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Discussion Starter #1 (Edited)
So last night I'm coming home from work and the wagon quit on me. Just shut down like I'd turned off the key. I coasted to the shoulder. I tried to restart it. Turns over great but no fire. Pop the hood. Everything looks fine. I have fuel pressure. (I have a little gauge in the line.) I get it towed home. I'm assuming no spark since I have fuel pressure. I'm fiddle farting around with the coil and wires while having wife turn it over when I notice the fuel pres gauge reads 0. I unplug the the fuel pump at the rear bumper. check it with multimeter while wife turns key to run. no power. I pull the F/P relay and check the terminals where the relay was. No power to any of the 5 terminals.
I need some more clues. Anybody?
Edit: one more thing that may or may not be related. 2 days ago the fuel level gauge quit reading correctly and stays pegged way beyond full.
 

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one more thing that may or may not be related. 2 days ago the fuel level gauge quit reading correctly and stays pegged way beyond full.
This may be a symptom of a bad ground. It is shared with the rear left lights and the fuel pump. I am not sure where the ground is in a wagon. Near center of LH "D" pillar FSM. Are your left brake lights as bright as your right?

The ground could get better or worse as you bump down the road. It could also be bad between the tank plug and the tank.

I pull the F/P relay and check the terminals where the relay was. No power to any of the 5 terminals.
Have you checked your fuel pump fuse? Are you sure you had a good ground and connection when you checked the relay socket?
The PCM only pulses the fuel pump when you turn on the key. You may have missed it?
There is a Fuel pump test connector. Red single wire not plugged into anything by the A/C accumulator. Power that and listen for the pump or try your pump plug again.
 

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Have you run the 2x4 accelerated tank contact diagnostic?
 

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Discussion Starter #5
I'll check the grounds by the drivers side taillight. However shouldn't I still get 12V to the gray wire of the fuel pump connector under the rear bumper when trying to start?
Where is the fuel pump fuse? I looked in both fuse boxes and I didn't see any fuse labeled fuel pump, only the relay labeled "F/P" which I assumed to be fuel pump. But again, no power to any of the terminals while wife had key in start.

I'll power the test connector and listen for the pump.
 

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Under hood box fuse #2 94/95years.


I still get 12V to the gray wire of the fuel pump connector under the rear bumper when trying to start?
Relay coil power from the PCM pulse at key on, constant when engine is running. When people have bad pumps they cycle the key several times to get starting pressure.


If the test point does not give you pump pressure make sure your meter has a good ground when you test the gray wire at the rear plug.


A test light is better than a meter for some work. The light draws some power and may not light up when connected to a bad wire, connector, or ground. A meter may show good voltage when it checks the same point. On a long wire run like the fuel pump wire my best test is a old driving light. When it lights up I use a meter to check the voltage. This test proves the circuit can provide enough power. I pick a light that will not blow the circuit's fuse or is equal to what it powers.


1995 under hood fuse info from Big Jack.
 

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Discussion Starter #7 (Edited)
sho 'nuff. fuel pump fuse was blown. I put a new one in and she starts right up.

So now the question is where was the short. If it shorted once, you can be damn sure it will short again until the cause is addressed.
So who has had this happen to them and where in the fuel pump circuit did you find the issue?

D-pillar ground behind taillight is good. Gas gauge still pegged beyond full. My guess is that the fuel level is actually about 5/8 - 3/4.
 

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If you have a tow plug check where it connects to the factory wiring.
The wiring under the car to the tank. Inspect and wiggle with the test point powered.
Unfortunately a worn or damaged pump will blow the fuse.


I keep meaning to take some amp measurement of this circuit so I know what is a normal current and maybe I can see a pump failure coming.


Have you run the 2x4 accelerated tank contact diagnostic?
96 Black
The tow home may have un jammed the pump motor.
 

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one more thing that may or may not be related. 2 days ago the fuel level gauge quit reading correctly and stays pegged way beyond full.

