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

[jojo]

Guys?? Ive done everything to try and find the cause of this. Fuel pressure regulator is brand new!! 60# inj are fairly new!! Fuel Pump is new!! and tested. Dropped the tank and check this, aslo blew high pressure air thru the line from the back of the disconnected fuel line all the way thru the line that runs on the passenger side of the motor. Blew air until it blasted out whatever fuel was left in there along with the pressure of the air after the fact..Ive hooked up a fuel pressure gauge twice dammit!! while driving with someone in the car monitoring the gauge under boost both times. Fuel pressure is set at 45-46 pounds line off. under 25# of boost the gauge did not go up above 45-47# or so...WTF?? The only thing I havent done yet is replace the original factory fuel lines. Oh and yes the fuel filter is pretty new also. I dont know what im missing here, I thought ive tried it all, but please let me know the guys that have had this same problem, and what you did to fix it. I know the fuel pressure should be rising for each # of boost ran. That gauge should have read 70# of freakin pressure under 25# of boost!!. And yes the fuel pump is a Walboro 340, hotwired and about a year old if that..

I dont want to post another thread, as ive read a lot on the BLM thing, but for what its worth, I cannot get mine down under 160. Ive checked vaccum lines ect... the basics, egr, new delco pcv, sprayed the **** out of the lines for leaks ect..The only thing different I did, was had an original Extender chip w/21/19 of timing, then I added the Julio Alky kit, and coincidentally my BL went from 134 or so at idle in closed loop with engine hot after taking it for a run, then let it sit and idle. The BL on the scanmaster would not drop under 160. At cruise they usally maintain about 138 or so.

Comments, Expert advice, Trial and Error fixes, from all the guys that have been able to fix these same problems, please throw your advise and fixes here.

Thx

Jojo

 

[TurboBuickSix]

Try to hook up the pressure side of a mightyvac hand pump and check for the rise that way.It's a little safer than using the boost as a pressure source to test the regulator.It sounds like the regulator is not functioning properly if at all.

 

[83ttypecooled]

Hi,
As Sherlock Holmes said,"when one eliminates all that is not possible,then only the truth remains". I would take another look at your pump. If that fails, all is lost. I wouldn't think that 60lb injectors would overtax a good in tank pump, such as a Walbro 340. However, stuff can happen. Maybe you need an external pump. Pressure and volume are important.I'll bet the block learn comes down when you fix the pressure problem.Good luck with your trouble!

 

[ijames]

The idle block learn could be an air leak around the alcohol nozzle, or maybe one of the intercooler hoses not tight or not on right. Something is letting you suck in air that the maf isn't seeing, so check all your vacuum hoses and intercooler hoses. (Or you have an exhaust leak letting fresh air get to the O2 sensor.) Does the fuel pressure drop when you put the vacuum hose back on? TurboBuickV6's test with either a mityvac or bicycle tire pump, while the engine is idling, will tell you a lot about the regulator and bypass valve in the pump. Make sure you can get at least 80 psi that way. If you can then you might have a volume problem, not a pressure problem - some restriction is causing the pressure to drop once the flow volume rises as the hp goes up. Disconnect the fuel return line down by the frame crossmember under the power steering pump and turn the pressure up as high as you can with the regulator adjusting screw, hopefully to 60+ psi. Use a test lead to go from the big terminal on the back of the alternator (handy 12 V source) to trigger the relay on your hot wire kit and time how long it takes to deliver a gallon of gas with the pump working against that back pressure. Should be 60-90 seconds, roughly. Any longer and check all of your supply line for kinks or problems, and maybe drop the tank and check the connections and sock in there.

 

[PhilM]

My pump went bad and the FP actually dropped under boost - ie NOT GOOD. This pump was only a year old and worked fine under average driving.

Phil

 

[jojo]

My pump went bad and the FP actually dropped under boost - ie NOT GOOD. This pump was only a year old and worked fine under average driving.

