hard starting
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Joined: Aug 2008
Posts: 53
Likes: 0
From: Pemberton NJ
hard starting
I have a 86...and it takes 3 or 4 times to start. It will start for a second or two and die out. This happens a couple times and then it will idle up and down and when it warms up everything is fine. Usually around 115 degrees she will purr nicely. Any thoughts on how to fix this?
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
Check your fuel pressure. It should be around 34-40 psi when you turn on the key and the pressure should hold. If it does not hold then do the following tests....
••••• TESTING FOR LOSS OF FUEL PRESSURE
... Here are the sure fail tests for the fuel system to save you time and money.. Take a fuel pressure gauge attach it to the Schrader valve.. Turn the key on and off a few times to build up the pressure in the system... If you are having starting trouble the pressure will probably drop as soon as it hits 38 or 40 and the pump turns off it will probably leak back to zero within a few minutes. Ok now right after you prime the system pinch off the return line near the tank if the pressure drop stops it is a bad fuel pressure regulator.... Next pinch off the feed line if the pressure holds then the leak is before the point where you pinched the line IE fuel pump check valve..hole in the metal line on the sending unit caused by it rubbing on the inside of the tank you should visibly be able to see this if you pull the pump and the sending unit...(this was my problem) or the pulse dampener which is the piece between the pump and metal line on the sending unit.. the diaphragm tears.. and last if you pinch both the feed and return line near the tank and the leak down of the pressure continues then a fuel injector is your problem.. This is the GM test.. saves time and money..
•• disconnect the vacuum line from fuel pressure regulator
••••• TESTING FOR LOSS OF FUEL PRESSURE
... Here are the sure fail tests for the fuel system to save you time and money.. Take a fuel pressure gauge attach it to the Schrader valve.. Turn the key on and off a few times to build up the pressure in the system... If you are having starting trouble the pressure will probably drop as soon as it hits 38 or 40 and the pump turns off it will probably leak back to zero within a few minutes. Ok now right after you prime the system pinch off the return line near the tank if the pressure drop stops it is a bad fuel pressure regulator.... Next pinch off the feed line if the pressure holds then the leak is before the point where you pinched the line IE fuel pump check valve..hole in the metal line on the sending unit caused by it rubbing on the inside of the tank you should visibly be able to see this if you pull the pump and the sending unit...(this was my problem) or the pulse dampener which is the piece between the pump and metal line on the sending unit.. the diaphragm tears.. and last if you pinch both the feed and return line near the tank and the leak down of the pressure continues then a fuel injector is your problem.. This is the GM test.. saves time and money..
•• disconnect the vacuum line from fuel pressure regulator
Instructor
Joined: Jul 2009
Posts: 242
Likes: 7
From: Bowling Green KY
My 94 is doing the same thing. Used to fire right up the first time and now it takes several tries, with the idle fluctuating up and down before it evens out. It's throwing a code too but it's a C15. Why would a fuel pump be the issue at start up and not after it gets warmed up? I'm ignorant so I'm just asking.
