Do_you_even_boost?? Posted December 20, 2015 Share Posted December 20, 2015 ive been round the houses with this one! would anyone be kind enough to offer some advice / opinions / general knowledge? 1995 jdm wrx saloon with standard internals fmic and td05 im experiencing fuel cut and boost issues - turbo spools up kicks then boost goes crazy sometimes up to 1.8bar!! then fuel cut Things I have checked so far: bcs (3 port) cleaned with carb cleaner maf cleaned actuator arm adjusted to 3mm of preload direct vac line on turbo (boosts to 0.5 bar and holds) check fittings on intercooler and vac lines read fault codes under the dash ( did return maf sensor code 23 but put a power probe on it and it raised with revs also dies when unplugged) I semi mechanically minded but begrudge going to a fitter for diagnosis that's even if you can find someone who would want to touch an impreza!! im really losing my patience a jap specialists did tell me that the intercooler is very poorly fitted prob a cheap £150 eBay job Next job is a smoke test may help to add that today it developed a schreech at mid boost which reading up may be the up pipe shagged? is only done it since I re fitted the air intake silicone pipe on the turbo. Quote Link to comment Share on other sites More sharing options...
savage bulldogs Posted December 20, 2015 Share Posted December 20, 2015 Is the screech a bit like when you blow through a blade of grass like a harmonica ? As it does sound like a boost leak probably from the intake pipe or fmic pipework. I assume you have a boost gauge ,where is the vac line it's getting a reading from plumbed into ? Ideally these need to be fitted directly from the inlet manifold . Or tee'd into a pipe directly from the inlet in order to get a correct reading. The pre v3 (97) map sensor will only work up to 1.2 bar and cause fuel cut after that ,even when mapped and the boost map threshold is increased (so most mappers will suggest that you upgrade the early map sensors) Has it been mapped and if so who and what method ? As classic ecu's do self learn to a certain degree but if you've got a decat turbo back ,fmic and intake mods ,it would probably breathing out of the standard ecus map parameters Quote Link to comment Share on other sites More sharing options...
Do_you_even_boost?? Posted December 20, 2015 Author Share Posted December 20, 2015 it does sound somewhat like blowing through grass yeah but not throught the whole rev range but that has only developed today? I still had fuel cut and hesitation / mostly through 3/4/5th before it. yes it has turbo back de cat and z4 ecu which I think is standard ecu? I haven't took it apart to see if there is a daughter board inside. My boost gauge is apexi and directly on the top nipple of the intake fed through the bulkhead. I have no idea if its been mapped I bought it with this issue but really am getting to end of my teather mate. would a smoke test be the best option for finding a leak or should I drive it in test mode and see what gets stored? Quote Link to comment Share on other sites More sharing options...
savage bulldogs Posted December 20, 2015 Share Posted December 20, 2015 A smoke test should show up any boost leaks but I'd check the intake pipe you fitted as you said it started screeching after you fitted it . You'd get more pressure in the vac line system when the engines under greater load in the higher gears .Which in turn would change the boost limits achieved. If it holds 0.5 bar when running "actuated" boost without fuel cut kicking in . I'd guess that it's due to the lack of back pressure (decat) and increased air flow (fmic /air intake). Are causing the boost to peak above the maps standard duty cycles which activates fuel cut . I wouldn't keep driving it on boost if it's cutting ,as it's probably trying to keep the boost in control or maxing out your injectors (If they're grey 380's ) so it doesn't eat itself by running lean . Is there a 4wd dyno near you as a dyno run (£60 ish) would probably be the best option for identifying leaks and over boost . If you can't afford the £550 to get it mapped you could try to get the intake /tmic back to standard and see if the problem persists Quote Link to comment Share on other sites More sharing options...
savage bulldogs Posted December 20, 2015 Share Posted December 20, 2015 missed a bit [emoji5] the z4 ecu is for a early wrx with a tdo5 16g turbo with 260 hp @0.9bar . yeah you'd have to open the ecu case to check for a esl board to check if it's been mapped[emoji6] Quote Link to comment Share on other sites More sharing options...
Do_you_even_boost?? Posted December 20, 2015 Author Share Posted December 20, 2015 Top man! Will have a poke around tomorrow and update mine is a '95 making it a v2 no? Quote Link to comment Share on other sites More sharing options...
savage bulldogs Posted December 20, 2015 Share Posted December 20, 2015 Yeah v2 with a phase 1 fuel / inlet set up . I had a boost leak on my temporary reverse inlet set up spotted on the dyno quite easily [emoji6] Quote Link to comment Share on other sites More sharing options...
Do_you_even_boost?? Posted December 21, 2015 Author Share Posted December 21, 2015 Took it to turner performance this morning They have a 4wd rolling road and had good reviews just going to surrender to it and pay them to sort it out had nothing but stress with the 'money pit' Appreciate the time took mate Quote Link to comment Share on other sites More sharing options...
savage bulldogs Posted December 24, 2015 Share Posted December 24, 2015 No problem bud, keep us updated and hope it's boosting better soon Quote Link to comment Share on other sites More sharing options...
Do_you_even_boost?? Posted January 6, 2016 Author Share Posted January 6, 2016 well the good news I found out the issue with over boost fuel cut! running suberp! bad new was it decided it didn't like being enclosed in the bay and wanted to come out, diagnosed as piston ring failure plooms of smoke and no boost! Have now took it off the road and will start from scratch! engine suspension gearbox diff will be rebuilt, I like this car more than my misses. I believe it is worth it on a near mint v2. ive started a new thread ' pop goes the scooby' and will document everything I do as I enjoy reading build threads. time of completion I would want this side of xmas. Enjoy! Quote Link to comment Share on other sites More sharing options...
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