Boost Problems: Very Strange - The Saab Link Forums

Go Back   The Saab Link Forums > Saab 9-5 '98-'09 Forum > Car Problems? 9-5 Only

Car Problems? 9-5 Only If you're experiencing problems with your 9-5, post your question in here. CEL Code or GTFO!

SaabLink.net is the premier Saab Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools
Old 12-06-2007, 03:25 PM   #1
SAAB Road Master
 
Cambiocorsa's Avatar
 
Join Date: May 2006
Location: New Mexico
Posts: 381
Send a message via AIM to Cambiocorsa Send a message via MSN to Cambiocorsa
Boost Problems: Very Strange

Alright I am really stumped. My problem doesn't seem to follow any logic that I know. I have Jak's Stage 3 tune on my 1999 9-5 SE, with the 2.3L engine, GT-17 turbo. When I talked to him, he said boost should be at "about 18psi". And boost should be pretty high considering I'm at 5,500ft elevation.

Well I finally got my boost gauge hooked up, and saw some minor issues. First of all, vacuum at idle is 15 in.hg. (should be around 20). Most likely that is just the old vacuum lines (I'll finish replacing them within the week hopefully). Driving around I got 8psi in first gear, 12-14psi in second, and a solid 14psi in third. Pretty decent, but I should be boosting more in third I believe.

Then, I come to my big confusing problem. The boost numbers I noted above only last for about 10 minutes after starting the car. Once I have driven around for about 10 minutes I get 8psi in EVERY gear, no matter what. It's like once the car gets nice and hot, boost gets cut. Also, boost NEVER spikes in my car, not when on the higher boost, and not when its stuck at 8psi. Isn't that slightly unusual? I don't get it. When first starting the car I never get more than 14psi ever, and after driving it around it is will not go past 8psi no matter what. What the heck can cause this behavior?

Theories:
1. Green spring in Forge 007 valve doesn't hold boost when warm? Not strong enough?
2. BPC taking a shit?
3. MAF (not sure how or why)
4. Bad tune?
5. Wastegate being shitty?

It would seem to be a computer related problem rather than a mechanical one, because I simply can't see a mechanical failure causing such exact and consistent of a problem...

Help?
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

1999 Saab 9-5 SE Sedan
JakStoll Stage 3+

Last edited by Cambiocorsa; 12-06-2007 at 03:28 PM.
Cambiocorsa is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 12-06-2007, 05:17 PM   #2
Elder
 
StX221's Avatar
 
Join Date: May 2005
Location: Greater Portland, ME
Posts: 4,295
Send a message via AIM to StX221
Does it feel any different in the seat of the pants when the boost changes?
Also, where did you tap for the gauge?
__________________
Time for a comeback tour?


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


'02 9-5 Aero
'05 Yamaha R6
StX221 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 12-06-2007, 05:23 PM   #3
Elder
 
soccerrplyr's Avatar
 
Join Date: Sep 2004
Location: Barre Town, Vt
Posts: 4,360
Send a message via AIM to soccerrplyr
i don't think you should vacuum of 20 in idle but deceleration. More like 14-16 on idle, Do you have your stock ecu. Run it with that and see what your boost levels are then. maybe your in base boost mode
__________________
1999 9 Stage 18t
2000 9 Stage 19t
2005 CRV


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
soccerrplyr is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
 
Old 12-06-2007, 05:26 PM   #4
Elder
 
StX221's Avatar
 
Join Date: May 2005
Location: Greater Portland, ME
Posts: 4,295
Send a message via AIM to StX221
T7 should be approx 19 InHg with the a/c on and approx 20-21 with the a/c off. I normally see 24-25 when coasting in gear.
__________________
Time for a comeback tour?


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


'02 9-5 Aero
'05 Yamaha R6
StX221 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 12-06-2007, 05:49 PM   #5
Elder
 
soccerrplyr's Avatar
 
Join Date: Sep 2004
Location: Barre Town, Vt
Posts: 4,360
Send a message via AIM to soccerrplyr
damnnn I didn't realize they were that far off from t5's/ ng900/9-3's
__________________
1999 9 Stage 18t
2000 9 Stage 19t
2005 CRV


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
soccerrplyr is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 12-06-2007, 06:32 PM   #6
SAAB Road Master
 
Cambiocorsa's Avatar
 
Join Date: May 2006
Location: New Mexico
Posts: 381
Send a message via AIM to Cambiocorsa Send a message via MSN to Cambiocorsa
Yeah I only get 20 in.hg. on decel (no a/c). I get about 15-16 in.hg. idling with no a/c. I'm trying to replace all my vacuum hoses right now, as they are old and worn (but in surprisingly good condition). I haven't found anything that looks problematic. And the gauge is reading correctly (or somewhat at least), I tapped it in the same exact place as in dip's tutorial (off that line from the throttle body). There is a huge seat of the pants difference. When I'm getting 14psi the car MOVES. When I'm stuck at 8psi it's like there is no torque, the car doesn't really accelerate with any kind of authority.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

1999 Saab 9-5 SE Sedan
JakStoll Stage 3+
Cambiocorsa is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 12-08-2007, 02:17 AM   #7
TSLMember
 
Join Date: Dec 2007
Posts: 99
Just double checking, your Forge 007 is recirculating, not open, right?

