Fuelling

[Benjibrady]

Hi all,

Right could someone help me out with my fuelling,

Idles nicely and drives nicely whilst off boost (albeit a bit rich 11-12's idling and driving) But when I come on boost there is a stutter before the car will boost and it becomes stupidly rich. Then if you bring the car to a stop and dont apply any revs the engine just dies, but give it a couple blips of the throttle and it'll tick over nicely again.

these are the bits and pieces from the fuel supply/return to the engine.

Supply:


return:


I do have this tee'd between pressure regulator and fuel rail. However I believe its an after market jobbie so blanked it off.




http://www.youtube.com/watch?v=Kjwy4...ature=youtu.be
^^^^^^ Thats what its like driving (I apologize for it being on its side however you can just about make out AFR's)

thanks all

[Markey Mark (BD)]

What size injectors you got in there?

[Woznaldo]

just sounds like it's rich everywhere? Like Mark says, we need to know what injectors you have (cc/min) and what fuel pressure you're running?

[Haz]

The stutter will be it going really rich just as it comes on boost and fouling the plugs.
The flying saucer thing in the second pic is a non return valve so the fuel doesn't drain back to the tank.
Sounds like the afm is adjusted too high if its on std injectors, if they are bigger there's no bypass or not big enough.
I presume with the different exhaust manifold, the turbo is bigger, t3? This will also alter when the boost comes in, as to when it's supposed to on the std ecu map.
Once you change too much from std the ecu becomes harder to trick.
I also noticed on you photobucket that you have blanked the idle control valve? This won't help matters either, that is what stops it dying once you come off the throttle.

Edit : ah, just saw the post with idle control valve.

[Benjibrady]

Standard green injectors, turbo is a t34. Not trying to make huge power atm just trying to get it road worthy.
I havent adjusted afm, still has the blue cap on it so im assuming its never been adjusted. I have the bosch equivelent of the phase 1 fuel pump.
No way of measuring fuel pressure

[Benjibrady]

Perhaps worthy of note, I am yet to have used a bypass hole. I pressumed that as i wanted to run, standard boost on standard injectors that i might not need one but as its that rich is it worth Running more boost and making a bypass hole

[Markey Mark (BD)]

Standard green injectors, turbo is a t34. Not trying to make huge power atm just trying to get it road worthy.
I havent adjusted afm, still has the blue cap on it so im assuming its never been adjusted. I have the bosch equivelent of the phase 1 fuel pump.
No way of measuring fuel pressure

I would start to adjust the MAF unit slightly but as Haz said as so much has changed it does get harder to get the standard ecu to play ball with the fueling
Even on low boost I found using the bigger injectors still needs a bypass hole, does make a fair difference

I remember you sticking a pick up of the idle control valve on here where you thought it was a dv, you haven't still got it blocked off have you?

I would run something a fuel injection pump rather than the phase 1 pump, something like a golf gti mk1 pump. Nothing too big but will cope with a efi system

[Benjibrady]

I would start to adjust the MAF unit slightly but as Haz said as so much has changed it does get harder to get the standard ecu to play ball with the fueling
Even on low boost I found using the bigger injectors still needs a bypass hole, does make a fair difference

I remember you sticking a pick up of the idle control valve on here where you thought it was a dv, you haven't still got it blocked off have you?

I would run something a fuel injection pump rather than the phase 1 pump, something like a golf gti mk1 pump. Nothing too big but will cope with a efi system

I thought adjusting the MAF unit would make it richer?

I havent gone with bigger injectors yet, but ill try a bypass whole, is there anything you can buy that people fit I.E. A section of stainless pipe that you can screw different size bungs into or is it simply a case of drilling into the silicone.

Yeah i still have it blocked. When im nect at the garage im going to refit the idle control valve, does it matter if it vents the back pressure to atmosphere as I have no where to stick it on the cold leg of the turbo.

why would i need to change my fuel pump? If its as rich as it currently is, why would it not be up to the job?

[Markey Mark (BD)]

I thought adjusting the MAF unit would make it richer?

I havent gone with bigger injectors yet, but ill try a bypass whole, is there anything you can buy that people fit I.E. A section of stainless pipe that you can screw different size bungs into or is it simply a case of drilling into the silicone.

Yeah i still have it blocked. When im nect at the garage im going to refit the idle control valve, does it matter if it vents the back pressure to atmosphere as I have no where to stick it on the cold leg of the turbo.

why would i need to change my fuel pump? If its as rich as it currently is, why would it not be up to the job?

No you can make it leaner on the MAF too

I drill a 22mm hole in an alloy pipe then slide a silicone hose over it to adjust the size to get the fueling sort of right, where you drill the hole matters too try get it as far from the MAF as poss mate (think that was right )

No you need to attach the other side of the idle control valve into a boost pipe or into the air filter hose, it doesn't vent all it does is pass an amount of air past the throttle body to allow it to idle better when the throttle is closed

It may be running rich now but its more about the flow, normally fuel injection pumps flow a lot more so the engine is fed with enough fuel

[Haz]

The std injectors are orangey brown, the Volvo 740 2.3turbo (with resistor pack) or Renault 21turbo run green injectors, best check the code on them.
T34 is gonna be laggy