transamice

87 GTA 350 turbo auto trying to tune using EBL with 3rd Walbro intank pump.
Using racetronix fuel pump hotwire upgrade as well...
I had 2 faulty Walbro pumps returned tested and failed, 2 new pumps were shipped from TI automotive under warranty and the one installed few months ago.
As I drive for 30-40 min I gradually loose 10 psi fuel pressure and I notcied the EBL is adding fuel while Im tuning as a result of not being able to get a consistant tune.
What are the odds of having another faulty pump and what other manufactors are to choose from for a turbo setup?
Could my car be causing these pumps to go faulty?

iroczracer07

iTrader: (2)

are you sure you don't have a faulty fuel pressure regulator? Kinda weird that you're losing pressure after it gets warmed up. If it was faulty injectors or fuel pump I would assume that would happen anytime. The diaphram in the regulator could be collapsing after it gets warm though. Just a thought...

transamice

Its a brand new Holley afpr I just installed a few weeks ago.
Maby I need a Fuel Pump Sender Harness Kit that racetronix has to offer?
http://www.racetronix.biz/customkiti...CWA%2DFL98&eq=
Seems to drop 10 psi whine a little but stay at that pressure, as example running the car when cold pressure is at 43 psi fpr vacuum unplugged BLM shows 128 and after running a while pressure drops to 30 psi unplugged BLM at 136.
Just wondering if anyone else is running a walbro using hotwire to power pump and needed the sender kit as well to work properly.

iroczracer07

iTrader: (2)

Okay, the fuel pressure needs to be checked and we need to establish a few things. Was the fuel filter changed? Was the fuel pump strainer changed? And are you sure they sent you the right fuel pump. If all of these are a yes, then we need a fuel pressure reading. If it's below 40 psi we diagnose one way if 47 psi we diagnose another one. But first we need that fuel pressure reading. And if you're renting it from a parts store, don't take it back just yet. We'll need it to verify a few more things depending on the initial reading.

transamice

Fuel filter was changed a month ago, fuel strainer was changed when I changed the pump few months ago.
Initial fuel preesure is at 43 psi vacuum unplugged, plugged around 35 psi, have new Holley afpr.
My fuel pressure reading is from a marshall gauge that I connected on the schrader valve, I made sure the gauge is working properly hooked it to my compressor and verified pressure is accurate.

iroczracer07

iTrader: (2)

Okay, hook the tester back up and then turn the key to the on position, but don't start it. If the pressure is 40.5-47 psi you're good, as long as it holds that pressure even after the pump stops. I'd give it 20-40 seconds just to make sure. If it's still holding, then start the car and let it idle until it reaches normal operating temperature. The pressure should drop anywhere from 3-10 psi. If that also turns out correct then there's a good chance there isn't a problem in the fuel system and we're looking for something else. If the pressure drop doesn't happen at all, you need to use an external vacuum source and apply 10 inches of vacuum to the fuel pressure regulator. Pressure should now drop 3-10 psi. If it does, then you need to repair the vacuum source to the regulator, if it does not, then you need to replace the regulator. One last thing. If the first test nets a reading of 40.5-47 psi, but after the pump stops the pressure doesn't hold or goes above 47 psi, not the reading and post it here and forget all the other tests, because we will perform a different set of tests to diagnose what is causing your problem.

transamice

Just went out to try, turned key on without starting pressure was at 41 psi after a min it dropped to 35 psi and kept dropping, by 2 min it reached 20 psi.
I forgot to mention that I cut off the evap line and left it open to vent if that matters.
It was holding steady at 43 psi when I first installed the regulator and only started dropping after 20 min...I dont get it

iroczracer07

iTrader: (2)

Okay...let's put that line back on for the evap and do the pressure test again and see if the results are the same.

transamice

Im saying I deleted the whole evap system, cut the line back to the passenger side seat, left the line open though, in this case should I plug the line?

iroczracer07

iTrader: (2)

Yeah, plug the line for sure. There can't be any vacuum leaks, or we'll have major problems with running and drive-ability.

transamice

Plugged it and acts the same, what about the vent on the drivers side axle?
How easy should it be to blow or suck air through it?

iroczracer07

iTrader: (2)

Unless there's a restriction it shouldn't be too bad at all. When you say it's running the same, do you mean at idle, or fuel pressure wise? Also, leave the ignition off for 10 seconds and then turn the ignition on. Pinch the flex fuel line and then re-check the pressure. If it holds you've either got a leaking pump coupling hose or pulsator, or the fuel pump is faulty again. If it doesn't hold, then run the above test again, only this time pinch off the fuel return line. If the pressure holds now, then you have a faulty regulator. If it still doesn't hold, then you need to hunt down some leaky fuel injectors. Let me know what you come up with. Personally I don't know whether to vote for the coupling or the pressure regulator....