Fuel economy

Rob Mayercik

Veteran Member
Joined
Dec 19, 2001
Location
NJ, U.S.A.
TDI
2002 Jetta GLS, Baltic Green/Beige
I'll have to do the mod. We're spoiled over here and have fuel attendants here. Not illigal to pump your own diesel but they sure look at you funny.
NJ is the same (self-service GAS = illegal, self-service DIESEL = legal), but I've not noticed any funny looks from anyone

I let the attendant start the pump, then I take over and do the topping off. In a little over 17 years I've only had an issue once, and rather than start an argument with the guy I simply let it go at the time and just haven't gone back to that station (plenty of others I can go to in that area).

Everyone else seems fine with it - lets them go off and service other customers.
 

leafs

Veteran Member
Joined
May 28, 2018
Location
canada
TDI
alh
Your car is a 5spd swap too right? (I think you posted a pic of your clutch pedal a while back and I noticed the wiring to it).

My car is also a swap and my fuel economy doesn't appear to be too great either. I gotta get to the bottom of it now that spring is here. Keep us updated if you figure it out.
 

Nero Morg

Veteran Member
Joined
Oct 19, 2017
Location
OR
TDI
2003 Jetta wagon, 2001 Jetta TDI, 2014 Passat TDI
Yeah it's a 5 speed swap, so I have the bigger pump. I'll be refreshing a lot of stuff on the engine here next weekend, so need to drive it a bit afterwards and I'll follow up.
 

leafs

Veteran Member
Joined
May 28, 2018
Location
canada
TDI
alh

Nero Morg

Veteran Member
Joined
Oct 19, 2017
Location
OR
TDI
2003 Jetta wagon, 2001 Jetta TDI, 2014 Passat TDI
Hey man didn't see you mention IQ so check your IQ. For some reason mine was at 0.8. Could be something to do with the swap, when the ecu soft coding is changed.
https://www.myturbodiesel.com/wiki/injection-quantity-adjustment-fuel-pump-hammer-mod/
It's currently set at 4.2, I adjusted it after the manual swap, nozzles, and tune were done several months ago.

I'll be installing new parts this weekend, I'll be updating the Upgrade the Wagon thread I started a while ago.
 

Rob Mayercik

Veteran Member
Joined
Dec 19, 2001
Location
NJ, U.S.A.
TDI
2002 Jetta GLS, Baltic Green/Beige
I have an 01M-equipped car (11mm pump native) with DLC520s and no tune, and I have my IQ set to about 6.0 (did not need to hammer mod do get there, was able to reach it in SW). 4.2 could be the right spot for you, Nero, but your tuner would likely know for sure.

Unless you're driving less efficiently (because of "enjoying" the 5speed swap), MPG should have only gone up by adding the 3rd pedal.

That said, the 11mm pump and the DLC520s should not be your problem - I filled up last night, taking on 14.943 gallons (fully vented) for 657 miles (with low fuel light coming on at about 640 or so), yielding 43.97 MPG for an 80/20 Highway/City mix on an 01M...
 

Nero Morg

Veteran Member
Joined
Oct 19, 2017
Location
OR
TDI
2003 Jetta wagon, 2001 Jetta TDI, 2014 Passat TDI
Finally burnt through one full tank after getting my goodies installed and my tune, fuel economy is back up to 38.5 with no change in driving habits! Woohoo!
 

Rrusse11

Veteran Member
Joined
Jan 23, 2014
Location
PA Deutsch Country
TDI
2002 Golf, 5spd; 05 Jeep CRD
After our trip to the Gulf Coast and back towing the camper with a variety of fuel prices and topography,
I'm thinking that a better metric for FE is cost per mile.

Roaring through the Appalachians at 75-80 returned a low of 25mpg,
whereas on the Florida flats on secondary roads at 55-60 I got 35mpg.


Average cost was $.075/mile.
 

Nyk

Active member
Joined
Jul 30, 2018
Location
Halifax, NS
TDI
2002 Jetta TDI (ALH)
Yeah it's a 5 speed swap, so I have the bigger pump. I'll be refreshing a lot of stuff on the engine here next weekend, so need to drive it a bit afterwards and I'll follow up.
Speaking of 'the bigger pump':

I have a 11mm pump that came with the car when I got it from the PO. I wasn't aware that is was an 11mm (just thought it was a spare 10mm) until I took a closer look a few months later after I did some reading and found that the 11mm can be used for upgrades.

