Starting-Stalling issues
#1
Starting-Stalling issues
I just want to start off saying that I am new to the forum, and did not take the time to see if there was a thread posted about the problem I am having with my 01 GP GT, 3800 V6.
I would say since about 120,000 miles, I have been having a "hard start" issue with my Grand Prix. I have 140,000 on it now, and recently replaced intake gaskets, entire plenum, and all the sensors attached to that, and the throttle body. New plugs, wires, coils, transmission fluid(complete flush including torque converter), radiator flush(no more dex-cool), valve cover gaskets. Also around 132,000 miles, I replaced the fuel pump with one that had 84,000 miles(limited funds, bought on ebay for $45 w/free shipping). Seemed like the hard start issue was a little better until recently.
The engine will crank over, and almost seem like it laps itself...the starter will crank the motor, then the motor shakes...if you apply a little gas pedal, it will start. After it starts the tach will jump from 900 rpms up to 1500 rpms, then down to 500 rpms, at which point it will either stall, or jump the RPM'* again and stay running. Usually it starts right back up, but I have noticed the time it takes to fire has increased dramatically. Fuel pressure readings are normal, no check engine light. I have driven several miles with the pressure gauge on, and when it does stall, I have only lost 1-2 lbs of pressure in the fuel line over an hour. I have checked all the grounds, put dielectric grease on everything with a connector. Things I have not changed are EGR valve, Fuel Pressure Regulator, Ignition module...but like I said, I have no check engine light to give me an indication where to start. I am 75% certain it'* a fuel/spark issue. If anyone has any idea'*, I would appreciate it.
I would say since about 120,000 miles, I have been having a "hard start" issue with my Grand Prix. I have 140,000 on it now, and recently replaced intake gaskets, entire plenum, and all the sensors attached to that, and the throttle body. New plugs, wires, coils, transmission fluid(complete flush including torque converter), radiator flush(no more dex-cool), valve cover gaskets. Also around 132,000 miles, I replaced the fuel pump with one that had 84,000 miles(limited funds, bought on ebay for $45 w/free shipping). Seemed like the hard start issue was a little better until recently.
The engine will crank over, and almost seem like it laps itself...the starter will crank the motor, then the motor shakes...if you apply a little gas pedal, it will start. After it starts the tach will jump from 900 rpms up to 1500 rpms, then down to 500 rpms, at which point it will either stall, or jump the RPM'* again and stay running. Usually it starts right back up, but I have noticed the time it takes to fire has increased dramatically. Fuel pressure readings are normal, no check engine light. I have driven several miles with the pressure gauge on, and when it does stall, I have only lost 1-2 lbs of pressure in the fuel line over an hour. I have checked all the grounds, put dielectric grease on everything with a connector. Things I have not changed are EGR valve, Fuel Pressure Regulator, Ignition module...but like I said, I have no check engine light to give me an indication where to start. I am 75% certain it'* a fuel/spark issue. If anyone has any idea'*, I would appreciate it.
#2
I have also thought about the possibility of a vacuum leak, but I replaced every vacuum hose I could locate, and even replaced the fuel cap o-ring..every 2 or 3 fill up'* I put a little vaseline on the o-ring to keep it from dry rotting...
#4
Ok, so I did go out, pulled the vacuum line off the FPR...I did not see any gas come out of it, and there aren't any puddles to presume it'* leaking. I did however smell gas...Please Car God, let it be that simple...lol
#5
Senior Member
True Car Nut
You would not see puddles, and you would not see signs of leaking. There is a rubber diaphragm inside the fuel pressure regulator that moves up and down with varying levels of vacuum to control fuel pressure. If that diaphragm tears, gas will be sucked into the vacuum hose. It won't leak outside the FPR, it won't puddle, the gas goes into the intake system through the vacuum hose. The only sign (other than the symptoms you are experiencing) is when you pull the vacuum hose off the FPR you can smell the gas.
Based on your observation it sounds like you need a new FPR. Don't pray to the Car God, its the GMForum that'* coming to your rescue.
#6
Senior Member
True Car Nut
The FPR'* failing on the vacuum side is pretty common with the 3800 II'* from what I have heard, and it will cause your exact issues as Roy has said already.
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