Fuel Pressure

[Gen3]

ok, I've read that I should have around 35 psi of pressure with the key on...well...I get about 40 psi and it drops real quick to zero. is it supposed to do this or is it supposed to hold it's pressure? when cranked, it holds a steady 35 psi...I *really* hope that it's not the Fuel pump...I hear they're quite expensive (much like pretty much everything else on this car)

btw. This is a '92...my nick is pretty misleading...

 

[revhardSHO]

Im not sure I understood whats happening. But, if you are getting 35psi while cranking the motor then your problem is not the fuel pump. Have you checked for spark? Is the check engine light on?

By the way, fuel pump install is not so bad. Especially if you cut out above the fuel tank and remove it that way. Do a search.

 

[Ishodu]

Are you having any issues? The fuel pressure should be 39 with no vacuum. If you have vacuum on the engine. You need to divide the amount in inches of mercury and subtract that from the psi. With the engine running pull the vac like to the reg the pressure should be 39 then.
When the fuel is primmed it should hold some pressure. But its not a huge deal normally if it doesn't unless you are having problems, but you didn't indicate if your having any. It could be the regulator passing or the check valve in the fuel pump.

 

[Gen3]

I actually am having problems...asked about it in another thread...when you step on the gas, the engine tries to stall (and usually does). It's running hot...pulled codes: 29, 52, and 77 (Just found out that the computer was changed with a Gen1) when you put a load on the engine, it sputters...It's hard to start the engine...at first I was thinking it's timing...now I'm not so sure...(sigh~)

 

[Ishodu]

Did you pull the spark plug boots and look for oil or water in there?

 

[Gen3]

sure did...contrary to what it looks like on the outside of the valvecovers, the plug wells are clean as a whistle spark plugs are very clean too (surprisingly so)

 

[Ishodu]

I didn't look up too see what the codes were for, most people have more sucess when they post the code and the meaning of that code.

 

[Gen3]

Checked them again today and got:

29 Vehicle Speed Sensor problem - VSS

52 Power Steering Pressure Switch/circuit open - PSP
(R) Did you turn wheel during test ?

61 Engine Coolant Temperature (ECT) sensor is or was too low - ECT

74 Was brake depressed after engine ID was received ?
Brake On Off (BOO) signal open or short to ground - BOO

77 System did not receive "goose" test


Also, I pulled the intake off and checked the rear plugs...#6 looks like it has been full of water at one point (completly dry now) and also quite rusty. and I couldn't get the plug out, first it was hard as **** to turn all the way through...and then it was finally loose, however, it would not come out of the well (like something other than the threads are holding the plug in...)

 

[AREA 91]

Checked them again today and got:

29 Vehicle Speed Sensor problem - VSS

52 Power Steering Pressure Switch/circuit open - PSP
(R) Did you turn wheel during test ?

61 Engine Coolant Temperature (ECT) sensor is or was too low - ECT

74 Was brake depressed after engine ID was received ?
Brake On Off (BOO) signal open or short to ground - BOO

77 System did not receive "goose" test


Also, I pulled the intake off and checked the rear plugs...#6 looks like it has been full of water at one point (completly dry now) and also quite rusty. and I couldn't get the plug out, first it was hard as **** to turn all the way through...and then it was finally loose, however, it would not come out of the well (like something other than the threads are holding the plug in...)

Perhaps part of the spark plug boot is still over the plug?

 

[SHOZ123]

I've seen fuel pumps put out good pressure when idling but at WOT and under load fall below 25 lbs. This would act just like a rev limiter and the car would not go any faster. But the car would cruise normally at high speeds if the throttle was opened gradually.