frustrating fuel delivery issue. Walbro 450,aeromotive regulator
12-07-2017, 07:26 PM
#1
Staging Lane
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frustrating fuel delivery issue. Walbro 450,aeromotive regulator So I'm having a fuel delivery issue that is driving me up the wall, I cannot drive the car at all. Here is my setup and a explanation
turbo lq4
Deka 80s
Ls3 fuel rail
turbo lq4
Deka 80s
Ls3 fuel rail
Aeromotive regulator
Walbro 450
-6 feed and return
Goldbox for ecu and trans control (yes the settings are right for map and everything)
So whats happening is that when you give the car throttle fuel pressure drops off like from 43 at idle down to 0-5 psi. I replaced the pump because I took the pump hanger out and found that when the car is running it looks as if fuel is spraying out from below the connector. So it has a brand new real walbro and it does the same thing which I believe is the relief valve?. I checked the lines for a restriction and feed and return were good. The car is running returns style with boost reference off the intake. So with the car running I pinched off the return line and pressure comes up to 100psi quickly. However when I pinched the return line and give it throttle the pressure drops off. It has a solid 12 volts at the pump. Regardless of throttle position. I'm usually really good with diagnostics but this has got me stumped. Anyone had a issue like this? It makes no sense to me at all. Thanks
Erik
Walbro 450
-6 feed and return
Goldbox for ecu and trans control (yes the settings are right for map and everything)
So whats happening is that when you give the car throttle fuel pressure drops off like from 43 at idle down to 0-5 psi. I replaced the pump because I took the pump hanger out and found that when the car is running it looks as if fuel is spraying out from below the connector. So it has a brand new real walbro and it does the same thing which I believe is the relief valve?. I checked the lines for a restriction and feed and return were good. The car is running returns style with boost reference off the intake. So with the car running I pinched off the return line and pressure comes up to 100psi quickly. However when I pinched the return line and give it throttle the pressure drops off. It has a solid 12 volts at the pump. Regardless of throttle position. I'm usually really good with diagnostics but this has got me stumped. Anyone had a issue like this? It makes no sense to me at all. Thanks
Erik
12-07-2017, 07:34 PM
#2
TECH Senior Member
Have you checked the regulator?
12-07-2017, 09:58 PM
#4
Restricted User
Try bypassing the relay and wiring the pump straight to the battery before you take it for a drive.
Also, disconnect the vacuum line on the regulator and let it run static pressure. If doing both of those still causes pressure to drop when you hit the throttle, then you likely have a mechanical failure somewhere.
Also, disconnect the vacuum line on the regulator and let it run static pressure. If doing both of those still causes pressure to drop when you hit the throttle, then you likely have a mechanical failure somewhere.
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12-08-2017, 12:14 PM
#8
FormerVendor
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Pump Cavitation Hi Cos, I have seen many fuel pump cavitation problems, similar to your report.
The pump has a "pre-filter" and can emit a different sound when the screen becomes clogged.
Would your report the sound of your pump when in operation ?
Could your regulator by "plumed" incorrectly ?
Lance
The pump has a "pre-filter" and can emit a different sound when the screen becomes clogged.
Would your report the sound of your pump when in operation ?
Could your regulator by "plumed" incorrectly ?
Lance
12-08-2017, 01:45 PM
#9
Staging Lane
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The pump has a new screen, the regulator has been plumbed the same way for over a year, it so here is how it is. Fuel pump, through a filter which has been replaced, to the regulator, then regulator to the fuel rail. The return goes out the bottom. I am messing with it right now and checking the current voltage supply and making sure it's not some dumb wiring issue that's causing the problem. The pump does not sound like it's cavitating, it sounds normal and quiet like the 450s normally do.
12-08-2017, 05:30 PM
#10
Staging Lane
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Whelp I redid the power and ground and my issue was resolved, I feel like a idiot, I was running the stock fuel pump ground and I guess after almost 40 years it gave up the ghost, thanks for all who responded. Check your grounds boys!
12-08-2017, 08:58 PM
#11
Hi Cos, I have seen many fuel pump cavitation problems, similar to your report.
The pump has a "pre-filter" and can emit a different sound when the screen becomes clogged.
Would your report the sound of your pump when in operation ?
Could your regulator by "plumed" incorrectly ?
Lance
The pump has a "pre-filter" and can emit a different sound when the screen becomes clogged.
Would your report the sound of your pump when in operation ?
Could your regulator by "plumed" incorrectly ?
Lance
12-09-2017, 11:12 AM
#12
12-19-2017, 07:44 AM
#14
Restricted User
I dead-head mine that way and it works fine.
12-20-2017, 08:15 PM
#17
TECH Senior Member
01-04-2018, 06:09 PM
#19
9 Second Club
It's an in-tank pump, it has a bag strainer at the pickup. You cannot fit what many might class as a normal filter to an intank setup. They all use bag strainers.
And with any "big" Walbro type pumps...ie 340 and upwards, wiring/connectors absolutely must be good as these draw a lot of current.
01-05-2018, 08:37 AM
#20
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Yeah yall are getting way too carried away with this filtering non-sense. All pumps that i know of (in-tank) have filter socks built in. Its common for OEMs to not even use an external filter (rely on the pre-pump socks only) and remember their wallets have to warranty 100k + vehicles a year. And its been that way a long time.