New fuel system, won't stay running. (Page 2/2)
theogre FEB 22, 10:06 PM

quote
Originally posted by Patrick:
Is there any chance that this might have something to do with the ignition assembly in the steering column? If it was somehow out of adjustment, could the mechanism that the key moves actually be in the OFF position when the key is still in the RUN position after being released from the START position? Just a thought!

The I-switch forces Run by a internal spring for Bulb Test and Start positions. You need to turn the key to make I-switch to turn Off.

I-key just rotates nearly freely. The switch does the location/detents like Auto Trans shifting.

That said... The I-switch could be bad in the Run position and get crap or no connect(s).
Can't remember if Run position only 1 or 2 "bridge(s)" making all things On when in that position. If have 2 "bridges," is possible only one side is bad. Like in PW and other switches, one side often fails first. (I-switch is made way different then PW but have similar failure modes.)

E2A--> Think is 2 "bridges" to kill power to Radio and some other things when you Start the engine. So Radio etc can be On in Run but other side have problems.
Same "bridge" then moves to other connections to operate Bulb Test and Start.

"bad" adjustment for the I-switch mostly means:
Can't turn key to Start.
Can't turn key to Aux.
But if is cause by iffy S-column parts then Both can happen at same time. See my Cave, Steering

[This message has been edited by theogre (edited 02-22-2023).]

Spoon MAR 02, 06:36 PM
Just in case anyone is interested $$$

https://www.summitracing.com/parts/dac-80161

https://www.summitracing.com/parts/dac-80160

Spoon

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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

Patrick MAR 02, 07:14 PM

quote
Originally posted by Spoon:

Dayco Submersible Fuel Hose - 5/16" - (100 psi) - 1.0 ft



The price has gone up since I bought it, but this what I got from RockAuto almost three years ago. Don't know how comparable the shipping is to what Summit may charge. [At the time, the shipping by RockAuto to Canada was only $7.99(US), which was very reasonable.]

Gates Submersible Fuel Line Hose - 5/16" - (100 psi) - 1.0 ft
armos MAR 03, 01:53 AM

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.


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.


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.
theogre MAR 03, 10:46 AM

quote
Originally posted by armos:
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.

Yes, CSI has a thermal switch that shuts off after internal heater "trips."
In warmer weather, may work for seconds or not turn on @ all. In very cold weather, takes longer to heat up.
In Short, is an "auto choke" that stops working after a few seconds to near 1 minute sim to many Carb engine auto chokes have electric heater in them.

So CSI maybe keep an engine running during cranking but only very temporary. Often won't work again for many minutes after this happens because the switch takes time to cool off.

CSI Switch is wiring to Starter Solenoid and only get power from I-key in Start position.

If CS Injector is leaking to keep the engine running... have bigger problems and have to leak a lot w/o having CSI switch being On.
ketstang MAR 03, 01:34 PM

quote
Originally posted by armos:

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.



Thanks Armos, You are correct that I am NOT cycling the key to the off position. I turn the key to start and the engine will run only when the key is turned. As soon as I let go of the key the engine stops. I then immediately turn it again and it will start and run for as long as I have it turned. Like you said, if I try this too many times that car won't start anymore.

I did buy new injectors, but haven't installed them yet. I will check the fuses you suggested.

BTW, how do you quote only a portion of a previous post? When I selected the quote button on your post it looks like it only quoted the last part of it. I really only wanted to quote the first two lines of your post. Thanks!
sanderson231 MAR 03, 02:23 PM

quote
Originally posted by ketstang:
BTW, how do you quote only a portion of a previous post? When I selected the quote button on your post it looks like it only quoted the last part of it. I really only wanted to quote the first two lines of your post. Thanks!



Select quote then edit what is between the quotes

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formerly known as sanderson
1984 Quad 4
1886 SE 2.8L
1988 4.9L Cadillac
1988 3800 Supercharged