fuel pressure will not rise for ****...OMG WHAT??

[jojo]

I just knew : ) ... so did my tuner... That and the reg was brand new.

Just because it pumps out fine under no load or low demands doesn't mean it's OK. Also check the internal rubber for cracks/splitting... I replace them with reinforced line since the ones they usually supply in kits are WEAK!

Phil

forgive the ignorance, but what is your tuner?? and internal rubber where?

thx

jojo

 

[441120]

$0.02
Does the fuel tank have a vent, through the cannister?
What I mean is, is the pump creating a vacuum in the tank under high demand?
Just a thought.

 

[jojo]

$0.02
Does the fuel tank have a vent, through the cannister?
What I mean is, is the pump creating a vacuum in the tank under high demand?
Just a thought.

Damn I cant remember or not...lol, will probably drop the tank again to check all things, fuel pump, vent, ect...

thx

jojo

 

[PhilM]

My tuner is a person... he knew his VE wasn't off so...

There is an internal rubber hose that connects the FP to the sending unit steel line... it is either hose clamped or uses one of those clicky things that i dont like so much... Sometimes the pumps come with a non-reinforced rubber hose that will split rather easily.

Phil

 

[VadersV6]

Are you still running through the stock fuel pump relay? When I popped my connector off of it, all the pins were so filled with 20 year old dieelectric grease that had turned to tar, that you couldnt see any sign of metal anywhere. Couldnt see the pins at all. After a good cleaning with ronsonol lighter fluid, a plastic bristle and wire bristle brush, compressed air and lot of patience, I got all that crap out. Did the same with my fan relays. My fans barely worked before, and after the cleaning they work great. You probably are hotwired though. I havent read the whole thread.

 

[jojo]

My tuner is a person... he knew his VE wasn't off so...

There is an internal rubber hose that connects the FP to the sending unit steel line... it is either hose clamped or uses one of those clicky things that i dont like so much... Sometimes the pumps come with a non-reinforced rubber hose that will split rather easily.

Phil

Well.....I did the pinch test on the fuel return rubber part with engine at idle, fuel pressure shot up to 85-90# or so Im assuming I could rule the pump out..lol but not done yet..

thx

jojo

 

[jojo]

Are you still running through the stock fuel pump relay? When I popped my connector off of it, all the pins were so filled with 20 year old dieelectric grease that had turned to tar, that you couldnt see any sign of metal anywhere. Couldnt see the pins at all. After a good cleaning with ronsonol lighter fluid, a plastic bristle and wire bristle brush, compressed air and lot of patience, I got all that crap out. Did the same with my fan relays. My fans barely worked before, and after the cleaning they work great. You probably are hotwired though. I havent read the whole thread.

Im assuming yes, its stock...Even though I havent checked the vicinity of this yet, maybe you can tell me where this is located...Ive been kinda down the fan relay road already...lol so I know where those are..

thx

jojo

 

[1 RARE T]

Oh, this brings back memories well maybe nightmares.

Get it real quiet in the garage and with a blow-gun and a few psi, (not too much) blow into your boost line for the gauge, alky kit what-ever. Listen closely for boost escaping out those connections. This would limit the boost going to the regulator and there-fore the pressure increase.

Chased the exact same issue myself. Found the leak and bingo, up went the pressure.

Good luck.

 

[bison]

Well.....I did the pinch test on the fuel return rubber part with engine at idle, fuel pressure shot up to 85-90# or so Im assuming I could rule the pump out..lol but not done yet..

thx

jojo

Only the ability to build high pressure at low volume. It doesnt rule out the pump until it flows volume and pressure.

 

[jojo]

Oh, this brings back memories well maybe nightmares.

Get it real quiet in the garage and with a blow-gun and a few psi, (not too much) blow into your boost line for the gauge, alky kit what-ever. Listen closely for boost escaping out those connections. This would limit the boost going to the regulator and there-fore the pressure increase.

Chased the exact same issue myself. Found the leak and bingo, up went the pressure.

Good luck.

