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"To prevent percolation of the fuel at hot restart idle, vacuum to the pressure regulator is momentarily cut and the fuel injection pressure is is increased to slightly more than 41.2psi." ...from the online manual.

When my engine is warmed up, the idle is erratic and goes as low as 550RPM or so. My ZE does not have a PRC solenoid. Vacuum is taken directly from the IM to the fuel pressure regulator. My ECU is throwing code 25. Does anyone think that this could be causing my poor idle when the engine is hot? It runs perfectly when cold and smoothly when driving, just poorly at hot idle.

Also, I'm getting all of the EGR codes. 16 - EGR valve position, 28 - EGR Solenoid Vacuum, 29 - EGR Solenoid Vent. Aren't these codes supposed to be erased by the Probinator chip? My Ze didn't have the block off plate on the EGR gallery so I bolted my EGR valve to it to cover it and connected the EGR pipe from the exhaust. Is this why the ECU is giving me codes?

Any input is appreciated.

Do curved neck ZE's have the PRC solenoid?

I'm going to grab one from the junk yard and hose it up to the IM the way it is on the K8 and see if that improves my idle.

Still wondering if others have had this problem. All you ZE guys...are you using the PRC system?

yeah with a probinator chip you shouldnt get any cel's especially not any egr related codes.

yo wytbishop

i just pulled my cel codes as well and i got 16, 25, 28, and 29.

i also dont have my fpr hooked up because the ze's dont have that.

are you using your k8 ecu?? you are getting the same codes as i am and i have my k8 ecu still. sounds to me like probinator didnt chip your ecu.

I've seen some diagrams with and without it, I have mine hooked up just in case, it doesn't hurt anything.

I installed the chip myself. I'm gonna reset the ECU and pull them again. Those are the same codes I had with the stock K8 ECU. When I first installed the Probinator ECU it wouldn't run because I had the chip backwards (there is no direction indication on the chip). I turned the chip around and it fired right up. It seems odd that I should get exactly the same codes with or without the Probinator chip.

Mad Cow wrote:I've seen some diagrams with and without it, I have mine hooked up just in case, it doesn't hurt anything.

I am just wondering if it is causing my rough idle. I don't think it should, but I can't figure out what is.

It might have something to do with it, it can't hurt to try.

Did you mange to fix your code 25?