Dtc P0450 Evap Press Sensor

[cwack29]

To start off the car is a 98 gst converted to awd, check engine light came on with these codes, P0300 Random misfire, and P0450 Evap emmisions control pressure sensor. Now in the manual it says that the P0450 is specific to the 2.4L and this sensor is only shown on the 2.4L gas tank whereas the awd tank has no sensor on it. When light came on I was on the highway cruising about 70mph and engine started misfiring and running lean acc to my AFR gauge (about 17:1) Car seems to run fine around town. Also there is a code for the fuel pressure regulator solenoid, I recently added a fuel lab FPR without reinstalling the solenoid as the new FPR adjusts itself to vacuum or boost, is this OK or should the solenoid be installed?

Is it possible that the computer was swapped with one from a 2.4L, and this code is actually something different? I still have the vent solenoid from the gst and routed it to the evap line coming off of the rollover valve on the tank and runs to the canister under the battery. I'm stuck so any info would help!! Thanks

 

[stevo911]

Did it work before the AFPR? Also you said its a AWD convert so chances are theres a AWD ECU put into it and they left the old gas tank on so the ECU is looking for a sensor that doesnt exist.

 

[stevo911]

Would also check all the lines going to the canister make sure they are not cracked etc...

 

[rush2252]

without reinstalling the solenoid as the new FPR adjusts itself to vacuum or boost, is this OK or should the solenoid be installed?

plug the solenoid back in if you want to get rid of this light. As for the others not sure...

If your running that lean I would definately recheck pressures. You should be running 33psi w the vacuum line hooked up on the stock FPR and 42-45 unhooked. If your new AFPR runs off vacuum/boost make sure you have a good source and its not T'd anywhere... It sounds to me like your REG isnt working properly or isnt adjusted correctly...


Kolby

If it helps I removed everything emissions wise on my 95 and it runs. It has a CEL but always has. I was going for the cleaner engine bay. I remove the FPR solenoid from what Ive read its only used for initial startup. I also removed the EGR purge solenoid and all the nasty vacuum lines.

 

[cwack29]

I did the swap and it's a gsx gas tank or driveshaft wouldn't fit. ONly some times it will do this, and only on the highway, FPR is set correctly. I have a gauge on it, it does however have a T on it but always has. Could it be a fuel pump? It drives fine around town, and when it does act up, as soon as I pull off the highway it runs fine again.

 

[cwack29]

Yeah it turns out my FPR was set to high, I readjusted it to 33 psi at idle with vacuum line connected. I took it for a couple test drives and hasn't done it again. Thanks for your help!!

 

[rush2252]

No prob.. To answer your initial question I dont think the 2.4L ECU will plug into the turbo harness.

If your worried about CEL after you get everything resolved get DSMlink you can get rid of some of the self checks at initial startup and wont have to worry about a CEL again


Kolby