Low volts- fuel pump going?
Thread Starter
Heel & Toe
Joined: Jan 2011
Posts: 22
Likes: 0
Low volts- fuel pump going?
Hey guys, throwing this out for thoughts/validation:
97 6speed, 78,000 miles. This just started, 12.9 (lights on or off )engine running (all rpms). Fuel pump seems louder that ever. volts go down and pump wine changes when brakes or turn signals in use.
new GM installed factory alteranator/batt cable and Battery 10 months ago.
Will these pumps pull extera amps when dying? anyone have a similar problem?
thanks in advance!
97 6speed, 78,000 miles. This just started, 12.9 (lights on or off )engine running (all rpms). Fuel pump seems louder that ever. volts go down and pump wine changes when brakes or turn signals in use.
new GM installed factory alteranator/batt cable and Battery 10 months ago.
Will these pumps pull extera amps when dying? anyone have a similar problem?
thanks in advance!
Tech Contributor
Joined: Jan 2007
Posts: 19,465
Likes: 1,167
From: Dyer, IN
Hey guys, throwing this out for thoughts/validation:
97 6speed, 78,000 miles. This just started, 12.9 (lights on or off )engine running (all rpms). Fuel pump seems louder that ever. volts go down and pump wine changes when brakes or turn signals in use.
new GM installed factory alteranator/batt cable and Battery 10 months ago.
Will these pumps pull extera amps when dying? anyone have a similar problem?
thanks in advance!
97 6speed, 78,000 miles. This just started, 12.9 (lights on or off )engine running (all rpms). Fuel pump seems louder that ever. volts go down and pump wine changes when brakes or turn signals in use.
new GM installed factory alteranator/batt cable and Battery 10 months ago.
Will these pumps pull extera amps when dying? anyone have a similar problem?
thanks in advance!
Thread Starter
Heel & Toe
Joined: Jan 2011
Posts: 22
Likes: 0
readings off the dic and dash gauge. I did run the tank low the other day(took 18.6 gallons at fillup $78.00 bucks). Hopefully dident run sediment through the pump(car still runs ok). Just put some lucas injector cleaner in the tank.
Tech Contributor
Joined: Jan 2007
Posts: 19,465
Likes: 1,167
From: Dyer, IN
Need to read off the battery. I would not worry about the sediment, provided the sock is intact.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
97 & early 98 C5s had KNOWN noisy fuel pumps. There was a TSB that covered that . I had the one in my early 98 replaced under that TSM when the car was a year old.
If your pump changes a LOT when other loads are being used, you could very well have a dirty ignition switch. Your car being as old as it is, unless the ignition switch has been changed previously, its most likely well past due to be repaired/cleaned/replaced. The DIC voltage and the actual battery voltage measured at the battery terminals "SHOULD" be very close to each other. The DIC and IPC voltages are supplied thru the IGNITION SWITCH
If the electrical contacts inside the ignition switch are burnt, you will have all kinds of electrical issues.
Heres a post i made to lead guide and direct you thru a complete ignition switch repair. Best part about the whole thing,,,, its FREE!
-C5 ignition Switch repair - http://forums.corvetteforum.com/c5-t...ch-repair.html
After the repair, the switch will feel nice and tight like a new one!!
BC
If your pump changes a LOT when other loads are being used, you could very well have a dirty ignition switch. Your car being as old as it is, unless the ignition switch has been changed previously, its most likely well past due to be repaired/cleaned/replaced. The DIC voltage and the actual battery voltage measured at the battery terminals "SHOULD" be very close to each other. The DIC and IPC voltages are supplied thru the IGNITION SWITCH
If the electrical contacts inside the ignition switch are burnt, you will have all kinds of electrical issues.
Heres a post i made to lead guide and direct you thru a complete ignition switch repair. Best part about the whole thing,,,, its FREE!
-C5 ignition Switch repair - http://forums.corvetteforum.com/c5-t...ch-repair.html
After the repair, the switch will feel nice and tight like a new one!!