Funny you should have mentioned that..lol I just found a little pin size hole in the hard white plastic line just outside the firewall. I cut it at the point of the hole and slid over some rubber vaccum line all the way over to the passenger side where the three line plastic piece thingy connects to the other vaccum lines. I havent taken it out for a run yet, since I did it late tonight and was tired.

thx

jojo

 

[jojo]

Only the ability to build high pressure at low volume. It doesnt rule out the pump until it flows volume and pressure.[/QUOTE

Ok what I did again, was pinched the return line with some channel locks and kept it pinched pretty much all the way while the car was idling. I then went to look up real quick at the fuel pressure gauge and I seen the gauge go all the way up to 80# or so. The funny thing was, or not soo funny...hehe, was Istood there and watched the gauge go all the way down from 80# to under 20# and it kept dropping. I then want and released the channel locks from the return line under the car, and went back up to the look at the gauge again, and it went back to around 39# or so with the line on, where I originally had it. So Im assuming I have a fuel pump problem after all right?..Also I did the mighty vac test with the car at idle, and pumped pressure into the regulator once again...around 15 pounds or so, and I watched it drop slowly again from 15# down to under 5#. Is it safe to assume Im having a fuel pump issue???? I dont know of anyone that has a good one for me to test, so I will have to buy another...Is there anything else I should check once I install the new pump and have the tank dropped again??? I want to get this thing fixed and over with, I have been having this on going problem with my fuel pressure not rising for a couple of years or so. I have more or less been just dealing with it. I dont want to do this anymore, I want to fix this once and for all and get this thing to flow the fuel its supposed to...Im sure you guys understand. The funny thing is, Ive replaced the fuel pump twice now and the regulator twice, only to have the same problem for two years..I mean what are the odds of the fuel pump twice and two regulators?? and still trying to locate the problem...Lemme know your thoughts on this plz, because I will figure it out, I can guarantee that..I bet its something soo simple that im not looking for or overlooking. While I was under the car doing the pinch test..lol I was looking at the return line connections, and the other fuel line..feed line I guess it is, and spraying some soapy water all around there to see if I could see any bubbling or any other signs of abnormalty while the car was idling, but couldnt see anything out of the ordinary..Dunno lemme know your thoughts and thx again....

jojo

 

[bison]

The pump has an internal shut off if the pressure gets to high. You have not proven the pump is faulty or not yet. I would inspect the line you sqeezed with pliers because i did this 12 years ago on the line between the sender and the metal line and 10 miles later the hose ruptured. Do the test where you pressurize the regulator with it running to rule out the reg first.

 

[VadersV6]

Why would you use channel locks on a fuel line? So where did you do this? Is this an area where the hose slips over a plastic line or anything? Could the plastic or even steel line have collapsed after you did this? Did you replace the pulsator on the fuel pump with a piece of straight hose like you should? I would bet the problem lies either with power supply under load, or something gone wrong with the pump assembly in the tank, such as the pulsator or hose isnt tight, is cut, has a hole, hose clamp not tight, missing O-ring...if there is one in the pump assembly...
Are all electrical connections solid...not super glued like Ive seen some people do? Do you have a solid, uncorroded connection at the source? You should always sand the 2 joints and coat with die-electric grease. Connections are everything. They need to be solid

 

[JSAautomotive]

Jojo's doing it right. You can "carefully" use a vise grip or preferrably, and line pinching tool (I know matco-snapon carries these) to pinch off the return line to test the dead head pressure of the pump. Rule of thumb would be 2 times the system idling pressure is what you need for delivery.

The connector that is between the fuel pump and the sending unit may be the culprit. I would replace it with some aftermarket hi pressure fuel injection hose. Make sure on the outside it's rated for at least 100-300 psi. Use 4 small hose clamps and re-test your fuel system. You don't have to remount your gas tank. Just leave it submerged in the gas tank with the car up on a lift. Pinch your return line again and see if the pressure drops again. Then use your shop air to test the regulator dynamically and see if it can respond to pressure.

Your high Block learn values indicate an air leak after the MAF or your O2 isn't switching fast enough (is just basically old or worn out). Use a genuine GM Delco O2 sensor as the aftermarket stuff doesn't seem to have the same response frequency as the aftermarkets.

