Low MPG, me or the car?

[Shikaroka]

I have a 99.5 Jetta, ALH, 5-speed.
EGR delete, recently cleaned manifold, aftermarket muffler, Sprint DLC nozzles, Kerma chip.

I usually get 32-34 mpg, mostly around town. I sometimes get 36-38 with more highway driving.

I tend to drive it fairly hard, but I think these numbers are low.

What do you guys think?
Anything I should try?

 

[supton]

That seems low. Unless if you cruise at 100mph.

How many miles on it? How long since it's last timing belt? I wonder if the timing is off somehow. Does it eat tires? I'd check the brakes after driving for a while, maybe one is dragging. The rear calipers are known to go bad.

 

[Shikaroka]

All good suggestions.
I usually cruise at 70ish.
She has 174k miles.
Timing belt was done about 12k miles ago.
Tires are good and wearing even.
Brakes are good, no issues. I did upgrade to VR6 brakes.
All wheel bearings have less than 10k miles

 

[supton]

I'd check just the same. Could be a brake that suddenly decided to drag.

 

[Shikaroka]

It's been like this for a long time, had several brake changes and no change on the fuel economy.

 

[Shikaroka]

It also smokes a decent amount on hard acceleration, but that could be the chip (although I requested low smoke).

 

[vwdieseling]

Low if you ask me. I have 1.9 TDI Beetle with an O1M. I get 37 MPG combined and over 40 MPG highway. I think it's the chip, black smoke over fueling. Could be anything. Have you checked your turbo and piping? I had the lower hose coming off the turbo split once due to oil degradation. I was losing boost really hurt the fuel mileage and smoke on acceleration. I guess if you have a boost gauge you know. Those lower silicon hoses coming off the turbo unto the pancake pipe don't last forever. I could feel air coming from below when I had my head stuck close to the EGR valve when my buddy hit the accelerator. ID parts sells them.

 

[Shikaroka]

I do have a boost gauge and don't think I have any leaks.

 

[LNXGUY]

Drive the car 'easy' for a full tank and see if it is really you that's the problem. Although those are extremely low numbers for a 5spd ALH unless you're doing nothing but city driving.

 

[IndigoBlueWagon]

I'd be apoplectic if my ALH FE was that low. Other than track days I can count on one hand the number of under 40 MPG tanks I've had in 292K. One was driving 90 MPH into the Rockies with the A/C on. I got 38. Driving 75-80 on the highway I typically get 46-50. And that's in a car that makes about twice stock power.

I think you have a fueling issue, perhaps along with some other problems (less than perfect timing, fading MAF, vacuum (turbo) problem, etc.) I bet the injectors aren't balanced/popping properly or the car is over-fueling. Fuel economy issues are usually a bunch of little things, not one big thing.

 

[vwdieseling]

I do have a boost gauge and don't think I have any leaks.

I agree with IndigoBlueWagon pretty low. Could be a lot of things. I did a block flush," Oh God Here It Comes." using a diesel oil flush. Increased my mileage a little bit getting the rings cleaned up. Also stick with Rotella T6. I'm ready to be ridiculed for the block flush, but it helped.

 

[Shikaroka]

Thanks guys.
I had Kerma TDI do the nozzles and they were supposed to balance them.
The car runs great, but I'm glad that you guys agree it's low.
I have been thinking of trying a MAF, since I'm pretty sure that could affect it and I've never changed it.

Where's a good place to get a MAF?

 

[LNXGUY]

What was the mileage before the nozzles?

 

[KAT90]

My numbers were dropping to the low 50's, found out my 99.5 was running cool, replaced the thermo now back above 55mpg.

 

[JB05]

Jack up each rear wheel and give them a spin to rule out any rear brake, parking brake cable malfunction. Were the rear calipers ever replaced?

 

[Shikaroka]

What was the mileage before the nozzles?

I think it was about the same, but I did the nozzles shortly after getting the car.

 

[Shikaroka]

Jack up each rear wheel and give them a spin to rule out any rear brake, parking brake cable malfunction. Were the rear calipers ever replaced?

I actually put cables on about 6k miles ago.
It hasn't affected the mileage any.

 

[LNXGUY]

How much city driving are you doing?

 

[Shikaroka]

How much city driving are you doing?

Well,that's hard to say.
I use the interstate to hop across town, so it's mixed.
But I'd say that 60% is "city" driving.

 

[LNXGUY]

high 30's low 40's is about average for a city driven TDI.

 

[IndigoBlueWagon]

high 30's low 40's is about average for a city driven TDI.

Low 40s, yes, high 30s, no. My experience in close to 400K of ALH miles is that anything below 40 is indication of an issue with the car. As stated above the only times I've gotten less than 40 in my wagon is under extreme conditions, and even then it's rare. Even if the OP is in traffic all the time he should be achieving the city EPA number of 42, and it sounds like his driving isn't pure city.

I'm willing to bet this car has a fueling problem. Not brakes, not tires, fueling. It needs someone to run some logs, look at injector balance, look at fueling levels in the tune. Something's not right.

 

[str8t six]

have you checked to see if your intake is clogged up?

 

[Shikaroka]

Low 40s, yes, high 30s, no. My experience in close to 400K of ALH miles is that anything below 40 is indication of an issue with the car. As stated above the only times I've gotten less than 40 in my wagon is under extreme conditions, and even then it's rare. Even if the OP is in traffic all the time he should be achieving the city EPA number of 42, and it sounds like his driving isn't pure city.

I'm willing to bet this car has a fueling problem. Not brakes, not tires, fueling. It needs someone to run some logs, look at injector balance, look at fueling levels in the tune. Something's not right.

I tend go agree. I've never seen low 40s.

I could log some runs. What should I look for?

I'm about to drive around 800 miles this weekend, so we'll see what strictly highway does.

 

[Shikaroka]

have you checked to see if your intake is clogged up?

I hot tanked and cleaned the intake when I did the EGR delete, so it should be good.

 

[BobnOH]

Did you say earlier the car has a chip? Which one?

 

[Shikaroka]

Did you say earlier the car has a chip? Which one?

Yes.
I had Kerma socket it and chip it.

 

[BobnOH]

Here's some basic stuff from Oilhammer

 

[LNXGUY]

I'm about to drive around 800 miles this weekend, so we'll see what strictly highway does.

This should be a pretty good test, looking forward to the results.

 

[eyeguy]

I drive from Sissonville to Kanawha City with the cruise usually set at 80 on I-77 and then at 70 once I hit Charleston when the speed limit drops. My only mod is a Colt Cam & I'd imagine that I get at least 42 on the drive.
Depending on where you're going through town, I could believe high 30's, especially during rush hour. If you're getting high 30's driving mostly in the 60 mph zone any other time, you should be doing much better.
I hate the drive home at rush hour!

 

[thos.cook]

I know this is obvious but you dont leave her parked at idle for any length of time do you? I'm sitting here in mine waiting out rain on a jobsite.

I try not to let her idle too long but I need the AC! I seem to lose some mileage if I idle her on a job.

Anyways, you know what they say about the most obvious solution...=p

Best,
Thomas