Fuel Pressure Regulator Question...

[engine24355]

Okay guys, I have the new regulator installed, but not sure it is working properly. No mater what adjustments I make (all the way one way and the other plus everythign in between), I cannot get any pressure above about 4.5 lbs. Also, the gauge does not change much at all as I adjust the regulator. So, me thinks I need to try another regulator. Am I thinking wrong here or am I missing somthing? Just seems like I should be getting some different readings as I adjust.

Thanks!

 

[Duke]

I would recheck to make sure you didn't plumb it in backwards. Other than that it sounds like a bad regulator. It could possibly have some dirt under the seat. You could always bench test it with air pressure and a gauge. New things nowadays are not the same as it used to be. I have gotten new parts that were junk.

 

[rooster57]

whats the pressure before you installed the regulator???

 

[FOX FABRICATION]

What kind of Fuel pump you using?????? Many regulators require a minimum input pressure for them to operate.

 

[Wild Mango]

When you adjust the regulator there needs to be some flow. Without flow the pressure will not respond correctly to adjustment.
Back the adjustment all the way off. Crack the carb connection to relieve any pressure, do it back up. Start the pump and slowly crank up the pressure adjust, the pressure should rise up with the adjust. As Duke says, could be in backwards.
Fuel system components do not respond with air like they do fluid sometimes.
Any time working on fuel systems that are "wet" make sure Mr Fire Extinguisher is close by.

 

[engine24355]

What kind of Fuel pump you using?????? Many regulators require a minimum input pressure for them to operate.

It is a Carter electric...should flow 4-12 lbs from my understanding.

 

[engine24355]

whats the pressure before you installed the regulator???

I do not know what pressure I was running before the regulator because I did not have a pressure gauge. However, my previous setup was just the fuel pump going running two Edelbrock 600's. My thinking is that if it was running two 600's before I have two much pressure and need to dial back some for my single 670 now.

 

[FOX FABRICATION]

What Regulator you using??? If it is a HOLLEY...they need to see a minimum of 4.5 lbs. pressure...anything below that..it just passes thru.

You can plug the output port of the regulator to DEAD HEAD the fuel system and see what type of pressure the pump puts out. Most electric pumps have an internal bypass...so have no fear of burning up the pump doing that!

And it is possible you have a bad regulator or maybe it could of accidently been plumbed wrong when you installed it???

Let us know!

 

[engine24355]

Well, I tried another regulator (holley) and I get the same reading (3-4 lbs). So, I am not getting enough pressure for some reason. I know I have the regulator installed correctly...fuel line in the bottom and two out lines to the carb (holley). At this point, I guess I need to look at my fuel pump to see if it can be adjusted. Or, look at a new pump. I never learn..."oh yeah it will not be that expensive to make this change"...famous last words.

 

[Wild Mango]

The gauge may not be accurate, even though it seems to repeat.
Check the wiring to the pump by measuring the terminal voltage when its running I would expect a volt drop of say 5% maximum pumping against a dead head.
Do not confuse pressure with flow - 4lb is enough IF the pump will deliver rated flow at that pressure. If you have a graduated container you can easily check the pump is delivering its rated flow.
Vane pumps tend to like to pump against a "head" pressure so as to seat the vanes on the outer pump cavity wall.

 

[speedkills502]

I would say your pump is only putting out the 4.5 lbs, I have seen alot of that pump running with no reg. at all on single carb set ups. I would not worry about the pump I would try it with no reg I don't think you will have any problems.

 

[engine24355]

Well, from what I can tell my problem is just not enough pressure (only 3 lbs). Initially, I thought I had too much (running two 600's), but it looks to be the opposite case. It makes sense now from the way the engine is acting, but how do I fix it? My only thought is to get another fuel pump with more psi. Help me out here guys.

Thanks!

 

[FOX FABRICATION]

Well, from what I can tell my problem is just not enough pressure (only 3 lbs). Initially, I thought I had too much (running two 600's), but it looks to be the opposite case. It makes sense now from the way the engine is acting, but how do I fix it? My only thought is to get another fuel pump with more psi. Help me out here guys.

Thanks!

Have you checked your inline fuel filters that are clean (not restricting flow) and no kinks in your fuel line?

Have you checked the voltage at the pump??? If you use a switch to manually turn your pump on/off...it is possible that the contacts inside the switch have pitted to the point they have a high resistance causing a voltage drop going to the pump.


