mhewitt

i have a 98 civic ex with a ls/vtec swap, im using the oem obd2 harness on the engine while using a chipped p28 ecu with a obd2/obd1 jumper harness. starts and runs fine, but thrws a code 6 and code 10. iat sensor and coolant temp sensor. i check both sensors via haynes manual n checks out good. i clear codes using back up fuse n try again, same thing. i change sensors out with known working ones from my other car n same codes pop up. i check voltage to plug, haynes says approx. 5 volts, both have 11v. what could be causing this problem?

0HAMOTORSPORTS

Have you checked continuity from each connector at the sensor to the correct pin at the ECU? chances are you may have some plugs mis-matched...

mhewitt

well the coolant temp sensor has to be the right plug because its the plug that comes out of the harness right beside the grounding bolt on the thermo. housing, not sure about the iat plug but its the only one that would reach the top of the gsr manifold where the sensor is located, it has a black wire n a green wire. anne have a ecu pinout so i can check continuity?

0HAMOTORSPORTS

That is the incorrect plug for the engine coolant temp sensor. The one you just mentioned is for the radiator fan switch (on thermostat housing). The engine coolant temp sensor is on the side of the head beneath the distributor and has a two pin connector.

You have the intake air temp and purge solenoid plugs flip-flopped. This is a VERY common mistake on the GSR manifolds. If you open your ECU you will also find that you've fried the transistor at Q31 now because you've sent positive battery power where it shouldn't have gone by switching those plugs.

grumblemarc

iTrader: (4)

Ouch.

mhewitt

wow, well that sucks, thanks for the info and help. what is that transistor for?

grumblemarc

iTrader: (4)

To make the ECU go. Does it really matter? Just get it fixed.

mhewitt

ummmm.... the ecu still works perfectly and the car runs fine other than the cel is on. if the tansistor is for something like reading knock sensor then im not worried because i dont have one, get what im saying?

0HAMOTORSPORTS

The transistor is used for the purge solenoid. The car will run perfectly fine without it, but may not meet emissions requirements for evap tests.

mhewitt

i cant even find my purge solenoid that was on the car so im not gonna spend too much time with it, thanks alot for all the info! im gonna swap this stuff up n hopefully get these cel's gone