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edfiero
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AUG 17, 03:20 PM
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Was driving the 84 Fiero today and it just died in the middle of the road, without warning.
Something electrical in the fuel pump circuit. Key on, the fuel pump is NOT priming.
Got it towed home. Confirmed the fuel pump fuse is GOOD.
Next jumped 12 volt from the battery to the green/wht wire on the fuel pump relay. SUCCESS, the pump runs. (Happy that I don't have to drop the tank)
Now I am stuck. What is the next step if the fuse is good, relay and pump are good?? Bad ECM? What should I check next?
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1985 Fiero GT
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AUG 17, 07:46 PM
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| quote | Originally posted by edfiero:
Was driving the 84 Fiero today and it just died in the middle of the road, without warning.
Something electrical in the fuel pump circuit. Key on, the fuel pump is NOT priming.
Got it towed home. Confirmed the fuel pump fuse is GOOD.
Next jumped 12 volt from the battery to the green/wht wire on the fuel pump relay. SUCCESS, the pump runs. (Happy that I don't have to drop the tank)
Now I am stuck. What is the next step if the fuse is good, relay and pump are good?? Bad ECM? What should I check next?
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If the relay is good, the pump should run whether the ECM works or not, it has a second circuit with the oil pressure sender, if there's oil pressure, the pump will run, with it without the ECM, it can run off both of those, or either individually.
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82-T/A [At Work]
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AUG 17, 08:04 PM
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| quote | Originally posted by edfiero:
Was driving the 84 Fiero today and it just died in the middle of the road, without warning.
Something electrical in the fuel pump circuit. Key on, the fuel pump is NOT priming.
Got it towed home. Confirmed the fuel pump fuse is GOOD.
Next jumped 12 volt from the battery to the green/wht wire on the fuel pump relay. SUCCESS, the pump runs. (Happy that I don't have to drop the tank)
Now I am stuck. What is the next step if the fuse is good, relay and pump are good?? Bad ECM? What should I check next?
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Are you sure that you're getting spark?
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jelly2m8
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AUG 18, 03:13 AM
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pull the connector from the FP relay, look at both the relay and connector for corrosion, if that is all good, pry the cover off the FP relay, it will be very apparent then if the relay is good or not . If the relay looks good, check the wiring right at the connector.
a few bad relays, once you pull the cover off[This message has been edited by jelly2m8 (edited 08-18-2024).]
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edfiero
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AUG 18, 07:29 AM
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| quote | Originally posted by jelly2m8:
pull the connector from the FP relay, look at both the relay and connector for corrosion, if that is all good, pry the cover off the FP relay, it will be very apparent then if the relay is good or not . If the relay looks good, check the wiring right at the connector.
a few bad relays, once you pull the cover off
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The relay works and the pump works when I apply 12v from the battery on to the green wire.
The problem is upstream of the relay. What causes the relay to energize?
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Vintage-Nut
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AUG 18, 10:39 AM
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I do not have the 1984 manual, but I believe this diagram is you're looking for.....
If you don't have the manual, pick one on this list.....
Fiero Manuals
https://fieroinfo.com/manuals/
------------------
Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles
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