Fuel pressure too high carbed

[Brownie Mobile]

So ive been getting rich running a lot lately, so i did some research and found some common problems one of them being fuel pressure. went to check my fuel pressure and its at about 8psi about 3-4 higher than it should be. What do i do Im not sure how to check what lies at fault it can be the carb or the pump. I ran it without the gas cap on to check for tank vent problems. The carb is a motorcraft 2150 i think the id tag reads e37e AAA

 

[Mark_88]

Have you changed the fuel filters lately? There may be a blockage at the carb via fuel filter that is clogged...

The manual pump only pumps at about 7 psi normally and if there is a narrowed passage that could lead to higher pressures...which generally blow out the needle and cause other problems...like float bowl overflow and saturation of the carb...leading to rich burning...

However, having said that, I would have to ask if you are using the manual pump or if you've swapped in an electric pump...and also how did you check the pressure...I have a vacuum tester that also doubles as a fuel pressure tester and I checked mine when I had a problem with vacuum (leaky manifold gasket)...

 

[Brownie Mobile]

Have you changed the fuel filters lately? There may be a blockage at the carb via fuel filter that is clogged...

The manual pump only pumps at about 7 psi normally and if there is a narrowed passage that could lead to higher pressures...which generally blow out the needle and cause other problems...like float bowl overflow and saturation of the carb...leading to rich burning...

However, having said that, I would have to ask if you are using the manual pump or if you've swapped in an electric pump...and also how did you check the pressure...I have a vacuum tester that also doubles as a fuel pressure tester and I checked mine when I had a problem with vacuum (leaky manifold gasket)...

well i just got the fuel filter 600-700 miles ago so its not that, and i used a kit that has a compression tester as well as a fuel pressure tester. its a manual fuel pump probaly never been replaced could that be it ?

 

[Mark_88]

Could be, but they usually give less pressure as they age...the diaphram pops and you end up with little or no pressure.

The fuel filter was changed...do you happen to have a crimped line? Perhaps a fuel line that is old and may be deteriorated inside...

8 psi isn't too far out of spec though...and may or may not be the cause of rich burning...I recall from another thread that you were going to rebuild the carb...before doing that, check on the side closest to the valve cover of the carb for a possible secondary fuel/air mixture screw...I found one on my 5200 that I had no idea was there...it is for the secondary stage of my carb and it managed to get turned out too far causing fuel dumping at higher rpms (or when I engaged the second stage typically)

If you can get a parts diagram of your carb it might help solve this mystery...one of those exploded views that shows where screws, gaskets, jets, and other things are located and their part numbers...

 

[doorgunner]

I ended up having to reset the float(s)/fuel level on my carb 1/4 inch lower...weird how some carbs "act" differently

 

[Brownie Mobile]

Could be, but they usually give less pressure as they age...the diaphram pops and you end up with little or no pressure.

The fuel filter was changed...do you happen to have a crimped line? Perhaps a fuel line that is old and may be deteriorated inside...

8 psi isn't too far out of spec though...and may or may not be the cause of rich burning...I recall from another thread that you were going to rebuild the carb...before doing that, check on the side closest to the valve cover of the carb for a possible secondary fuel/air mixture screw...I found one on my 5200 that I had no idea was there...it is for the secondary stage of my carb and it managed to get turned out too far causing fuel dumping at higher rpms (or when I engaged the second stage typically)

If you can get a parts diagram of your carb it might help solve this mystery...one of those exploded views that shows where screws, gaskets, jets, and other things are located and their part numbers...

well i already rebuilt the carb and i dont really want to look at my chiltons right now ( its in my truck) but it said i think 3.5-5 psi i definitely think 3 psi is too high. Next chance i get ill go and take a look at my lines and stuff see what we got but im pretty sure i didnt notice anything when i was checking the lines before. I think i might take the hose out from the carb and run some compressed air through it is this a bad idea? I know any chunks or particulates will go back in the gas but it would at least help pin point my problem

 

[Brownie Mobile]

I ended up having to reset the float(s)/fuel level on my carb 1/4 inch lower...weird how some carbs "act" differently

I actually did that, i set it so it was quite the bit lower and i still get black smoke all day. Its really starting to piss me off though im getting about 5 mpg ive gone like 70 miles on 3/4 tank this entire 23 gallon tank is gonna turn out being a 100 mile tank its like wtf!

