Air/Fuel guage issue.

[quantum]

I have a 89 (2.5 turbo, Garrett T2, intercooled, 12-13psi) minivan I just installed a sunpro A/f guage on. I connected the ground right to the battery, the power to the radio fuse, and the dimmer to the dash lap fuse. When I turn to key to just before tunring over the engine, it sits at ideal (right in the middle) and if I turn on my blinkers I can make it jump a bit. While running I seems to work well till I get into boost. At WOT or even at 5psi it will show rich for a sec then jump to the last bar on lean and it will stay there till a little while after I let off the gas, sometimes it even stops showing lights at all. I know I'm not lean the engine runs great and there are no signs of detonation. Any ideas on what the problem could be. I would say it is the ground, but with it connected right to the battery that doesn't seem likely. Thanks for your help.

[stoney wilson]

mine did that before and i had connected it to the wrong wire on the o2 sensor

[quantum]

Quote:

Originally Posted by stoney wilson mine did that before and i had connected it to the wrong wire on the o2 sensor

Really?.....hmmm...I'll check my wires...thanks.

[quantum]

I rechecked all the wires, and it was connected correctly. It's the only wire that puts our between 0-1 volts, the others are grounds and ~13v. I reconnected and re soddered evey connection to the O2 sensor and the ground. Still the same thing, it works great (bouncing) till I get on it then it goes from rich to full lean in an instant and when I take my foot off the gas the guage doesn't show anylights for a bit and then coms back on at lean then works again. Maybe I'll change my power from the radio to something else...any ideas? Thanks again.

[william]

Mine drops to one or no lights sometimes at throttle close/decel. Sounds like your power or ground sources are iffy.

[quantum]

I tried a different power source (different fuse that comes on at engine on), and I still get the same thing. I pulled a couple plugs to make sure I wansn't going lean and they were all a nice tan color. I'm about ready to call this guage a wasted install. I think I may replace my o2 sensor and see if there is any difference. if not then maybe the guage.

[quantum]

Before I buy another o2 sensor or guage. Is it possible for me to be that lean and not know it? It seems to me that if the guage says the last bar on lean at 13psi, I should have ash trays for pistons if it is reading correctly.

[puppet]

It would probably be knockin' like crazy at the least.
I wonder if you could test the gauge with a small "AA" battery?
You could hook a multimeter up to the sensor to see if it's putting out.

[quantum]

I checked my fuel pressure and I think it's good. Unless it's possible for the regulator to raise correctly under a small amount of pressure (60psi at ~3psi boost) but not at 13psi? I guess my next test is to buy 8 d cell battries and connect them in series for and 12v power source and ground. Can someone let me know about the fuel pressure regualtor question please. To top it all off I think my front main seal is leaking a bit, I get a couple drops from it when I park :. Thanks again

[puppet]

Quote:

Originally Posted by quantum I checked my fuel pressure and I think it's good. Unless it's possible for the regulator to raise correctly under a small amount of pressure (60psi at ~3psi boost) but not at 13psi? I guess my next test is to buy 8 d cell battries and connect them in series for and 12v power source and ground. Can someone let me know about the fuel pressure regualtor question please. To top it all off I think my front main seal is leaking a bit, I get a couple drops from it when I park :. Thanks again

You need 0-1 volt to test the O2 gauge. Your only testing the sensor side.

[Jayar]

do you have a four-wire 02 sensor? if so, which wire (what color) did you tap into?

i'm about to do the same thing.

[speedyshelby16]

I got the sunpro guage in my SC with no problems. But in my charger only a one wire O2. In my sundance I got a faze gauge the car is a 4 wire O2 sensor. I went on dodge garage to get the right one.