As my car is pretty much stock (aside from an EGR delete), would there be any benefit for swapping out my 10mm for this 11mm? I know it's usually done after bigger nozzles and a tune, but would the 11mm by itself be advantageous?

Edit: Also, glad to hear your FE issues got sorted!
 
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Rrusse11

Veteran Member
Joined
Jan 23, 2014
Location
PA Deutsch Country
TDI
2002 Golf, 5spd; 05 Jeep CRD
Speaking of 'the bigger pump':

I have a 11mm pump that came with the car when I got it from the PO. I wasn't aware that is was an 11mm (just thought it was a spare 10mm) until I took a closer look a few months later after I did some reading and found that the 11mm can be used for upgrades.

As my car is pretty much stock (aside from an EGR delete), would there be any benefit for swapping out my 10mm for this 11mm? I know it's usually done after bigger nozzles and a tune, but would the 11mm by itself be advantageous?

Edit: Also, glad to hear your FE issues got sorted!

Yes, you'll get more fuel, you'll have to play with the IQ, VCDS
and possibly hammer mod as well.
 

Nero Morg

Veteran Member
Joined
Oct 19, 2017
Location
OR
TDI
2003 Jetta wagon, 2001 Jetta TDI, 2014 Passat TDI
More fuel, higher head pressure, so better atomization of the fuel, and if you drive it right, fuel eco.

As far as I know, there's no difference between summer and winter fuel in diesel, unlike gasoline where they put ethanol in it. Unless there's something I'm missing? I run LiquiMoly in every fill up, or power service. Gotta keep that high mile 11mm running smoothly.
 

MichaelB

Veteran Member
Joined
Aug 11, 2009
Location
SE Wisconsin
TDI
2014 Passat SE DSG
As far as I know, there's no difference between summer and winter fuel in diesel, unlike gasoline where they put ethanol in it. Unless there's something I'm missing? I run LiquiMoly in every fill up, or power service. Gotta keep that high mile 11mm running smoothly.
Yes, there is a winter diesel blend. To prevent fuel gelling at freezing temperatures D1 (kerosene) is blended into D2 at percentages up to 20%. Some blenders use other anti-gel add packs too. D1 is more highly refined and has less energy (BTUs) then straight D2. You do not need to add diesel fuel adds at every fill up the only gain, is to the manufacturer of said additive. PS white is sort of an insurance policy in the winter to prevent water freezing and fuel gelling.
 

Rob Mayercik

Veteran Member
Joined
Dec 19, 2001
Location
NJ, U.S.A.
TDI
2002 Jetta GLS, Baltic Green/Beige
Was wondering if we'd switched back, when I filled up last week I found I had cracked 44mpg for the first time since October.
 

Nero Morg

Veteran Member
Joined
Oct 19, 2017
Location
OR
TDI
2003 Jetta wagon, 2001 Jetta TDI, 2014 Passat TDI
OK all. I just spent a large chunk of time with Franko6 on the phone, and we believe we've found the fuel economy issue. Wanted to update due to a few members expressing interest in the cause.

Turns out, if you go under block 13 for injector balance, at idle numbers may look good. Raise the RPMS to 1500 and hold it, see where the numbers go. That operates the second stage of the injector. I found that my injector 1 is all screwy and overfueling. Which is sad, being as they have less than 3k miles on them. So I'll probably be sending those to him in the next month or so.
 

STDOUBT

Veteran Member
Joined
Jul 30, 2007
Location
Portland, effing Oregon
TDI
ALHx2
OK all. I just spent a large chunk of time with Franko6 on the phone, and we believe we've found the fuel economy issue. Wanted to update due to a few members expressing interest in the cause.

Turns out, if you go under block 13 for injector balance, at idle numbers may look good. Raise the RPMS to 1500 and hold it, see where the numbers go. That operates the second stage of the injector. I found that my injector 1 is all screwy and overfueling. Which is sad, being as they have less than 3k miles on them. So I'll probably be sending those to him in the next month or so.
Thank you for this!
I've been running out of things to check, and though I've read this site pretty much daily for the past 7 years, I've never seen this diagnostic method mentioned. Cool!
 

