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"Octane Count" can lower max boost? #174411 June 01, 2004 12:19 pm UTC June 01, 2004 12:19 pm UTC
Joined: Feb 2004 Posts: 317 Toronto S Sean Foots OP Member
Sean Foots OP Member S Joined: Feb 2004 Posts: 317 Toronto	I have a problem that occurs once in awhile. Some times my max boost is around 9psi. It gets up there fast and holds there. Normally I can get a max of 13-14psi. It will rise there and lower ever so slightly. Most of the time I can get 13-14psi of boost but sometimes (2 times so far) I will get a max of 9psi and then for no apparent reason it will go back to letting me get a max of 13-14psi. Sometimes the problem will come and go away within a few hours and sometimes it will last a few days. Anyone know what this could be? Could it be the "Octane Count" going off and letting the ECU cut the max boost? Does it put the boost solenoid in a "safe" mode? If so how can I test/correct it? Any help would be greatly appreciated. Thanks Sean

Re: "Octane Count" can lower max boost? #174412 June 01, 2004 04:43 pm UTC June 01, 2004 04:43 pm UTC
Joined: Apr 2002 Posts: 15,322 Loc: Loc: Rob Strelecki morum foderator
Rob Strelecki morum foderator Senior Member, with Far TOO Much Time on Their Hands Joined: Apr 2002 Posts: 15,322 Loc: Loc:	When the ECU detects excessive knock, it can trigger the BCS (boost control solenoid) to limit your boost for a certain amount of time. Pulling the MPI fuse under the hood temporarily will reset the computer and put your boost back to normal. The knock could be real knock (due to bad gas) or it could be phantom knock due to a noisy valvetrain or exhaust leak. 1993 Eagle Talon TSi FWD 13.8 @ 106 :::: 14.1 @ 117

Re: "Octane Count" can lower max boost? #174413 June 01, 2004 04:47 pm UTC June 01, 2004 04:47 pm UTC
Joined: Feb 2004 Posts: 317 Toronto S Sean Foots OP Member
Sean Foots OP Member S Joined: Feb 2004 Posts: 317 Toronto	I know I have some knock, I believe it is phatom knock. I get up to 43 counts about 1/2 the time under 2500 rpms. Sometimes I get around 15 counts at higher rpms. I guess that knock is triggering the ECU to cut boost. I will have to get the knock taken care of. Sean

Re: "Octane Count" can lower max boost? #174414 June 01, 2004 04:53 pm UTC June 01, 2004 04:53 pm UTC
Joined: Jun 2002 Posts: 5,009 Kitchener N Noah Wiles Senior Member, with Far TOO Much Time on Their Hands
Noah Wiles Senior Member, with Far TOO Much Time on Their Hands N Joined: Jun 2002 Posts: 5,009 Kitchener	Quote Originally posted by Rob Strelecki: When the ECU detects excessive knock, it can trigger the BCS (boost control solenoid) to limit your boost for a certain amount of time. Pulling the MPI fuse under the hood temporarily will reset the computer and put your boost back to normal. The knock could be real knock (due to bad gas) or it could be phantom knock due to a noisy valvetrain or exhaust leak. Or just remove the BCS from the equation all together.... 1997 Eagle Talon TSi - JDM 6 bolt = SOLD! 2008 Mistubishi Lancer GTS 2008 Chevy Equinox

Re: "Octane Count" can lower max boost? #174415 June 01, 2004 05:31 pm UTC June 01, 2004 05:31 pm UTC
Joined: Feb 2004 Posts: 317 Toronto S Sean Foots OP Member
Sean Foots OP Member S Joined: Feb 2004 Posts: 317 Toronto	How do you remove the BCS? Do you mean replace it with a manual boost controller? How do you run it without the ECU complaining about not having a BCS? Sean

Re: "Octane Count" can lower max boost? #174416 June 01, 2004 05:35 pm UTC June 01, 2004 05:35 pm UTC
Joined: Jun 2002 Posts: 5,009 Kitchener N Noah Wiles Senior Member, with Far TOO Much Time on Their Hands
Noah Wiles Senior Member, with Far TOO Much Time on Their Hands N Joined: Jun 2002 Posts: 5,009 Kitchener	http://www.freewebs.com/seanspage/BCS.html 1997 Eagle Talon TSi - JDM 6 bolt = SOLD! 2008 Mistubishi Lancer GTS 2008 Chevy Equinox

Re: "Octane Count" can lower max boost? #174417 June 01, 2004 05:38 pm UTC June 01, 2004 05:38 pm UTC
Joined: Apr 2002 Posts: 15,322 Loc: Loc: Rob Strelecki morum foderator
Rob Strelecki morum foderator Senior Member, with Far TOO Much Time on Their Hands Joined: Apr 2002 Posts: 15,322 Loc: Loc:	Quote Originally posted by Sean Foots: How do you remove the BCS? Do you mean replace it with a manual boost controller? How do you run it without the ECU complaining about not having a BCS? Sean I believe you can just remove the vacuum lines and leave the connector plugged in. Connect the vacuum line from the compressor housing (or j-pipe) directly on to the wastegate actuator. Remember to plug the line that goes to the intake tube (before the turbo). 1993 Eagle Talon TSi FWD 13.8 @ 106 :::: 14.1 @ 117

Re: "Octane Count" can lower max boost? #174418 June 01, 2004 07:35 pm UTC June 01, 2004 07:35 pm UTC
Joined: Mar 1999 Posts: 1,704 Calgary, AB, Canada S Sean Costall Serious Member
Sean Costall Serious Member S Joined: Mar 1999 Posts: 1,704 Calgary, AB, Canada	1G cars don't care if the BCS is plugged in or not. No need to leave it in at all. S. I know everything. 1000q.dsm.org

Re: "Octane Count" can lower max boost? #174419 June 02, 2004 12:14 pm UTC June 02, 2004 12:14 pm UTC
Joined: Feb 2004 Posts: 317 Toronto S Sean Foots OP Member
Sean Foots OP Member S Joined: Feb 2004 Posts: 317 Toronto	I reset the ECU and now am getting full boost again. Now I know that I set off the octane count. By removing the boost solenoid what boost levels would I get on a stock car? I have already removed the little restrictor piece from it. Do I need a boost control solenoid? I plan on getting one soon anyways but just curious what would happen. Thanks Sean

Re: "Octane Count" can lower max boost? #174420 June 02, 2004 12:34 pm UTC June 02, 2004 12:34 pm UTC
Joined: Jun 2002 Posts: 5,009 Kitchener N Noah Wiles Senior Member, with Far TOO Much Time on Their Hands
Noah Wiles Senior Member, with Far TOO Much Time on Their Hands N Joined: Jun 2002 Posts: 5,009 Kitchener	I think you mean a manual boost controller? 1997 Eagle Talon TSi - JDM 6 bolt = SOLD! 2008 Mistubishi Lancer GTS 2008 Chevy Equinox

Re: "Octane Count" can lower max boost? #174421 June 02, 2004 02:32 pm UTC June 02, 2004 02:32 pm UTC
Joined: Feb 2004 Posts: 317 Toronto S Sean Foots OP Member
Sean Foots OP Member S Joined: Feb 2004 Posts: 317 Toronto	Yeah I did mean manual boost controller, sorry my bad. Sean

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