how to test fuel presure on 93 b2200 fi?

hey guys i just got another truck, and it has a missfire mainly under load, but you can see and feel it slightly at idle too. it's a bad miss basically anything above 20 km/hr. and tries to bog down when you get moving in first. (5 spd tranny), really anything above 1/3 - 1/2 throttle it bogs. truck dosent seem to(and i was told), burn any fluids. oil is new clean.

a list of parts i have swapped from my daily driver (which runs perfect), and things i have looked at/tried:

pulled plug wires off while running to see if each wire was sparking...yes
swapped spark plugs
swapped wires
swapped distributor, and tried twisting/adjusting before removing, swapped cap and rotor both before that
yanked timing covers and checked cam at 1, crank at marks (both aiming straight up), i dont have a timing light, so i havent checked timing while running really.
swapped coil
swapped compu's with known good one
swapped air flow sensor at the airbox
checked throttle body, looks clean
exhaust disconnected before cat to see if it is exhaust restriction
all vacuum ports seem to be hooked up or plugged off (same on my daily-back-firewall side of intake manni), vacuum hoses in good shape hooked up to same spots as my daily.
fuel filter on passenger side firewall replaced with new (off of a chrysler car...just a metal regular inline canister filter)
full tank of gas- well 3/4 now after i brought it home, i asked if it was an older gas station (water leaking into inground tanks... no... but still doesnt mean its not water in the fuel. he mentioned water in the old fuel filter... maybe bad gas.

it seems to be sucking in a lot of air... really noticeable.

what im thinking of trying next, checking fuel pressure, and maybe draining tank and trying different gas.

any other ideas?

just put a bottle of octane booster you put in cars that sit for a while, it cost maybe 5 bucks.. i get it at autozone just to make sure my gas burns everytime i fill up anyways..

also try injector cleaner and maybe the plugs to the injectors are loose, happened to me on an escort once had same problems you described

thanks neptune that shall be my next step

well a couple days ago now i did:

pulled the line from the fuel filter and put line into a gas can... put a piece of wire between the connections of the yellow connector (fuel pump primer/full power override), not that i could actually test how much fuel pressure, but there's a good flow. i wanted to empty at least half a tank in case it was bad gas. then i found that theres a bracket on the passenger fender well with 2 things mounted on it that have to do with vacuum... theres about 5 lines running to and from the 2 sensors(? -there are 2 electrical connections).

i pulled one vacuum line off of the front of the fuel rail. found that it didnt have any vacuum. so i checked my other truck and it should have vacuum. so i swapped that whole bracket with sensors(?) and lines from my parts truck, and i how have vacuum at that point. but it didnt make any difference.

i got a bottle of seafoam earlier in the day, and so i sucked 1/2 a bottle through the manifold (used one of the spare vacuum lines i pulled from the aforementioned attempt) and hooked to the firewall side of the intake (2 plugged off vacuum ports). then i tossed the rest in just over 1/4 tank of gas that was left.

took the truck for a hwy cruise to go pick up some center caps for my wheels (yeah! finally!). truck runs a bit better, but still has the miss. i think im going to pull the fuel rail with injectors and then test them and see how they spray, and compare to my spare.

From Alldata

Relieve fuel system pressure by starting engine with fuel pump relay (circuit open relay) disconnected and let run until engine dies, then slowly and carefully remove hose on outlet side of fuel filter. Cover with a clean rag while removing hose, to avoid spraying fuel in your face.
Checking Fuel Pressure








Using an extra piece of injector hose, connect fuel pressure gauge as shown in illustration.
Fuel Pump Test Connector








