SaabCentral Forums banner

1 - 20 of 74 Posts

·
Registered
Joined
·
1,739 Posts
Discussion Starter #1
Ok, there is tons of info on this subject on this forum, but I didn't quite find the problem like mine. So. here it is.
I got stage 3 on my 1995CSE. So, when I floor it, the needle spikes into the middle of the red zone, and then VERY QUICKLy(too quickly for a heatsoak at 40 ambient I think) reduces to stock boost and sometimes almost to base boost. It seems that this problem is getting worse, because before at the same temp I could get the needle of the gauge and it would go back to the middle red zone. But with same dynamics. I thought that this was heat soak, but after some research on these forums it seems that it is indeed to quick. Also, yesterday I drive her hard, and got the boost down to yellow zone. Then I stopped and touched the IC and the intake manifold. IC was cool and the intake manifold I could hold my hand on without it getting too hot. I thought that if it would be due to heatsoak, it would get hotter then that.

What I tried:
1) Cleaned the BPC valve with WD40 and compressed air. Had no effect.
2) Disconnected the wastegate hose from the BPC. The boost went all the way off the gauge till a fuel cut. I also accelerated and kept the boost just over the red zone, and it stayed there stable. herefore no leak in the system.

Three possibilities:
1) It is indeed the heatsoak, air gets very hot, the thing starts knocking, ECU reduces boost...not very probable.
2) DI cassette. I am inclined to think that it is indeed this problem, because I drove for some time with wrong ECU, and it seems as if the car was running lean so much that there was CEL on. I didn't run that for long, but the CEL was blinking, meaning A LOT of knock. At first it bleanked only on high boost, but then it started blinking as soon as I would give it throttle. I think i killed the DI:cry:
3) Something wrong in the fuel system. This would lead to too lean mixture at high boost, and ECU would reduce the boost. Just want to note, that fuel filter was changed like 10K miles ago, and I experienced misfire at high boost with sparkplugs without the grease. It would make think that fuel system sends a lot of fuel in.

So, I need your help ladies and gentlemen.:confused:

Thanks,

klim
P.S. And I got the boost gauge and just ordered the pod. I know, speaking in terms of colors is not very scientific.
 

·
Registered
Joined
·
1,036 Posts
does the performance vary in line with the boost drop ? if not maybe youve got a faulty / leaking hose to your gauge
Another alternative is your dump valve is letting go at high pressure, again maybe leaking vacuum hose to it
 

·
Registered
Joined
·
1,739 Posts
Discussion Starter #3
Norman Lovie said:
does the performance vary in line with the boost drop ? if not maybe youve got a faulty / leaking hose to your gauge
Another alternative is your dump valve is letting go at high pressure, again maybe leaking vacuum hose to it
No, that's the problem, the perofmance is WAY down, like stock. And when you get used to be pushed against the seat, it is not fun:((
Hmm, if it would be the BOV, when I disconnected the W hose from BPC wouldn't it not hold high pressure? I tried it, and I kept it at the border of the gauge for some time. Very stable and steady. So, it didn't seem like something was leaking...how could I check for BOV?

Thanks,

Klim
 

·
Registered
Joined
·
590 Posts
Posted by mulik51: Disconnected the wastegate hose from the BPC. The boost went all the way off the gauge till a fuel cut. I also accelerated and kept the boost just over the red zone, and it stayed there stable...
That means turbo, wastegate & hoses are probably OK, so I bet the culprit is the BPC. I know you cleaned it, but it sounds like it's jammed open. See if you can borrow one and test.
 

·
Registered
Joined
·
1,739 Posts
Discussion Starter #5
Hmm, is there another way to check if BPC is stuck open, other then exchange it?
Why I am not sure about BPC is that the reduction of boost correlates somewhat to the outside temp. I would assume if the BPC would be stuck open, it would be stuck open at the same spot or move erradicly. But there is a correlation: the higher the temp, the lower the boost. Also, the more I floor it the lower the boost. BUt not fast enough to heatsoak I think...
THanks for the answer though, as soon as i get a hold of someone, Ill check the DI and the BPC.

