fixing my fuel pressure issues FOR GOOD!
08-01-2006, 07:14 AM
#22
Notorious BIG
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ok, i carefully monitored my fuel pressure on the way home from work yesterday, here is what is happening:
Key on, engine off = 50psi, then bleeds off to 44psi
engine on, in park, idling = 48psi
idling in drive and/or very light throttle = 45psi
light part throttle driving = 50psi
WOT = 60 psi
WOT, at about the 1000' mark = fuel pressure "dancing" to down into the 30's, then back into the 50's, then down into the 30-40's, then back to 60psi. during this fuel pressure drop time period of about 2 or 3 seconds, wideband drops from 11.4 to 13.5+ a/f ratio. LEAN.
according to zippy and Krambo, i VERIFIED my fpr vacuum line is connected to the radix manifold at the barb right next to my boost gauge. there are two barbs on the radix manifold drivers side, one is my boost gauge, the other is my fpr vacuum line, so it IS seeing boost. HOWEVER, someone suggested i test the fpr by starting the truck, then disconnecting the vacuum line from the fpr. i was told that if the fbr is bad or going bad, that it would leak fuel out of the vacuum line when i pulled the vacuum line off. It did NOT,...HOWEVER! with the vacuum line attached to the fpr, as stated before, i am seeing 45psi at idle. when the vacuum line was removed during idle, my fuel pressure shot up to 58psi! if i plugged the vacuum line back in, fuel pressure dropped back down to 45 PSI. then i disconnected the vacuum line again, and same thing happened, fuel pressure jumped to 58psi. what does this mean?
Key on, engine off = 50psi, then bleeds off to 44psi
engine on, in park, idling = 48psi
idling in drive and/or very light throttle = 45psi
light part throttle driving = 50psi
WOT = 60 psi
WOT, at about the 1000' mark = fuel pressure "dancing" to down into the 30's, then back into the 50's, then down into the 30-40's, then back to 60psi. during this fuel pressure drop time period of about 2 or 3 seconds, wideband drops from 11.4 to 13.5+ a/f ratio. LEAN.
according to zippy and Krambo, i VERIFIED my fpr vacuum line is connected to the radix manifold at the barb right next to my boost gauge. there are two barbs on the radix manifold drivers side, one is my boost gauge, the other is my fpr vacuum line, so it IS seeing boost. HOWEVER, someone suggested i test the fpr by starting the truck, then disconnecting the vacuum line from the fpr. i was told that if the fbr is bad or going bad, that it would leak fuel out of the vacuum line when i pulled the vacuum line off. It did NOT,...HOWEVER! with the vacuum line attached to the fpr, as stated before, i am seeing 45psi at idle. when the vacuum line was removed during idle, my fuel pressure shot up to 58psi! if i plugged the vacuum line back in, fuel pressure dropped back down to 45 PSI. then i disconnected the vacuum line again, and same thing happened, fuel pressure jumped to 58psi. what does this mean?
08-01-2006, 07:20 AM
#23
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Originally Posted by BLOWN 364
Who at magnuson told you a walbro 255 would work? It would take some major work and hacking to make it work in the return system fuel basket. I had fuel pressure drop problems too and replaced the stock fuel basket with fuel pump and my drop went away, but i also had 95,000 hard miles on it.
Check to make sure fuel filter is installed to arrow of flow. GM filter only.
I have a magnavolt and 60lb. injectors. I have 60 psi WOT 50 psi at idle and more fuel than i know what to do with in the tune.
Hope this helps, Tony
Check to make sure fuel filter is installed to arrow of flow. GM filter only.
I have a magnavolt and 60lb. injectors. I have 60 psi WOT 50 psi at idle and more fuel than i know what to do with in the tune.
Hope this helps, Tony
Tony, this person did not work for magnuson directly, they are a independant authorized magnuson dealer. i'd prefer not to mention names just to keep things from getting personal. i'm sure you understand.
so your suggestion, Tony, is to replace the stock in-tank fuel pump/assembly/module/basket (whatever you want to call it) with a OEM one? if that is your suggestion, let me know, and thats what i'll do. I have found a very good price on a ACdelco (19121626 GM PART# ) unit from a GM dealer. is this what you are recommending?
08-01-2006, 07:31 AM
#24
Originally Posted by Holty
according to zippy and Krambo, i VERIFIED my fpr vacuum line is connected to the radix manifold at the barb right next to my boost gauge. there are two barbs on the radix manifold drivers side, one is my boost gauge, the other is my fpr vacuum line, so it IS seeing boost.
Last edited by krambo; 10-31-2009 at 08:31 AM.
08-01-2006, 07:45 AM
#25
wow, 30? that's not a IDC issue IMO.
