to hell with it, ill replace both. But i have a misunderstanding of the problems with opti's and how to repair them..or not

Im failing to grasp where slapping a C&R will fix an opti, and where you just need to flat out replace it. Is that where inspecting the bearing comes into play? Cause all im finding along the lines of ac delco and delphi are remans on ebay so thats russian roulette. Hell, some of the sites only offer the C&R, the rest are weird unknown named companies.

 

It's very simple to test your fuel pump. Get yourself a fuel pressure gauge at any parts store and fasten it to the Schrader valve on the fuel rail on the back of the intake. Take the vacuum hose off the FPR and it should read between 43 and 45psi. I think 43.5 is optimal. Opti, not so easy, but what are your symptoms? Your best bet is to stick with delco or delphi even if it's a reman.

 

Of course youre the first person to write. i should just have you on speed dial brother.

I went through the normal rigmarole of testing for fuel problems. I rented a pressure tester and as you stated before in a post awhile back, i too had problems getting the damn thing to engage the schrader. So i simply yolo'd it and used a pick to pushed down the schrader. readin shoebox's stuff i should have showered my bay with gas if its supposed to be above 40 psi there. But i may not have done it properly. I primed the pump, took the key out, pressed schrader valve down, nothing. primed the pump, left key in, pressed it down, nothing. The only thing i didnt try is pressing it down while trying to crank. im flyin solo on this. in doing all this, unhooking, hooking, unhooking the tester, i have evidence of gas in the fact that while doin all that some came out of the hose and valve between my weaseling. Plus the smell of flooding the damn thing while trying to crank it, so im not 100%, but it may not be my fuel pump.

I have already replaced my ICM and coil with new, no go.

"Why it my be my opti". leading up to this, for the better part of 2 months it has increasingly become hard to start while cold. Now, warm or cold, it would drop ever so much at idle at a stop light in the sense my *** measuring tool would feel the car vibrate in a way it normally dosent. sometimes almost enough to die, but didnt. And i also began to sense a slight surge or hesitation around 3k rpm through 2-5th gears.

Does that mean its the opti for sure? of course not. From all that ive read on here fuel and opti problems produce almost the same damn symptoms. The fuel problem is easy to fix. new pump, filter, check injectors, possible a new regulator (which i see no evidence of gas coming out the vac tube). My problem is figuring out a path on the opti. but if reman is all i can do, i dont have much else.

 

The pump should hold pressure for a period of time due to a ball check valve in the pump after the key has been turned off. Does your Schraeder still have the screw on lid on the valve? It's possible you didn't push the core down far enough? It can take (at least for me) several attempts to get a read on my FP. You may want to try a different FP gauge from a different parts store.

 

naw it still had the cap over it. no debris from what i seen/felt. i felt the spring tention of the valve as i pressed it down so i know i was hittin the valve squarely. just nothing coming out.

the last thing i was gonna do today is get some started fluid, have my old lady try to crank it and spray into the TB. i figured if it even attempted to fired up then its a fuel problem cause right now all it does is crank and crank and crank. no ignition.

 

OP

...you need to get a FP gauge that screws onto the Schrader valve that works. It is the same process as checking tire pressure.....just screw it on and read the gauge with engine running and vac line pulled and plugged. should be 43.5 at idle

Just because fuel comes out if you press the Schrader valve itself does not mean you have correct "pressure". If no fuel comes out while someone turns on key (pump only primes for a few seconds) than pump is bad...but car would not even start if you have zero pressure.

First rule out if FP is the issue before moving onto ignition

If you are going to continue owning a 20+ year old LT1...a FP gauge should be part of your tool box.

 

I understand.

"with engine running" thats a problem.

Well, seeing as how its not starting, i understand that can be a fuel related issue. I will try to find the $35 test gauge set, the ones ive run across are with the volt meter upping the price $100 extra.

will do sir. Ill try to hunt down a reliable one if it exists and go about this the proper way then.

