When you're not holding/getting boost.

 

I have boost 5-8psi but as the revs go up i see the boost going down, is it normal? Also when it shifts gear i see spikes to 10 psi...

 

When mine went bad, I only noticed an issue after a little while of spirited driving. If I got on the gas hard, it would accelerate really well (possibly better than normal) until about 20 mph and then it went into what felt like a limp mode. Power was cut in half and you really had to give it the beans to go anywhere. It would be impossible to miss this happening as it is properly terrifying. Shutting the car off and waiting 30 seconds before restarting would reset it, but it was more prone to return to that limp mode. What I think was happening was that it allowed too much boost which told the computer there was something wrong and to open the wastegate to avoid damaging the engine. Since replacing it, boost is much snappier and steadier. This occurred at 128K miles. I don't really know what symptoms, if any, there were before that because I bought the car with 126K on it.

 

This and at around 100k miles I'd start suspecting it as the cause.

 

TCV good = 10psi of maximum boost around 6psi in 1st gear, 8psi in 2nd gear and 10psi in 3-5th gears...

TCV bad = 5psi in every gear... no other noticeable differences.

So if your car just doesn't seem like it pulls hard at WOT lets say on a on ramp acceleration from low speed to say 70mph yours is probably bad.

One thing i do notice is a very linear acceleration that seemed rather sluggish when it was bad. Once i replaced mine ~50$ i get a rush of power that is felt in every gear and that is felt when we get from 5-10psi range based on my Boost gauge.

 

I noticed at high revs the boost jumps and the car a little jerks (no misfire)

 

I replaced the tcv and now i see around 7 psi every gear. What else can it be? The car accelerates 9 seconds to 60 mph, no codes using vida except of U0301 - Software Incompatibility With ECM/PCM (remap), can it be possible the remap went bad?? The tuning firm says everything is good but i dont trust them.

 

Remaps don't "go bad" on their own. It could have been done improperly, though. If not, it could be a boost leak.

 

Torque program tells me -10 psi at idle, is it related?
I checked the hoses no cracks were found.

 

You have vacuum pressure and if it stays steady then there's less fear of a leak. I'm not sure what the normal at idle vac is.

What else did you change before this came up? What tune do you have?

 

Bsr, i started to change things after the tune because i thought there is something that is not working well because as i know stage 1 is around 12 psi and i never saw this number lol, i also swaped the fps, original spark plugs, no misfires.

 

If that's where you started having the issue, after applying the tune, I'd work with BSR to get that working.

 

The tuning company had to disconect the ecu and to take it apart because you cant flash it using obd. They had to conect to it directly. They say that they did the remap but i dont see any change..how bsr can help me with that? I live in israel lol

 

What P1 requires you to send in the ECU? That's weird. You have to work with them and they need to cover the costs involved.

Where in Israel are you?

 

Beer sheva, because its a bosch computer

 

Ah, that's where I stay when I visit. It's getting much nicer there, too

 

Next time you visit bring me some parts

 

Probably not this year. I was there for Pesach last year and again a few months before that for a wedding up in Tel Aviv - so, sorry I won't be bringing parts

 

Mine let me know it was bad when it would over-boost way beyond 10psi and then go to reduced performance mode. I suspect that it wasn't holding boost very well before this which is why I happened to have a boost gauge hooked up when it really went bad.

 

Today i disconnected the maf sensor, no difference at all! Is it ok? What suppose to happen?

 

Huh. You're definitely supposed to get a check engine light for that one and the engine will run rough. Interesting!

Maybe all it needs is some cleaning/replacement. If you were able to scan for codes with VIDA or a good OBDII scanner you'd know for sure!

 

I tried to disconect while the car runing, i saw the rpm go up from 770 to aroind 780 and then go back to 770 idle... how the car should drive without the maf? The boost remains the same...
I will try to clean the maf today and update then.

Another issue i noticed, today i drove 100 km and i did some pulls (highway), when i arrived to the city i saw that my boost jumped to around 9 psi almost as it should. When i parked the car for 20 minutes and started it again the boost returned to 6.5~psi. What is wrong with the car??

 

I tried to disconect while the car runing, i saw the rpm go up from 770 to aroind 780 and then go back to 770 idle... how the car should drive without the maf? The boost remains the same...
I will try to clean the maf today and update then.

Another issue i noticed, today i drove 100 km and i did some pulls (highway), when i arrived to the city i saw that my boost jumped to around 9 psi almost as it should. When i parked the car for 20 minutes and started it again the boost returned to 6.5~psi. What is wrong with the car??

Okay, sounds like something easy to try for now. I wish your screenshot was in English or Hebrew - what are your codes saying so I don't have to look them up? Interestingly enough I think I can also get a good idea about where you are in the city based on the Russian

I did a little searching and remembered a thread referring to an issue where boost was good at times, but also bad at times.

http://forums.swedespeed.com/showthread.php?163933-Unsolved-problem-getting-expensive-2005-S40-T5

The eventual fix was replacing the check valve on the turbo (P/N: 30677524). Have a read.

Problem:
When I first start the car, it runs great with full power as if nothing is wrong.
However, after as little as 5 minutes of driving it goes into 'limp mode'.
When I am at a stop, I can put the pedal to the floor, and the car accelerates like an old Dodge Omni pulling a trailer. This loss of power persists until I turn the car off and back on again. While driving, if I need to pass or keep up with traffic, I just throw it neutral, turn if off and back on while coasting, put it back in drive and it runs with full power again for a little while.

 

2 of them about ecm the program, parking sensor and climate control. Thats it.

Before i cahnge the check valve i still dont know if there any problem with the maf, i cleaned it but nothing changed, if i disconect it remains the same lol.

B.t.w how do i change the valve? From the bottom? What should i remove to acces it?

 

Bump

 

New info: After a long drive on highway my boost jumped to around 9 psi. I stopped the car, shut it off and then after half second started it again. The boost dropped back to 5-6, what can it be??

 

Hashem is ****ing with you. Lol, jk. I'm not sure outside of what I've posted so far.

 

Update:
Changed the check valve, old one was dirty but working (with the ball design) but still replaced with new one same design. NO difference, 6 psi top. What else?? Im losing my mind.

So far: new tcv, cleaned maf, new fps but still the car does 8.5 sec to 60mph. No leaks found. Only two obd errors: u0100 u0301 software related.

 

Tried this just now: after the tcv replacement i didnt have the chance to reset the ecu and i decided to try it now, i conected +- for 5 minutes and started driving slowly, when i got to the high way after a few pulls the boost jump to 9 (!) 10 peak, and stayed that high on every gear, i started to hear the turbo build boost. Any way i parked for 1 minute and started the car again. The boost dropped to 6 psi top and the turbo sound less noticeble. Any suggestion? Is it electrical problem or mechanical?