irf Posted December 7, 2007 Report Share Posted December 7, 2007 i've got a problem thats seriously doing my head in if i go all out in third, then fourth and then fifth then i'll get a little fluctuation of boost from 15-17psi in fourth and fifth gear. if i start from low revs in fourth or fifth, boost builds nicely and then at 95(in fifth) i get a sudden loss of boost going from about 16psi down to 8ish psi and then it builds up again.i've done all the stage 0 afaik except the O2 sensor, i've tightened the wastegate up a bit, changed spark plugs, all the vacuum pipes, pcv, leads, distributor cap, cleaned the icv, afm and throttle butterfly amongst other stuff i cant remember. i've taken the dump valve off in case that was leaking, a forge blanking plates been fitted.i've done hundreds of searches under "wastegate", "spark plugs"(and gapping of spark plugs), "boost leak" and nothing has helped. i know its not the ecu as the upsolute i have now was fine in a previous car and the RICA i had(auto ecu, car is manual) done the same thing.i'm at a complete loss now, please help in case it helps, spec isupsolute ecuBMC CDA2.5" cat backdiy RIP. Link to comment Share on other sites More sharing options...
JHEIII874T5M Posted December 7, 2007 Report Share Posted December 7, 2007 Have you tried bypassing the BCS and running a MBC? Link to comment Share on other sites More sharing options...
George @ ViVA Posted December 7, 2007 Report Share Posted December 7, 2007 i've got a problem thats seriously doing my head in if i go all out in third, then fourth and then fifth then i'll get a little fluctuation of boost from 15-17psi in fourth and fifth gear. if i start from low revs in fourth or fifth, boost builds nicely and then at 95(in fifth) i get a sudden loss of boost going from about 16psi down to 8ish psi and then it builds up again.i've done all the stage 0 afaik except the O2 sensor, i've tightened the wastegate up a bit, changed spark plugs, all the vacuum pipes, pcv, leads, distributor cap, cleaned the icv, afm and throttle butterfly amongst other stuff i cant remember. i've taken the dump valve off in case that was leaking, a forge blanking plates been fitted.i've done hundreds of searches under "wastegate", "spark plugs"(and gapping of spark plugs), "boost leak" and nothing has helped. i know its not the ecu as the upsolute i have now was fine in a previous car and the RICA i had(auto ecu, car is manual) done the same thing.i'm at a complete loss now, please help in case it helps, spec isupsolute ecuBMC CDA2.5" cat backdiy RIP.Sounds like a tired CBV and/or wastegate. Do you have the original downpipe? Link to comment Share on other sites More sharing options...
Karlson Posted December 7, 2007 Report Share Posted December 7, 2007 I had the same problem, mbc fixed that problem. Mine was going to 12 psi, dropping to 8, and then all the way to 20 Link to comment Share on other sites More sharing options...
Ihatespeedbumps Posted December 7, 2007 Report Share Posted December 7, 2007 You added a blanking plate, but did you add any sort of BOV? Link to comment Share on other sites More sharing options...
drin850 Posted December 7, 2007 Report Share Posted December 7, 2007 i have the same problem, hits 12 then drops to 7 then back to 9 then 7 then 9 etc Link to comment Share on other sites More sharing options...
95 854 t-5 Posted December 7, 2007 Report Share Posted December 7, 2007 Sounds kind of like what used to happened to my buddys cobra he was pegging his mass air and he would get a sort of a cut and resurge check yours out... not sure if cleaning these things actually works you may have to replace it Link to comment Share on other sites More sharing options...
irf Posted December 7, 2007 Author Report Share Posted December 7, 2007 have an ebc thats in the car, just need two pipes connecting. will try that. i do have a bov. it's an HKS SSQV that i genuinely don't know wether it's original HKS or not. so i took it off and blanked off the hole but still the same problem. so i got an ARC bov yes, it is the original downpipe. thanks for the help so far guys. tbh i'm loathe to give it to anyone to fix. want to do it myself. will try the ebc today and let you know. Link to comment Share on other sites More sharing options...
DARKSIDE Posted December 7, 2007 Report Share Posted December 7, 2007 You added a blanking plate, but did you add any sort of BOV?+1 exactly what I was thinkin...ARC bov...?!? What kind of bov is that...don't think I ever heard of it... Link to comment Share on other sites More sharing options...
Oreo931 Posted December 7, 2007 Report Share Posted December 7, 2007 ARC bov...?!? What kind of bov is that...don't think I ever heard of it... :lol: riiiighttt...www.google.com Link to comment Share on other sites More sharing options...
Lab_Rodent Posted December 7, 2007 Report Share Posted December 7, 2007 It is because 5th gear is considered "over-drive" and the ECU is prolly' not programmed to put out full power in this gear. My S80 will kinda stall @ 4k RPMs when trying to accelerate hard if I havent been driving the car for a few minutes (like it has an engine warm up mode). Volvo did some funky tuning tricks so it would put down decent power numbers to brag about, yet make if fuel efficient for those who dont know to keep the RPMs low to save gas. Link to comment Share on other sites More sharing options...
irf Posted December 7, 2007 Author Report Share Posted December 7, 2007 i doubt it as it happens in fourth as well.just waiting for the mrs to go to sleep and then go for a quick drive. connected the ebc earlier so will see how it goes :) Link to comment Share on other sites More sharing options...
irf Posted December 7, 2007 Author Report Share Posted December 7, 2007 just been for a drive. car is sorted tried fifth low down and wasn't getting any issues, a slight hiccup maybe but nothing disastrous.i tried the ebc before but that was before i tightened the wastegate a touch. thanks everyone now need to get a bcs from somewhere. just hurts to spend £70 plus from a volvo dealer though whats that, about $150 for a crappy piece of plastic!! Link to comment Share on other sites More sharing options...
ToxicLemonade Posted December 8, 2007 Report Share Posted December 8, 2007 just been for a drive. car is sorted tried fifth low down and wasn't getting any issues, a slight hiccup maybe but nothing disastrous.i tried the ebc before but that was before i tightened the wastegate a touch. thanks everyone now need to get a bcs from somewhere. just hurts to spend £70 plus from a volvo dealer though whats that, about $150 for a crappy piece of plastic!!I have an extra BCS laying around that works. PM me. i dont want anything near 150 for it. -Ryan Link to comment Share on other sites More sharing options...
irf Posted December 8, 2007 Author Report Share Posted December 8, 2007 thanks for the offer, i originally got a secondhand one for £20. ended up spending money where i didnt need to so i'm just gonna get a new one now. Link to comment Share on other sites More sharing options...
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