PR8urVtec

iTrader: (1)

I have been having a strange problem for the last month and I can't seem to figure out what is going on.

Car: 1990 Acura Integra LS - B20B turbo - P75 ECU w/ Hondata S300

Street tuned
B20B turbo
GM 3bar MAP
AEM FPR
R/C 550cc injectors

Problem 1

When letting my car run for about 15 minutes or so, with my laptop connected, my a/f on hondata will start to lag and not "keep up" with my a/f gauge (AEM wideband). I have the voltage offset set setup correctly and it works when I first start the car up then it will start mess up and go out of sync and or lag on the laptop end. I have never had an issue like this before. It's also doing it on my CRX using a P28 ECU w/ S300v2 on it. To me it seems to be my laptop or Smanager having issues. I can't datalog and fine tune my p/t b/c I can't get good readings with all the lagging.

Problem 2

After the car runs for about 30 minutes (closed or open loop) the fueling all of a sudden goes very rich. My gauge shoes 10.00 for a/f and it goes to 12.xx a/f at idle. When in closed loop I usually idle at 14.2 (my target set by voltage using my wideband o2). The car will drive perfect until it just goes rich. Once this starts to happen my a/f is never really correct. IT's either to lean or very rich. I can feel the engine breaking up with I'm getting these readings so I'm assuming the fueling is messing up and not just a bad reading.

I can send my calibration and get a datalog to people who want to take a look. The car has been street tuned and is only using 5.5psi. It runs fine in boost. Just really rich on p/t for and after 30 minutes of driving.

I have changed the FPR to rule that out but the problem is still around. It happens open or closed loop. Under normal conditions in closed loop, I don't see to much correction happening with my Strim and Ltrim b/c my tune is pretty close to my target.

My battery voltage stays ~14.0v pretty much all the time and even with my headlights, fogs, ect... on the lowest voltage is 13.8v with the same fuel problem. I thought maybe my voltage was dropping and my deadtimes were maybe off at a lower voltage.

My next thought was maybe some sort of temp. correction taking place but why would it happen way after my car is warmed up. The next thing was maybe my wideband o2 is taking a crap but why would it happen during open loop as well as closed loop. I will note that my car is converted to obd1 and the resister box has been deleted to use the R/C injectors.

Anyone with any knowledge please help out. I have searched for some answers or related problems and I can't find anything or I'm not looking in the right direction to my problem.

m4xwellmurd3r

Sounds like the o2 sensor is failing. My mtxl o2 sensor is begining to act in a similar fashion. Most times its fine but then it starts freaking out, either showing incorrect values or getting "stuck" at whatever afr value it was on. Eventually it sticks at dead lean. Takes a while for the sensor to heat up on occasion too.
Power cycling the ignition switch fixes it till it glitches again.

I tuned my entire map for open loop so it doesnt act up when this problem occurs.

Try getting a new o2 sensor

PR8urVtec

iTrader: (1)

I think that might be my next move. I'm sure it could be replaced as I have been using the same o2 for a while now. I made sure all my grounds were good as well. I'm going to go ahead and check all my injector wires while I'm at it.

If I can break free from the family tonight, I'll take her out for a little spin and see if I can datalog while it's happening and even record a video of the gauge activity to help elaborate on what I'm experiencing.

Turb0 Guy

Double check your grounds, looks like theres some loose connections.
Bad ground = erratic hondata log.