migs647

iTrader: (19)

UPDATED SOLUTION POSTS 8 & 9

Yesterday we finally got my Stack wideband and boost gauges installed. I was so excited. I've read a lot of good about these gauges, being stable, accurate and unique.

Unfortunately, the wideband seems to be ALL over the place, and the boost gauge seems to be 4-6psi higher than it should be.

I have gone over every connection I can think of for both gauges, and everything seems to be solid.

The boost gauge is connected at the fuel pressure regulator line (the famous line that pops off under high boost on Xs). I usually put them close to the turbo, but the installer put it there, which I've been told is an ok place to put it. What concerns me about that place is the boost gauge does an automatic calibration at the start of the car (which works as intended), if there is any pressure in that line at the time the car starts, i could imagine that would throw it off. Can anyone confirm this being an OK place to put a boost gauge that auto calibrates?

As far as the wideband, it is all over the place. I've tried adjusting the AFR point, I've tried adjusting the sensor being heated automatically vs manually, and have gone through all of the electronics. I'm thinking, possibly that the o2 sensor is bad. But if it was bad I would think it would just not read anything at all.

The last thing I can think of is the electrical signal lines being ran together in the firewall, are possibly affecting each other with electromagnetic signals since they aren't shielded. This is really stretching it imo.

Here is a url to the boost gauge documentation:
http://www.stackltd.com/pdf/manuals_gauges/1292.pdf

Here is a url to the wideband documentation:
http://www.stackltd.com/pdf/manuals_gauges/1294_GB.pdf

And here is a video of the really odd behavior of both gauges:


Any help would be appreciated =)

black E

iTrader: (77)

If you have a small exhaust leak upstream from the o2 sensor then it would react the same way as in the video. The boost gauge I would connect to the BOV port.

migs647

iTrader: (19)

It's all factory piping that has never been taken off from the turbo to the cat. I add a bung right in front of the cat. I'm going to move the boost gauge connection tonight =)

black E

iTrader: (77)

The only reasons the sensor would act like that are:
1- exhaust leak upstream of the sensor.
2- bad sensor free air calibration (I'm not sure if the stack wideband has to be calibrated like the innovate).
3- bad ground or shorted/shorting ground.

migs647

iTrader: (19)

Well I've gone through all of the documentation I can find, and don't see any calibration. Just setting the center point for AFR. Which i set to 14.7:1 for pump. I need to get under the car to check the ground. I'm wondering if the ground just isn't that good.

I relocated the boost gauge to coming off of the diverter valve and I'm getting the exact same readings.

migs647

iTrader: (19)

Today I changed my line on the boost gauge. Seems to be reading 2psi higher than before now.

I'm wondering if not having the line perfectly fit on the adapter is making it read a bit more than normal? Also the line I'm using is 7/64, the line they show in the documentation is much much smaller. Normally I wouldn't think that would make a difference because pressure is pressure, but perhaps that adapter makes sure the pressure is perfectly going in without any rubber interference.

migs647

iTrader: (19)

I talked to an engineer from Stack today.

He said the vacuum line wouldn't make a difference. He narrowed it down to a few issues.

Either I'm not getting over 12.5v out of the line, have a bad ground, or the power is going away as the boost gauge is taking a snapshot.

There is a possibility my o2 sensor is bad for the wideband, but he really thinks it boils down to an electrical issue.

More to come after I test these connections.

migs647

iTrader: (19)

Tested the electrical connections today. All read correct. Power was almost spot on 12.5, and ground was .45ohms.

However, we did find that having the boost gauge hooked up to the cigarette lighter fuse, dims during starting. This means it can't get an accurate snapshot as the car is started. We moved the line from there to the gauge cluster fuse. Works great now. Seems to be quite accurate compared to Evoscan.

At this point it appears that the wideband either has a bad o2 sensor or one of the wires in the harness has a poor connection. More to come.

migs647

iTrader: (19)

OK, so finally a resolution to the issue. The wideband had a bad o2 sensor as previously suggested. Stack has sent back the wideband and I'll be installing them this weekend. Thanks to everyone for your input.

I'd really like to thank Stack LTD for working with me to figure this out. I can't say enough about their customer service, second to none.