2002 Chevy Tahoe - 5.3L Code VIN Z P0327

[abmauto]

I Have a 2002 Chevy tahoe 5.3 Vin z Code PO 327 KS 1 Short/low voltage

This Car Is From Another Shop I was Told they replace the 2 knock sensors and this code keeps coming back. I Installed a scanner and the code is there On Data Screen Ks reads 0 Is it a normal valve of 0 or should it be something else. This Also Had A short in the ecm fuse which i fixed the wire harness rub on the the front driveshaft. i repair the harness and we had to replace the ecm and flash it. Also It Has A stalling problem. the other shop told me they replaced the fuel pump and its still doing it. I put a fuel pressure gage on the rail and found that the fuel pressure is only 42 lbs it should be 56 tp 66lbs under all conditions. I am thinking it the fuel pressure regulator.
There Is a zero reading on the knock sensor. I just put a new fuel pressure regulator in and now the pressure is where it should be, But it still stalls when you floor it to pas or if you are driving at 30to 55 mikes per hour.
Any help on this thanks mike A.B.M Automotive 631-878-0713 or http://www.centermorichesgulf.com e mail abmauto@optonline.net

[ricmorin]

You can check the sensor by measuring resistance. Should be between 93 and 107k ohms. I believe the harness runs under the manifold. Prime candidate for a rub-through. Tapping near the sensor should produce AC voltage at the PCM. Single wire sensors should have 5 volts on the wire pcm side when unplugged. There is a TSB fr the REAR sensor water intrusion. Your code is for the front, but it's not unreasonable to check anyway.

We've fixed a few of these with stalling/stability problems with a throttle body cleaning. There's a TSB on that too. Wouldn't have beleived it if I didn't see it with my own two eyes. The fuel pressure specs for vin Z (flex fuel) are lower than gasoline. Should be 48-54. Your's may be just gauge error.

HTH

[steven kiser]

completely agree with the throttle body cleaning and like ric said i wouldn't believe it until i saw it with my own eyes. my sighting was a stumble on a corvette ZR1. i use the b&g kit, seems to work the best for me. another issue with the fuel supply is a lean knock. although not on this particular model i've had lean knocks mess with the sensors and scatter the timing. the other stall issue may be that if the pvm is reading a knock the timing will be so retarded it will cause a stumbling issue. watch the scanner readings while vehicle is running with and without the sensors unplugged and see if the timing roams. with them connected it should a bit with them unplugged it should remain constant with the rpm off idle. this may also need a set of plugs and you may have to go on a witch hunt to repair other repairs from other shops. on harness repairs with multiple splices from other shops i always make sure the wires haven't been crossed. seen that a few times. also take a good look on the harness for probe punctures.

[abmauto]

Well I did the cleaaning and we still have a stalling problem.

[steven kiser]

when you matt it it stalls as well as between 30-55 mph. what about above 55. does it stall right out or flatten or strain before it dies. i would watch the tps reading through my scanner to see if it zeros out and is causing the stall. does this act like a rev limiter?