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| 85 Fiero problem solved ! (Page 1/3) |
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Lou6t4gto
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MAR 05, 06:47 PM
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Been chasing this problem" literally for YEARS". 85 4 cyl / auto . car would Always start and run good, Great low miles car, but every once in awhile just DIE, wait 30 seconds and it would start again. About 6 months ago I installed a" Mechanical fuel Pressure gauge" in the console (so I could "Watch" the fuel pressure when the problem presented itself). car would start and run fine as usual,(also ran a wire with a button from the lighter to the fuel pump). haven't messed with it for a long time now, almost a year. But always went out and ran it for awhile. today, I went out and it started right up, ran for about 2 min and quit. But "This time" I was able to "watch the fuel Pressure As it died" !!! as it was dieing, I jumped the hot wire from the lighter to the pump and the pressure would NOT COME UP ! Waited about 5 seconds and tried it again and the pressure went right up and started and ran fine, then pressure dropped and it shut down. SO SOMETHING IS GOING ON WITH THIS FUEL PUMP, when it works the car starts and runs fine, but sometimes EVEN HOT WIRED, it will not build fuel pressure ! (Pump will Not run even Hot Wired). 5 seconds later it will. So even with Pump being" hot wired", it won't start, gotta be the PUMP ! all lines are clean, new filter, new injector. yes there's gas in it. if the pump will not run "hot wired", got to be the pump overheating or something. Gotta love all this Chinese made garbage.
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pontiacfierokid1985
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MAR 05, 11:43 PM
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Do you still have the original sending unit in it. If so that could be shorting out that happened on my current 86 gt I just bought back in June of last year. Car would run fine for 5 minutes but then die out thinking it was the pump get a new one install it car starts then just stall. I found out the wire on the connector going into the tank so so corroded that it was causing a open circuit not sending power to pump. Replaced the sender and all is good now been driving it daily since 😊. I will suggest if you get one from the fiero store that you remove that crappy black float that comes on it transfer the orange float from the original. You can also cut a inch off it and the lever so it doesn’t hit on the baffle inside the tank. My sender is dead accurate as well now 190 miles to a full tank 2.8 4 speed keeping it at 65.
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Lou6t4gto
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MAR 06, 01:49 AM
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I may try to rewire it from the pump to the power source. there will be no bad connections. thanks for the idea
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Phil
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MAR 06, 04:30 PM
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Sounds like a fuel pressure regulator problem
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moophatcow
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MAR 06, 04:40 PM
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theogre
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MAR 06, 06:18 PM
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| quote | Originally posted by Phil:
Sounds like a fuel pressure regulator problem |
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Has not electrical parts and won't cause FP not running.
| quote | Originally posted by pontiacfierokid1985:
Do you still have the original sending unit in it. If so that could be shorting out that happened on my current 86 gt I just bought back in June of last year. Car would run fine for 5 minutes but then die out thinking it was the pump get a new one install it car starts then just stall. I found out the wire on the connector going into the tank so so corroded that it was causing a open circuit not sending power to pump. Replaced the sender and all is good now been driving it daily since 😊. I will suggest if you get one from the fiero store that you remove that crappy black float that comes on it transfer the orange float from the original. You can also cut a inch off it and the lever so it doesn’t hit on the baffle inside the tank. My sender is dead accurate as well now 190 miles to a full tank 2.8 4 speed keeping it at 65. |
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Crap Level Sender shouldn't cause no power to pump.
+ wire from gauge to sender.
+ wire from Relay, OPS and and ALDL G to pump.
Ground wire for both goes into cabin to ground @ G201 & G202.
Can easily back probe all of them at C502 under Wire Bulkhead pass-thru in engine bay.
Can disconnect to try to check wires from there to the tank w/o dropping the tank. Can check ground on car side too.
Tank and sender/pump plumbing is a crap ground at best w/o the ground wire being good. This might get connection to run the pump but never made to do so.
Shorted sender Should = Gauge reads Empty all of the time.
But Iffy Ground wire can "kill power" to FP & Sender and might fry either or both.------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave
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Lou6t4gto
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MAR 06, 07:36 PM
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bad "wire" about 4" Before the" 203" plug, coming From the car to the 203, not going out of the 203. wasn't the connection, was actually a Bad Wire "INTERNALLY" . if I "bent" the (TAN/White)wire the pump would stop ! I "rewired" from 1 foot Before the 203 to 6" After the 203, ( bypassing the 203 plug altogether). now it seems to be fine. Never would have suspected a wire going bad "internally" with NO "External" damage ! I took it for a couple mile ride, seems fine now. find out for sure tomorrow. If i didn't have that mechanical FP pressure gauge to "watch", I probably never would have found it . LOL
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theogre
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MAR 06, 08:49 PM
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| quote | Originally posted by Lou6t4gto:
Never would have suspected a wire going bad "internally" with NO "External" damage ! |
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Oh yes... Wires Can rot or break w/o obvious damage to the insulation. Seen this on cars and more.
2 quick examples:
WeatherPac and others types Are Not water proof only weather resistance and drive thru deep water etc then polluted water on wires can get into most connectors. More so when wires are loaded so seals won't seal right or no at all.
Insulation pierced to test then some fool didn't do anything to seal the hole.
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Lou6t4gto
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MAR 09, 06:15 PM
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seems it was indeed the bad wire, drove it around quite a bit today with no more problem. :-)
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Lou6t4gto
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MAR 11, 06:47 PM
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forgotten how much I enjoy driving this car !
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