fuel pressure
#1
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fuel pressure
where should the fuel pressure be regulated at? i took off the hose at the end of the fuel rail and put a gauge on it. does anyone know what the fuel pressure should be at the end of the fuel rail? i think i have a fuel pressure problem the car has been unfloodable for the last week or so and i have around 90 psi of compression on the rear rotor. its an 87 tll. oh, one more thing does anyone know if a N/A regulator would work? thanks james
#2
HAILERS
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They method your using is measuring the output of the fuel pump.
To find out the regulated rail pressure, just TEE into the fuel feed line on the left side of the engine. The fuel has to be allowed to flow to read the regulated rail pressure.
The fuel pump should be putting out approx 71.1-92.4 psi and the rail pressure should be approx 34.1-39.8 if the engine is not running and approx 28.4 at idle.
That's for a turboii. The n/a is very similar. It's in the online manual.
To find out the regulated rail pressure, just TEE into the fuel feed line on the left side of the engine. The fuel has to be allowed to flow to read the regulated rail pressure.
The fuel pump should be putting out approx 71.1-92.4 psi and the rail pressure should be approx 34.1-39.8 if the engine is not running and approx 28.4 at idle.
That's for a turboii. The n/a is very similar. It's in the online manual.
#3
I wish I was driving!
If you tee into the fuel line with a tee-fitting, you can mesaure rail pressure, which is really what we care about. With the car off, you should see 39-42 psi. With the car running, you should see 30-34 psi of fuel pressure, depedning on your engine vacuum.
By simply taking a hose off and connecting the gauge to it, you are measuring the maximum fuel pressure your pump can generate and the pressure drops associated with the lines... this is useful in itself when testing and designing a very high-performance fuel system, and testing the stock pump for extreme wear, but next to useless for determining any problems realted to the vehicle running.
Max pressure on a stock style pump will vary... expect 80 psi or so.
By simply taking a hose off and connecting the gauge to it, you are measuring the maximum fuel pressure your pump can generate and the pressure drops associated with the lines... this is useful in itself when testing and designing a very high-performance fuel system, and testing the stock pump for extreme wear, but next to useless for determining any problems realted to the vehicle running.
Max pressure on a stock style pump will vary... expect 80 psi or so.
#5
I wish I was driving!
Originally Posted by HAILERS
I obviously have a quicker computer than the scathcart. humor
OOH, burn!... wait... to myself... aww, dammit.
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I tee into the line at the end of the fuel rail? where is the regulator at?i thought that the line on the front of the motor ran from primaries to secondaries. if so shouldnt that be regulated as well?i thought the regulator was before the fuel came into the rail.if not how does it work?
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#8
I wish I was driving!
Originally Posted by red87tll
I tee into the line at the end of the fuel rail? where is the regulator at?i thought that the line on the front of the motor ran from primaries to secondaries. if so shouldnt that be regulated as well?i thought the regulator was before the fuel came into the rail.if not how does it work?
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Originally Posted by red87tll
wait..."The fuel has to be allowed to flow to read the regulated rail pressure." can someone explain?
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Maybe this will help. The fuel pressure regulator dumps any pressure above what it is supposed to be regulating the pressure at, at a given moment in time.
It does that by bypassing the excess fuel back into the tank. There is fuel flow ALL the time thru the fuel rail, when the engine is running.
That's a slightly flawed description, but it's the best I can do right now
It does that by bypassing the excess fuel back into the tank. There is fuel flow ALL the time thru the fuel rail, when the engine is running.
That's a slightly flawed description, but it's the best I can do right now
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