Hey guys,

I got my car tuned last thursday and was very happy with the results.

Had a question. About a month ago I installed a chipped p28 and OBD2->OBD1 conversion harness(JDM ITR) Since then every once in a while like 4-5 days my engine light will come on with a Primary o2 Sensor code. The car feels okay when this happens but the idle does start to hunt(idle surge) between 1000-1500rpm.

When I reset the ECU or turn the car off the light goes away and when I jump the code it is gone, it will hunt for a bit then settle at regular rpm. I have replaced the o2 sensor 3 times with new ones but it still comes on every 4-5 days.

I e-mailed the guy I got the ECU from and am awaiting a response but had another question too. Will it mess up my tune when the engine light comes on?

Like will it affect the maps and cause me to lose power? I tuned with a VAFC2 so I figured that it should be fine since all the settings are in the VAFC2 and they shouldn't change but I was wondering if anyone could confirm this.

Has anyone had this problem before??

TIA for any help guys

 

sounds like your o2 sensor is possibly bad or maybe a bad connection. check to see that all the pins in the connectors are all ok.

 

Yah I'll check the connectors tomorrow at work and make sure they are okay. I don't think it's the o2 sensor as I've replaced it 3 times in the last 2 weeks with new ones.

Just wondering if it is possible that it's the ECU or something inside it that's causing this as it's been happening since the ecu went in.

 

are you replacing the o2 with oem honda or an aftermarket company?

 

OEM Honda. I work at Honda so I replaced it the first time with a used but known good one. After that I replaced with a brand new OEM.

 

Sounds like when they tuned it, they forgot to put it back into Closed Loop and reburn the chip for you before you left. Just tell them your ecu is still in Open Loop from the tune and they should be able to just reburn your chip in Closed Loop in a few minutes.

 

all i want to see is you get this thing fixed.. run it down the 1320 with your new numbers and tuning and you break 13's..

But im not too sure about the o2 code. try to ask them about the open/closed loop like he said..

 

I've heard though that if you put it back into closed loop that your ECU will try to fight it's way back to stoich 14:7.1 is this true??

 

If it was in open loop it shouldnt throw a code..

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1999all_motoR_teg &raquo;</TD></TR><TR><TD CLASS="quote">I've heard though that if you put it back into closed loop that your ECU will try to fight it's way back to stoich 14:7.1 is this true??</TD></TR></TABLE>
It will try for part throttle but thats ok because thats where it should be..On wide open it goes off the actual tune map and doesnt use the 02 sensors reading at all, so that shouldnt be a problem..