Fuel economy

Nero Morg

Top Post Dawg
Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
Amazing results! Any more data points to share?
Not yet, I filled up on Sunday, so far only 60 miles in. I also have new engine side skirts/ducting to install which I'll do tomorrow. Anything to maximize fuel eco.

Where can i get one of these?
I bought mine at Autozone, but I'm sure they can be found elsewhere. It's called a Scangauge II.
 

Nero Morg

Top Post Dawg
Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
And the results are in. My same drive I do, I managed 33mpg. Mind you, this is a week of driving with my alignment severely toed in. I'm hoping the next tank will be better!

On another note, at what point does the coolant temperature have to be, before the fueling changes from warmup to regular driving? I've noticed my car drives different until it hits 190 degrees, but it hovers around 182 for most of my 17 mile trip.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
I run between 194 and 202
 

Nero Morg

Top Post Dawg
Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
I run between 194 and 202
Huh... Wonder why mine is running so cold. Ambient temperature is only about 60 right now. Might be time for a new thermostat.
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
Thermostat could be getting tired. But whether or not your car gets up to temperature could also depend on the type of driving you do for that 17 miles. I have a 15 mile commute but about 13 of it is at 70-80 MPH. So my car gets to 190, not problem. Suburban speeds might not allow that.
 

Nero Morg

Top Post Dawg
Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
Thermostat could be getting tired. But whether or not your car gets up to temperature could also depend on the type of driving you do for that 17 miles. I have a 15 mile commute but about 13 of it is at 70-80 MPH. So my car gets to 190, not problem. Suburban speeds might not allow that.
Well I've been leaving my frostheater plugged in every day since I got my injectors back, it's instantly at 160 degrees, but even at the end of my trip it's still hovering 186-188. Shame, it's not even two years old. I'll order one from you guys tonight.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
Both my temps are at idle. If I remember, it is slightly higher under load at low rpm in higher gears. Check your new stat to see what temp it closes at, that has a big effect on operating temp. Sooner it closes, higher the operating temp. Mine also would start to defrost at idle, when new anyway. Somewhere on a thread I posted those temps
 

gmenounos

Vendor
Joined
Jun 26, 2003
Location
Watertown, MA, USA
TDI
'99.5 Golf GLS, '01 Jetta GLX Wagon (TDI conversion)
And the results are in. My same drive I do, I managed 33mpg. Mind you, this is a week of driving with my alignment severely toed in. I'm hoping the next tank will be better!

On another note, at what point does the coolant temperature have to be, before the fueling changes from warmup to regular driving? I've noticed my car drives different until it hits 190 degrees, but it hovers around 182 for most of my 17 mile trip.
Wait, so after all this adventure with injector rebuilding, you're getting the same mpg as before?

BTW, my commute is a leisurely 5 miles through the suburbs, with several traffic lights and never exceeding 30 miles/hour. This morning the coolant temp started at 52f and at the end of the drive, it had just reached 189f. ('99.5 ALH, thermostat replaced a couple of years ago with, I think, a genuine VW one). This commute nets me about 35mpg (according to a ColorMFA display).
 

Nero Morg

Top Post Dawg
Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
It jumped from 28 to 33, so it's a step in the right direction. I had a feeling it was a multi point issue. Hence why I did my suspension refresh, got new engine side skirts, belly pan, fender liners, ect. Trying to follow all points on oilhammer's fuel economy 101. I'm hoping the thermostat is the last piece of the puzzle. Or a tired cylinder head. I know my coolant temp readings are accurate, when I repaired my coolant leak a week ago I installed a new sensor from IDparts. Same readings.

Also to add, my coolant temp barely gets to 189 climbing both hills on my way home from work. Was almost debating putting cardboard in front of part of my radiator.
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
I just looked back at your original post. Not sure I'm reading it right, but did your FE drop after getting the tune? Or was there other work you had done that may have caused it to drop? If it was after the tune alone, then I'd be talking to Malone about what's happening and see if they can help you. I don't think a (slightly) tired thermostat is costing you the 10+ MPG or so you're missing.
 

Nero Morg

Top Post Dawg
Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
No, tune was done, then about two months after it started to degrade slowly from 38 to 28. I've already checked the usual culprits, maf, filters, snow screen, ect...

Update, on my way into work today, my coolant temp jumped to 201, which is the first time it's EVER done that. Stayed there for a solid 5 minutes, cruising at 60 on level road, then dropped to 186, and stayed there the remainder of the trip. Drove a lot nicer with it warm.
 
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Rob Mayercik

Veteran Member
Joined
Dec 19, 2001
Location
NJ, U.S.A.
TDI
2002 Jetta GLS, Baltic Green/Beige
Maybe it had an air bubble in the coolant and it might have finally burped it out? Be interesting if today's temp pattern is a one-shot or repeats...
 

Nero Morg

Top Post Dawg
Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
Filled up before a long drive, since my initial post about coolant Temps, it's oddly been staying between 191-197 since then, doing my usual drive, I'm now at 36.6mpg!
Now, to do that said long drive... Fill up again, and more maths.
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
Here's a target: IBW's been on a roll. And there are two road trips in here, both over 2K miles.
 

