Ok, this is getting annoying (lack of boost)

Hey guys, I'm stumped here, here's a description of the problem I'm having.

I have a Stage 3 setup with an AGP S3 WGA, running boost control off the solenoid so DAB still works, and with the WGA set to spike 25psi in DAB2/3.

Since I fixed a huge boost leak, my car won't give me more than 15psi with the e-cutout closed, and 17psi with it open.

If I reset the ECU, it will jump to 25psi for about 1 second, then quickly dial the boost back to 15psi.

I checked for codes, and other than the P0517 which is normal for an 04 S3 computer on an 05 car, I got nothing. Why would the ECU pull all that boost on me without giving me a code?

I changed the plugs out with fresh plugs, NGK Iridium IX, gapped at .032, no help there.

I have a scangauge and I've watched, I'm not getting any knock at all. I looked over the vac lines and they're all zip tied tight.

Some wierdness: sometimes it will just inexplicably give me 22psi with the cutout open, and last night driving back it fluttered on me when I punched it in 4th from about 65-70mph, it went 22-17-22-17-20-17. Might be compressor surge, but I was over 3000rpms, so why would it surge like that? Anyway I don't think surge is the problem, I've hit it from 3rd gear at 60mph and watched it spike 25, then quickly dial itself back to 17 (cutout open).

I'm thinking I could just run a MBC and see if it holds, but I don't want to do that yet because I feel there's got to be a reason the ECU is taking the boost away, it's just frustrating that it's not throwing any codes.

Suggestions?

 

take it off pcm boost and use th wga to set boost cause there no point on using the agp wga if your still on pcm boost cause u may think its set for a certain psi but it could be lower

 

crap I thought I replied to this thread...

+1 to what Goats said...:viking:

 

Heh, yah that's what everyone said that I've asked so far. I'm going to try that as an experiment, but I have to believe that there's some reason the ECU wants to pull the boost away.

The thing is, it used to be just fine like this, it gave me 25psi in DAB2/3 for 3 months, it only started acting up a couple weeks ago after I fixed the boost leak. Oh well, I'll get a vac line and go straight to the WGA tomorrow and see how that does.

 

Thats why. The turbo/WGA was pushing 25 psi, but the motor is only getting 17-18 psi. Now that the boost isn't wasted, it's pulling it back.

I bet the car doesn't feel any slower, though...does it??

 

It's a lot slower. There might be some correlation between the boost leak and the boost problem now, but I've reset the ECU multiple times. There's no way the car is as fast on 15psi as it was when it had the leak, when it had the leak I still trapped 117mph, and there's no chance in hell it can trap that high on 15psi.

 

Try this:

except delete the line to the tip solenoid and tip sensor

 

I believe the TIP sensor line is already gone, the only vac lines are the two running to the boost solenoid right now.

I just need to go get a short vac hose and bypass the boost solenoid, I'll try it out today.

 

Oh and I have an external BOV too, not using the surge valve.

 

Ok, ran the vac line straight from the turbo to the WGA, but only got 14/15psi. I didn't have time to try to adjust the WGA, but should I have to do that now that I took it off the solenoid? I'm afraid to crank it up too high because it was making 25psi with the WGA set the way it is right now when it was connected to the boost solenoid.

 

1)Are you tuning the car?
2)do you have a return line? if so what pressure?
3)What are your AFs

 

I'm not trying to tune the car, just trying to get it back to 25psi, it was doing 25psi just fine a couple weeks ago, for a while.

I do have a return line, and the fuel is trimmed using an adjustable 1:1 rising rate regulator, Aeromotive, I believe idle pressure is 48psi.

Don't know the A/F's off hand, haven't connected my wideband yet, but I can monitor knock with the scan gauge and I don't get any knock at all.

 

When you reset the PCM your suppose to not spike past 15psi. Each stage pcm might be different but being that the PCM controls boost it might fall into the category. Resetting the PCM there's two ways of doing it... I prefer the disconnection of the negative terminal on the battery for 30 min.

