S.TRIM pulling to much fuel

Vanilla · Post by **Vanilla** » Tue May 18, 2010 3:53 pm

So I have a problem with my short term fuel trim..it seems to get "stuck" at -29% during driving in closed loop which cause my car to go lean.. it doesnt happen all the time normally after about 20 minutes of driving cruising at about 80km... if i run in open loop the car drives fine..and my a/f's never go lower then 13.0.. I thought it may be the O2 so i replaced it. but no luck...

thoughts or solution?

im running a p08 converted to vtec
turbo h22 in a accord
720cc greddy injectors

Post by **Spunkster** » Wed May 19, 2010 9:25 am

http://www.hondata.com/forum/viewtopic.php?t=3772

Vanilla · Post by **Vanilla** » Thu May 20, 2010 2:16 pm

sorry..added the required info... a datalog of the problem...a datalog of the car running in openloop with no problems...and a copy of my calibration..

the datalog is pretty big...but the problem starts happening around the 30 minute mark...

thanks

Post by **Hondata** » Fri May 21, 2010 7:58 am

There is an intermittent bad connection between the ECU and o2 sensor. Unplug and clean the ECU connectors, o2 sensor connector and the connectors on the right hand suspension tower in the engine bay.

Vanilla · Post by **Vanilla** » Sat May 22, 2010 6:02 am

Hondata wrote:There is an intermittent bad connection between the ECU and o2 sensor. Unplug and clean the ECU connectors, o2 sensor connector and the connectors on the right hand suspension tower in the engine bay.

Ok...ill give that a try...do u mind me asking how you were able to tell that from my datalogs?

Post by **Hondata** » Mon May 24, 2010 8:47 am

Because the reading is ok most of the time, but then goes to 1.5 volts or more, which is from the ECU pull up resistor on the o2 sensor input, which shows that there is a bad connection between the ECU and o2 sensor. If the o2 sensor itself was bad then there would be a slower response time.1