The fuel pump was changed,now it idles high. - 1990 Volvo 740

WOW YOU DID IT ALL THERE, SUPER GOOD JOB
10-PSI IS DEAD WONG.

1. bad pump ir rusted wires to it, or pins,
2. bad FPump relay. burned contacts in it. bad.
3. bad FPR FP regulator. and vacuum nipppple not leaking fuel./
4. clogged inline fuel filters. even pump sock bad.

for sure new filter is easy, inline easy to put hands on first.
does F250 have front and rear fuel tanks? and fuel tank selector valve?
The Fuel Tank Selector Valve allows the driver to switch between the vehicle's front and rear fuel tanks. hummmmmm?
this is mpi (efi) engine right. v8,
they made 3 systems sadly the year, 1 pump or 2pumps.
"The fuel delivery system uses either a high or low-pressure in-line or in-tank electric fuel pump, with some models equipped with both
fuel pumps."

in a real shop we can see on scope that the Brush segments on the commutator or the pump are dead. and now pump is weak. even about to fail amazing no? there is Youtube that vie Duane page.
what is spec, ok I will look in your service manual for that.

the FPR (if pump good and passes the shunt test)
the FPR vacuum conn. must have good no vacuum key off and full vacuum max 20inchs Hg. at idle and when throttle gunned vaccuum falls fast, and fuel pressure goes 6psi changed from
idle to driving up a hill full load wot, wide one throttle.
at full idle vacuum fuel pressure is lowet, and at WOT, fuel pressure is the most. near 40 PSI or HP will not happen (full power full fuel flow)

10PSI usually means pump is bad. FPR can not hold 40+ when weak pump.

the other test is keyon pressure is max then but pump only runs 1second, so the trick is, crank for 5sconds max (save da battery)
46psi/
OMG this beast has 2 fuel pumps . ONE IN LINE.
"include a high pressure inline electric fuel pump, a low-pressure tank-mounted fuel pump, fuel charging manifold, pressure regulator, fuel filter"
ok let me look that up.
quote
"The pressure regulator reduces fuel pressure to 39-40 psi (269-276 kPa) under normal operating conditions. At idle or high manifold vacuum condition, fuel pressure is reduced to approximately 30 psi (207 kPa).(idle is lower PSI due to huge vacuum in he plenum)?

Schrader type valve at rail

I trying hard to learn the exact parts for fuel this v8 uses
the only tricky parts here is dual tanks
and the number of pumps on the truck
some low pressure tank pump and frame mounted high pressure 40psi up , pump and shunted can do over 60psi. a shunt test is output hose (blocked) old pump fail this easy with bad brushes deep inside. (commutator segments some wrecked)
that is all , hope it helps you, need more fact to deep, for sure 2 thanks.

Changing a fuel pump shouldn't affect the idle.Was it ok before the pump was changed? Look for any source of vacuum leak under the hood from the hoses causing unmetered air to enter the engine. Make sure the throttle is not stuck open slightly. Is the check engine light on? If so have the codes scanned for possibleTPS or IAC problems

Troubleshooting steps:

1. When you first turn the key on, listen for the sound of the FUEL PUMP (humming sound). If you just turn the key on but don't turn it to START, the fuel pump should run for no more than 3-5 seconds. If it does, continue troubleshooting;
2. If the FUEL PUMP runs longer than 3-5 seconds, check for fuel leaks.
3. Test pressure at the fuel rail. If pressure is erratic or too high at idle, replace the fuel pressure regulator;
4. If fuel pressure is too low at idle, replace the fuel filter. Still too low? Replace the fuel pump and fuel pickup strainer.

IF the motor is cranking, is it getting any fuel? When you turn your key on, do you hear the fuel pump kick on? Most cars today are fuel injected, and use an electric fuel pump. With another partner, have them stick their ear on the gas tank as you are turning the car on. You should hear some kind of pump, if not, your fuel pump may be dead.

The fuel pump would not cause a high idle. That is probably a faulty idle air control valve or vac leak. And your friend might be right on the EGR idea.
If you look at any of the auto parts stores online you can get a photo of the valve to help you find it.
The computer uses the idle air control valve to control idle speed by how much air enters the intake.
Is the check engine light on ?

As with any no-start or stall problem you will need to figure out if it is a fuel or ignition issue.
The high idle usually means you have a vac leak or a problem with the throttle body or idle air control valve. The control valve is how the computer controls the idle speed.
You'll need to watch the fuel system and spark to see which is being affected when the engine dies.
You might want to hook a test light up to the coil to see if it is loosing voltage for example.

Have the fuel pump pressure tested,also,check out the idle air control.

Hello,
The car may be hard to start because it may need a normal tune-up. If the spark plugs are pretty used, they will slowly stop burning as much fuel because the spark slowly gets lesser and lesser. On a cold day the fuel is harder to ignite with a small amount of spark.
Normal idle when its cold means that your cars idle is probably too high. If you lower the idle, the choke on a cold day will keep the idle a little higher until the motor warms and then it will kick back off. If the idle is too high, it will run very rich, smothering itself with fuel, and causing the idle to stay low. When the car warms, its creating better spark when its warm, and with the idle being too high its running at a fast idle.
The car wont start sometimes can be the cause of a few things. If the ground is bad on the fuel pump, it wont make a good connection sometimes for when you turn the key on, the fuel pump dont pump the fuel to the engine. Another one can be that your accessory switch can be loose going to the fuel pump. I think its your ground though. Good luck! Hope this helps.
Have a nice day. -Steve

You haven't changed everything...map sensor controls spark and fuel mixture as does the throttle position sensor, also check the idle control valve...Don't just buy stuff...do testing first.

Check the fuel filter-they had a recall on replacement filters(fram?-just google GMC Recalls) or go to 91 GMC Sonoma Repair=many sites to tell you and download manuel. Then the library has books if you dont. Good luck and God bless1
Scoyboy