questions about my ecodiesel - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• questions about my ecodiesel by mantajohan on 02 Mar, 2008 13:20
• yesterday I bought a vw golf-92 mk2 1,6 ecodiesel with nice 44kw/60hp
  
  is there anyway i can improve milage and get more power by turning up the fuel just a tiny bit
  
  it seems to be running (very?) lean right now, seems to be no smoke at any load
  
  note: I have no catalyst in the exhaust
  
  if you recomend me to turn up the fuel please post a picture on the ip so I know where the fuel-screw is located
  
  thanks/Johan
• #1 by blkboostedtruck on 02 Mar, 2008 13:36
• the best way to go is swap out that injection pump for a tru turbo diesel pump that has the fuel inrichment (LDA) on top!
  that will make it faster!
  thanks Duane
• #2 by mantajohan on 02 Mar, 2008 13:43
• Quote from: "blkboostedtruck"

  the best way to go is swap out that injection pump for a tru turbo diesel pump that has the fuel inrichment (LDA) on top!
  that will make it faster!
  thanks Duane

  
  
  this I already know, since I dont have the money(im a student) its simple things like turning a screw that i can afford
  
  where does the fuel-enrichment screw sit on these injection pumps?
  
  can someone please post a picture?
  
  and how much can i turn it/at which direction?
• #3 by QuickTD on 02 Mar, 2008 15:10
• There is no correct answer in your poll.
  
  There is no rich or lean in diesel combustion, the engine does not injest a "mixture" in the same way as a gasoline engine. A diesel intakes a full charge of air on every intake stroke, the air is compressed (and heated by compression) during the compression stroke and a quantity of fuel dependent on the desired power is injected. This fuel combusts more or less as it is injected, at the bounderies between the fuel spray and the air where the mixture falls within the specific flammability limits of the fuel. The actual ratio of fuel to air within the cylinder is always quite lean even when the exhaust is showing lots of smoke, this is because not all of the air can be made available for combustion within the short duration of a combustion cycle. Some fuel is not sufficiently oxidized, just blackened and partially burned before being exhausted.
  
   If you add more fuel to a diesel engine, the engine will simply develop more power and you will go faster, inject less fuel and the engine power is reduced. So turning up your fuel screw will give you more power, but it will not ever give you better economy. Fuel economy is entirely dependant on the position of your foot on the accelerator, regardless of the setting of the fuel screw.
• #4 by mantajohan on 02 Mar, 2008 21:21
• well I didn´t know how else to explain the situation, when a diesel engine has a fuel pump delevering fuel like 1/2 throttle compared to another identical diesel engine doing full throttle  isn´t that diesel engine running "lean" then?
• #5 by jimfoo on 02 Mar, 2008 21:29
• Leaner, but both are lean.
• #6 by Vincent Waldon on 02 Mar, 2008 21:47
• IMMO you need:
  
  [c]  none of the above     :wink:
  
  
  Turning up the fuel screw doesn't make the car thirsty, nor will it improve power and mileage at the same time.
  
  Adjusting the fuel screw simply moves the throttle map up and down the overall range of the pump... in and of itself no panacea for either power or mileage.
  
  Everything else being equal:
  
  - your feet are what determine mileage for the most part... easy on the throttle and easy on the brakes ;-)
  - power is fuel AND air, at the right mix, at the right time
  
  
  Here's a good thread for some further reading:
  
  http://vwdiesel.net/phpBB/viewtopic.php?p=48634#48634
  
  Note that it starts with some things you should do, for the health of your engine, before you even begin to tweak stuff.
• #7 by QuickTD on 03 Mar, 2008 17:10
• Quote from: "mantajohan"

  well I didn´t know how else to explain the situation, when a diesel engine has a fuel pump delevering fuel like 1/2 throttle compared to another identical diesel engine doing full throttle  isn´t that diesel engine running "lean" then?

  
  
  Not really, the car with the pump that is delivering more fuel will be developing more power and will be going considerably faster though. Depending on boost pressure, the "more fueled" engine may actually be running leaner then the "less fueled" engine. Forget rich/lean, it doesn't apply. More fuel simply produces more power if everything else is equal. There is a limit, of course, you need to provide sufficient air to burn all the fuel. Insufficient air will cause black smoke.
• #8 by rabbitman on 03 Mar, 2008 18:11
• Ok, the way I understood it "lean" simply means less fuel. You go real lean, and yer idling, go rich and you got power. Just a simple way to explain it. , diesels are so simple.
  
  Now, my attempt to answer his question, feel free to correct me if I'm wrong.
  I tore apart a pump and studied it and it seems to me that turning up the fuel, (clockwise on the screw) only allows more fuel to be injected when you push the go pedal. Also, you must adjust the idle speed down since turning the fuel screw in "favors" the max throttle area. I turned my fuel up and I thought I got better mileage, but it doesn't make sense because it only allows more fuel on demand, nothing else. I definitely have more power at all throttle settings, like Vincent says, it moves the throttle map.
  So I say screw it in a bit (small increments) and feel the power :twisted: , and burn more fuel :cry: good luck
• #9 by mantajohan on 05 Mar, 2008 09:12
• is it this screw that reglates the fuel?
  
  here is a picture of a pump that looks almost as mine
  
  
• #10 by rabbitman on 05 Mar, 2008 12:19
• yes, it is that screw. Though you should note that it is your foot that does most of the regulating.
• #11 by mantajohan on 05 Mar, 2008 12:41
• sure do know that  :wink:  since I travel long distances at mostly 90km/h some 70km/h and one stop (89km one way to be exact) I drive almost the same all the time and don´t speed....
  
  unless i´m passing that yellow bus or that old man in his saab-gasser  :twisted:  
  
  so I will drive a few tanks more before I turn up the screw to see if it really affects fuel-consumption
  
  
  
  the engine braking is awsome with this engine, hardly need to use brakes at all  :wink:
  
  is it the turbo that does that BIG difference from the N/A???
• #12 by theman53 on 09 Mar, 2008 13:00
• as you have seen on this forum already I am sure only turn the screw a little at a time like the other guy said.
  you asked how much and which way. If I Remember Correctly... not more than a 1/4 turn ( I went an 1/8th to a 1/16th ) and it gives more as you turn it to the right. So 1/8th of a turn clockwise set and test
• #13 by mantajohan on 11 Aug, 2008 06:54
• after lots of testing here´s the results
  
  fuel screw turned in about 1turn 80-120km/h 9,5 sec(in 4th gear) fuel consumption between 4,9-5,2litre/100km tested for about 16000km
  
  fuel screw in it´s original position(or close to) 80-120km/h in 18,5 sec(in 4th gear) fuel consumption between 5,2-5,4litre/100km
  tested for about 15000km
  
  I have had the same tires and tried this on and of a few weeks at the time so overall the same weather and other variables would not result in inproper fuel consumption readings
• #14 by RabbitJockey on 11 Aug, 2008 16:15
• the safety collar is a real *** to get off of some of them.