mph. It dropped to 27 when I turned on the AC in Georgia. It was hot!

Here are all the things I did to it before I left in the past month. It's been a learning experience and I appreciate your advice/help/patience fixkick! ...

1. Lashed valves and new gasket.
2. New gates timing belt
3. New dizzy cap and Rotor
4. New walker ss exhaust
5. New denzo fuel pump
6. New fuel sending unit.
7. New brake calipers.
8. New forward fuel tank bar.
9. Cleaned throttle body.
10. Cleaned EGR system.
11. New plug wires and plugs.
12. Cleaned air filter.
13. Undercoating on frame and underbody.
14. Tranny, crankcase and transfer housing oil replaced.
15. New fill plug on diff to replace stripped plug.
16. Bled the cooling system.
17. Installed battery disconnect switch.
18. Installed Curt hitch.
19. New PCV valve and gasket.
20. New water pump.
21. New wiper blades
22. Set engine timing.
23. New clutch cable.
24. New shift mechanism plastic parts.
25. New thermostat.
26. New 02 sensor.
27. New spare tire.
28. New fuel filter.
29. Oil Change and oil Filter
30 Adjusted emergency brake to 7 clicks per FSM.
31. Used POR-15 on rear bumper.


I feel pretty good about everything and car runs very good except for the idle. It's just a tad rough. Clutch will need replaced soon and engine overhauled. But, I'm putting these off until I get a shop setup. I know I don't have a vacuum leak on any of the hoses. I'm hoping some of the carbon from the EGR port cleaning did not fall down and jam a valve. I stuck a rag in there, but some may have bypassed the rag and fell down.

John
95 Geo Tracker, Build Date 1/95,16v, Fed, Cami, 4x4, MT, Headed for Grenada.
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#8
nice work, and well worth it.
it will serve you well.
i think the valves ok if the leak downs tests pass.
bad idle might be leaky or sticky egr main or injectors
"rough idle"
run some Techron additive through one tank.
http://www.fixkick.com
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#9
Fixkick,

I was having a slight acceleration issue that I tracked to the EGR valve. I purchased the new valve and the car runs fantastic. The acceleration issues went away. However, what I see happen is that the fuel economy dropped from 28.5 to 26.5. Like it was running lean due to the air leak. When I check the fuelly.com website, other owners show about 26.5 as average for a 95 tracker 4x4.

My question is should I be getting higher MPG? Or, is the car now running more optimal with the working EGR valve? Or, did I get a bad EGR valve? I've seen you post articles that this model should get near 30 MPG.

thanks,
John
95 Geo Tracker, Build Date 1/95,16v, Fed, Cami, 4x4, MT, Headed for Grenada.
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#10
lost my answers, my data base (mysql) got hosed and had to restore, 3 days old.

but you can defeat the EGR on top of engine, pull hose, plug it with Golf Tee.
and does idle still misfire?

the car does 19 to 30 mpg, depends on 2 things(engine ok, brakes not dragging tires not low)
1: speed.
2: right foot too busy.

do you use GPS miles? i must.
and make sure you average 3 tanks to off set errors in auto gas station pump shut off at fill.
usa pump(station) so is real gallons not Imperial sure.'
E10 fuel is less E0 is better. a/c off better if going 40 but at faster speeds windows closed a/c on, gets better mpg.

http://www.fixkick.com/specs/orig-sales-sticker.jpg
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