fuel pressure regulator?

Have a 99 ranger and millage went down the tube and finally found that the pressure regulator in the automatic trans was defective and not letting the power to go to the wheels ( 70% to wheels 30% to gas tank)

If the check engine light is on, have the computer scanned. Check fuel pump pressure to make sure it is within spec. As far as the vacuum hoses beind the engine, they run to the 4wd.

So this is the second time I have posted on this topic. I have run through all the previously suggested tests and I'm still having the same problem. I have replaced the fuel pump, only to find that I wasted $75.00. I did come acrossed an issue that I could see would cause a fuel pressure issue. The hose that connects the pump to the sending unit was split down the side and basically shooting gasoline back down into the tank. Attached is a pic of what I removed and replaced. I'm pretty sure the pump is still good but I replaced it anyways because with the hose like that I simply dont know how long that pump has been over working itself. With the new fuel pump, I still only get 26psi running pressure, but the static pressure is holding at about 36 pis(key on engine off)
The diaphragm on the fuel pressure regulator seams to be holding a vacuum well, and isnt leaking any fuel. The injectors dont seam to be leaking off per the test I ran. I have a timing light that I'm going to hook up to it and replace the fuel filter again. Any other suggestions would be helpful.
Thanks.

pinch off the return line to the tank at the pressure regulator and see what the pressure measures.

Roy

Symptoms indicates the fuel pressure regulator is faulty.

OK, the pressure went up to about 50psi. Does that explain it?

Yup, that means a bad pressure regulator.

ok, I unhooked the vacuum line off the fpr and the pressure went up to normal operating pressure 35-36 psi

35-36 psi is at lower edge of specs but vacuum line should be attached.

that is normal. with no vacuum, the pressure should rise.

put a brand new regulator on it with no change in results it seams the regulator works properly without a vacuum line hooked to it.?????

with vacuum, it will lower the pressure. thats normal as i said before.

what kind of pump did you use??

Roy

the name brand on the pump is airtek.
now the truck is getting 26psi @ idle but if I give it a little more throttle, the pressure goes up to 36psi. naturally a higher rpm is going to require more volume @the same pressure correct? so, does that mean the regulator is operating correctly? maybe the old regulator was bad and i just need to take it for a spin and see what happens in stead of looking at the pressure gauge.

the regulator is fine. when you decrease manifold vacuum, the pressure increases.

the pressure is on the low side. i like to see around 35 at idle with the vacuum line on the regulator

Roy

ok, i took it for a test drive and its still bogging down under a load, not as bad but still is. when you throttle the engine doesnt that give you more vacuum???
the pump should be more than enough to provide adequate pressure to the rail. the specs on the pump call for minimum of 80 psi and max 100 psi. unless i got a bad pump which has happened before.

no, less vacuum under load. yes, you could have a bad new pump. airtex is a good pump but you never know.

Roy

regardless of the rpms of the engine, an electronic fuel pump is going to continuously give you the same pressure, and the regulator is going to adjust the pressure into spec right?

the only things on the fuel system that arent new as of today are injectors, fuel rail, lines and filter. the filter is the only thing left that would cause loss of fuel pressure

nope, wont do it. there is a bypass if the filter gets clogged.

Roy

ok, so less manifold vacuum increases the fuel pressure right, so does that mean i have too much manifold vacuum at idle???
how does manifold vacuum get too high there are any vacuum regulators anywhere, I cant find any. could that mean I have a vacuum clogged somewhere? an open vacuum line would reduce vacuum elsewhere or could my idle be set too high? Im stumped here. could the throttle position sensor cause this?

