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Hello everybody. I got a situation and could use some input.
93 TA. Car has been hard starting a while. The other day, it just kept cranking. Then next attempt it started and has been since. This morning it only cranks. Has fuel. Gauge is at half tank. No codes. Pump primes but is very faint. Used to be a nice audible buzz, but now a very quiet hum. I've depressed the Schrader valve before and it would shoot up a strong 6 inches to a foot. Now it's a inch or two at most. Not a official method to test but it's something I've paid attention to. I'll check later for spark at the reachable plugs later tonight when it's dark.
Ive read about testing the fuel pump prime connector. Is this it in my picture? My understanding is attach a wire to the positive battery post (would alligator clip or something better work?) and attach to the FPP connector with what kind of attachment? Paperclip? Then start the car and it should run for 2 seconds if the pump is good?
Would jumper cable from positive post to the mentioned paper clip inserted into the FPP connector work? I read a post where someone in the same situation used one and it worked.
I would take 12 volts from the red plastic “+” distribution box on the passenger side inner fender. Alligator clip, or just wrap the bare end of the wire under the post nut and tighten down. Run at least a 12-ga wire to the connecter. Being an OCD engineer I would include an 15-amp fuse in the wire, but that's optional. If you had a 1/4” male spade connector to crimp on the end of the wire would make the cleanest connection to the prime connector. If not the paper clip would work. Just make sure the fit is tight.
Just to be clear: battery left alone, 12ga wire from the post of the red + box to the FPP, the try to to start engine. Correct? I'll give it a shot.
Used some starter fluid. It started twice but just sputtered and died. Used half a can over 45 seconds. It did change the behavior introducing some fuel I suppose. Any sort of indicator?
The battery is already connected to the plastic “+” box. The whole purpose of the box is to provide a place to connect the many wires that supply 12 volts to the various parts of the car. That way there aren’t 10 or 12 wires hanging on the battery terminal.
No, the purpose of using the prime connector is to insure the fuel pump is working, and supplying the correct pressure. It bypasses the fuel pump relay, removing the PCM and the VATS system from the equation. If you could simply hook up a pressure gauge while the pump is running you will know if the fuel pump is the problem. Pressing the valve core of the Schrader valve is not a reliable way to see if the pump is healthy. A decent fuel pressure test gauge is ~$30-35. If you plan to keep your car, it's pretty much a mandatory tool. If you were in NJ I would give you mine. It's almost 30 years old, and I don’t need it any more.
Ok the FPP test is next. Need to source 12ga wire.
My Schrader valve on the rail has never given me a reading. I've rented 3 or 4 different fuel pressure gauges. Ive used them succesfully before on my older cars.
Hooked up some speaker wire I found at home, and a paper clip. It took a bit but started right up. Reved up pretty clean. Killed it. Disconnected the wire. Started up twice again right away. No hard starting. Waited a minute..started it up right away again.
I'm going to go out in an hour and try again. Don't want to drive it very far in case. Try one more time to attach a fuel gauge?
Changed the fuel pump. Did it the old fashioned way, dropping the rear. Only took 3.5 hours start to finish with my brother's help. Getting the neck filler positioned and routing the hoses at the same time was the difficult part but wasn't a big deal.
People say to trapdoor it to save some time and hassle, but dropping the rear and doing it the right way was pretty sweet.
Sadly no. Still turns slow or stubborn to start. If I cycle the key on/off/on/off like you've said to do, it's definitely faster to turn on. That points to a fuel pressure problem, correct?
I replaced a battery ground a few years ago, maybe it's loose. I'll check that and tighten the battery posts as well. The FPR is a few years old and didn't have gas in the vacuum line. I'm leaning towards the original injectors being old and gummy with 200k on them?
Fastened the rented Autozone gauge, immediately fuel was coming out the clear tube. Primed. No reading. Turned engine on, shoots up to 30 and climbing according to my brother but fuel was spraying out of that clear hose. So I shut it off. The button near the clear hose on the gauge shot off. Some sort of pressure cutoff, idk. Different than the one in your pic.
My brother says the fuel shooting out the hose alters the gauge reading. Is that true?
The “button” (assuming it’s up near the gauge) with a clear hose is there to relieve pressure from the gauge assembly before you disconnect the hose from the Schrader valve. Allows you to discharge the fuel/pressure into a small container, rather than have fuel spraying out around the hose connector. The greater the leak at the button, the lower the gauge is going to read.
08-18-2024, 02:45 PM