 

[doorgunner]

My holley did the same thing:
1. Accellerator pump lever was set too tight against pump rod causing engine to "siphon gas" thru the squirters
2. floats were too high
3. main jets were .008" too big
4. choke plate was sticking halfway closed
5. had primary butterflys open too much causing engine to siphon too much gas thru idle circuit

all the above will get you 5 to 9 mpg...

I corrected evrything & got 22 mpg in overdrive on interstate

 

[Mark_88]

My holley did the same thing:
1. Accellerator pump lever was set too tight against pump rod causing engine to "siphon gas" thru the squirters
2. floats were too high
3. main jets were .008" too big
4. choke plate was sticking halfway closed
5. had primary butterflys open too much causing engine to siphon too much gas thru idle circuit

all the above will get you 5 to 9 mpg...

I corrected evrything & got 22 mpg in overdrive on interstate

^^ Good things to check...the butterfly (choke plate) sticking closed was a problem on one of my carbs...the auto choke was wonky causing it to remain partially closed...that should be wide open at warm idle...

I checked the ARRC on-line manual and there were some things there that might be of interest to you...but the diagnostic section was pretty much empty and it only listed the 2.8 with a carb for the model year 1985...1984 was blank...

When you rebuilt the carb, did you use a partial or full rebuild kit?

The fuel pressure should be 4.5 to 6.5 according to the specs in that reference...anything higher and the needle will be fighting to stay in place...and may have already been blown out...

Does the fuel actually spill over the bowl at any time? Can you see fuel spillage?

And there is a second stage on that carb according to ARRC...and there is an adjustment for it but you will probably need to have a look at it yourself and remove the carb to access it...

Here is the link to ARRC...when you click on it you will need to log into the site...user name and password are both tech

http://search.ebscohost.com/login.aspx?authtype=url,uid

Once inside scroll down to the link for the ARRC and click that...then choose the repair section at the top, then select the year (1985 only), make and model...

There are also diagrams of the 2150 carb under other sections but you will need to select 1978 or other year, select a model like the Thunderbird or other, and poke around till you find it. Sorry, I went through that a few years ago and found what I needed...and I know the other carbs (stock only) were all listed...but there is no direct link...so you will need to search through it...

 

[Brownie Mobile]

My holley did the same thing:
1. Accellerator pump lever was set too tight against pump rod causing engine to "siphon gas" thru the squirters
2. floats were too high
3. main jets were .008" too big
4. choke plate was sticking halfway closed
5. had primary butterflys open too much causing engine to siphon too much gas thru idle circuit

all the above will get you 5 to 9 mpg...

I corrected evrything & got 22 mpg in overdrive on interstate

1. How would one check the accelerator pump?
2. I set my float by eye i know its not exact but it was very much above where it should be before
3. I dont have another carb kit nor the money to get one so i cant really check my jet size unless the gaskets stay nice but i think they are right because i didnt replace them it was only a partial rebuild
4. Not happening my choke is perfect, the only thing on my truck that runs right
5. How would i fix this if it was the problem?

^^ Good things to check...the butterfly (choke plate) sticking closed was a problem on one of my carbs...the auto choke was wonky causing it to remain partially closed...that should be wide open at warm idle...

I checked the ARRC on-line manual and there were some things there that might be of interest to you...but the diagnostic section was pretty much empty and it only listed the 2.8 with a carb for the model year 1985...1984 was blank...

