98 volvo s70 t5 wont boost beyond stock psi with ecu tune

benyos · Post by **benyos** » 09 Apr 2012, 06:05

I have the same problem. Doesn't want boost over 9psi, i can get 15psi with mbc. I have hd tcv,ipd cbv,bsr chip ecu,obx turbo back no cat, new spark plugs and wires, silicon vacuum lines, silicon ic hoses,no boost leak.I tried reset the ecu but no result.
Donno what to do could be wrong chip or ecu?

volvohighway · Post by **volvohighway** » 09 Apr 2012, 15:43

Yeah am installing my mbc very soon, I really hope I can get past 10 Psi, will keep you guys updated

mrbrightside2009 · Post by **mrbrightside2009** » 09 Apr 2012, 22:25

yeah but are you guys monitoring your cars with widebands when your putting the mbc's on? Just saying what if the tune is somehow not right and were running really lean by upping the boost, I actual don't have a wideband right now, waiting for some more moolah, just taking it easy getting into higher boost.

Post by **matthew1** » 10 Apr 2012, 13:10

What's everyone's manifold pressure when at idle (warm engine)?

Mine is -17psi.

I don't know that this is as useful as psi under boost, but there it is either way. A lower number like say -10psi might be indicative of a vacuum leak.

mrbrightside2009 · Post by **mrbrightside2009** » 10 Apr 2012, 15:09

matthew1 wrote:What's everyone's manifold pressure when at idle (warm engine)?

Mine is -17psi.

I don't know that this is as useful as psi under boost, but there it is either way. A lower number like say -10psi might be indicative of a vacuum leak.

you mean in/hg, mine is 20 at idle, warm engine, in p, in drive im at 18. i think 17-21 is a good number. I doubt our gauges will detect a small vacuum leak or even cause this boost problem, like i said, mine is smooth power with the stock tcv only hitting 9 psi, seems like the ecu is limiting boost for some reason, as soon as my mbc is in there i can boost w.e, obviously since the ecu has no control over boost anymore, and more than likely if you have a major vac leak or boost leak you would def. feel it and probably get a misfire code and probably lack of power, i've had this happen before when my one boost hose collapsed under pressure and i had one pop off.

volvohighway · Post by **volvohighway** » 11 Apr 2012, 18:47

Yeah am at 21hg, but that is not an accurate way to determine if there is a boost leak, unless its a major one. You have to preform a boost leak tester which I read is very easy and cheap to make. Which I will do the seconed I have time to play with l. If the mbc works am gonna lose my mind and try to return my Ecu, cause then I just lost 600 something dollars. Which is alot of money.

Post by **matthew1** » 11 Apr 2012, 19:49

mrbrightside2009 wrote:
matthew1 wrote:What's everyone's manifold pressure when at idle (warm engine)?

Mine is -17psi.

I don't know that this is as useful as psi under boost, but there it is either way. A lower number like say -10psi might be indicative of a vacuum leak.
you mean in/hg, mine is 20 at idle, warm engine, in p, in drive im at 18. i think 17-21 is a good number.

No, my iPD "R" gauge is labeled PSI, and at warm idle it's -17. According to this page, 20 in/hg = 9.82 psi, which as a positive number can't be correct. You should have vacuum at idle.

mrbrightside2009 · Post by **mrbrightside2009** » 11 Apr 2012, 23:51

matthew1 wrote:
mrbrightside2009 wrote:
matthew1 wrote:What's everyone's manifold pressure when at idle (warm engine)?

Mine is -17psi.

I don't know that this is as useful as psi under boost, but there it is either way. A lower number like say -10psi might be indicative of a vacuum leak.
you mean in/hg, mine is 20 at idle, warm engine, in p, in drive im at 18. i think 17-21 is a good number.
No, my iPD "R" gauge is labeled PSI, and at warm idle it's -17. According to this page, 20 in/hg = 9.82 psi, which as a positive number can't be correct. You should have vacuum at idle.

yea i know that lol, the bottom numbers are always vacuum, your gauge just doesn't say inhg like some gauges do, mine is reading right. i'm pretty sure its actually read just 17 not negative, but yes mine is reading vacuum.

mrbrightside2009 · Post by **mrbrightside2009** » 12 Apr 2012, 00:01

volvohighway wrote:Yeah am at 21hg, but that is not an accurate way to determine if there is a boost leak, unless its a major one. You have to preform a boost leak tester which I read is very easy and cheap to make. Which I will do the seconed I have time to play with l. If the mbc works am gonna lose my mind and try to return my Ecu, cause then I just lost 600 something dollars. Which is alot of money.

are you getting your front o2 replaced? I am replacing mine next week and praying that fixes my boost issue, as I think it may be limiting boost. I would get yours fixed since that might throw your air/fuel ratio off.

volvohighway · Post by **volvohighway** » 12 Apr 2012, 01:24

Yeah am gettting that replaced too, lets hope that was the issue. I doubt but you never know

98 volvo s70 t5 wont boost beyond stock psi with ecu tune

Re: 98 volvo s70 t5 wont boost beyond stock psi with ecu tun