Anyone have any other ideas? Is my theory about DI at least right, or is it improbable? Can DIs do that, or they fail rapidly?

Thanks,

Klim
 

·
Registered
Joined
·
590 Posts
Posted by mulik51: Hmm, is there another way to check if BPC is stuck open, other then exchange it?
Yes, there is - just bypass the BPC completely and connect the turbo output directly to your wastegate. You'll probably be right back to base boost.

If you like, you can then put a low-cost MBC in the line, and use it to bleed off some of the turbo pressure until you get the boost gauge up into the red.

My next bet would be the DI, as I have had the same problem as you when I put pedal to the metal.
 

·
Registered
Joined
·
1,036 Posts
Robinb said:
Yes, there is - just bypass the BPC completely and connect the turbo output directly to your wastegate. You'll probably be right back to base boost.

.
Agree & it does sound like your valve could be sticking in the C to W route ( not venting) in which fitting the C hose direct to the actuator should simulate same driving observations.
But i,d avoid going manual on the boost control, yet, as there could be other issues & hence the ECU stopping you blowing the engine
For example is your fuel delivery on spec
 

·
Registered
Joined
·
1,739 Posts
Discussion Starter #9
Thanks for the answers.
Ill try connecting the tubes like that. The only thing which makes me think that it is the DI is that the boost changes with temp, like now it got colder and I got much better boost, but still not there yet:))
The thing about MBC is that I got stage 3 from maptun, and theoretically I should be flowing the t25 turbo to the max on it. ANd I feel really stupid after paying 1600$ for the setup to put the MPC in it. Also, if it is indeed the DI and the boost is reduced due to safety, ill probably kill the engine by knocking too much.
So, Ill try to bypass the BPC. Then Ill meet up with Imran and exchange the DIs and maybe the BPC. Ill get back to you as soon as I find out what it is.

Thanks a lot again,

Klim
 

·
Registered
Joined
·
590 Posts
Posted by mulik51: The thing about MBC is that I got stage 3 from maptun, and theoretically I should be flowing the t25 turbo to the max on it.
Don't worry - if you once disconnected the wastegate line and then were able to get into the boost gauge red zone, everything is probably OK except for the BPC, and you are almost certainly getting max output from the T25.

I think the colder air temp is just masking the problem - what you need to do is to prove beyond doubt that the BPC is faulty, Maptun or no Maptun. Once that's done, remove the MBC, because Maptun gets very upset with people who use an MBC to trick their software into giving more HP than intended.
 

·
Registered
Joined
·
1,739 Posts
Discussion Starter #11 (Edited)
Here are the vids of my boost, sorry for the quality, made it from my phone. Ambient was about 50F. Runs were in 5th, 3rd or 4th gear. 3rd and 4th were from around 2000rpm to 4000. %th was from around 1500 to around 3000.
Here is the link:
http://www.youtube.com/watch?v=VZbf3-3iRaE
http://www.youtube.com/watch?v=vRR63xNRZwc
http://www.youtube.com/watch?v=6Sa6wSSEx0Q
That's definitly less then the car can handle...the needle goes all the way of the gauge if the wastegate hose is disconnected...

Thanks,

Klim
 

·
Registered
Joined
·
1,739 Posts
Discussion Starter #12
So, the movies don't give any extra info? Allright then, Ill check the PC and DI cassette then if there is no new ideas, and report back shortly.

Thanks,

Klim
 

·
Registered
Joined
·
590 Posts
Posted by mulik51: So, when I floor it, the needle spikes into the middle of the red zone, and then VERY QUICKLy(too quickly for a heatsoak at 40 ambient I think) reduces to stock boost and sometimes almost to base boost.
I didn't see any sign of that happening on your videos - I assume you were taking your foot off the gas at the end?

Anyway, I'm still voting for the BPC.
 

