So I installed a S2 IM, ITR cams and stock unchipped USDM ITR ECU in my buddies 98 GSR. Figured this setup is close to a stock ITR and won't need a full blown tune. It's a GSR block with ITR pistons and Edelbrock header with 2.5" exhaust. Anyways, after the install he got a CEL P0453 and a P0450. Both pertaining to Evap solenoid if my scanner is right. What would be causing this CEL? I have the evap solenoid vacuum line T'ed to the PCV valve vacuum line which is getting vacuum from the nipple at the top front of the S2 IM.
On the stock GSR IM, this Evap solenoid vacuum line has it's own dedicated vacuum line connected to the intake manifold.

 

Someone told me the ITR ecu is looking for a fuel tank pressure sensor signal, but the GSR is not equipped with one. Any truth to this?

 

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I am doing an obd2a swap on my 95 DB so I can smog it with a 98 ITR. I used a 97 GSR main harness and found that it was not pinned for the fuel tank pressure signal. I have been worried that I may get this code when I finish up later this week. My research has found that JDM ecu’s don’t look for the fuel tank pressure solenoid. But if you use a 98 USDM ecu the pressure solenoid needs to be added to the tank. At this time I cannot say whether or not you need to replace the entire tank or just the assembly. If you look at a 98 Service Manual you will see that pin D15 is used for the signal to the ECU. The Fuel tank pressure sensor is a 3 pin sensor. There is some confusion as to what cars and years it shows up on but here is an article that may help you.
http://www.ff-squad.com/technet/code91.htm
hope this helps.

 

Yeah I seen that article and was hoping it wouldn't be the Fuel Tank Pressure Sensor, cause here in Cali, JDM Ecu won't pass smog test. Looks like I'm gonna have to try the linear potentiometer trick.

 

Why would the ecu be looking for a Fuel Tank Pressure Sensors? Don't GSR's come with them?