I assume you still have this problem?
This is why I was recommending checking the grounds. If ungrounded the pump may ground through the tail light harness. This will not show up with meter tests. It will give you some weird symptoms.
Does the pump give the same pressure with the headlights, brake lights, and backup lights on? Do the rear light look correct?
 

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Discussion Starter #10
trailer lights

If you have a tow plug check where it connects to the factory wiring.
The wiring under the car to the tank. Inspect and wiggle with the test point powered.
Unfortunately a worn or damaged pump will blow the fuse.




96 Black
The tow home may have un jammed the pump motor.

I do have a relay harness for the trailer lights. There's a T plug that grabs the signals from the taillights.
 

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Discussion Starter #11
I assume you still have this problem?
This is why I was recommending checking the grounds. If ungrounded the pump may ground through the tail light harness. This will not show up with meter tests. It will give you some weird symptoms.
Does the pump give the same pressure with the headlights, brake lights, and backup lights on? Do the rear light look correct?
Yes, fuel gauge still pegged beyond full. Ground on drivers side D pillar looks fine. Are there others related to fuel pump circuit I should check? I can check pump pressure vs lighting later tonight.
 

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Ground on drivers side D pillar looks fine.
Wish I had a dollar from everyone who has said that. Some times even when it looks good removing the bolt and ring terminal and replacing it will result in a much better connection.


Are there others related to fuel pump circuit I should check?
For grounds (G300)this one handles everything on the LH side rear. LH lights, fuel sender, fuel pump, tail gate relay, Air shock sensor(when equipped) and some inside lights.
RH ground (G400) RH lights, rear wiper, defroster, and some inside lights.


I expect your problem will be between the outside plug and the tank. If your wire harnesses are in the factory location and not messed with they cannot shake and should be fine. The ones outside on the bottom of the car take more damage.



If you have a meter that measures ohms you can check the fuel sender directly. On the meter's lowest range you can connect to the plug going to the gas tank. Purple is the sender and black for ground. 0 is empty 90ohms is full. Open circuit would sent the gas gauge to over full.


https://www.impalassforum.com/vBulletin/26-electrical/1300658-fuel-gauge-calibration-cluster-circuit-board.html


This thread has more than you want to know about the gauge and sender with hand drawn diagrams of the circuit.



I do have a relay harness for the trailer lights. There's a T plug that grabs the signals from the taillights.
I was thinking of the hack up the factory harness type. I do not see how this could effect the tank circuits.
 

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You Have Been Warned

dragin-,
I been taking all this in and from where I sit I'd say your car is taking to you to drop the tank for some normal 20 year programmed maint. New pump, upgraded harness, fuel level sender, not to mention fresh sock. Hell, a new filter and FPR too if 'twer me. Best 5 hours you'll spend for piece of mind not getting stranded again. If the second time then only 2 hours. Crimp (or solder) all connections firm.



Rooting around under the tailend might help spy the ground issue(s). I bet you find a least one other maint. repair restore item while you're under there too. :cough:: decayed/missing looks like mouse ate it return fuel line coupler /::cough::


And of course Z09B4U on the outside chafed wiring stuff.
 

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Discussion Starter #14
dragin-,
I been taking all this in and from where I sit I'd say your car is taking to you to drop the tank for some normal 20 year programmed maint. New pump, upgraded harness, fuel level sender, not to mention fresh sock. Hell, a new filter and FPR too if 'twer me. Best 5 hours you'll spend for piece of mind not getting stranded again. If the second time then only 2 hours. Crimp (or solder) all connections firm.



Rooting around under the tailend might help spy the ground issue(s). I bet you find a least one other maint. repair restore item while you're under there too. :cough:: decayed/missing looks like mouse ate it return fuel line coupler /::cough::


And of course Z09B4U on the outside chafed wiring stuff.
I with ya, except that I did all that last summer. New fuel filter, fuel pump/sending unit, routed wires in factory location the whole deal. So pump is only a ear old.
I'm guessing there's a short somewhere. I just need to find it before it blows the fuse again.
 