What else can we check......Hmmmmmmmm....How about your fuel tank...think you may have some rust issues possibly causing a blockage at the outlet????

Not sure what else if all checkes out good....


...kinda sound like it is new pump time :sad:

 

[GT63]

There should be a 30 amp relay installed with that pump. I'm running a Holley Red pump, no regulator, on dual carbed blown SBC with no problems.

 

[engine24355]

Have you checked your inline fuel filters that are clean (not restricting flow) and no kinks in your fuel line?

Have you checked the voltage at the pump??? If you use a switch to manually turn your pump on/off...it is possible that the contacts inside the switch have pitted to the point they have a high resistance causing a voltage drop going to the pump.


What else can we check......Hmmmmmmmm....How about your fuel tank...think you may have some rust issues possibly causing a blockage at the outlet????

Not sure what else if all checkes out good....


...kinda sound like it is new pump time :sad:

I have not checked the voltage as I have no voltage meter (knew I should have bought one...LOL). I took the old pump off last night and looked over and everything appears to be in good shape. I checked the switch and wiring connections not too long ago, but will check again.

My fuel tank is a plastic type fuel cell so rust should not be a problem, but other trash will cause a problem. I am going to replace my fuel filter before the pump to rule out that possiblility. Stay tuned...

 

[Hotrod46]

I am going to replace my fuel filter before the pump to rule out that possiblility.

Engine - The instrucions that came with the Carter fuel pump I installed on my car said not to install a paper filter in front of the pump. They recommended a strainer type unit only upstream of the pump and a filter after the pump.

I don't have the instructions handy right now, but I think they recommended 60-100 micron size screen upstream. If you have a paper filter upstream, the pump may be starving for fuel even if it's clean.

I don't know how your filter is installed, but you might try bypassing or removing it long enough to check the pressure.

Also, while I was on Carter's website looking for a copy of the instructions (which I couldn't find), I noticed that they sell pumps with output pressures as low as 4 PSI. Might be worth checking the pressure without the regulator. (Edit: Sorry. Been a long week. You've probably already done this. Mike)

Mike

 

[Lee_in_KC]

The instrucions that came with the Carter fuel pump I installed on my car said not to install a paper filter in front of the pump.

Hmmm, that might explain why I burned out my Holley Blue after only about a thousand miles. I have a Fram cannister-type filter between the tank and the pump. Might also explain why I went lean when I really stomped on it down at Ashlock's last year. Need to find the instructions for the Holley and see if they make the same recommendation. You might have just earned yourself a cold one, Mike! Too bad you won't be in MH this weekend to collect it!! (neener-neener-neener :razz

 

[Hotrod46]

Too bad you won't be in MH this weekend to collect it!! (neener-neener-neener :razz

Oh sure!! Go ahead and rub it in!!!!:flip: Hope you have a great time. You can owe me that beer.:toast:

 

[engine24355]

Engine - The instrucions that came with the Carter fuel pump I installed on my car said not to install a paper filter in front of the pump. They recommended a strainer type unit only upstream of the pump and a filter after the pump.

I don't have the instructions handy right now, but I think they recommended 60-100 micron size screen upstream. If you have a paper filter upstream, the pump may be starving for fuel even if it's clean.

I don't know how your filter is installed, but you might try bypassing or removing it long enough to check the pressure.

Also, while I was on Carter's website looking for a copy of the instructions (which I couldn't find), I noticed that they sell pumps with output pressures as low as 4 PSI. Might be worth checking the pressure without the regulator. (Edit: Sorry. Been a long week. You've probably already done this. Mike)

Mike

I think you are on to something there Mike. Thinking back, I do have a paper type filter between the tank and pump...proplem. However, it did not cause a problem with the edelbrocks I had before, but we are talking holley now so lets not look to the past. I will try to run just a straight hose to see if the pressure goes up. If so, then I can order the proper micron filter. Thanks for the help and stay tuned.

 

[FOX FABRICATION]

If you were running EDELBROCK carbs before.....they like to see 4.5 - 5.5lbs of fuel pressure....A Holley needs to see at least 6 PSI (always ran mine 6.5-7.0lbs) for the to "function" properly (at least the 4150 series).

So...maybe you pump was only putting out 4.5lbs of pressure or so..and the EDELBROCKS like it....Now with the HOLLEY.......more pressure is needed.

Check that filter anyway...and change it to a screen type!