Joel93 Posted June 15, 2019 Share Posted June 15, 2019 Hi iv realised that after driving my impreza for 30 mins or so after a few hard accelerations the boost drops from 14psi to around 7psi. From what I've read this is limp mode but there is no CEL on, car has a cat back exhaust a panel filter and remap. Pulls really nice until boost drops off, after turning car on and off for 5 mins bost I'd back up to normal? Any ideas? Thanks Quote Link to comment Share on other sites More sharing options...
DaveRAC Posted June 15, 2019 Share Posted June 15, 2019 do you have an aftermarket boost controller fitted to vehicle if so my be worth dropping the max boost down a tad i had the same issue when it hit peak boost it shuts fuel off for a second and then runs normal. Quote Link to comment Share on other sites More sharing options...
Joel93 Posted June 15, 2019 Author Share Posted June 15, 2019 No, no boost controller, iv just got a boost gauge. It won't return to normal until I turn the car off and back on. Quote Link to comment Share on other sites More sharing options...
DaveRAC Posted June 15, 2019 Share Posted June 15, 2019 what impreza model have you got? how long ago did you get the map and what have you changed on the car most recently? Quote Link to comment Share on other sites More sharing options...
Joel93 Posted June 15, 2019 Author Share Posted June 15, 2019 It's a 2004 wrx and I only had the car on the road a week, map was carried out about 8 years ago, there must be somthing bost related tripping it into low boost setting because its only happening after a few hard accelerations Quote Link to comment Share on other sites More sharing options...
Linx Posted June 16, 2019 Share Posted June 16, 2019 Do you have super unleaded in it? Quote Link to comment Share on other sites More sharing options...
Joel93 Posted June 16, 2019 Author Share Posted June 16, 2019 Yes I put tesco moment in it although I'm not sure the previous owner did possibly still on some of his fuel. Can that make it lower the boost? Quote Link to comment Share on other sites More sharing options...
savage bulldogs Posted June 16, 2019 Share Posted June 16, 2019 Yes ,Lower octane fuel can cause it to lean off under boost, which in turn might cause limp mode . Have you got any proof it's been mapped ? As 14 psi (just under 1 bar) is a low boost target for a mapped car ,admittedly that could just be a inaccurate boost gauge .Most mapped cars will have the boost target upped to 1.2 to 1.5 bar pending on mods and engine condition . If you dont have proof of a remap standard boost target would be between 0.6 bar and 0.8 bar , you'd have to Google your model and year specific oe boost target. So if you're hitting 0.9 bar on a standard map boost target ,it could well be overboosting and that might cause it to go into limp mode . Although you haven't got a cel light , I'd suggest to get the codes read while it's in possible limp mode . As it might log a minor fault on the ECU but not show a cel, due to it resetting when you restart the car . Quote Link to comment Share on other sites More sharing options...
DaveRAC Posted June 16, 2019 Share Posted June 16, 2019 it could be due to the map that it needs to run only on high octane fuel too Quote Link to comment Share on other sites More sharing options...
Joel93 Posted June 16, 2019 Author Share Posted June 16, 2019 I have proof of a rolling road running 270bhp it feels fast enuf, I'll keep trialing the car and see exactly what coursing the limp mode. Quote Link to comment Share on other sites More sharing options...
Joel93 Posted June 16, 2019 Author Share Posted June 16, 2019 My boost gauge is a cheap eBay one is it possible it is reading low by a couple of psi? It does seam a car of my remap should be running 16 psi ish. Quote Link to comment Share on other sites More sharing options...
DaveRAC Posted June 16, 2019 Share Posted June 16, 2019 at least does it have upgraded turbo at all ? i know the standard ones can handle up to 320bhp Quote Link to comment Share on other sites More sharing options...
Joel93 Posted June 20, 2019 Author Share Posted June 20, 2019 No it just has a td04, drove 180 miles today and still boosting fine, parked car up and when to the beach. Next drive I put my food down 1st gear boosting nice, 2nd gear boost to 14-15 psi, 3rd gear boost to 15psi then dropped back down to 7psi it then stayed like this until I turn the car off and back on. It seams to droop off as I hit 5000rpm ish. Is this over boost? After trialing out it can pull boost all day in 1st and 2nd but a hard pull in 3rd upsets it. Quote Link to comment Share on other sites More sharing options...
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