Fuel Pressure drops to zero after start
Fuel Pressure drops to zero after start I went to the track today and made three passes and then the fuel pressure drop to 0 before I started the car for a fourth pass.
I can hear the pump prime when turning the key to on. Its holds about 10psi before I start it. Soon as I start the car the fuel pressure drops to 0.
Any ideas?
I can hear the pump prime when turning the key to on. Its holds about 10psi before I start it. Soon as I start the car the fuel pressure drops to 0.
Any ideas?
Best way to drain the tank is with a small diameter hose. Push it in the fuel filler, just hold the little flap with a screwdriver or your finger. If you screw with it a while you'll hit gas. I blow in the hose and listen for bubbles in the gas. Then start a siphon. It's not easy to get the hose to go to the bottom of the tank. Took me 4 tries to get it. It kept hitting something and I was sure there was a screen or something in the way. Just keep at it and you'll get it.
If you're going to drop the tank, get a manual and follow it. I did it today. 3 1/2 hours. There are write ups on the web. I went to the library and printed out the instructions. They were close but not exactly right. I dropped the muffler and left it under the car. Covered it with an old blanket and used it for a pillow. I'm not looking forward to putting it back in
Al
2002 Z28 M6
If you're going to drop the tank, get a manual and follow it. I did it today. 3 1/2 hours. There are write ups on the web. I went to the library and printed out the instructions. They were close but not exactly right. I dropped the muffler and left it under the car. Covered it with an old blanket and used it for a pillow. I'm not looking forward to putting it back in
Al
2002 Z28 M6
https://ls1tech.com/forums/fueling-injection/855202-98-walbro-pump-install.html
this is the way I did it. good luck...
this is the way I did it. good luck...
Thanks fellas.
I have dropped the tank before and put it back in, I just never have had a full tank of gas in it before I did dropped it.
That is I wanted to find out a easy way to siphon the tank.
Thanks agin fellas.
I have dropped the tank before and put it back in, I just never have had a full tank of gas in it before I did dropped it.
That is I wanted to find out a easy way to siphon the tank.
Thanks agin fellas.
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What kind of fuel pump are you using? It sounds like there is a problem with something surrounding it. Either that, or your fuel pump itself is taking a dump on you.
When I initially did my dual in tank Walbro system, I had an issue with the fuel pump always popping off the rubber fuel line that attached itself to the fuel pump. It would pretty much do the same thing you are describing. I would see the fuel pressure drop to about 0. The rubber hose would never stay on no matter how tight I clamped it on the pump, and the tighter I clamped it, the more it destroyed the hose. After having to deal with this at least a dozen times, I ended up going with a steel braded line instead of the rubber, and I haven't had any issues with it since. I could still hear the pump trying to prime, but no fuel pressure. This possibly could be what you are experiencing. Get the fuel tank opened up and take a look. I would bet that the issue you are experiencing is coming from there.
If its not, there is probably a fuel leak somewhere. Check all your fuel lines and hoses, including the fuel pressure regulator and injectors.
Good luck. Let us know what happens.
When I initially did my dual in tank Walbro system, I had an issue with the fuel pump always popping off the rubber fuel line that attached itself to the fuel pump. It would pretty much do the same thing you are describing. I would see the fuel pressure drop to about 0. The rubber hose would never stay on no matter how tight I clamped it on the pump, and the tighter I clamped it, the more it destroyed the hose. After having to deal with this at least a dozen times, I ended up going with a steel braded line instead of the rubber, and I haven't had any issues with it since. I could still hear the pump trying to prime, but no fuel pressure. This possibly could be what you are experiencing. Get the fuel tank opened up and take a look. I would bet that the issue you are experiencing is coming from there.
If its not, there is probably a fuel leak somewhere. Check all your fuel lines and hoses, including the fuel pressure regulator and injectors.
Good luck. Let us know what happens.
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Uhhh.... No they don't. 
We have been seeing the rubber line that comes with the Walbro pumps turning (for lack of a better word) gummy, with whatever is in todays fuels. The inside of the line can eventually become blocked off, and we have found that using either braided line or oem line cures the problem. Bob
Thanks, fellas!
I have a serious bug to work out.
I cut a fuel door in rear of the car so that I can see the pump working and acesses it quicker.
All of a sudden the pump has started working but there is no fuel pressure. I am going to check the guage ground tommorow to see if that is the issue. Last time the car would go all the way lean and then shut off. I am going to also log the injectors pids too see if they may be causing the problem.
Bob it is a walbro
I have a serious bug to work out.
I cut a fuel door in rear of the car so that I can see the pump working and acesses it quicker.
All of a sudden the pump has started working but there is no fuel pressure. I am going to check the guage ground tommorow to see if that is the issue. Last time the car would go all the way lean and then shut off. I am going to also log the injectors pids too see if they may be causing the problem.
Bob it is a walbro
