Horrible Mileage...STILL...after alot of work/troubleshooting

[Doakster]

One question, did you change shoes after you got it back ? Maybe the new shoes were made in China and the soles have loads of lead in them ?  LOL !!

Just a thought, I understand you tested the speedo with your GPS and it was off 3%, so the other 17% is what we are looking for. Did you change the tires since you got 44 mpg ? Tire type can easily have a 17% change. Have you been checking the MPG from a variety of differnent sources ? The volume / content of the fuel could be different - like are they adding ethanol in your area ? Some are doing experiment on adding ethanol. There an SAE paper out on it.

The larger summer tires, my 205/50/16s, were the orginal tire that I swapped on after I did all the front end work, I've been running them since, got good mileage with them when I first swapped them, they only have about 8k on them, they wear perfectly even, no obvious issues I can see with the tires.

I have purchased fuel from a variety of different locations over the past year...same result with mileage

[Doakster]

What about adjusting  internal pressure,if put little more same talk achieved good mpg.

I've tried this with my original ECO pump....no change in mileage, see earlier posts in this thread for details.

As I've said I've had two different Giles pumps installed, same result, I'm not going to alter the internal pressure on a fresh rebuild from Giles, when all indications point to the pump(s) not being the issue.

[Doakster]

Some greats thoughts and suggestions here, see my answers in blue.

A few questions and ideas for you.

 Where do you buy your diesel?   (maybe they are buying cheeper/lower grade to save money)(Watered down) I but my diesel from a variety of different locations, have been for the past year, same mileage regardless of where it is purchased

 have you tried using a diesel additive (to boost c-tain by 8 points or so) Haven't tried this, but I don't see how 12-15mpg can be made in an additive, I've never been sold of additives

 have you replaced your thermostat  (the one in there may be worn out or stuck open) hasn't been changed, will tear into the coolant system soon, since i have a leak in the system

 forgot if you have A/C, if so, maybe compressor is stuck to run all the time or the bearings are dragging I have A/C, but it's not stuck on, I can here it cycle on/off when turning on the AC or defrost
 
 alternator may be worn out, causing drag on yout system  (bad bearings) Good thought, I will probably check

 water pump or power stearing pump or any other accessory driven by a belt Another good thought, will check

 the fuel water seperator in the back may be full of water (needs drained) Fuel/Water separator has been completely removed, straight fuel line is installed.

what kind/type of grease did you use to do your wheel bearings,For rear bearings I did myself, with good quality wheel bearing grear, but the mileage was poor before I redid the brake/bearings on the rear.

For the front...when I did my front break upgrade, I installed a new spindle which came prepacked/pre-installed with wheel bearings....this is the front brake kit I have installed.....

http://www.bahnbrenner.com/vw_audi/products/101/OEM_11_3_Early_MK2_Complete_Brake_Upgrade_Kit

maybe something got assembled wrong, can't trust anyone but yourself, right? These are MK4 bearins and hubs, which are sealed bearings and pre-packed with grease

did you go from drum to disk brakes? did you change your rotor sizes? Rear...all new drums, brake cylinders, shoes.....on the front MK4 VR6/1.8T 11" Rotors/Calipers

      Ok, so after replacing all of the parts you said you did
maybe lets say you lost 2 mpg by putting in the new injectors(better flow=more fuel), 2 mpg by using the new super pump, 2 mpg by fixing the air leaks (which allows you to use more fuel for more boost) (and becasue we are just saying) 1-2mpg for dragging wheel bearings due to bad machining and bad grease, and bearings maybe too tight as well (cause where just saying) If your belts are too tight or too loose and your accessories are dragging 2mpg(alt/power stearing, a/c etc...) if your thermostat is stuck or not working right that can also suck 2 mpg.   add some watered down diesel, restricted filters, and maybe a heaver foot (with all that extra power you now have) or even driving 10mph faster,  keeping up with traffic, or stop and go traffic. SO, if all that could be so, theres 15mpg in the mix there.  though its just me thinking aloud and assuming that these might be issues

just another thought, since you had your alignment,  how are you tires wearing, Tires wear perfectly, no issues there

Just a few more ideas, for you
Hope it helps

 -Ron

[Mark(The Miser)UK]

What about adjusting  internal pressure,if put little more same talk achieved good mpg.

I've tried this with my original ECO pump....no change in mileage, see earlier posts in this thread for details.

As I've said I've had two different Giles pumps installed, same result, I'm not going to alter the internal pressure on a fresh rebuild from Giles, when all indications point to the pump(s) not being the issue.

Does your mileage vary according to town/fast interstate/slow interstate? If you're missing the noticable benefits of the last one, then that could be a pump advance issue. However you are pretty sure that your pump is good.

Have you checked the resistance of the air filter? A combined boost/vac gauge from a carb/gasser fuel pump tester inserted in the boost signal line to the pump, will show a vacuum until boost starts.

You say that you can push the car freely at rest, suggesting nothing binding, yet you have this strange phenonemon of the 'rather high' boost when cruising. This boost is the only 'evidence' agreeing with the poor fuel economy. Did the ECO pump give you boost of more than a few psi when cruising?

I would suggest running the car with the boost line disconnected for a few gallons of fuel, to see if things improve.

