| | | quote | Originally posted by ketstang:
the engine started, but as soon as I release the key it dies. I can restart it right away and it does the same thing (over and over). I have connected a fuel pressure checker to the fuel rail and I have 43 psi at the rail and it doesn't drop when cranking or after it dies. I left the car sit with the pressure gauge on it and after about 30 minutes just sitting, the gauge pressure has dropped to 30 psi and stays there.
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Just to be sure - you're not ever cycling the key back off, are you? You're just leaving the key in Run and can keep restarting without ever losing fuel pressure?
The fuel pump will prime for 2 seconds when you first turn the key on. Then when you crank the starter and start the car, the ECM will restart the fuel pump whenever it receives pulses from the distributor to indicate that the engine is turning.
If you can keep restarting the car *without having to cycle it off*, and it's not losing fuel pressure from the restarts, then it appears those reference pulses are reaching the ECM (sometimes this is an issue).
If you do have to cycle the key though, then this might need to be explored.
(Those pulses can also be checked directly by using a laptop with WinALDL plugged into the diagnostic port - and that's also a handy tool for checking sensor readings and such)
These cars have a weird kludge, the cold start injector. During cranking the cold start injector opens, which is not controlled by the ECM. This will put fuel into the intake but only during cranking. Once you release the key this injector closes.
However, the cold start injector is designed to heat itself and stop opening when it gets hot enough - so at some point I think you'd no longer be able to keep restarting it. But sometimes they leak.
Check your fuel injector fuses under the dash. There are 2 of them, one for each bank of 3 injectors. I don't remember how they're labeled but I think it's something like "INJ1" and "INJ2".
It is possible to run on 3 cylinders but it might be difficult on some engines - I think one that's been sitting for 10 years would qualify.
While you're there just check all the fuses.
But I do agree with the other comments - most likely you have clogged injectors. After sitting for that long they probably need replacement or professional cleaning, especially if you already know the fuel system was gunked up.
A port fuel injector is like an inkjet printer. They have to stay active to stay clean.
The cold start injector is a much larger type that isn't prone to clog, so it's not surprising if it still works when the others don't.
| | | quote | Originally posted by 82-T/A [At Work]:
Shot in the dark here... but I seem to recall that the Fiero will not continue running if it's not getting oil pressure from the oil pressure sending unit. |
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This behavior can happen, but it's not supposed to. There are 2 circuits that can power the fuel pump. One of them is via a relay that is controlled by the ECM, and the other is controlled by the oil pressure sender. Either one of those is enough to power the fuel pump.
Sometimes the fuel pump relay (controlled by the ECM) will die and the owner doesn't notice, so at that point the oil pressure sender is the only thing powering the fuel pump and can cause the fuel to cut off as you described. If the fuel pump relay is good though, then it's not supposed to work that way. The 2 circuits are redundant, they are not in series.
I've seen a bunch of Amazon reviews for oil pressure senders that insist on them fixing a "no start" issue. Either other GM cars are wired differently than the Fiero - or else an awful lot of people out there have dead fuel pump relays.