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dragin-,
I been taking all this in and from where I sit I'd say your car is taking to you to drop the tank for some normal 20 year programmed maint. New pump, upgraded harness, fuel level sender, not to mention fresh sock. Hell, a new filter and FPR too if 'twer me. Best 5 hours you'll spend for piece of mind not getting stranded again. If the second time then only 2 hours. Crimp (or solder) all connections firm.



Rooting around under the tailend might help spy the ground issue(s). I bet you find a least one other maint. repair restore item while you're under there too. :cough:: decayed/missing looks like mouse ate it return fuel line coupler /::cough::


And of course Z09B4U on the outside chafed wiring stuff.

This was my "gut reaction" as well but not every problem is the common one.


If you have a meter that measures ohms you can check the fuel sender directly. On the meter's lowest range you can connect to the plug going to the gas tank. Purple is the sender and black for ground. 0 is empty 90ohms is full. Open circuit would sent the gas gauge to over full.
Z09B4U
I might bet on a open circuit between the plug and tank for the fuel sender. The fuse can be a short or motor problem, I expect the sender issue will lead to a tank inspection.


I was thinking that anyone who has a fuel pressure gauge has had problems with the tank.


If you want to test from the car plug to the fuel gauge find a resistor 20-50ohms. This would show as 1/4-1/2tank.
 

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I with ya, except that I did all that last summer. New fuel filter, fuel pump/sending unit, routed wires in factory location the whole deal. ......

Same here but plus the pump when I got stranded at the filling station an had to be towed home.


I ended up having to drop errthing agin and "re-crimp the GD "not crimped enough" GD connections agin. Running purfic for 1.5 years.
 

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Discussion Starter #17
Y'all called it on the sending unit- open circuit. I just filled up on Monday so it will be two weeks before It's low enough to drop the tank. That f'n thing is only a year old. Grrr. Fyi, I think it was a spectra.
 

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Discussion Starter #18
Update: So I replaced the fuel pump fuse hoping I could drive it and run the fuel down. That worked for about a week. Fuse blew again. Tank still half full. I dropped the tank and Sho'nuff, the blue wire for the sending unit was off it's connector. So that was causing the pegged gas gauge and the fuel pump short, F'n Spectra.

Oh, and it get's better....
I fixed the loose wire. I installed the pump back in the tank. I connected the electrics with the tank still on the ground and let the fuel pump run out most of the fuel into gas cans to make the install a little easier. Then, while trying wrestle the tank back into place, one of the tank straps broke. YAY! I ordered new straps from Rock Auto, (F'n Spectra). So they're coming. In the mean time, I need to either cut or torch the rear strap bolts out. They are so rusted, you'd never know the nuts used to be hexagonal.

So the question is: Is there anything special about those rear pivot bolts? They look like 5/16" X 3". Can I just get some at the hardware store. ( Except I don't have one anymore. Home Depot and Menards came to town, and my favorite hardware store couldn't compete. They went out of business last year.) I'm still cranky about that. I loved that place. They had a whole wall of little drawers containing any and every nut, bolt, bolt, screw or doohickey of every size you would every need. AND, unlike the big box stores, one could buy just 1,2, or 3, you didn't have to buy a blister pack of 50 when you only needed 2. The hardware store employees actually could be found, and helped you, AND DID know their ass from a hole in the ground.
 

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The bolts are "special". They are only threaded on the last 1/2 inch or so. They are more like aircraft bolts, but have course threads. The next time I go to the local P-N-P yard I can grab a pair.
 

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on my 96 Impala those bolts are metric and have a fine thread.



IMO a 5/16in bolt 4 inches long.. then use nylon self locking nuts...no need to get picky on the shoulder issue . the bolt will rust quickly so no need to tighten those self locking nuts just screw into place .. could also use some blue lock tight .


IMO I use gas siphon ball and gravity drain the tank .. I have 3, 5 gallon plastic tanks and when I suck the gas out place a gas filter on the suck hose that runs into the storage tank..


on the pump connections I would get soldering iron low watts and some silver solder rosin flux core .. do not use those BS connectors..


never run these below 1/3 of a fuel level because these tanks not designed for in tank fuel pumps... check that the sender is properly indicating the correct fuel in tank...
 
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