View Full Version : Running lean
Hi guy`s, a little help needed, at interpro on sunday they put my car on the rollers and stoped halfway through the run saying the car was running to lean [so gutted]:annoying_cut: ,they said it wasent putting anymore fuel through when it was on boost ?, has anyone got any ideas of what the prob could be. some advice would be great.
Cheers
Matt
scoobysteve
30-01-2006, 20:43 59
Mine nearly went the same way mate but just made it. Im going for uprated fuel pump and 440cc injectors then a rolling road tune. Might be an air leak between the turbo and the maf sensor?? Just a thought as im gonna replace the hose that goes onto the turbo as its a bit knackered.
The Daddy
30-01-2006, 22:54 53
you need to remember that you should replace the pressure regulator when doing fuel mods........if you change your pump and injectors you still wont gain much atall as the standard regulator is set to around 2.5 bar at and you should look at running 3.2 bar at to keep the flow rate at the injectors.....
as for running lean....maybee an airleak, dodgy maf or crap pump/regulator?
Neil G
31-01-2006, 10:09 36
Good job they picked this up and stopped the run though.....saved your engine
glad they stopped the run but wish they gave me more of an idea of what was rong.
Guess thats the only problem with rolling road days. They could check your car out and find the fault but that may take an hour or two. Then that would not be a rr day as if a few cars had problems no one would get on the rollers.. You could book the car in for another day and get it sorted.
The main thing is they have found a fault with the car and informed you. This itself could very well save you the price on a new engine...:wink:
scoobysteve
03-02-2006, 14:00 07
With air leaks on turbo'd engines, it would make it run rich which is the opposite to N/A cars as the inlet manifold is blowing out air with the boost instead of sucking it in.
Olly P
03-02-2006, 18:01 26
Mines still on the standard regulator and its running fine.
If the air leak is coming from the turbo pipework it will act like a bleed valve and run lean.
scoobysteve
03-02-2006, 19:49 56
Thats good to know olly. I'll get mine vacuum tested just to be on the safe side. though wouldnt that kill the boost?
Mines still on the standard regulator and its running fine.
If the air leak is coming from the turbo pipework it will act like a bleed valve and run lean.
Other way around chap.
If it's leaking after the maf, It'd think there was more metered air than there actually is (cos some is leaking out) and so would be throwing in too much fuel..
If you see what I mean:43:
Olly P
03-02-2006, 20:27 26
I know what you mean.
But think about how a bleed valve works.
It bleeds off air before the actuator to fool the turbo into making more boost.
Is this air already metered?
But I do understand that air past the maf is accounted for and any loss of that air would result in a rich mixture.
So where does the air come from that controls the wastegate?
I'm having brainmelt now:annoying_cut:
The bleed valve works on the little pipe that goes to the actuator. And doesn't leed THAT much air really..
Some Dawes devices use a ball and spring which doesn't open until a certain boost pressure then allows air past to open the acuator.
Olly P
03-02-2006, 21:02 32
Had a ball and spring on mine, I know how it works.
I was using the bleed valve as an example.
If he has a leak it may be a much larger hole.
So the air is metered then? However small the amount?
Why are the Dawes type devices prefered over bleed valves if the amount they bleed is insignificant? (just curious)
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