Nero Morg

Top Post Dawg
Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
Here's a target: IBW's been on a roll. And there are two road trips in here, both over 2K miles.
That's some impressive stuff. My scangauge said 42 on my way out of town. I'll be heading home soon, and I'll fill up when I get back to see what my fuel eco is. Honestly I'll be happy with 38 mixed driving. Way better than the 28 I was getting.
 

TDI-WNC

Well-known member
Joined
Jun 26, 2018
Location
Asheville, NC
TDI
2000 Jetta TDI 5-speed
2000 Jetta, bought from a friend several years ago. He had notebook with a record of every fill up since the first fill up at 502 miles, assuming the dealer gave them a full tank


I have kept it up, and for 243,109 miles the overall average MPG if 51.64.
 
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Nero Morg

Top Post Dawg
Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
Well, verdict is in. Round trip, 82 miles, 90% freeway averaging about 65 mph, managed to squeeze 43.4mpg out of it. Filled all the way up on each time. 1.88 gallons upon returning. I'm happy with this. With how hilly this area is, without going severely out of town, I think this is the best I'm going to get. Sure beats the 28 I was getting.


I wanted to do a few special thanks to some people that had some key advice that helped me get my fuel economy back up.
Thanks oilhammer for your great thread on tips for fuel economy,
thanks IndigoBlueWagon for his rubbing-it-in to keep me motivated to figure out what was going on ;) also the great deal of parts I ordered to refresh my suspension/skid plate to make my rolling refrigerator aerodynamic.
Thanks to aNUT for his thread on revisiting TDI timing injection, and how setting it advanced really doesn't affect timing for fuel economy, that it actually can decrease it based on your normal driving.
Thanks to BobOH for pointers on things to check,
And a very big thanks to Franko6 for taking the time to show me how to check injector balance at two RPM ranges, and what to determine from them, and repairing my injectors that were very... very bad.
I apologize if I missed anyone, I appreciate everyone whose helped me on this forum. I'll be monitoring my fuel economy very closely from now on, and now know how to address it. I also wanted to combine all the sources I used to return my fuel eco to what it was before, for any future TDIclub member.


By the way IBW, where I live is very hilly, constantly getting 6-8 degree inclines, I don't think I'll ever hit your kind of mileage, unless I decide to take the I5 corridor to southern Oregon. Maybe I'll do a round trip in one tank. Who knows :)
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
It's true that a lot of the long trip driving I do is on pretty flat terrain. Berkshires, some "mountains" (east coast style) in NC, but nothing really big. But my average FE since I've been tracking with Fuelly (182K miles) is 46.4. And about half of that was with a car much more extensively modified than it is now.

I think you're on a good path, but you may find some other things to work on. But the improvement you've made is impressive!
 

Franko6

Vendor , w/Business number
Joined
May 7, 2005
Location
Sw Missouri
TDI
Jetta, 99, Silver`
It's been August since I looked in on this thread... I haven't forgotten you, Mr. Tift. As a matter of fact, another of your TDI soul mates is asking for similar treatment.

If I remember right, the nozzles set were Bosio 764's, with which I have some of the most problem (assuming you understand I never will install the Race 520's), as they tend to vary a great deal. There are years past I swore off using Bosio, as quality was in the tank. We had been accepting a loss ratio of 1:10, then it increased. I believe they were outsourcing the bodies.

Since then, the quality has rebounded, but I still stand on my previous comments about Bosio.

'They are CAPABLE of producing good nozzles.'

However, when re-working Nero Morg's, I was given permission to replace them, but found that was not necessary, or the issue. I have several methods to 'repair' nozzles that are incorrectly flowing or spraying. When I reworked the nozzles, they all fell into range, with just a little effort. It was the #3 body that was the culprit.

That falls to the issue of why we do not perform 'instant gratification' nozzles any more. We had too many core nozzles that were damaged or destroyed. We don't like to send replacements with broken wires or that are badly corroded. Instead of coating injector bodies black, where you can't see any pitting or corrosion, we clear-coat, so the quality of the injector is plainly visible. So, if you send a bad #3 injector or injector bodies that look like they came out of the 'Great Salt Belt', you get the rust polished off, but they are the same ones you sent. I'd say 95% of all injectors are reusable.

The control of installing in a perfect running car eliminates the possibility of sending out a injector that is flowing poorly, but even if your engine is running just as well, does not mean you have the Injection Quantity (IQ) set correctly. At least 10 years ago, we developed a method of driving the car in 3rd gear, starting at 35 mph. Fuel in applied to Wide Open Throttle (WOT). When speed hits 40mph, turbo kicks in. Count 3 seconds and check speedometer. If the initial IQ is set low enough, the exhaust will show smoke. Raise the IQ (See Hammer Mod) and repeat WOT runs until the some performance (Loss of speed) is noted. Revert to the last IQ number that did not lose performance speed run. By doing this you will have optimized your IQ to acceleration and minimized your smoke.

I think Nero Morg has been explained this method and it is worth the try to increase FE if it has not been attempted.

It has been a pleasure to work with you Nero. I hope you continue your improvement.
 
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