Ok, so my truck has been running pretty rough here lately, I have replaced the plugs and wires, mass air flow sensor, Ignition coil, and ran sea foam through it. My friend came over last night and hooked his computer up to it and we got 512 (Ithink) which I believe is No Codes In Memory. We also ran a fuel pressure test. The static pressure has me kind of puzzled... As soon as you turn the key on, the pressure jumped up to 35 psi but within a second, it drops to 6 psi. I believe the specs call for 35-45 psi (key on engine off) The fuel pressure is also a few pounds low while the engine is running too. With the engine running i am getting like 24-26 psi. I think the specs call for 30-40 psi here. (key on engine running) Today i pulled the Fuel pressure regulator off, it was holding pressure to the fuel rail. The diaphragm is not leaking but I don't know if there is anything else to check on it, it is holding vacuum, and has good vacuum to it. Any suggestions would be helpful.
Thanks in advance

fuel pressure bleed down is caused by: leaking regulator (internal or external leak) injector(s) stuck open leaking return line. All three are important and need to be addressed. This guide will help

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Please run down this guide and report back.

you vacuum is fine, your regulator is fine. there is no vacuum issue. it is a pressure issue possibly from a weak new pump.
Roy

the fuel filter was recently replaced. I have also pulled the tank, flushed it and cleaned the sock.

engine runing fuel pressure is 28-45 sounds like your pressure is low.

yea i googled the pressure specs last night and got a result of 35-45psi while running and 30-40psi static but that might be wronge im gonna do some more research

The fuel filter has no efficiency on inj. bleed off. Cycle the key 8-10 times, waiting for the pressure to bleed off. DO NOT turn the engine over while cycling the pump. Then simply pull the spark plugs and look for one that is fuel saturated. That hole is your leaking injector. Disable the ign. system and spin the engine over, prior to re-installing the plugs. this will prevent bad things from happening when you restart it. Hope this helps, Doc

ok will check that out tomorrow
about the low fuel pressure, and loss of power, will a leaking injector cause both symptoms together?

Fuel pump runs continuously
Changed fuel filter and fuel pressure regulator

In a nutshell, yes. I could tell you how to confirm it with a scanner using mode 6 data... but I'm thinking you probably don't really have those kind of tools just lying around. I bet your mileage has dropped way off, and the exhaust is probably really warm, both at the tailpipe and at the cat. converters. But I bet it starts great when cold but harder when its warm, am I getting close? Let me know, Doc

What do you mean, while the engine is running or after the engine is shut off?

Well Doc, you're real close, it always starts up great, but yes, it runs worse under higher ambient temperatures. after the engine warms up, it does get better. When the engine is cold, I have to pretty much floor it when pulling away from a light. It does better at higher rpms than if I would pull away from a stop normally. I have noticed some carbon buildup on the outside of the bed above the tail pipe. It actually doesn't have any cats on it. they were removed before I got it.

When I first turn the ignition switch on, fuel pump used to run 3 to 5 seconds then shut off till cranked, runs continuously now, act like maybe too much fuel or not enough when turning over but not starting.

Sounds like an open injector to me.... If nthe O2 sensors still are reading O2 content, every time a cylinder misses,the sensor see alot of oxygen and tells the ECM that the motor is running lean,so it adds more fuel.... making the problem only get worse. Try the plug thing and let me know. Doc

It is supposed to only run 2 seconds if the engine isn't cranked but that is a safety feature only and has no effect on engine performance.

OK Doc, so I did the plug thing, cycled the key about 30 times then pulled all six plugs. none are wet although they are brand new, four out of six have a light white burn to them while the back plug on both sides look new besides a little black carbon on the couple threads that stick through the bottom of the heads. So unless I'm doing the test wrong, I dont have a leaky injector... What would be my next step????

Am thinking about changing throttle air bypass valve next, unable to scan for codes on this '93 Ranger. Changed fuel pressure regulator, the fuel pump came on then off when ignition turned to on, cranked up fine, revved up fine, I drove about 2 miles and check engine light came back on, ran poorly when accelerator pressed past half way down, came back home, turned off, turned key to on and fuel pump running continuously again.???

How do you change fuel regulator in 1990 Ford ranger

What engine does it have? 2.9 or 4.0?

SO, just to be sure of myself, I ran the plug test a second time, this time leaving the key on a little bit longer each time I cycled it to make sure the injectors were getting fuel to them. I got the same results as the first time. I'm leaning pretty far towards the fuel pump being the problem. If I get low pressure to the rail while its running, and lose static pressure, and the fuel rail and injectors aren't showing any sign of leaking, while the fuel pressure regulator isn't showing signs of failure, that would leave the fuel pump being faulty, or ECM problem. I also unplugged the O2 sensors and MAF sensor and didnt get any change from them being out of the equation. Should I go buy a fuel pump???