Extender and boost help (Bob?)

[JDEstill]

Okay, my car is behaving oddly. Been running the Extender chip for a while, and only been running about 15 psi boost or so. No changes to the car, then I get a step change a few weeks ago - boost is only going up to about 10 psi and won't go higher. Car feels sluggish too, so I've ruled out a gauge problem - pretty sure its real.

I'm thinking something, somewhere has changed, probably broken. No reason to suspect the chip, ecm, etc.. since I haven't been fooling with anything. Took some DS data to see if I could spot something odd going on, and I see something that I think is weird...

The Boost DC shown is up in the 80-100% range until I get to 42 mph, then it drops to zero and is zero the whole rest of the run. Basically right about the time I get to full WOT and hold it there. ie, while the TPS is moving up I'm getting Boost DC (I'm rolling into the throttle here), then when I get to 4.6ish V on the TPS and I'm holding it there the Boost DC goes to zero. No knock is showing, so that's not it. It's not a gear change that I can tell, 3rd gear switch doesn't come on until it hits 54mph.

Is this behavior normal and I should be looking elsewhere for my problem? Or is something screwy going on? DS file is available if anyone wants to look at it. Is there some sensor input, etc... that I am overlooking which would cause the wastegate duty cycle to go to zero? Besides knock I mean.

I disconnected the wastegate hose going from the Y to the wastegate solenoid and got into it gently, and the boost came up quick and hard, 20+ psi in a flash. So it's not any gross mechanical problem, if it isn't chip related it must be a minor mechanical thing. Any advice would be appreciated!

John

[davzgn]

Sounds almost like it is in valet mode.
:fragez:
David
87gn

[JDEstill]

An excellent idea! I hadn't thought of that. Looking through the instructions though, it says that in valet mode the engine will cut out if its floored. Mine's not doing that, it seems to run fine at WOT, the boost just never comes up.

John

[Eric Marshall]

Hi John,
Hey, you going to BG this year?

If you zip the DS file, you could attach it here.

[JDEstill]

Hi Eric - I sure hope to make BG this year! Always a good time. Just depends on the ole work load, but if things pan out like they should, I ought to be able to spare a few days to make it there.

I'll make an attempt to attach the DS file in question.

Looks like it worked!

John

[Badinblack6]

Maybe the boost solenoid is shot. When mine went bad the boost would shoot up and then drop off to like 10lbs. Replaced it and all is fine. :rock:

[JDEstill]

hmmm, could be something like that. I do have a spare solenoid to check with. I'm still wondering about the chip though. Does anyone know if the wastegate DC behavior I'm seeing on DS is normal or not?

John

[TurboBob]

In the Extender, the boost "Change Engine Light" is turned off, but the software that diagnoses the wastegate solenoid still runs. It takes about a second to trip the failure, and then the solenoid shuts off.


I'll try to look at the DS file later.

B


:marchmell

[JDEstill]

Got a resolution to report, for anyone curious:

- learned from Bob that the Extender chip doesn't turn on the Check Engine Light for a code 31, but it does observe that there is a problem and will stop pulsing the wastegate solenoid. So that was my problem - a code 31.

- pulled the fuse, fuse was blown. A new fuse blew as soon as the key was turned on, so I had a short somewhere.

- a little research on the boards showed me that there is a bunch of stuff on that circuit. I always thought of code 31 as being wastegate only, but in fact there are 6 things on that circuit - wastegate solenoid, EGR solenoid, cannister purge solenoid, TCC lockup solenoid, some a/c thing, one of the switches on the brake pedal. A problem with any of those circuits gives a code 31! Which then causes the ecm to stop pulsing the WG solenoid, which then results in lower boost.

- mine turned out to be the TCC solenoid. Haven't replaced it yet, though I do have the pan drained. The wire providing power to the TCC solenoid showed a short to ground, unplugged the solenoid and that problem went away. Power supply terminal on the plug itself shows a short to ground, the wire itself is fine. So it's in the power supply wire that is inside the pan or something in the solenoid itself that is shorted to ground. I'll find out more this weekend when I drop the pan. Weird.

John

[JDEstill]

It was the wire running from the plug to the solenoid. It was stretched super tight, and it rubbed through. Bare power wire was touching the valve body. All happy now.

John