Boost reference regulators...10psi drop?
Boost reference regulators...10psi drop? First off, moderators, please dont move this as all the regulator users are in this forum...
I have a single walbro 340 intank running through an -8an feed to billet rails. The CAS regulator is on the end of the passenger rail, and then the return line is the stock feed line. At WOT , I drop 10psi instantly, and then it raises up to 58 over the next 2 seconds or so. Bare in mind, this is on a Heads/cam only motor, no turbo yet. I was putting in this system in preparation for a turbo. Oh, the Walbro is hotwired too!
So CAS regulator owners, whats the deal? Can the single walbro intank not keep up with the -8an feed or what?
I have a single walbro 340 intank running through an -8an feed to billet rails. The CAS regulator is on the end of the passenger rail, and then the return line is the stock feed line. At WOT , I drop 10psi instantly, and then it raises up to 58 over the next 2 seconds or so. Bare in mind, this is on a Heads/cam only motor, no turbo yet. I was putting in this system in preparation for a turbo. Oh, the Walbro is hotwired too!
So CAS regulator owners, whats the deal? Can the single walbro intank not keep up with the -8an feed or what?
Still have the P1-SC on or are you N/A right now? The fuel pressure drop when I turn the key is normal on my car....haven't been in another car with a built fuel system....I take it as normal as the fuel is returning back to the tank so the fuel press drops.
J
J
Moderator
Joined: Nov 2001
Posts: 3,048
Likes: 12
From: Raleigh, NC
The pump runs a moment, then stops, when u turn the ignition key on. Sort of like a prime. Then when you crank it, it should be running again.
I have two walbros in my tank. Pressure increases as soon as boost cuts in. I have no such drop.
I have two walbros in my tank. Pressure increases as soon as boost cuts in. I have no such drop.
On a factory system there is a check valve to keep the fuel pressure up from the time the pump primes untill you start the car, you can get an aftermarket fuel check valve from Earl's. On a factory car, you can turn the car on and the fuel pressure should stay up for 5-10 minutes (unless you have a leaky injector).
But as to your other question, it sounds like the regulator is not responding quickly enough, the regulator is X% open at light throttle and when the fuel demand goes up it needs to send less back down the return line. Check your regulator diaphram for leakage, take the vacum line off and see if there is any fuel on the vacuum side...
Ryan K.
But as to your other question, it sounds like the regulator is not responding quickly enough, the regulator is X% open at light throttle and when the fuel demand goes up it needs to send less back down the return line. Check your regulator diaphram for leakage, take the vacum line off and see if there is any fuel on the vacuum side...
Ryan K.
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The thing is that im running N/a at the moment so a 10psi drop doesnt seem normal at all. Im only running a 380ish hp heads/cam combo...
As for the check valve, where is it located on the factory system, in the regulator?
As for the check valve, where is it located on the factory system, in the regulator?
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Verdad Gallardo I was also wondering if the Regulator has to be mounted vertically (ie with the vacuum nipple straight up)? I have it turned sideway for hood clearance at the moment.
So I need to cap the vacuum port when not running boost?
So I need to cap the vacuum port when not running boost?
Its set at 58 psi with the port capped. I am running NA right now. The other weird thing is that it seems like it drops 1-2 psi after the car warms up and when the fan comes on, it drops 3 psi for half a second then rises back up. Is the regulator just trashed or what?
Yes it is 10 gauge through a 20 amp fuse back to a bosch relay. In park, I can rev it and not get a pressure drop at all. In drive cruising, I rev it and there will be a 3-4 psi drop.
Is there a voltage pid on HP TUners? All I found was Ignition Voltage, and that was reading around 13.4v at idle.
Is there a voltage pid on HP TUners? All I found was Ignition Voltage, and that was reading around 13.4v at idle.
The other thing is that I am getting STFT's in the -25 to -30 range. Are those even possible ranges? I have been having some serious issues with the car laterly and im beginning to wonder if the computer is fubar
FIXED!!!!
After talking to Tom at ls1speed about the regulator that I though was junk, I asked Tom about the fact that my pressure would drop after priming the pump. Now the odd thing was that some days it would drop to 0 after 2 seconds, and some it would slowly drop to around 20. Well, turns out the rubber hose I used in the tank had split! The walbro fuel pumps have an internal check valve to hold pressure once primed. That walbro pump must have been killing itself trying to maintain the pressure at wot.
Piece of -6an braided hose and hopefully I solved my problem for good!
So frcefed98, I would check your intank hose. Now after priming, the pressure drops to 50 psi from the 58 thats its set at and stays!
After talking to Tom at ls1speed about the regulator that I though was junk, I asked Tom about the fact that my pressure would drop after priming the pump. Now the odd thing was that some days it would drop to 0 after 2 seconds, and some it would slowly drop to around 20. Well, turns out the rubber hose I used in the tank had split! The walbro fuel pumps have an internal check valve to hold pressure once primed. That walbro pump must have been killing itself trying to maintain the pressure at wot.
Piece of -6an braided hose and hopefully I solved my problem for good!
So frcefed98, I would check your intank hose. Now after priming, the pressure drops to 50 psi from the 58 thats its set at and stays!
Dammit not again with that stupid hose
I've been through this twice. Looks like I have a project for the weekend....glad I looked into this post.
Now where did I put that stupid -6AN braided line
J
I've been through this twice. Looks like I have a project for the weekend....glad I looked into this post. Now where did I put that stupid -6AN braided lineJ