fuel preasure drop
Thread Starter
Drifting
Joined: Aug 2011
Posts: 1,861
Likes: 1
From: panama panama
fuel preasure drop
My vette having preformance problem.
I plug my fuel preasure gauge today
idle at parking. about 35 psi.
put it in drive and step on the gas. the fuel preasure drop to 20 psi for about 2 seconds. I let go the gas and fuel get back to 35 psi some time up to 40 psi.
when step on the gas pedal the fuel preasure act erratical. like I mention before
If I put in parking and step on the gas fuel preasure show ok 35 psi no problem. the poor preformance start when driving the car
the fuel pump is almost new. about 6 month maybe less.
fuel filter about 8 month.
I dont drive the car much maybe once a week
forgot to mention. the fuel preasure hold ok, when I turn off the engine
I plug my fuel preasure gauge today
idle at parking. about 35 psi.
put it in drive and step on the gas. the fuel preasure drop to 20 psi for about 2 seconds. I let go the gas and fuel get back to 35 psi some time up to 40 psi.
when step on the gas pedal the fuel preasure act erratical. like I mention before
If I put in parking and step on the gas fuel preasure show ok 35 psi no problem. the poor preformance start when driving the car
the fuel pump is almost new. about 6 month maybe less.
fuel filter about 8 month.
I dont drive the car much maybe once a week
forgot to mention. the fuel preasure hold ok, when I turn off the engine
Last edited by hitmanpty; Dec 10, 2013 at 08:54 PM.
Safety Car
Joined: Jan 2004
Posts: 3,783
Likes: 15
From: Northern California
What are the fuel injectors resistance in Ohms?...
Disconnect each fuel injectors wire clip and measure the resistance in ohms, just touch the voltmeter leads to the two terminals on top of each injector.
Each injector should measure around 16 ohms, 15 ohms or less usually indicates a failing injector.
.
Disconnect each fuel injectors wire clip and measure the resistance in ohms, just touch the voltmeter leads to the two terminals on top of each injector.
Each injector should measure around 16 ohms, 15 ohms or less usually indicates a failing injector.
.
Last edited by GKK; Dec 10, 2013 at 10:20 PM.
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
If the pressure comes, up your fuel reg is faulty and bleeding off pressure.
Pull the vac line off the reg and check for raw fuel inside ; indicates a broken diaphragm in the reg.
FWIW
Should have closer to 39 psi @ idle ( with vac line connected ) and 43.5 psi with the vac line disconnected.
Thread Starter
Drifting
Joined: Aug 2011
Posts: 1,861
Likes: 1
From: panama panama
Clamp the return line closed and retest.
If the pressure comes, up your fuel reg is faulty and bleeding off pressure.
Pull the vac line off the reg and check for raw fuel inside ; indicates a broken diaphragm in the reg.
FWIW
Should have closer to 39 psi @ idle ( with vac line connected ) and 43.5 psi with the vac line disconnected.
If the pressure comes, up your fuel reg is faulty and bleeding off pressure.
Pull the vac line off the reg and check for raw fuel inside ; indicates a broken diaphragm in the reg.
FWIW
Should have closer to 39 psi @ idle ( with vac line connected ) and 43.5 psi with the vac line disconnected.
what is (FWIW)
Thread Starter
Drifting
Joined: Aug 2011
Posts: 1,861
Likes: 1
From: panama panama
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Just on a guess, it sounds like a flow problem similar to a clogged fuel filter but we know it's new so I will forget about it for now.
But I would check the installation of the new pump in the tank. Make sure the sock is positioned correctly and not restricting flow in some strange way. I would also just take a look at the bottom of the tank to see if you got a load of bad gas with lots of crap in it. If there is a lot of dirt and stuff in the tank, may cause a flow problem.
But I would check the installation of the new pump in the tank. Make sure the sock is positioned correctly and not restricting flow in some strange way. I would also just take a look at the bottom of the tank to see if you got a load of bad gas with lots of crap in it. If there is a lot of dirt and stuff in the tank, may cause a flow problem.
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Thread Starter
Drifting
Joined: Aug 2011
Posts: 1,861
Likes: 1
From: panama panama
Today i try to start the car. And the fuel pump did not work.
I jump the fuel pump relay. Giving direct volts to pump. And nothing.
I disconect the oil swich and jump that to and no fuel pump
I will put a direct wire from battery to full pump tomorow. For test. If the pump work i know i have a short some where. If the pump not work then i know something is wrong with the fuel pump
I have to get my car home
I jump the fuel pump relay. Giving direct volts to pump. And nothing.
I disconect the oil swich and jump that to and no fuel pump
I will put a direct wire from battery to full pump tomorow. For test. If the pump work i know i have a short some where. If the pump not work then i know something is wrong with the fuel pump
I have to get my car home
Thread Starter
Drifting
Joined: Aug 2011
Posts: 1,861
Likes: 1
From: panama panama
update. I set a direct wire from battery to fuel pump. and the fuel pump did nothing.
so I narrow the problem to the fuel pump. I thought the fuel pump isnt the issue, because I change it my self about 4 month ago.
I was going to remove the pump but I don't have my tools here. so I will have to wait into tomorrow
so I narrow the problem to the fuel pump. I thought the fuel pump isnt the issue, because I change it my self about 4 month ago.
I was going to remove the pump but I don't have my tools here. so I will have to wait into tomorrow
Safety Car
Joined: Jan 2004
Posts: 3,783
Likes: 15
From: Northern California
Well, at least you narrowed it down and the fuel pump is very easy to replace!...
Also, make sure the inside of the fuel take is clean with no debris or rust floating around, which can clog the fuel pump and make it work harder.
Also, make sure the inside of the fuel take is clean with no debris or rust floating around, which can clog the fuel pump and make it work harder.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
check the connector on the fuel pump, and re ground the wire on the tank. If yours is as cruddy as the one in the picture, it could just be the ground.
Thread Starter
Drifting
Joined: Aug 2011
Posts: 1,861
Likes: 1
From: panama panama
yesterday I remove the fuel pump rush to the store and get a new one. when I beging to install the pump on the bracket. I notes the ground wire kind of loose. so I know them . the problem was that wire. but I allready had install the new pump. so I decide to keep the new pump.
I reinstall everything this morning and the car fire right up. still have some fuel preasure issue. that I will pust in a new threet.
here is a picture of the small wire causing all this problem.
[IMG]
[/IMG]
Drifting
Joined: Mar 2012
Posts: 1,492
Likes: 61
From: New Jersey
I'm not as knowledgeable as many of the others on this forum so I wasn't able to contribute to this thread. But I want to give Hitmanpty a big 
for two reasons:
1. He always listens to the advice and tries to follow it to resolve his issues; and
2. He always posts back with the solution that worked to fix the problem.
Too many people start a thread about their problem; various solutions are suggested by the knowledgeable members; and then the thread dies. The OP never posts back whether any of the solutions worked or if he still has the problem. I like to read the threads and learn about the different issues and solutions for future reference (if necessary).
So again, great to hear you got it fixed!
for two reasons:1. He always listens to the advice and tries to follow it to resolve his issues; and
2. He always posts back with the solution that worked to fix the problem.
Too many people start a thread about their problem; various solutions are suggested by the knowledgeable members; and then the thread dies. The OP never posts back whether any of the solutions worked or if he still has the problem. I like to read the threads and learn about the different issues and solutions for future reference (if necessary).
So again, great to hear you got it fixed!