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closed loop problem

Posted: Mon Mar 01, 2010 10:18 am
by Wolli
hello.

i installed the plx wideband 2 weeks ago, and wired the nb to the o2 pin and the wb to the D12 EGRL. i started the engine and, it worked. it was running without problems in closed loop. short trim was about 7%, everything seems perfect.
after one week doing nothing, the car is jacked up in the garage over winter, i started it again. but now, it doesn´t run in closed loop anymore. when i run in open loop, everything is fine. when i click to closed loop, it stalls. but there are no corrections in short or long trim. the percent value stays @ 0%, but something else must happen. i logged it today. startup in open loop, fine, then going to closed loop, it immediately stalls.
does anybody have an idea?
please do not tell me to check the ground or wiring. nobody was @ the car this week. and it worked fine a week before!

i also had problems with the usb connection with my netbook i used the whole last year, so i took my old lappy, and it worked. but the closed loop problem kept the same.

Posted: Mon Mar 01, 2010 11:58 am
by Spunkster
according to that datalog and calibration you have it in open loop. I do not see any problem with it as it currently is. If the problem is in closed loop, you need to datalog and post the calibration and datalog showing the problem.

Posted: Mon Mar 01, 2010 12:03 pm
by Wolli
when you look to the datalog, it is in open loop first. the moment i switch to closed loop, the engine stalls. so the last 2 seconds, when the engine dies, is in closed loop!!

Posted: Mon Mar 01, 2010 12:40 pm
by Spunkster
What vehicle is this in (model and year)? Are you using an adapter harness?

Posted: Mon Mar 01, 2010 12:53 pm
by Wolli
it´s a 92 civic eg with the b16a2 engine, p28 ecu, no adapter.

Posted: Mon Mar 01, 2010 5:40 pm
by Spunkster
This sounds like a wiring fault since the engine actually dies as soon as you put it in closed loop. The datalog does not show any strange behavior. Just because it was working a week ago does not mean that it is not a wiring problem. You must focus on the problem you have now and look at all possible causes.

Posted: Mon Mar 01, 2010 5:45 pm
by Wolli
do you have any idea why there is no short t. correction?
i make a new calibration now and try that tomorrow. i also take a look for the wiring.
and it´s a p30 ecu, not a p28! but that makes no difference i guess.

Posted: Mon Mar 01, 2010 5:58 pm
by Spunkster
It dies too quickly to do any short term correction

Posted: Mon Mar 01, 2010 6:06 pm
by Wolli
one time it was running longer but very bad in closed loop. lambda was good, but there where also no corrections!!

Posted: Tue Mar 02, 2010 9:18 am
by Wolli
i tried it again today with a new map. when i go to closed loop, the o2 voltage drops down to zero, and the lambda to maximum. it looks like a short circuit to me.