[burn_your_money]

Some greats thoughts and suggestions here, see my answers in blue.

did you go from drum to disk brakes? did you change your rotor sizes? Rear...all new drums, brake cylinders, shoes.....on the front MK4 VR6/1.8T 11" Rotors/Calipers

That's a lot of extra weight you have spinning around up front. Did you make this change before or after the mileage drop?

[arb]

So your lovely Giles pumps are at the mercy of what ever filtering you filling station offers ? I'd at least have a filter. One drop of water in the IP isn't a good thing.

On the fuel, your 33 mpg in European terms is a 7.1 L / 100 km. http://www.tdiclub.com/misc/conversions.html

and your former 43 mpg is 5.5 L / 100 km. So, if this extra fuel is being burned, that's 1.6 L per hour (at 62 mph) or 235200 BTU's per hour, equal to about 92 hp (if 100% efficient) . That's a LOT of heat going someplace, if its all being burned.

So, the real question is, what changed while Mom was driving the car ?  33 mph is in line with what many others get when they are enjoying high speeds and acceleration.

[Mark(The Miser)UK]

So, the real question is, what changed while Mom was driving the car ?  33 mph is in line with what many others get when they are enjoying high speeds and acceleration.

Yea, racing through a 20mph zone at that speed'll get yer nicked over here

[rabbitman]

Next fillup dump a quart of 2-stroke oil in the tank, can't hurt anything.

[Doakster]

Does your mileage vary according to town/fast interstate/slow interstate? If you're missing the noticable benefits of the last one, then that could be a pump advance issue. However you are pretty sure that your pump is good.

Have you checked the resistance of the air filter? A combined boost/vac gauge from a carb/gasser fuel pump tester inserted in the boost signal line to the pump, will show a vacuum until boost starts.

You say that you can push the car freely at rest, suggesting nothing binding, yet you have this strange phenonemon of the 'rather high' boost when cruising. This boost is the only 'evidence' agreeing with the poor fuel economy. Did the ECO pump give you boost of more than a few psi when cruising?

I would suggest running the car with the boost line disconnected for a few gallons of fuel, to see if things improve.
[/quote]

Haven't checked the resistance of the air filter, but I got poor mileage on my past older filter (that wasn't really dirty), changed to a new filter for the heck of it and still poor mileage.

I can't speak to the ECO pump showing high boost, since I got my gauges in after the ECO pump got pulled out

Which boost line are you referring to disconnecting the boost advance on the pump?

[Doakster]

Some greats thoughts and suggestions here, see my answers in blue.

did you go from drum to disk brakes? did you change your rotor sizes? Rear...all new drums, brake cylinders, shoes.....on the front MK4 VR6/1.8T 11" Rotors/Calipers

That's a lot of extra weight you have spinning around up front. Did you make this change before or after the mileage drop?

All front end work, new brakes, new bearings, new shocks struts, all new bushings, and the bigger wheels were put on at the same time......got great mileage afterwards.....43mpg, then the drop about 4-5months later

[Doakster]

So your lovely Giles pumps are at the mercy of what ever filtering you filling station offers ? I'd at least have a filter. One drop of water in the IP isn't a good thing.

So, the real question is, what changed while Mom was driving the car ?  33 mph is in line with what many others get when they are enjoying high speeds and acceleration.

I still have the standard fuel filter in the car (which is brand new), just not the water separator anymore, should not be an issue since not all 1.6s had the water separator on them. And when I gutted the separator there was no water in it, and probably had never been drained prior to me purchasing the car.

I'd like to find where my 12-15 mpg is going, unfortunately I don't enjoy high speeds and acceleration in this car....care never sees over 65-70mph, that's just the way I drive it.

[Doakster]

Next fillup dump a quart of 2-stroke oil in the tank, can't hurt anything.

Already tried that when the ECO pump was in.....no difference in mileage.

[Doakster]

Alright to re-cap, these are my thoughts based on all the good comments.

Since my boost is up and my odometer is very close to dead on, that points to a rolling resistance somewhere. I think we can agree that after 3 different pumps and no change in mileage, the pump is not the issue, or even the entire fuel system is not the issue, since it's been gone over more than once.

- I'm eliminating the rear as an issue, wheels turn/spin very very freely when car is jacked up and spinning by hand. They turn freely to the point you can get them spinning and they will continue to spin on their own for quiet some time.

- On the front, nothing indicates I have an issue.....but I still had that odd noise after the car sat awhile over the winter, I think my next option is to go over the front with a fine comb, as in disassemble and inspect if needed.

-Since I have a peloquin in the trans the wheels naturally are a little harder to spin by hand (than a standard open-diff trans)....so this mean if I really want to see if my bearings are binding, I need to pull off spindle/hub and rotate by hand, that way I can rotate the hub and check the bearings while it's completely disconnected from the car.

Thoughts??

[theman53]

Has anybody else ran a peloquin? Maybe that plus.... plus .... etc ends up in a total 13mpg loss? Hope you find it soon. I think you are headed correctly. Good Luck.

[Doakster]

Has anybody else ran a peloquin? Maybe that plus.... plus .... etc ends up in a total 13mpg loss? Hope you find it soon. I think you are headed correctly. Good Luck.

I got 33mpg, before the trans rebuild and peloquin install......and 33mpg afterwards.....not the trans that's causing the issue.

But...the peloquin is pretty sweet, especially for winter months, that's mainly why I got it, expensive little bugger though