 

I don't think it matters which one you get. I think the core is inset too far into the valve so it can be a clusterfuck to connect. If your car is not running, do the redneck thing and get some brake clean or carb cleaner, spray it into the intake plenum and turn the engine over to see if it will fire. Do not spray it into the MAF. Take the elbow off and spray it directly into the throttle body. But yes, if it's not running, and it seems you can't get any pressure out of the Shraeder, it could mean your fuel pump is bad. When turning the key to the "on" position, can you hear the fuel pump prime? That doesn't mean anything regarding fuel pressure. Just wondering if it's getting power. Reason being is the fuel pump relay had been known to go bad on these cars, so it's another possibility.

 

Or, just use the test lead and jump the fuel pump relay to force the fuel pump on.

if that works, and it still doesn't start, prob isn't fuel pump related

 

Alright well, i bought a pressure tester. its not showing anything either. not sure if its engaging that valve or not. sprayed brake cleaner into the ports, fires right up, try to press on the gas, will not stay running. When the key is turned, you can hear the pump prime so that parts doing its job. But as far as getting flow, i cant for the life of me get this pressure tester to work even after modifying it. so either this damn things got zero at the rails, or im just not able to test it, but it does run for 1 second if you spray **** into the intake.

 

Use a core puller to pull the core out of the Schrader valve, be careful, it may spray fuel.
put the gauge on or put a hose on it in to a gas can turn on the key you should see
pressure/fuel flow, without starting. if you don't check the fuel pump relay.
I've seen pumps tear out the core of the impeller, so they spin up, but don't move fuel,
the ECU often drops the pump after a few seconds if the engine doesn't crank up.

I've also used a external pump and a can to directly feed the rail through the shrader
valve to see if the motor will fire and idle. (core removed as well) You can't do this very long if your tank is full
it will be filling the tank through the return or back feeding though the supply.

Good Luck.

 

I know 95 cars have these, so if you do, try this

http://shbox.com/1/fuel_pump_prime.jpg
To test the fuel pump directly with 12 volts, bypassing the relay, connect 12 volts to the fuel pump prime connector, near the computer.

Then try to start it.

 

When is the last time you changed the fuel filter? Seems the pump is getting voltage if you can hear the pump prime with the key, but perhaps the fuel lines are clogged. For me the next step would be to change out the fuel filter. If that doesn't work then go into the tank and see what the fuel pump sock looks like. It's also quite possible the pump has overheated if it somehow became clogged, and may still run, but not produce any pressure.

 

alright so im not gonna be able to remove the core as of now, i dont have a core puller and im not breakin the thing by accident.

i have a jumper wire clamped on the pos side of battery and plugging into the red bypass wire does nothing.

the fuel filter was installed in september 1997 in canada...when the car was built. im hesitant to just install a new filter without at least lookin at the pump.

have cut the trap door in the trunk. 6 hrs crawlin on the car, its 107 outside, im done for the day gentlemen. i will update with any progress.

 

Honestly I'd say **** all to the fuel pressure gauge and worry about it another day. I'm assuming you pushed the core down as far as it could go and no fuel leaked out and it's obvious you are getting insufficient pressure to the injectors. Next step is to figure out why.

 

Dude thats where im at currently. i appreciate the help but as for troubleshooting the problems im having troubleshooting, the damn pump is on its way, the whole octopus, pump, in tank filter, sending unit, ill pick up a filter if i can tomorrow, 21 years old equipment, lets just call installin all that preventative maintenance. and if that dont produce a change ill go from there.

 

Certainly one way to do it, hope it works for you

 

Alight, i may have lied through ignorance, but again ive been doing this all as one person. the whine im hearing i dont think its my fuel pump cause i thinks its coming from the front end when i turn the key. Yesterday i had the wife turn the key over while i put my ear in the gas tube and my hand on the pump, heard and felt nothing. can someone school me on what that whine from the front would be? not that i think its a problem just not what i thought i was hearing.

New filter installed, got impatient, no changes. Pump still on the way. ETA, tomorrow.

 

Do you still have an AIR pump?

 

hah, i dont know, did 97s come with an air pump for some reason? the hell would that be for? i can ident plenty of things under the hood, never looked for one of those.