No more problems with 550 cc injectors and higher boost !!

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Eric Yellow

Guest
I'm having kind of a strange problem.
I've fitted a set of 550cc injectors and upped the boost a "bit"
So I'm runing at 1.6 bar at the moment on the standard turbo :? , Q45 MAF, 550cc injectors and an SAFC to control them, but when I accelerate (full throttle offcourse!) and pull through to about 6500rpm+ and shift to next gear and floor is again, it starts to splutter a bit and then goes on like nothing happened...
It's overfuelling at that time, could it be that there is getting to much fuel in just before the turbo is on full boost again?
Tried setting the SAFC lower at higher rpm's but then it's not getting enough fuel and it's holding back a bit when flooring it...don't want that to happen..
Tried altering timing, advance and retard, didn't have a good effect.
Fuel filter is new, plugs (iridium) new, full Goose, Walbro pump new, etc...
Injectors are 2nd hand and will be cleaned today.
Anybody got other suggestions where to look at?
 
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N1SMO

Guest
have u got the correct iridium heat range for 1.6 bar as i run 1.6 on 550cc and the standard heat range was no good once the engine came up to running temp.

ps 1.6 on the standard turbo is quite high is it possible that the dump valve cant cope and you are getting turbo stall.
 
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Eric Yellow

Guest
Injectors were cleaned today, had no effect...
Turbo stall may effect things a bit, but in my case it really looks like it is overfuelling when I floor it again in the next gear...
Found out that if I shift at Let's say 7000 rpm and shift like a granny (very slow) and then floor it again there is no problem...
Maybe the dumpvalve hasn't got enough time to close??
Will try heavier spring..
The search continues.....
 
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N1SMO

Guest
tell me about it i am trying to find out why i am about 60bhp down on what i should be :(
 
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Eric Yellow

Guest
Heavier spring in dumpvalve didn't work.....
Checked pugs if I could see something but they are about 99% the same colour etc...
Think I'm going to fit the original injectors back and try to get some other 550's....
With the 4 I had cleaned was 1 that had about 10% more flow then the others...
Maybe it's leaking under high boost or something...
And again the search continues...
 
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Eric Yellow

Guest
Found the problem today !!!!!!!!!!!! :mrgreen:
It was a problem with the fuel return line.
Have replaced it today and all is fine, tried running 1.7 bar and that even worx fine now :twisted:
The inner material of the fuel return line has come loose at the fuel pressure regulator and I guess it would block the fuel returning to the tank at higher boost.
So much trouble over 1 CheapAss fuel line...;)
 
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