Ok I have a 91 civic DX I bought about a month ago, It has a B20 mated to a s1 trans, when I got it I took off the crappy B20 mani and swapped it for a LS.

Now im throwing a code 12 which is the iat but my ? is I am getting a surging problem throughout the rpm band and sometimes it sounds like it is running on 3 cylinders. Now if I clear the ecu by letting the ecu drain with the battery terminals off, it doesn't do it untill about 20-30 minutes of driving but it starts acting up again.

In warmer weather it doesn't do it but when it's cooler it does it alot.

Any help? No other codes were thrown.

 

Ok I have now checked again and the code 10 I just threw when I unhooked the iat plug. It seems to be a EGR code for the 12 since it's a obd1 ecu.

I don't have a EGR on the B20 do I? How do I get rid of this crap?

 

What ECU are you running? I didn't think any B series had EGR valves but I never work on B20s.

Code 10, replace the sensor with a known working one (your old motor has the perfect one for you) and check it.

IAT sensor are the same from 88-00 so pick one up at a junk yard.

 

ok I have a Po7 ecu which is out of a Vx hatch with e-vtec Found out after some searching this is not the ecu for my set up. Im now looking for a obd1 Ls ecu. Anyone know where I can get a good price on one?

After clearing the codes by draining the battery I checked the codes again after a short drive and came up the code 12 which is the egr system, the iat was thrown because I dissconnected it to see if that was my problem since I looked on a code sheet for obd0 and found 12 to be the iat on the sheet.

So after thinking for a minute I suddenly got this idea "hey im obd1 Dumbass" rechecked them and got the 12 to the new obd1 sheet and have a egr problem but no egr LoL.