Nero Morg

Veteran Member
Joined
Oct 19, 2017
Location
OR
TDI
2003 Jetta wagon, 2001 Jetta TDI, 2014 Passat TDI
Yeah, that would definitely explain why it steadily got worse. I only imagine it'll continue to get worse until I have them fixed. As of Tuesday I started getting smoky starts and rough start idle. Means one nozzle is bleeding down. Darnit.
 

STDOUBT

Veteran Member
Joined
Jul 30, 2007
Location
Portland, effing Oregon
TDI
ALHx2
Assuming you had them balanced and pop tested to spec, what could
cause one to poop out like that? I mean they're basically brand new.
Just a bum unit from the factory most likely?
 

Nero Morg

Veteran Member
Joined
Oct 19, 2017
Location
OR
TDI
2003 Jetta wagon, 2001 Jetta TDI, 2014 Passat TDI
Assuming you had them balanced and pop tested to spec, what could
cause one to poop out like that? I mean they're basically brand new.
Just a bum unit from the factory most likely?
I ordered my injectors from Kerma via the hotswap. From what I understand is Kerma has DBW build them, so I was surprised to find them our of whack. No idea what caused them to go bad so quickly. I have a 2 micron fuel filter and run fuel addative almost every tank.
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Following. I have same bad FE, not sure if it's injectors. Is it possible those bad readings in one hole at RPM could be the IP? Frank would know. I did a bunch of logs he had suggested to measure rate of fuel consumption. Found it to be low, still no conclusion why.
 

Nero Morg

Veteran Member
Joined
Oct 19, 2017
Location
OR
TDI
2003 Jetta wagon, 2001 Jetta TDI, 2014 Passat TDI
Following. I have same bad FE, not sure if it's injectors. Is it possible those bad readings in one hole at RPM could be the IP? Frank would know. I did a bunch of logs he had suggested to measure rate of fuel consumption. Found it to be low, still no conclusion why.
Frank said it was definitely injector. When I was idling at 1500, cylinder 1 was at 0.02 mg/st, 2 at -0.82, 3 at 0.24, 4 at 0.24. He said he likes to see them within 0.20 of each other. With these readings he said cylinder 2 was severely reducing fuel to counterbalance #1 overfueling.

It'll be about a month before I send Frank my injectors, once I get them back I'll update. He said he's a bit loaded up with work right now :)
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Yea, saw that. I know my old 99.5 was never within 0.2 when new. IIRC more like 1.2.

And when I read this-
I ordered my injectors from Kerma via the hotswap. From what I understand is Kerma has DBW build them, so I was surprised to find them our of whack. No idea what caused them to go bad so quickly. I have a 2 micron fuel filter and run fuel addative almost every tank.
made me think those injectors would be fine.
 

Franko6

Vendor , w/Business number
Joined
May 7, 2005
Location
Sw Missouri
TDI
Jetta, 99, Silver`
Two-stage injector's fueling theory...

I have found that the operation of the unit PD injector and the mechanical VE share a similar fueling characteristic. Both injectors receive all of the needed fuel from the pilot pop (NOP1) injection for idling the engine and only require the second stage for performance levels about 2x idle speed.

How I deduced this starts with problem with second stage for Pumpe Duese injectors, '04-'06, BEW, BRM and BHW in the US. These nozzles have a bad habit of losing the main stage (NOP2) fueling caused by the injector's solenoid device failing.

One way the fueling can fail is if the injectors are left out of the engine for an extended period of time, especially for a couple of hot summer weeks, the solenoid will glue shut if not stored submersed in diesel. This can be a very expensive mistake, with little recourse, but to have the injector rebuilt. But the point is, when the injector's second stage fails, the engine will start easily, idle well, but run very poorly... little better than high idle.

This is what we theorized is happening. The pilot pop (NOP1) in the PD injectors is mechanically provided, just like a VE injector. The main injection for PD nozzles is electronically controlled by the solenoid. So, the injector, if damaged in this manner, will start the engine instantly and idles very smoothly. By that effect, we can determine NOP1 is sufficient to run a PD motor at idle, plus a little bit more. But when the engine gets above around 1500 rpm, the second stage must provide a volume of fuel or the engine will not perform above about 25-30mph.