 

[PhilM]

Just get a new FP and check the lines... can never hurt to have a spare FP anyways... If that don't do it, check the reg. Get it DONE already! I feel bad for you spending all your time here trying to figure it out instead of driving her! lol

Phil

 

[jojo]

Why would you use channel locks on a fuel line? So where did you do this? Is this an area where the hose slips over a plastic line or anything? Could the plastic or even steel line have collapsed after you did this? Did you replace the pulsator on the fuel pump with a piece of straight hose like you should? I would bet the problem lies either with power supply under load, or something gone wrong with the pump assembly in the tank, such as the pulsator or hose isnt tight, is cut, has a hole, hose clamp not tight, missing O-ring...if there is one in the pump assembly...
Are all electrical connections solid...not super glued like Ive seen some people do? Do you have a solid, uncorroded connection at the source? You should always sand the 2 joints and coat with die-electric grease. Connections are everything. They need to be solid

I just did this to check the pressure from the return line to the gauge. It rised real quick when I did this. This gave me an idea that the pump was capable of putting out the volume to the return line, and I guess it was since it spiked up to 80# or so. I did the pump check thing when I dropped the tank, but I couldnt find anything out of the ordinary..But I will check the other stuff as well..

thx

jojo

 

[jojo]

Jojo's doing it right. You can "carefully" use a vise grip or preferrably, and line pinching tool (I know matco-snapon carries these) to pinch off the return line to test the dead head pressure of the pump. Rule of thumb would be 2 times the system idling pressure is what you need for delivery.

The connector that is between the fuel pump and the sending unit may be the culprit. I would replace it with some aftermarket hi pressure fuel injection hose. Make sure on the outside it's rated for at least 100-300 psi. Use 4 small hose clamps and re-test your fuel system. You don't have to remount your gas tank. Just leave it submerged in the gas tank with the car up on a lift. Pinch your return line again and see if the pressure drops again. Then use your shop air to test the regulator dynamically and see if it can respond to pressure.

Your high Block learn values indicate an air leak after the MAF or your O2 isn't switching fast enough (is just basically old or worn out). Use a genuine GM Delco O2 sensor as the aftermarket stuff doesn't seem to have the same response frequency as the aftermarkets.

Ok ill check this out again first chance I get. I know im missing something probably simple..

thx again

jojo

 

[BlackBandit]

Ok, I wrestled with a problem like this for almost a year. Sounds allot like a regulator problem. First, when you shut off the car does the fuel pressure stay on the rail? Second, have you taken the regulator off the rail and tried to blow through it. I had an issue with my car where I couldn't get the pressure to rise properly or adjust the way I wanted it to. Turns out the regulator wasn't sealing off the fuel (from the return) so the pressure I got was mainly from the natural restriction of the stock return line. Then I had a problem getting pressure to rise and just keeping it on the rail. It turned out my body bushings had gone tits up and as the body sat down on the feed line it had rusted through. Over several years of course. Anyway, the line had pinhole leaks that made it look like the check valve in the pump had gone out. In reality the line was leaking off the pressure, just slow enough so the gas would evaporate before it got to the ground. Anyway, if the presure isn't rising I would take the regulator off the car and use an air compressor to check it. Hook up the air with a regulator to the pressure side and then see where it starts to bleed off. Then use a mighty vac to simulate boost pressure on the referance port. Also, use the mighty vac to see if the vacuum chamber on the regulator is leaking. HTH james

 

[jojo]

Ok, I wrestled with a problem like this for almost a year. Sounds allot like a regulator problem. First, when you shut off the car does the fuel pressure stay on the rail? Second, have you taken the regulator off the rail and tried to blow through it. I had an issue with my car where I couldn't get the pressure to rise properly or adjust the way I wanted it to. Turns out the regulator wasn't sealing off the fuel (from the return) so the pressure I got was mainly from the natural restriction of the stock return line. Then I had a problem getting pressure to rise and just keeping it on the rail. It turned out my body bushings had gone tits up and as the body sat down on the feed line it had rusted through. Over several years of course. Anyway, the line had pinhole leaks that made it look like the check valve in the pump had gone out. In reality the line was leaking off the pressure, just slow enough so the gas would evaporate before it got to the ground. Anyway, if the presure isn't rising I would take the regulator off the car and use an air compressor to check it. Hook up the air with a regulator to the pressure side and then see where it starts to bleed off. Then use a mighty vac to simulate boost pressure on the referance port. Also, use the mighty vac to see if the vacuum chamber on the regulator is leaking. HTH james

James....

Thank you, I will check this also...Im at the point now where there is no reason for this to happen without a logical exp..ive got more than enough fuel, and every other upgrde imaginable thats all functioning properly, since i try to stay on top of this old bag..lol

thx

jojo

 

[SIXBANGR]

had this problem this years ago turned out to be the filter