Bad fuel pressure regulator? need advice for problem - Third Generation F-Body Message Boards

mos68x · 09-20-2009, 10:24 PM

I have a Spectre fuel pressure regulator 2517 and I'm having troubles with the engine staying running. I am having trouble getting fuel to continue getting to the carb. I can get the pumps to fill the carb before I start the motor, but as soon as I start the motor and rev it up a few tims it drains the bowls and the engine dies. I took it off the carb with the pumps still running and the fuel wasn't getting past the fuel pressure regulator at all. I double checked it and with the pump off and the regulator off the carb, turning the pump on starts putting fuel out the regulator. The one that I have only goes up to 5.5 psi though, is that going to make a difference? I'm sure that I probably need to get a different regulator but I'm not sure which one works the best.

Thanks

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FueledSoul · 09-20-2009, 10:27 PM

what carb do you have?

MR NICE · 09-21-2009, 05:56 PM

are you running stock efi in tank fuel pump?if so wrong regulator.

mos68x · 09-22-2009, 03:48 AM

Got the Edelbrock 1406 and both stock fuel pump and an electric carb pump, both deliver fuel fine through the regulator until it biulds pressure at the carb then that regulator locks up I guess.

MR NICE · 09-22-2009, 07:12 AM

you may need a return regulator.

mos68x · 09-22-2009, 12:35 PM

Bought another regulator and also got a guage to use so I don't have to pull it apart to see if it's getting fuel. Since I have both pumps running I'll probably disconnect the in tank one to see if that's going to make a difference. I will also put the guage before and after the electric carb pump that I installed to compare the fuel pressure from both pumps. At 12-15 psi I very seriously doubt that we will need a return style, but I'll check to see what the difference in pressure is. If I have to I'll pull the in tank one sometime and make it a carb pick up instead.

five7kid · 09-22-2009, 03:52 PM

Yes, 12-15 PSI is a problem.

mos68x · 09-22-2009, 07:36 PM

Well I'm going to go check the PSI from the carb fuel pump and see if it's under 10PSI, if it is I'll use the carb pump until I get money for the bypass type to use with the stock pump. I finally found instructions for the regulator that I have and it says not to install on systems greater than 10PSI. It also says that the internal valve of the fuel regulator closes when the outlet pressure reaches the pressure set on the adjustable dial. It may be possible that greater then 10PSI keeps the vavle in the regulator from opening back up.

mos68x · 09-22-2009, 10:11 PM

Quote:

Originally Posted by five7kid

Yes, 12-15 PSI is a problem.

I can say this for a fact since I just tested it...12-15 PSI is not a problem for this pressure regulator even though it says a max of 10. HOWEVER... 20+ IS a problem and it won't work.

I just got done with the car and I can get it to work with just the carb pump running. The time that I had tested it before I had forgotten to unplug the oil pressure sensor/switch so the stock pump was turning on with the engine. I saw that pressure so I thought that maybe the carb pump had too high of pressure until I remembered to unplug the OPS. After I pulled that plug the fuel pressure was about 12-15 with the carb floats closed and about 9 PSI when they opened.

Remember that these PSI numbers that I'm citing are BEFORE the pressure regulator, NOT after. I have the pressure regulator before the carb and after the pressure guage.

I did check the setup with the engine running and the engine finally stays running!!! Hopefully I don't screw anything else up now, lol.

five7kid · 09-23-2009, 12:52 PM

12-15 psi is a problem for the pump because of the reg you're using. A dead-head reg will kill even the low pressure in-tank electric pumps.

Don't run your in-tank pump with that dead-head regulator. Period.

mos68x · 09-24-2009, 10:28 AM

Apparently you didn't read my post, I'm NOT using my in-tank pump. I'm using a CARB pump that I bought a while ago for a different project. I even unplugged the OPSU to keep the in-tank one from turning with the oil pressure switch.

MR NICE · 09-24-2009, 10:47 AM

Quote:

Originally Posted by mos68x

Apparently you didn't read my post, I'm NOT using my in-tank pump. I'm using a CARB pump that I bought a while ago for a different project. I even unplugged the OPSU to keep the in-tank one from turning with the oil pressure switch.

Ok now you disconnected the in tank pump,what are you doing for a pickup?You should get a return reg. and just run the in tank pump.IMO

five7kid · 09-24-2009, 01:07 PM

Yes, I read your post. You didn't acknowledge that running a dead head reg with a low pressure in-tank electric was not the right thing to do. Merely saying you disconnected it (which sounded like a diagnostic action) doesn't get there.

Now, as MR NICE pointed out, you have another problem, that being trying to suck gas through a non-operating in-tank electric. You might get by with it for a little while, but it will lead to other problems.

mos68x · 09-24-2009, 06:06 PM

This 'bypass' of the stock in-tank pump is not permanent, just a temporary fix until I have more funds...which will hopefully be midmonth Oct. I will probably order the Mallory 4309 regulator since this is the only one that I have heard anyone actually mention by part number. Almost all of the ones that I saw that were bypass type were meant for FI type pressures. This Mallory one should do just fine I think, unless anyone else has a better alternative.

MR NICE · 09-24-2009, 08:34 PM

You can find a ProComp Return Reg. on the auction site for 29.00 + shipping, no clue if they are any good tho.

Grumbles · 09-26-2009, 04:18 AM

The Procomp regulator you are talking about is not a diaphragm style regulator and will not work for a stock fuel pump/return line application.

Check out holley 12-803BP. Same thing as the mallory, save you 20 bucks.