When you rebuilt the carb, did you use a partial or full rebuild kit?

The fuel pressure should be 4.5 to 6.5 according to the specs in that reference...anything higher and the needle will be fighting to stay in place...and may have already been blown out...

Does the fuel actually spill over the bowl at any time? Can you see fuel spillage?

And there is a second stage on that carb according to ARRC...and there is an adjustment for it but you will probably need to have a look at it yourself and remove the carb to access it...

Here is the link to ARRC...when you click on it you will need to log into the site...user name and password are both tech

http://search.ebscohost.com/login.aspx?authtype=url,uid

Once inside scroll down to the link for the ARRC and click that...then choose the repair section at the top, then select the year (1985 only), make and model...

There are also diagrams of the 2150 carb under other sections but you will need to select 1978 or other year, select a model like the Thunderbird or other, and poke around till you find it. Sorry, I went through that a few years ago and found what I needed...and I know the other carbs (stock only) were all listed...but there is no direct link...so you will need to search through it...

Thanks for the reference definitely going to be doing some research while at school of course . Ive ran with my air cleaner off and never seen any fuel spillage even after full throttle and full throttle then instantly letting off never seen any spillage ( even before i readjusted my float). I will research the secondary adjustment and pull my carb soon but im thinking its not the secondaries only because i can get it to start ( not turn on but start moving) if i basically floor it. but when not using as much gas its bull crap. I was doing some research and i think it might be my o2 sensor if you guys didnt see one of my previous thread my muffler blew up so im thinking the 02 sensor is probaly getting a lean reading and putting far too much gas into the carb i think i might try wayyyy leaning it out for a bit and see how it runs although im weary because ive heard the stories of burnt valves. What do you guys think?

 

[85_Ranger4x4]

1Thanks for the reference definitely going to be doing some research while at school of course . Ive ran with my air cleaner off and never seen any fuel spillage even after full throttle and full throttle then instantly letting off never seen any spillage ( even before i readjusted my float). I will research the secondary adjustment and pull my carb soon but im thinking its not the secondaries only because i can get it to start ( not turn on but start moving) if i basically floor it. but when not using as much gas its bull crap. I was doing some research and i think it might be my o2 sensor if you guys didnt see one of my previous thread my muffler blew up so im thinking the 02 sensor is probaly getting a lean reading and putting far too much gas into the carb i think i might try wayyyy leaning it out for a bit and see how it runs although im weary because ive heard the stories of burnt valves. What do you guys think?

If you have secondaries (as in a 4 barrel) all the 02 sensers are doing is plugging hole(s) in the exhaust.

However I have seen bad ones act up (either the sensers or the wiring) and cause the engine to run very rich. You can check them electronically (there has to be a witeup somewhere) before you run out and buy new.

If you do have the stock carburator and didn't plug it in the default setting is "as rich as possible"

 

[Brownie Mobile]

Well its definitely not a 4 barrel and yes ive found write ups on how to do the testing it should be at like .6 volts at 600 degrees F fully farm but the problem is i cant test it because my motor wont stay running because it misses on 2 cylinders every rotation so its really rough and barely runs Basically all these tests have to be done motor off and cold.

 

[85_Ranger4x4]

Burn out the carbon with a torch, they won't work for very long but they will work for awhile... and if that helps you need new. If you haven't changed them for awhile it probably wouldn't hurt to change them anyway.

 

[Brownie Mobile]

Burn out the carbon with a torch, they won't work for very long but they will work for awhile... and if that helps you need new. If you haven't changed them for awhile it probably wouldn't hurt to change them anyway.

Change what? my spark plugs im guessing and those were about 800 miles ago just before i changed the fuel filter but those undoubtedly were 800 very rich miles

 

[85_Ranger4x4]

Change what? my spark plugs im guessing and those were about 800 miles ago just before i changed the fuel filter but those undoubtedly were 800 very rich miles

We were talking about O2 sensers last I checked...