Best regards,

KK
KKAero is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 12-08-2007, 06:54 AM   #8
SAAB Road Master
 
Cambiocorsa's Avatar
 
Join Date: May 2006
Location: New Mexico
Posts: 381
Send a message via AIM to Cambiocorsa Send a message via MSN to Cambiocorsa
Yeah it's recirculating. Stock position and everything. I just rebuilt it and it has fresh Mobil 1 Synthetic Grease in it. Finished replacing vacuum lines with high quality silicone ones too. Everything is in place.

What seems to be happening is that once the car gets nice and warmed up, I get base boost and nothing more. This makes me think it may be some fault with the wastegate or BPC valve.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

1999 Saab 9-5 SE Sedan
JakStoll Stage 3+
Cambiocorsa is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 12-08-2007, 11:17 AM   #9
Elder
 
jssaab's Avatar
 
Join Date: Aug 2006
Posts: 2,930
HHMMM...

The dreaded LPT tune issue problem.I had the same thing happen. I think Stx experienced something similar. His was the BPC I think so check that first..

I changed out plenty of hardware and now I have only seen it once or twice while quickly shifting but not for like three months. I shoudl try to clean my BPC too.

I talked with Jak and he said it is some type of saftey profile to maybe protect against overboost??? Acording to Vigge if the ecu senses a huge diffference in boost it wll go into a saftey 8 lb profile. Don't know where it detects that info though

I think there is s difference in the LPT hardware that sets off some type of issue that the ecu sees and cuts into that safe mode...

I have only seen this reported by a couple of others who have had lpt to aero conversions. You are the first I have seen who is running the GT17.

If you turn off the car it is ok. so it seems like it is reset right?

For me it would occur if I quick shift or push the pedal halfway let off then slam it..

Last edited by jssaab; 12-08-2007 at 11:21 AM.
jssaab is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 12-08-2007, 05:55 PM   #10
Elder
 
StX221's Avatar
 
Join Date: May 2005
Location: Greater Portland, ME
Posts: 4,295
Send a message via AIM to StX221
Nope, my issue is sometimes still present...

I am trying a different MAF tonight or monday probably. I would do it tomorrow, but a 21st birthday on a sunday leads me to find a DD.
__________________
Time for a comeback tour?


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


'02 9-5 Aero
'05 Yamaha R6
StX221 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 12-08-2007, 08:33 PM   #11
SAAB Road Master
 
Cambiocorsa's Avatar
 
Join Date: May 2006
Location: New Mexico
Posts: 381
Send a message via AIM to Cambiocorsa Send a message via MSN to Cambiocorsa
The funny thing is, if I drive it super slow like a grandma and don't boost it at all, it will still kill the boost once the car is warmed up. The only way to get it to boost again is to shut the car off for at least 10 minutes and then restart it.

You guys have had a similar problem? I think I'll start looking for a new BPC. Is there a testing procedure to check if it is the BPC?
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

1999 Saab 9-5 SE Sedan
JakStoll Stage 3+
Cambiocorsa is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 12-19-2007, 01:37 PM   #12
SAAB Road Master
 
Cambiocorsa's Avatar
 
Join Date: May 2006
Location: New Mexico
Posts: 381
Send a message via AIM to Cambiocorsa Send a message via MSN to Cambiocorsa
Fixed! At least most of my problem anyways. I replaced the O-Ring on the throttle body to delivery pipe connection and wrapped the cracking sections of my intercooler hoses with 600+ degree aluminum duct tape. I now get 5psi in 1st gear, 12psi in 2nd, and in the higher gears it bounces between 13-15psi. This happens ALL the time, it never cuts back to base boost anymore. I'm still not hitting full boost, and my vacuum is still a bit off, but that will be dealt with when I put on my new turbo (should be receiving it by the end of the week).
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

1999 Saab 9-5 SE Sedan
JakStoll Stage 3+
Cambiocorsa is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the The Saab Link Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Vehicle Info.
Enter your vehicle information (year, model, mods)
Insurance
Please select your insurance company (Optional)

Log-in


Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -8. The time now is 07:35 AM.


Powered by vBulletin® Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Friendly URLs by vBSEO 3.5.2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
All content is copyright The Saab Link and it's original authors.


 

Garage Plus vBulletin Plugins by Drive Thru Online, Inc.