·
Registered
Joined
·
1,036 Posts
tell you what, I can get more boost with my waistgate tied fully open

what Ex you running & could it be blocked - cat, muffler padding etc..
Hold the WOT to the rev limiter & see what it does, by the time i,m over 5000 rpm I get over 17 psi, as described
 

·
Registered
Joined
·
1,739 Posts
Discussion Starter #15 (Edited)
Yep, in the end I took off my foot, there was a lot of traffic:evil:
Well, that's the strange thing. Before it used to shot up into the middle or to the end of the gauge and then return to about the edge of the yellow and red, just a bit less then the boost in the videos. Now it just behaves like this. Could it be due to adaptation or something?
Ill try to disconnect the battery (I need to do so anyways, to install a boost gauge) and then try to film it again. Maybe then the spike will come back...

Hopefully will meet up with Imran somewhere next week, check both, DI and BPC.

Klim


Robinb said:
I didn't see any sign of that happening on your videos - I assume you were taking your foot off the gas at the end?

Anyway, I'm still voting for the BPC.
 

·
Registered
Joined
·
1,739 Posts
Discussion Starter #16
I disconnected the BPC and my boost gauge went ALL the way of the gauge, to the fuel gauge till the fuel cut of. I run 3inch turbo back and it is fresh, less then 5000miles on it, so nothing could be blocked. If I disconnect my wastegate hose from BPC, i get A LOT of boost very early. By 3000rpm, the boost needle is way over the stock gauge...

Thanks,

Klim

Norman Lovie said:
tell you what, I can get more boost with my waistgate tied fully open

what Ex you running & could it be blocked - cat, muffler padding etc..
Hold the WOT to the rev limiter & see what it does, by the time i,m over 5000 rpm I get over 17 psi, as described
 

·
Registered
Joined
·
1,739 Posts
Discussion Starter #17
Just made another video. Here is is very evident how the boost is trailing off, in the end, right before I take the foot of the gas. I was on it till the last move of the needle to the green zone, so, the movement of the needle into the yellow was still under WOT. It was around 58F and REALLY humid, I just came of a highway, and didn't use boost much, so, it shouldn't be heatsoaked. The run was in 4th gear, from about 2000rpm onwards.

Here is a link:
http://www.youtube.com/watch?v=ySXyci-rxjU

Thanks,

Klim
 

·
Registered
Joined
·
1,036 Posts
mulik51 said:
I disconnected the BPC and my boost gauge went ALL the way of the gauge, to the fuel gauge till the fuel cut of. I run 3inch turbo back and it is fresh, less then 5000miles on it, so nothing could be blocked. If I disconnect my wastegate hose from BPC, i get A LOT of boost very early. By 3000rpm, the boost needle is way over the stock gauge...

Thanks,

Klim
Sorry what i ment was, remove the actuator from the WG & hence the WG is wide open ( removing the hose means the WG is fully closed)
The worst thing a faulty BPC valve can do is keep the gate open.
Looking at your vid,s you could be stuck in base boost - why?
signal from your cruze control ( limits you to base)
brake light switch active ( limits you to base)

When you hook the C line direct to the Wgate watch carefully at the initial throttle / boost - if it is slower to build ( marginally! only) then this could sugest your stuck in base boost, i.e. the BPC was trying to control
 

·
Registered
Joined
·
1,739 Posts
Discussion Starter #19
Cool, ill try connecting C to wastegate. I just gave the example of the disconnected W hose to show that my piping should probably be OK(like exaust, leaks in the intercooler, wastegate open, etc). I know for a fact that it is not the stoplight, because I investigated it for some time, and fixed the problem with my lightbulbs(after like two tickets for broken taillight:evil: ). My cruise is not working though. How would I check it, pull a fuse?
The thing is that I had this car stuck in the base boost, and it is definitly different, the boost needle only goes to the 3/4 of yellow. Also, if I give it WOT and then push a brake slightly, then the boost is reduced. So, it seems like something is bringing it activly down, like in the vid.

Thanks,

KLim
 

·
Registered
Joined
·
1,171 Posts
hey klim,

sorry i didnt get back to you, iv been very busy with school and work, im in retail so during the holiday times im working 30+ hours a week and going 2 school full time so i have like no time, ill look at my schedule and let u know when im free
 
1 - 20 of 74 Posts
Top