Fuel pressure at 20-22 max...
Fuel pressure at 20-22 max... Well my car was shitting out on me, starting then dying immediately after, or starting and running for 4 seconds then dying. I took off the water pump and opti, replacted the water pump, put it all together and it runs now, but my fuel press is at 20 - 22ish max, even when reving.. Shouldn't it be about 40?
Turn the key on but don't start the engine. FP should jump to ~43 psi, then start to slowly drop off into the 30s. If it drops off quickly to very low numbers, you need to check for leaks. FPR diaphram, in-tank line, injectors.
Now start the vehicle. It should be ~38-40 psi.
Now pull the vacuum line off the FPR (it is located on the passenger's side of the vehicle, on the intake manifold, near the back. FP should jump ~4 psi, simulating WOT operation.
All numbers are approx. b/c of manufacturing and vehicle variations.
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Incorrect. You should try it 3 ways:
Turn the key on but don't start the engine. FP should jump to ~43 psi, then start to slowly drop off into the 30s. If it drops off quickly to very low numbers, you need to check for leaks. FPR diaphram, in-tank line, injectors.
Now start the vehicle. It should be ~38-40 psi.
Now pull the vacuum line off the FPR (it is located on the passenger's side of the vehicle, on the intake manifold, near the back. FP should jump ~4 psi, simulating WOT operation.
All numbers are approx. b/c of manufacturing and vehicle variations.
Turn the key on but don't start the engine. FP should jump to ~43 psi, then start to slowly drop off into the 30s. If it drops off quickly to very low numbers, you need to check for leaks. FPR diaphram, in-tank line, injectors.
Now start the vehicle. It should be ~38-40 psi.
Now pull the vacuum line off the FPR (it is located on the passenger's side of the vehicle, on the intake manifold, near the back. FP should jump ~4 psi, simulating WOT operation.
All numbers are approx. b/c of manufacturing and vehicle variations.
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Fuel preasure should be checked under load For preasure and also for VOLUME. I check preasure while running down the highway under load and monitor the preasure. A volume test is done in the shop. Bleed down engine not running is another in shop test. Hope this helps. Always test preasure on the road and running the engine HARD. Preasur should not drop below 43.5 lbs.
Fuel preasure should be checked under load For preasure and also for VOLUME. I check preasure while running down the highway under load and monitor the preasure. A volume test is done in the shop. Bleed down engine not running is another in shop test. Hope this helps. Always test preasure on the road and running the engine HARD. Preasur should not drop below 43.5 lbs.
Fuel preasure should be checked under load For preasure and also for VOLUME. I check preasure while running down the highway under load and monitor the preasure. A volume test is done in the shop. Bleed down engine not running is another in shop test. Hope this helps. Always test preasure on the road and running the engine HARD. Preasur should not drop below 43.5 lbs.
You can't have pressure without a volume of fuel in the lines, so I don't quite get that.
GM spec is (quote) With ignition "ON" and fuel pump running, pressure should 284 - 325kPa (41-47 psi)....When the engine is idling, manifold pressure is low (high vacuum) and is applied to the pressure regulator diaphragm. Vacuum will offset spring pressure and result in lower fuel pressure. Fuel pressure at idle will vary somewhat depending on barometric pressure but, should be less than pressure noted. (end quote)
Whether you're driving or idling, the same manifold vacuum is applied to the fuel pressure regulator. It doesn't matter.
I too would like to know how to do a volume test.
A simple way to test for a good pump is to put a fuel pressure gauge on the Schrader valve and make it visible while driving.
Take vacuum hose off (which means pressure should be a consistent 43-45psi at all engine speeds).
Do a few quick throttle bursts/nothing crazy.
If fuel pressure dips at all below 43psi then the fuel pump needs to be replaced.
So that can't be done using a fuel pressure gauge on the Schrader valve?
A simple way to test for a good pump is to put a fuel pressure gauge on the Schrader valve and make it visible while driving.
Take vacuum hose off (which means pressure should be a consistent 43-45psi at all engine speeds).
Do a few quick throttle bursts/nothing crazy.
If fuel pressure dips at all below 43psi then the fuel pump needs to be replaced.
So that can't be done using a fuel pressure gauge on the Schrader valve?