Energize fuel pump by bridging the terminals of the yellow fuel pump test connector (located near the firewall below the windshield wiper motor, see illustration) and turning ignition "ON" .
Pinch off hose between gauge and pulsation damper with a clamp.
Observe fuel pressure on gauge (this will be the maximum fuel pressure available from the fuel pump). 64 - 85 psi (441 - 589 kPa) If pressure is higher than the maximum specified, replace fuel pump. If pressure is lower than the minimum specified, check fuel filter. If filter is OK, replace pump.
Disconnect jumper wire from test connector and turn ignition "OFF". Wait 5 minutes, then observe fuel pump residual pressure on gauge. Minimum 50 psi (343 kPa) If residual pressure is less than specified, fuel pump pressure relief valve is leaking - replace pump.
Remove pinch clamp from hose between gauge and pulsation damper.
Start engine and let idle.
Observe fuel pressure on gauge (this is the system operating pressure). 28 - 37 psi (196 - 255 kPa) If pressure is higher than the maximum specified, check fuel return line for kinks or restriction. If pressure is lower than the minimum specified, check fuel filter. If filter and return line are OK and pressure is still not within the specified range, replace pressure regulator.
Disconnect vacuum hose from fuel pressure regulator with engine idling.
Fuel pressure should increase when vacuum hose is removed.
38 - 46 psi (265 - 314 kPa)

If not, replace pressure regulator.



Shut engine "OFF" and wait 5 minutes, then observe residual pressure on gauge.
Minimum 21 psi (147 kPa)

If not, check for leaking fuel injectors. If injectors are not leaking, replace pressure regulator.

If all test results are OK, fuel pump and pressure regulator are OK.

Are you hearing a hiss of some kind while the truck is idling?

Maybe you have a vacuum leak.

That would give you a lean misfire.

If the exhaust smells like raw gas. . .it's rich. Just for information sake.
If the exhaust smells like dragon breath. . .it's lack of hydrocarbons sufficient to support complete combustion.

A can of propane with a pinpoint hose or a can of carb spray can be used to direct hydrocarbons to various locations to locate vacuum leaks. Base of the intake manifold. . . where the brake booster line connects to the manifold. . .base of the injectors where they go into the manifold. . .if the idle quality changes, you have found your leak.

thanks for the how to and tips. i will try the throttle body spray around the vacuum hoses, as i havent done that yet. i checked the hoses themselves and look in decent condition and connected, but there could be a leak somewhere still i guess.

the intake itself is sucking a lot (making a noticeable noise)

i will probably swap regulators first and see what that does... but when i pulled the vacuum line to it, there was no change at all. i read that it should bump up fuel pressure. so that may not be working if i didnt notice a difference.

alrighty today started it up, pulled it out of the garage and after it was running for a couple mins i got my propane torch out, i opened the valve to let some propane out and ran that near the brake booster, along the metal hose on the firewall, all vacuum connection points and around the intake manifold. there was no change in rpm of roughness/smoothness.

then i yanked the intake plenum and and pulled the furl rail out a bit, pulled spark plugs and coil wire (so no sparky will happen and easier to turn engine over). all injectors fire decent, one had more of a straight ahead beam of spray compared to the others lil more wide pattern, so i pulled that one and blew air through it backwards, and forwards, and dripped a lil bit of seafoam into it, let it sit and blew it back through again front and back. put it back in tested again quick and its just as good as the others now. i also swapped the regulator on the rad side of the engine (vacuum fed).

then i went to 2 stores to try to get the intake plenum gasket, but neither had a listing for my FI b22. only carbed. i should have asked to see the carbed gasket set. for all i know it could be the same. need to look at some pictures. the old gasket was maybe original.. came off in pieces and required a scraper and blade to clean of the manifold and plenum. so i need a new one. i'm going to look for the part # online now, and bring that in. or else maybe i'll just get gasket paper and make it...

ok found the gasket rockauto lists it the same as the carbed gasket at least in 92-93... found at partsource (crappy tire) for $8.50 or so. fair enough. so new plenum gasket in, and everythin back together. runs better, but still not perfect. swapping and testing the spare fuel rail next. prolly tomorrow.

is the fuel pressure regulator on the fuel rail close to the fire wall of the rad? theres 2 'cylinders' that look similar... the rad side one has a vacuum hose going to it, the other is just on the fuel rail. has a screw in the center end. i havent tried turning it... i suspect it would break if i did try. i ran my propane torch (unlit... lol) around everything again.... trying to get as deep and close to the intake to head gasket as possible. i dont think thats ever been touched at all though. i have the gasket, i will prolly just do it next time i swap stuff...