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Rb20det Losing Power Under Boost

soopa

By soopa,
in Engines & Forced Induction

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soopa Explorer

soopa

Posted
Posted

hey there... hope someone can shed light on this problem...

had a bit of a race the other night and after i backed off the car just all of a sudden lost power and spluttered under boost... it had done this on a couple of occasions before this but all i did was turn the car off and back on and the problem went away...

it also is hard to start (mainly when cold) eg. it just kicks over and wont start then pops back through the inlet then eventually runs ok-ish

it runs ok until it gets to 3-5 psi then splutters and misses and is under power...

my turbo is shagged so its blowing oil into the inlet and the factory bov was putting oil spray on the AFM so i tried cleaning it with degreaser then metholated spirits, after this it didnt seem to change anything

i then thought coil packs leading to waek spark so i checked over them found 2 that looked like they might need replacing, plugs are less than 6 months old but pulled them out to see if they had carboned up... and they look slightly black but still in good condition

its kind of like its leaning out under boost maybe but no pinging, no raised engine temp, and plugs dont look burnt,

no oil in water, no water in oil, not losing water so doubt its head gasket

i just cant work out what it might be... asked a couple of mates and they have no idea either...

could it be the AFM on the way out and messing up the fuel mix

any ideas or info would be much appreciated :)

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https://www.sau.com.au/forums/topic/186009-rb20det-losing-power-under-boost/
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soopa Explorer

soopa

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Posted

havent checked that yet... can that just happen and it be fine to drive under boost?

spoke to a mate with a rb like mine in his silvia and he said i'm having fuel pressure issues and it might be pump or filter as what i discribed was what his did so i'm gonna have a look at my filter and pumps now and see if anything comes up

abu Grand Master

abu

Posted
Posted

Check the fuel filter.

Plugs may look fine but maybe the gaps are out.

Maybe bad batch of fuel?

Also have a look/check your intercooler piping incase something has popped off.

Don't think it would splatter if it was running lean. By the sounds of it it seems as if its over fueling.

Hope that helps some how.

soopa Explorer

soopa

Posted
  • Author
Posted

not the fuel... same tank as when it was running well...

how could the gaps change from when i gapped them when i put them in?

checked the filter just then... now i just have a strait bit of pipe where it was

just checked the pumps... tried reversing them to blow out anything stuck in them... managed to kill my low pressure but thats no biggie as i have 2 spares....

if its a fuel thing i'd have to say the high pressure pump isn't pumping good pressure making it hard to start and bad when on boost... but its a bit of money to spend on just a hunch

not meaning to shoot anyones ideas down... i'm just trying them as i go and writing them out

thanks for the help everyone

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