Question about 1986 Pontiac Fiero
Actually the injectors don't spray "all the time". They pulse open for a few milliseconds then close every time they are grounded by the ECM. The distributor has a pick-up coil (Variable Reluctance sensor) that provides an A/C (Alternating Current) pulse every 120 degrees of crankshaft revolution to the Ignition Control Module also contained inside the distributor. The I.C.M. amplifies, rectifies and passes along the pules as a +12V square wave to the ECM. The ECM uses these pulses to calculate RPM and determine when the engine is rotating vs. stopped. Together with this information and more from Coolant Temp., Throttle Position, Manifold Pressure and Air Temp. the computer constantly 'looks up' what the appropriate amount of time it should pulse the injectors for to deliver the required amount of fuel.
With that in mind, the injectors are supplied with +12V via a 3 AMP fuse labeled INJ 1 for 1 bank of 3 injectors, and INJ 2 for the 2nd bank of injectors. Make sure your injectors are getting +12V whenever the key is ON or they wont fire (or at least 3 won't).
If all 6 injectors have +12V and you have fuel pressure (checked by pushing down in the center of the Schrader (tire valve stem looking thing) valve and fuel SPRAYING out, and your still not getting fuel it is probably because the injectors aren't pulsing. They are probably not pulsing because the ECM is not receiving any reference pulses from the distributor. If you have spark then you are producing reference pulses.
I hope some of this explained from an actual '86 Fiero GT 2.8L V6 owner/mechanic will help narrow down your problem.
Posted on Aug 11, 2014
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Posted on Jan 02, 2017
SOURCE: fuel injector over fueling
all the injectors are supposed to constantly spray fuel when the car is runing,
but on the hard to start it might be a worn out fuel pump or
a leak on the fuel pressure regulator, unplug the vacium hose from the regulator and if there is any fuel at all then regulator is not good
Posted on May 29, 2008
SOURCE: cold start valve problem
if you have an electric cold start valve make sure to unplug it and if keeps apling fuel with electrical conector unpluged that means the valve is not good, but if not then you have an electronic problem, possible a bad cold start sensor or cold start module or cicuit problem, and might be a time to take it to an electrical shop
Posted on Jun 17, 2008
SOURCE: Fuel Pump Relay Switch
Underneath your hood, behind the passenger side headlight, behind the core support, is a bank of 2-8 relays. One of those relays is the relay needed for your fuel pump. There will also be a fuel pump relay fuse located there. The relay designation should be on the cover of the relay compartment.
Posted on Jan 03, 2009
What you need to do is have an assistant turn the key on (not try to start, just turn the key on) while you have the gas cap removed and your ear down by the gas tank fill tube. When they turn the key on you should hear a whirl only for 3-7 seconds. If you hear nothing more than likely you will need to change your fuel pump. Attempt this test on several tries at different times several hours apart before you **** your tank out to give it ample time to relieve any fuel pressure that may be built up thus causing your pump not to respond. BUT, if you are not getting any fuel you are not getting any pressure built up so it should be making some sound. How many miles do you have on this vehicle? 9 times out of 10, sorry to say, you'll be replacing the fuel pump. It sounds like to me that you have thourouly checked every other possible thing. Good luck my friend. Let us know how you come out.
Posted on Mar 09, 2009
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