How do you check the fuel pressure on a 1987 GMC v-1500 pickup with a 350 tbi motor?

Question

I do not believe there is any valve for me to hook to so i can check it(i could be wrong).How do i check the pressure and what is the pressure suppose to be at??My check engine light comes on and the code reads a lean condition.The O2 sensor has just been replaced twice ,so that isnt the problem.Thanks.

--there is no fuel rail on this truck.It is just a single throttle body sitting on the top of the motor.

Please just tell me how to check the fuel pressure.Everything under the hood is new or less than a year old including the engine.

Answer 1

FUEL PUMP?

I can only tell you the problems I had on my '91 Chevy 2500 w/350 tbi.

Over a three month period, the truck developed less "top end" power. It would rev up to redline, but didn't have the same power as moderate throttle and moderate engine speeds.

It got to the point where it would crapout if I floored it trying to get on the freeway, but would still run fine in downtown traffic.
It would start right back up, but die as soon as I tried to merge back into the freeway traffic.

As it worsened, I could not get above 50 MPH, then, it finaly would not do more than idle.

I changed the fuel filter, and that helped briefly, and then finaly died completely.

The pump and fuel gage component in the tank is about $250.00

I had to change mine, and haven't had a problem since.
I take that back....I had to change the rotor and Dist. cap.

If you have to change the pump, the locking ring is kind of tricky to figure out how to remove it. It's got a center locking ring that turns. NOT the outer ring.

Answer 2

I have the exact same problem only I allready changed the fuel pump a year ago! I found this on the web ; chances are it is one of 3 things, a bad fuel pump relay: if it is, it costs about $15 and is located in the "under the hood" fuse box. Look under the fuse box lid for location of the relay. #2 The oil pump pressure switch/sending unit: you can determine this by unplugging the wire connector to the sending unit and jumping the 2 end terminals together it is a 3 wire connector. If the fuel pump starts which is identified by a hum from the tank then it is most likely the oil press/sending unit.#3 The wire connector to the fuel pump itself could also be bad, but this is difficult too because you have to drop the fuel tank to get to it also. I know the oil pressure switch/sending unit sounds unrelated but the wiring circuit to the fuel pump has a branch that is routed through the oil sending unit and it can cause the pump not to operate if it goes bad. The oil sending unit (OSU) is in a difficult location in the back of the engine under the distributor and it takes a deep socket to remove. The fuel pump, if it is actually bad, is a big job especially if you have a full tank of gas. It is usually best to remove the gas before trying to drop the fuel tank. Most tanks nowadays are difficult to get a siphon hose into. The fuel pump I bought cost $180 from an auto parts store and figure 2 or 3 hours of labor just depends on how good/quick they are. There are a few tricks to dropping the tank and there are some fuel line connector tools required but they are not expensive. If you do change the pump, you'll also need to change the fuel filter. After everything I said earlier, you may want to check that the fuel filter is not plugged up...it is a possibility, but I have never seen a plugged up fuel filter. I, of course, buy my gas at reputable places, but if you don't I guess it's reasonable to look at in addition to what I told you. Good Luck Hope this helps!

Answer 3

When you replaced the sensor, did you reset the computer? If not, that still needs to be done. Also, do a tuneup if you haven't done so. Replace plugs wires, and cap and rotor. any of these will cause that.

Added: Fuel pressure is 9-13 psi. There are two lines near the back side of that throttle body. Think the inlet is on the right(passenger side) pull that and hook up a pressure gauge to that.

Answer 4

Any auto parts store can sell you an inline fuel pressure guage for about $40.00