Another bad milage thread

[AUGSX]

I am having some serious issues with my car. I runs great as far as everything else goes but my mileage is horrible. I am averaging about 35 mpgs mostly city with a minimal amount of hwy. Now I do idle for about 30 minutes a day while I work from the car and I run the A/C all day. I don't have a typical day that I can refer to as I am driving from property to property and the distances vary. I do alot of heavy city stop and go driving and a small amount of hwy were I try to keep it under 60mph. The car is modified and apart from the mods listed in my sig I just had the Tstat replaced and the coolant sensor, fresh fuel filter and a 5spd swap with a 3.16 final gear. I don't drive the car hard only once in a while to give it a good ole Italian tune up. IQ was just checked and adjusted by my local Guru and i at least am stumped. I am going to have the car aligned next month when I do the suspension but besides that I think we have covered everything. Maybe my tune needs to be adjusted some as the car smokes, when I get on it it rolls the coal. If I blip the throttle at a light it will below out so smoke.

Sorry for the novel but I wanted to try and give as much info as possible.

Thanks

 

[MikeMars]

City driving + stop&go -> bad mileage
A/C -> bad mileage (*particularly* in city driving)
Idling -> bad mileage (*particularly* when A/C is on).

5th gear upgrade is irrelevant for city driving (improves things for interstate)


Considering all those things, I think 35mpg is perfectly reasonable.

 

[Joester]

mostly city with a minimal amount of hwy. I idle for about 30 minutes a day while I work from the car and I run the A/C all day.

i dont really see a problem with your milage.... i get 40-42, and i never use A/C idle minimally, and do mostly highway driving. i would say 35 is spot on.

if you really want to check it out i would check injection timing to see if you are slightly advanced.

 

[flatlanded]

PP764s and city driving... I step on it around the city with my PP520s and I get 30ish MPGs.

Raise your IQ to get rid of that smoke. 5.0-6.0 is where most people find it comfortable (with an upgraded nozzled car).

Other than that.... keep your foot out of it and keep the boost under 5psi. Coast to stop lights and downshift regularly and you might see 40MPG.

I get 30 MPG, thrashing in the city.
I get 48 MPG, driving nice city/highway mix.
And I get 55+MPG highway.

 

[RebelTDI]

I agree with Mr. Mars. For your situation 35 mpg is reasonable. Before you make any more adjustments or put money into it, I'd go for a nice long highway trip to see how well it can do. Hard to get good mpg in anything if your stuck going light to light with a/c blasting in Miami heat.

 

[AUGSX]

Thanks fellas, I feel some what relieved now. If I do pick up some mpgs from allingment and tune adjustment It will be great. I will try to take a trip some were in the near future were I can see what it can do on the open road.

 

[AUGSX]

Ok so I think one of my issues might be my A/C compressor, Should I be loosing 10mpgs at cruise? I was doing 60mph with the A/C off and the scan gauge was hovering between 66 and 60 mpg for a few miles, then I turned on the compressor and wow 51 to 55 mpgs for a few miles. Well I did a 37 mile trip this morning mostly hwy with 4 stop lights. Averaged 51.7 mpgs on the scan gauge which is dead on. I then took another trip around town to do some work all city in neighborhood driving avg speed 17mph with A/C on 26mpgs with out A/C 32mpgs. This seems to be a really big hit for the A/C, my car also sounds louder at idle with the A/C on as well as it has alot more vibration with the A/C on.

 

[Joester]

Are you calculating your mpg or just using scangauge?

 

[MikeMars]

Well, he's using fuelly, so that implies he is calculating properly. But scangauge is the only way to get trip MPG. So as long as the scangauge matches up with the full-tank figures it should be OK.

... This seems to be a really big hit for the A/C, my car also sounds louder at idle with the A/C on ...

Well, A/C does take a lot of power, so you'd expect it to make idle sound different. The A/C takes a constant load regardless of vehicle speed. So that is why the A/C impact is so much more obvious when you are doing city / stop&go / idling.

 

[schwarze Käfer]

Hot Weather + A/C + stop & go city driving = 30-35mpg.

I don't think even a Prius would do much better with the A/C blasting.

 

[DanG144]

The AC draws a lot of power when it is hot and humid out and it is first turned on. A Very impressive change in fuel consumption. If the car ever cools down, and dries out, such as on a long interstate trip, the AC power draw drops dramatically and mileage drops very little. This is even in the South along I-10 trips.

But getting in and out often (letting in humidity), in town driving, the AC is going to be a very large factor in mileage.

 

[AUGSX]

Are you calculating your mpg or just using scangauge?

As was answered I am using Fuelly and my scan gauge is dead on, it's been calibrated over 4 years.


As for the A/C I can attest to the change in humidity issue as I see better MPGs from the car after the A/C has been running for longer periods with out letting in any outside air, not to mention it is alot colder.

 

[WVU TDI]

Fuelly says this was originally an auto car? 11mm pump and pp764s = a ton of fuel...

I really don't think you can complain about the mileage you're getting considering your circumstances.

 

[AUGSX]

Yes it was originally an auto. My mileage has only marginally increased since the swap may be 2mpg and that's with the 3.16 RG.

 

[K5ING]

I've noticed that my mileage has taken a huge hit lately too. At first, I thought the new tires I got were to blame, but that was also about the time we hit triple digit temps here in North Texas. I had my A/C recharged about that time also.

I've taken about a 8 to 10mpg hit average. I think it's A/C related. Running with ambient temps in the 80's (about as low as it's been getting here), I'm right at 50mpg for my 30 mile freeway commute. On the way home, when it's over 100 outside and the A/C is running, it's more like 41mpg.

One test to try to see if it's A/C related (if you have a Scangauge) is to look at your gallons/hour reading at idle. On mine, with the A/C off, it's around .15 GPH. Turn on the A/C, and that shoots up to around .27 GPH. Is that excessive A/C drag? If anyone else with a Scangauge can do the same test, and post the results, I'd appreciate it.