Phil

How did you determine it was the fuel pump??

thx

jojo

 

[jojo]

The idle block learn could be an air leak around the alcohol nozzle, or maybe one of the intercooler hoses not tight or not on right. Something is letting you suck in air that the maf isn't seeing, so check all your vacuum hoses and intercooler hoses. (Or you have an exhaust leak letting fresh air get to the O2 sensor.) Does the fuel pressure drop when you put the vacuum hose back on? TurboBuickV6's test with either a mityvac or bicycle tire pump, while the engine is idling, will tell you a lot about the regulator and bypass valve in the pump. Make sure you can get at least 80 psi that way. If you can then you might have a volume problem, not a pressure problem - some restriction is causing the pressure to drop once the flow volume rises as the hp goes up. Disconnect the fuel return line down by the frame crossmember under the power steering pump and turn the pressure up as high as you can with the regulator adjusting screw, hopefully to 60+ psi. Use a test lead to go from the big terminal on the back of the alternator (handy 12 V source) to trigger the relay on your hot wire kit and time how long it takes to deliver a gallon of gas with the pump working against that back pressure. Should be 60-90 seconds, roughly. Any longer and check all of your supply line for kinks or problems, and maybe drop the tank and check the connections and sock in there.

Fuel pressure set at 45-46# line off, then when line is back on....yes it goes back down to about 40 or so..

 

[jojo]

Try to hook up the pressure side of a mightyvac hand pump and check for the rise that way.It's a little safer than using the boost as a pressure source to test the regulator.It sounds like the regulator is not functioning properly if at all.

I believe I checked this, as the regulator is brand new more or less..

thx

jojo

 

[jojo]

Is it possible at all that it could be the fuel tank itself?? Im not sure, as I do know my fuel gauge doesnt read correctly. Kinda funny, when I fill it up it reads 3/4 of tank and so forth. This has been going on for some time, but I wouldnt think it could be the fuel tank itself, but im not sure like I said.

 

[jojo]

How did you determine it was the fuel pump?? I actually dropped my tank twice, and tested the pump with old school shizz, like postivve ground from a battery to the pumps power source while it was submerged in some gas, and it started pushing fuel out fine.

thx

jojo

I actually dropped my tank twice, and tested the pump with old school shizz, like postivve ground from a battery to the pumps power source while it was submerged in some gas, and it started pushing fuel out fine.

 

[wiked87gn]

the fuel pump socket maybe kinked and collapsing under vacumm at WOT, or it could be a vacumm leak at the block, check all hoses the line maybe closing at idle but opening under boost thus letting vacumm out that is needed to raise the FP. check both.

 

[ijames]

Fuel pressure set at 45-46# line off, then when line is back on....yes it goes back down to about 40 or so..

So the reg looks okay. You really need to do the volume test I outlined, then.

 

[Mike Licht]

Do you have an air compressor? if you do set the regulator for 15 PSI and blow into the top of the reg with a blow gun while it is running, prssure should go up 15 PSI. Make sure the reg is not leaking. New parts do not always mean they are good or working parts.
Mike

 

[BobbyBuick]

put a mighty vac on the reg to see if it has an internal leak .Ive seen many leak

 

[jojo]

put a mighty vac on the reg to see if it has an internal leak .Ive seen many leak

WILL DO TY..

JOJO

 

[jojo]

Do you have an air compressor? if you do set the regulator for 15 PSI and blow into the top of the reg with a blow gun while it is running, prssure should go up 15 PSI. Make sure the reg is not leaking. New parts do not always mean they are good or working parts.
Mike

I dont have on Mike, but can get a hold of one im sure and check this.

thx

jojo

 

[bison]

Do you have an air compressor? if you do set the regulator for 15 PSI and blow into the top of the reg with a blow gun while it is running, prssure should go up 15 PSI. Make sure the reg is not leaking. New parts do not always mean they are good or working parts.
Mike

This is the correct way. I actually do this with a pressure guage in series to see how much air pressure im getting. Then you can start the car and pressurize the regualtor and see if your pressure is right. This only checks pressure and not volume though. It will eliminate the regulator as the problem though.

 

[jojo]

This is the correct way. I actually do this with a pressure guage in series to see how much air pressure im getting. Then you can start the car and pressurize the regualtor and see if your pressure is right. This only checks pressure and not volume though. It will eliminate the regulator as the problem though.

Thx bison, will check this also.

jojo

 

[jojo]

Not to get off the subject, but im sure im not the only one who has done this. Replacing the damn pcv valve, along with that pain in the azz grommet that it seats in. I got the grommet in ok, but when I lubed up the grommet and the bottom of the pcv, then did the pushing of the pcv valve into the grommet, and ended up pushing the grommet down into the valley I guess its called. Is there an easier way?? and im assuming this will do know harm to the intake right??

thx

jojo

 

[PhilM]

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