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| Fuel pump suddenly not working - already replaced... (Page 1/2) |
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842m4SE
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MAY 11, 01:30 PM
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For the first time yesterday I finally was able to drive my Fiero on the road - insurance and all. It was going great for a while up until the point I smelled something hot, stopped at the side of the road and turned the engine off to check it out.
Nothing was wrong, but now the car wouldn't start. I tried pop-starting it a few times, but I noticed the lack of fuel pump priming and delivery and had to get it towed home.
I checked the fuses and did a cursory inspection of the wiring and it all looks to be good, but still the fuel pump doesn't run. I had also replaced the fuel pump after getting my '84 Fiero 8 months ago.
The factory manual doesn't have much on the wiring situation or troubleshooting that I could find, so any suggestions or advice would be much appreciated.[This message has been edited by 842m4SE (edited 05-11-2021).]
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fishsticks
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MAY 11, 04:32 PM
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Let's get the basics out of the way.
There's a 3 wire connector from the fuel sender assembly that snakes up the firewall towards the main harness.
Black should show continuity to ground and tan(sometimes gray) should show 12v during initial key on (just a couple seconds for prime) and cranking.
Does your fuel gauge read correctly?[This message has been edited by fishsticks (edited 05-11-2021).]
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Dennis LaGrua
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MAY 11, 04:45 PM
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I would check the fuel pump relay and the oil pressure sender both of which are in the current path of the fuel pump. You might first check the connector to see if there is power feeding through. What brand of fuel pump did you use for the replacement? ------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "
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fishsticks
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MAY 11, 04:48 PM
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This should help you get your bearings as well.
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842m4SE
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MAY 12, 12:12 PM
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| quote | Originally posted by fishsticks:
Let's get the basics out of the way.
There's a 3 wire connector from the fuel sender assembly that snakes up the firewall towards the main harness.
Black should show continuity to ground and tan(sometimes gray) should show 12v during initial key on (just a couple seconds for prime) and cranking.
Does your fuel gauge read correctly?
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It reads 8.1 when the key is on, and stays that way. The fuel gauge reads correctly to my knowledge, not sure how accurate it is though.[This message has been edited by 842m4SE (edited 05-12-2021).]
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skywurz
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MAY 12, 12:24 PM
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you said you did work.. perhaps check your plug and cable? they run by that CAT and are prone to melting if routed incorrectly . [This message has been edited by skywurz (edited 05-12-2021).]
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842m4SE
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MAY 12, 01:33 PM
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| quote | Originally posted by skywurz:
you said you did work.. perhaps check your plug and cable? they run by that CAT and are prone to melting if routed incorrectly .
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I have, all looks to be well - no melting, cuts, or anything weird on the shroud or visible wires. Dis and reconnected the plug leading to the fuel pump a few times and it is reading ~8 volts.
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skywurz
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MAY 12, 02:27 PM
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id say jump 12v to the pump and see if it kicks. You should be able to read the voltage to of the fuel pump directly on the ALDL connector next to the lighter on/in the center console. Im not sure of 90% of things on 84s but you should be able to jump 12 volt to it there. its a Tan/White wire top row all the way on the drivers side. 8v seems too low could be a bad relay.
if not its not uncommon for a tank to have rust you did not see and for it to kill a new fuel pump. Im starting to think you need to drop the tank and look.[This message has been edited by skywurz (edited 05-12-2021).]
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Patrick
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MAY 12, 02:50 PM
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For fuel pump testing purposes, jump 12v from the cigarette lighter to the ALDL fuel pump terminal.
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842m4SE
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MAY 12, 11:55 PM
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| quote | Originally posted by skywurz:
id say jump 12v to the pump and see if it kicks. You should be able to read the voltage to of the fuel pump directly on the ALDL connector next to the lighter on/in the center console. Im not sure of 90% of things on 84s but you should be able to jump 12 volt to it there. its a Tan/White wire top row all the way on the drivers side. 8v seems too low could be a bad relay.
if not its not uncommon for a tank to have rust you did not see and for it to kill a new fuel pump. Im starting to think you need to drop the tank and look.
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Replaced the relay today and same thing happened - nothing at all from the fuel pump. Jumping it did make a sound, each time they connected it made a short tap or clunking sound, but nothing else even when connected. What is it supposed to do?
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