BC
Thread Starter
Heel & Toe
Joined: Jan 2011
Posts: 22
Likes: 0
Thanks for the ideas so far!
checked the volts at the batt terminals last night with the car running and all options on(a/c, lights, hazards, radio) and it read 13.5. The dash showed 12.6-12.9.
the batt tested 12.5 with car turned off (hood and maybe courtesy lights on)
Do you guys think the ignition switch contacts will cause the dic and gauge to be off? Also effect the volts to the fuel pump, causing the pitch to change when signals or brakes(other loads) are applied?
Gonna try and clean regrardless though.
thanks
checked the volts at the batt terminals last night with the car running and all options on(a/c, lights, hazards, radio) and it read 13.5. The dash showed 12.6-12.9.
the batt tested 12.5 with car turned off (hood and maybe courtesy lights on)
Do you guys think the ignition switch contacts will cause the dic and gauge to be off? Also effect the volts to the fuel pump, causing the pitch to change when signals or brakes(other loads) are applied?
Gonna try and clean regrardless though.
thanks
Tech Contributor
Joined: Jan 2007
Posts: 19,465
Likes: 1,167
From: Dyer, IN
Thanks for the ideas so far!
checked the volts at the batt terminals last night with the car running and all options on(a/c, lights, hazards, radio) and it read 13.5. The dash showed 12.6-12.9.
the batt tested 12.5 with car turned off (hood and maybe courtesy lights on)
checked the volts at the batt terminals last night with the car running and all options on(a/c, lights, hazards, radio) and it read 13.5. The dash showed 12.6-12.9.
the batt tested 12.5 with car turned off (hood and maybe courtesy lights on)
Last edited by lucky131969; Mar 18, 2011 at 11:53 AM.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
IF,,, you examine the schematic provided below,, you will see that the battery powered source is labled "HOT in ON & START".. That is the ignition provided power source. Im cant say for sure that you have a bad ignition switch or not cause Im not at your car taking voltage measurements. But,,YES, it very well could be a bad ignition switch contact that needs to be cleaned. The FUSE has two small slots on top of it. Those slots are TEST POINTS. If you read those to chassis ground, you will see what the fuel pump supply voltage is out of the switch.
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Thread Starter
Heel & Toe
Joined: Jan 2011
Posts: 22
Likes: 0
will check volts at the fuse and the alt tonight and hopefully get to cleaning the switch this weekend. wiill let you know.
thanks for the schematic bill! and the help lucky(love that part if illinois, even went to a couger game when i was last out there)
thanks for the schematic bill! and the help lucky(love that part if illinois, even went to a couger game when i was last out there)
Tech Contributor
Joined: Jan 2007
Posts: 19,465
Likes: 1,167
From: Dyer, IN
Only use the dash readings for a reference. What is the reading at the battery, engine running, no accessories turned on?
Thread Starter
Heel & Toe
Joined: Jan 2011
Posts: 22
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right around 13.7 at the batt, car running, no acc on. Im useing a sweep gauge, not digital so could be a few off either way.
since cleaning the contacts, have seen 13-13.1 on the dic, but still will drop to 12.8-12.9 with load running. At the same time the batt reads 13.5-13.75 constant with load running.
maybe its my old age, i dont recall the dic ever showing that low before.
What do other stock C5's show ion the dic under these conditions?
thanks
since cleaning the contacts, have seen 13-13.1 on the dic, but still will drop to 12.8-12.9 with load running. At the same time the batt reads 13.5-13.75 constant with load running.
maybe its my old age, i dont recall the dic ever showing that low before.
What do other stock C5's show ion the dic under these conditions?
thanks
Thread Starter
Heel & Toe
Joined: Jan 2011
Posts: 22
Likes: 0
sorry for the late response! rain delay. you know us lightweights on the west coast. Anyway, im using a old school sweep meter and i read 1/2(prob 14.9) between 10 and 20 volts at the lug on the alt with the motor running. Also at the batt and the pump fuse. Dic shows 12.9 I swapped out the relay out with another(horn i belive, same number) and no change.
I guess testing volts at the fuel pump would be next? where would the best location/fitting be?
thanks
B
I guess testing volts at the fuel pump would be next? where would the best location/fitting be?
thanks
B
