mine was $100

 

could an emission evap purge valve cause lots of issues ??
have been dealing with codes :
P0172 system too rich bank 1
P0175 system too rich bank 2 just not able to delete ! so I was trying to DO a fuel pressure check - out of curiosity disconnected the evap purge valve and connected back in again..
so I started the car several times them started getting codes P0172 and P0445 … system purge control valve circuit shorted .. deleted several times kept coming back .. then car just wouldn't start just crank .
looked at fuel pump no power looked at fuse no power , fuel pump plug no power - disconnected evap purge valve and one of hoses too reconnected them again .
car started AGAIN..

COULD THIS DARN EVAP PURGE VALVE BE THE CULPRID OF LOTS OF ISSUES : SUCH running a bit rough , restricted performance ,, to all the codes from misfires on cylinders 1.3.5 to system too rich bank1,2 ???

 

I'd read the fuel pressure first.

Next, figure out the misfires. EVAP stuff might be involved but typically isn't.

With the work that's been done, disturbed wiring & connectors must be suspects.

A tangent is sort of interesting but not worth exploring yet.

 

this morning, I used my carsoft I930 to read the fuel rail pressure 381 kpa = 55.25 psi I 55 psi should be at wide open throttle AND 45 psi at idle ?? according to the FUEL SYSTEM SPECIFICATION

also code P0445 evap purge valve... gone only P0172 and P0175 remains there .. checked all wiring connections pretty secured tight..

I m getting a 51k miles throttle body from Ebay includes sensors hoping it will Do some good .. I know it looks like I keep throwing money into it .. it has been a hit and missed !!

many thanks Again to all..

 

your fuel pressure specs are correct....55psi at idle is too high...I have checked mine at wot and it is 55 to 56...idle 45 to 46...i am not very familiar with the operation of these returnless fuel systems, so why yours is high I cannot help...i am thinking the fuel pressure is too high at prime and startup and causing troubles...maybe the secondary full load pump is turning on way too soon...at throttle body is not a bad idea because that is where the rubber hits the road as far as fueling goes

 

One possibility is the fuel pressure sensor is reading high. Unfortunately, the computer uses this sensor to control the fuel pump output. It sees 55 PSI and scales back the pump output to reach the intended 45 PSI. If the sensor is stuck at 55 PSI, the computer never gets the feedback of accurate fuel pressure, and keeps scaling back the pump, unaware of what is really happening.

I'm not sure if this would set any fault codes. But it would be very helpful to get a true reading with a mechanical pressure gauge, and compare to the scanner value. IIRC, there's no test port on 2003+ cars, so this may not be an easy task.

 

Did you check the vacuum line and electrical connection to the FPR?

 

One quick thought for roughly checking the accuracy of the fuel pressure sensor:

Pull the fuse or relay so the fuel pump won’t run. Bleed off the injector rail so the fuel pressure drops to zero. Not sure exactly how to do that without a test port, but hopefully it’s not too difficult.

Connect your scanner and turn on the ignition. Don’t try to start. Just read the pressure seen by the scanner. If all is good, it should show zero.

This won’t guarantee the sensor is accurate at the upper end of the scale, but if inaccurate with no pressure, then you’ve got a problem.

 

WELL...….. I got the throttle body from ebay this afternoom, swapped them out . drove it around few times started up several times - . it seems to idle much better NO current codes ,, just the pending codes same two ..(hopefully those will be gone after certain miles or start ups )

I keeping my fingers cross this issue is solved ..

IF IT doesn't then I'll be following that procedure KR98664 thanks for figuring that out.. also how do you check the vacuum line is that the schrader valve by evap purge valve ..? and there was no power to the fuel pump relay FPR before I worked on the purge valve ..

few hours later ……..
car getting all codes back again from I mean even the misfires WTF..... I m considering the car battery 7 years old ??? even thought autozone says is ok . when I do charge it on my charger it does take hours to get it fully charge..

 

story goes on...……..

I have bought a new battery , replaced it drove car yesterday It drove pretty good . an observation previously a/c climate control read out would NOT come on for the most part - NOW is always ON when system its turned ON ! happy about that ..

this morning . I started the car left it warming outside after few minutes car just DIE....so I proceeded to disconnect the EVAP purge valve plug and hose from the charcoal canister -
plugged everything back in again - WALLA... car started again

so I m thinking the EVAP purge valve is definitely causing problems ?? I ordered one from ebay around 55.00

your thought ??