QuestionQUESTION: I recently replaced the fuel pressure regulator in my 1995 blazer (had good pressure until the pump shut off). After replacing it didn't want to run or idle. I put new injectors in it and now it runs better but still idles rough and has no power. I just took the plugs out and all but 2 are white. I cleaned my EGR valve and still nothing. Replaced all my relays and Im stuck dont know what to do please help
Frank
ANSWER: HI FRANK,HOW DO YOU KNOW YOUR FUEL PRESSURE IS GOOD ??? DID YOU CK IT WITH A GAUGE ?? IF SO WHAT WAS THE READING 40 TO 50 LBS ??? YOU SAY IT HAD GOOD PRESSURE TILL PUMP SHUT OFF ??? DO YOU MEAN WHEN YOU TURN THE KEY OFF THE PUMP WENT ON FOR 3 TO 4 SECONDS. THIS IS NORMAL, BUT WE STILL DO NOT KNOW WHAT YOUR FUEL PRESSURE IS,OR MAYBE YOU DO..AS FAR AS THE PLUGS BEING WHITE ALOT OF THINGS CAN CAUSE THIS. BAD O2 SENSORS,VACUUM LEAKS ETC..IF YOU DO NOT HAVE A FUEL PRESSURE GAUGE TRY THIS POOR MANS TEST,REMOVE THE FUEL RAIL TEST PORT CAP,WILL LOOK LIKE A TIRE VALVE STEM CAP..HAVE SOMEONE CRANK THE ENGINE OVER FOR 1 MINUTE WHILE YOU PUSH DOWN ON THE SHRADER VALVE AT THE TEST PORT. ALL THE WHILE THIS ENGINE IS CRANKING OVER THERE SHOULD BE FUEL COMING FROM THIS PORT,NOT JUST WHEN YOU TURN THE KEY FOR THE FIRST 2 OR SO SECONDS,[ALL THE TIME]IF THERE IS FUEL THERE ALL THE WHILE THE ENG IS CRANKING OVER THEN THE FUEL PUMP IS MORE THEN LIKELY OK..IF PRESSURE IS THERE ONLY FOR THE FIRST FEW SESONDS THEN THE FUEL PUMP IS BAD. THIS IS CALLED RESIDUAL PRESSURE,,, AND IT WILL FOOL YOU ALL THE TIME !!!!!THIS SHOULD KEEP YOU BUSY FOR AWHILE..LET ME KNOW HOW IT GOES..GOOD LUCK,,,TOM
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QUESTION: Before I replaced the fuel pressure regulator I hooked up a fuel pressure tester. It read 50psi when I turned the key on but the engine was not running as soon as the fuel pump turned off, the pressure immediately started to drop I solved that by replacing the regulator and now it holds 52psi for hours. My question is what would make it run/idle roughly after replacing the regulator? could it be a bad EGR valve? I tried to clean the valve but idk if it worked
ANSWER: HI FRANK,OK NOW I SEE WHAT IS GOING ON..WHEN YOU CLEANED THE EGR VALVE DID YOU NOTICE ANY CARBON STUCK UNDER THE PINTLE VALVE ??? IF SO DID YOU REMOVE THIS,THIS IS VERY COMMON ON THESE ENGINES.
A STUCK OPEN EGR VALVE WILL CAUSE THE ENG NOT TO IDLE AND RUN VERY ROUGH..IF YOU DID NOTICE A PIECE OF CARBON STUCK UNDER THE VALVE [PINTLE] THEY SELL A SCREEN TO GO OVER THE EGR VALVE HOLE TO PREVENT ANY CARBON FROM GETTING STUCK IN THIS VALVE..BUT LETS SAY YOU DID NOT NOTICE ANY CARBON IT IS POSSIBLE THAT THE VALVE IS NOT CLOSING OFF AT IDLE,WHICH WILL CAUSE WHAT YOU ARE HAVING.IF YOU REMOVE THIS EGR VALVE PUSH THE VALVE IN AND OUT IT SHOULD MOVE VERY FREELY..NO BINDING ALLOWED HERE AT ALL.IF IT IS BINDING,REPLACE THE EGR VALVE....AS FAR AS WHAT COULD HAPPEN AFTER YOU REPLACED THE REGULATOR IS MAYBE SOME DIRT GET STUCK IN A FUEL INJ. IF SO YOU WILL NEED TO DIAGNOSE WHICH CYLINDER IS CAUSING THIS TO SKIP AND CK THE PLUG AND POSS INJ..LET ME KNOW WHAT HAPPENS,GOOD LUCK TO YOU,,,TOM
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QUESTION: Thank you so much. When I cleaned the EGR I didn't notice any carbon in the EGR itself but the hole that the EGR bolts up to was caked with carbon so I broke it off but I never cleaned any of it out and just left it there. Could that be causing my problem? Could that carbon have got into the EGR and be stopping it from closing? And which part is the pintle valve on the EGR?
AnswerHI FRANK,YES NOT REMOVING THAT CARBON COULD CAUSE A PIECE OF CARBON TO GET CAUGHT UNDER THE VALVE AND PREVENT IT FROM CLOSING. YOU WILL SEE THAT WHEN YOU REMOVE THE VALVE AND FLIP IT UPSIDE DOWN..THE VALVE THAT YOU PUSH IN AND OUT ON THE BOTTOM SIDE IS CALLED THE PINTE VALVE. THIS NEEDS TO MOVE FREELY IN ITS BORE AND SEAT FULLY..WHEN YOU PUSH IT IN LET IT SNAP SHUT. YOU WILL HEAR A AUDIBLE CLICK. IF YOU HEAR THAT,,, IT IS SEATING...LET ME KNOW TOM....