For two-stage VE injectors (AHU-ALH), the same theory applies. NOP1 is what makes your car start and idle. There are two separate shims for each stage of the injector. The setting of NOP1 is relatively easy to achieve and can get the engine to start and idle smoothly. Years ago, we proved the effectiveness of using the VCDS and idle balance in block 13 to perform a test, comparing one injector's values against another. As long as the pop pressures were in the realm of OEM stock pressure settings (220 bar), this test would show differences in idle fuel volume between injectors. It turns out, we find VCDS can also be manipulated to read NOP2.

About 2 years ago, we received a set of injectors where the fuel economy (FE) dropped dramatically on a set of 764 nozzles. The idle balance numbers at 903-907 rpm looked good. But when the engine speed was increased, the idle balance numbers ran out of range, with one injector showing -1.6 and the rest of them slightly positive reads. The injector reading the negative amount is over-fueling and the idle balance program is attempting to decrease the fuel to that injector. The pop pressure MUST be adjusted to provide the correct fuel flow amount. It is not pop pressure, but FLOW VOLUME that is most important. We see some companies that provide information for NOP1 and NOP2 values, but 1) the test is done into atmospheric pressure; not cylinder pressure and 2) the company specifically states FLOW VOLUME is NOT warranted. That has become a very serious issue with some of our customers. With NOP2 poorly set, we have seen pistons melted or cracked from NOP2 overfueling.

So, what we found using VCDS for block 13 (Idle balance compensation) and block 15 (liter per hour fuel usage..), the idle balance can be raised somewhere between 1500-1600 rpm and the idle balance program in VCDS will still operate and display balance numbers. Above that rpm, the injectors better be set for the correct flow, or at very least, the engine is wasting fuel; at performance levels, melting a piston. The method allows a peek at the NOP2 numbers. If the high idle numbers change dramatically compared to 903-907 rpm idle speed, the NOP2 imbalance is the cause.

Our method is to install newly shimmed injectors in our operating engine with cylinder compression 500 psi across the board, with our ported cylinder head, our Stage II cam, VNT-17 Garret turbo and RC 4. We think pushing the injectors a bit more will exaggerate any variation between injectors.

Using the high idle setting, we re-shim the nozzles second stage for fuel volume, based on reported high- idle balance numbers in Block 13. This may take some iterations, as changing one nozzle’s flow will affect the relative value of all four.

By doing this process, we have seen FE numbers climb, smoother injector fuel delivery and performance improve, sometimes dramatically. The end result is nozzle balanced in actual operation, rather than emulations.
 

STDOUBT

Veteran Member
Joined
Jul 30, 2007
Location
Portland, effing Oregon
TDI
ALHx2
Frank, another enlightening post. Has me wondering about who should
be rebuilding my injectors...do you happen to offer a hot-swap
injector exchange service?:D
 

Franko6

Vendor , w/Business number
Joined
May 7, 2005
Location
Sw Missouri
TDI
Jetta, 99, Silver`
Sorry STDOUBT,

We got burned with several #3 injectors many years ago, when we would do the 'instant gratification' swap and we would get back injectors with hacked up wires, bio dieseled to death or a number of other things. We didn't always catch them on the way in that they were bad and that ate up our profit margin. Since that happened, we work with the customer's existing injector bodies. What you sent, you get back. If that doesn't work, we can't do em.

Also, we are a one-man shop and keep very busy. We do everything by appointment and are, at this time, at least 1 month out. Best thing to do is call and beg for an appointment.
 

PakProtector

Veteran Member
Joined
Jan 5, 2014
Location
AnnArbor, MI
TDI
Mk.4 and the Cummins-es
Take 5 gallons out near the top of the fill...and the gage will move some amount, call it delta 1. Take 5 gallons out when the tank is lower and the gage will move some amount, this we will call delta 2. The delta 2 will be larger than the delta 1.

And...now that I have read Frank's post I am more than a wee bit paranoid about those BHW injectors...LOL Likely going to take off the seal rings, remove some crud and drop then in a tank of fuel loaded with injector cleaner until I am ready to use them.
cheers,
Douglas
 
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