After you reset your PCM, your suppose to drive 10 minutes or 10 miles whichever comes first taking it easy on the car while the pcm relearns some parameters. Being that you have a Scangauge you would see this happening. You can get on it but as soon as its going to touch 15 psi let off, keep doing that for about 10 minutes or 10 miles. After a PCM reset and the 10min/10mile ordeal the PCM is still learning and adjusting.

You were running with a big leak and you fixed it. Give the pcm time to learn. Its like resetting the stock pcm and on pcm controlled boost. Yeah you'll spike intially higher numbers but then the pcm re-adjusts the boost and lowers it to the range it defines.

 

Also a thing about AGP wga's... you can turn it in to spike a certain boost pressure BUT ever notice it will take about 6 turns just to jump to the next psi reading or two. AGP wga's slowly put tension on the spring unlike other manufacturers wga's.

I say connect your wideband, watch ignition adv timing and knock retard on the Scangauge, put a little bit more tension on the spring of the wga... 2 turns and see what happens. It might still stay at 25psi spike but might hold more. Like I stated it takes a few turns just to get it to go up a psi or two.

Most s3 owners I know this way run pcm controlled boost on their AGP wga in order to use their toys DAB feature. So... yes the AGP wga for an s3 equipped SRT-4 can be used off pcm controlled boost or with pcm controlled boost.

 

Thanks, good information.

So you think it might just be an extended learning process? Here's what happened when I lost the boost:

1) Got the boost leak fixed
2) Went out and ran it pretty hard for an evening, 25psi spike, tapering off to 17psi (seems like it's still leaking or something, that's too low)
3) Went on vacation for a week, left it parked
4) Got home, took it out, bam 15psi max
5) I've reset the PCM a few times, and it will hit 25psi for an instant, but then pull it back down to 15psi. After this first initial spike post-PCM reset, it will never go above 15psi unless I reset it again.

Is that consistent with the PCM learning? I mean, it still spikes 25psi but only when I reset the PCM, and then only for a split second, then from that time on it just stays at 15psi pretty much no matter what I do.

Also, since I switched off of PCM controlled boost, shouldn't it have gone back to 25psi? Or is the adjustment on the WGA different when running straight to the turbo? In other words, the WGA setting right now was good for 25psi on PCM controlled boost, so shouldn't it be good for 25psi when the boost solenoid is cut out? Or is it different.

 

If you haven't done so run another boost leak test.

See what happens is if you spike too high during the learning period (after pcm reset) the PCM will freak out.

Set it to DAB 0 (which I believe its just running what the wga is preset at, reset the pcm (disconnect the negative terminal for 30 minutes), cruise around, getting on it after 3k and immediately letting off when it hits 15psi (repeat a few times for 10 min/10 miles whichever comes first).

I think one problem is your resetting the pcm too many times and haven't let it learn and after resetting it your spiking too high immediately freaking it out. Also the problem might be after the pcm reset your running it on DAB 2/3. Try running it at DAB 0 until PCM learned its paramters. Then go DAB 1 then 2 then 3.

If you switch off pcm controlled boost you would need to turn in the wga more to get 25psi spike. Its different then when the solenoids are controlling it. On pcm control boost there's less load on the spring, off pcm control boost you would need to put more load on the spring. Hence why when you took it off pcm control boost and didn't adjust the wga it spiked so low. The wga was at a preset setting of 15psi spike for DAB 0 more then likely.

 

Ok, so you're saying hook it back up to PCM controlled boost, set it to DAB 0, and drive aruond for a while?

 

Yes put it back to PCM controlled boost.

Set it to DAB 0 (which I believe its just running what the wga is preset at, reset the pcm (disconnect the negative terminal for 30 minutes), cruise around, getting on it after 3k and immediately letting off when it hits 15psi (repeat a few times for 10 min/10 miles whichever comes first).

Drive around like that for a day or so, then try DAB 1, DAB 2, DAB 3.

I recommend you do another boost leak test as well.

 

I'll do all of that, thanks man.

I'll try it out tomorrow, except for the leak test, I can't do that until the weekend, but I'll let you know if it works out after driving it for a day.

 

No problem! Let us know how it goes.