If you unplug the fpr the fuel isn't being "bypassed" anymore, it's all going to the rail, that's why you will see the pressure increase. All of your numbers sound to be off by 3psi or so.
I out fo curiousity did mine yesterday as well after talkin to ya. I put my results in red in your quote below.
For comparison purposes, if my setup is working the way the fueling system is supposed to, I'd take a guess at your stocker isn't doing what it should.
If you unplug the fpr the fuel isn't being "bypassed" anymore, it's all going to the rail, that's why you will see the pressure increase. All of your numbers sound to be off by 3psi or so.
I out fo curiousity did mine yesterday as well after talkin to ya. I put my results in red in your quote below.
Originally Posted by Holty
ok, i carefully monitored my fuel pressure on the way home from work yesterday, here is what is happening:
Key on, engine off = 50psi, then bleeds off to 44psi
MINE= 60psi then bleeds down to 55psi
engine on, in park, idling = 48psi
MINE= 52-54psi sometimes, very rarely but sometimes 50psi
idling in drive and/or very light throttle = 45psi
MINE= 50-54psi
light part throttle driving = 50psi
MINE= 55-58psi
WOT = 60 psi
MINE= 63-65psi
WOT, at about the 1000' mark = fuel pressure "dancing" to down into the 30's, then back into the 50's, then down into the 30-40's, then back to 60psi. during this fuel pressure drop time period of about 2 or 3 seconds, wideband drops from 11.4 to 13.5+ a/f ratio. LEAN.
Key on, engine off = 50psi, then bleeds off to 44psi
MINE= 60psi then bleeds down to 55psi
engine on, in park, idling = 48psi
MINE= 52-54psi sometimes, very rarely but sometimes 50psi
idling in drive and/or very light throttle = 45psi
MINE= 50-54psi
light part throttle driving = 50psi
MINE= 55-58psi
WOT = 60 psi
MINE= 63-65psi
WOT, at about the 1000' mark = fuel pressure "dancing" to down into the 30's, then back into the 50's, then down into the 30-40's, then back to 60psi. during this fuel pressure drop time period of about 2 or 3 seconds, wideband drops from 11.4 to 13.5+ a/f ratio. LEAN.
08-01-2006, 07:49 AM
#26
Notorious BIG
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Originally Posted by krambo
Are you sure that the barb you are using for the FPR IS seeing boost? 
Do yourself a favor and put your boost gauge on the barb that your FPR is on now and see if you see boost...the results may surprise you....
Do yourself a favor and put your boost gauge on the barb that your FPR is on now and see if you see boost...the results may surprise you....
08-01-2006, 08:57 AM
#27
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Originally Posted by dewmanshu
wow, 30? that's not a IDC issue IMO.
If you unplug the fpr the fuel isn't being "bypassed" anymore, it's all going to the rail, that's why you will see the pressure increase. All of your numbers sound to be off by 3psi or so.
I out fo curiousity did mine yesterday as well after talkin to ya. I put my results in red in your quote below.
For comparison purposes, if my setup is working the way the fueling system is supposed to, I'd take a guess at your stocker isn't doing what it should.
If you unplug the fpr the fuel isn't being "bypassed" anymore, it's all going to the rail, that's why you will see the pressure increase. All of your numbers sound to be off by 3psi or so.
I out fo curiousity did mine yesterday as well after talkin to ya. I put my results in red in your quote below.
For comparison purposes, if my setup is working the way the fueling system is supposed to, I'd take a guess at your stocker isn't doing what it should.
08-01-2006, 09:11 AM
#28
I am sure this has been gone over a few times, but have you replaced the FPR? Made sure that the o-rings are there and not damaged? By the description, its a bad FPR.
As for the intank, not sure who told you that.....independant Magnuson dealer or not, they were wrong.
As for the intank, not sure who told you that.....independant Magnuson dealer or not, they were wrong.
08-01-2006, 10:04 AM
#29
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Originally Posted by BlownChevy
I am sure this has been gone over a few times, but have you replaced the FPR? Made sure that the o-rings are there and not damaged? By the description, its a bad FPR.
As for the intank, not sure who told you that.....independant Magnuson dealer or not, they were wrong.
As for the intank, not sure who told you that.....independant Magnuson dealer or not, they were wrong.
no, i have no replaced my FPR. i will do so this weekend.
do you have anything else to add to this topic? am i going down the right path with the manifold barbs? compared to mine, how does you fuel pressure look? i'm getting frustrated because everyone said oh just get a magnavolt and that will solve your problems. it did not.
08-01-2006, 03:21 PM
#30
supposedly, quicksilverado installed a Walbro 255lph in-tank in his 2000 like mine w/ a return system w/o any issues either...I spoke w/ cablebandit who helped on the install and he said it was no problem...maybe one of them will chime in...
Last edited by Superado; 08-01-2006 at 03:33 PM.