Fuel pump or bad wiring? (Page 1/1) saving_rossi JUN 14, 11:33 AM I’m nearing the end of my LG8/F23 swap. The pump was priming and it was cranking but not getting spark—now it’s getting spark but the fuel pump isn’t even priming. the tan/white wire gets 8 volts when the key is in the on position. The pink wire gets 0V but is continuous throughout the circuit (I have just been checking continuity as I go to check for breaks), and the black wire I assume is a ground, but I don’t know how to check for a faulty ground. And I haven’t messed with grounds recently. I tried unplugging the connector and giving tan/white 12V, and it still didn’t prime. This pump is a couple months old but it has been sitting for most of those months. How can I know for sure that this is a pump issue and not a wiring issue? Thanks Mike in Sydney JUN 14, 04:37 PM Make sure the battery is good. You shout be seeing close tom12 volts at the connector. Next, check the fuel pump relay. If it is okay, replace the pump. Injustice replaced the pump on my car. Same symptoms. If you replace the pump, change out all of the hoses and fuel filter while you’re there. saving_rossi JUN 14, 10:07 PM quote Originally posted by Mike in Sydney: Make sure the battery is good. You shout be seeing close tom12 volts at the connector. Next, check the fuel pump relay. If it is okay, replace the pump. Injustice replaced the pump on my car. Same symptoms. If you replace the pump, change out all of the hoses and fuel filter while you’re there. Hoses and filter and everything are all brand new. Battery is solid. Which pin should I be seeing 12 V from? I know there’s a voltage drop due to the length of the circuit, I only saw 8.5 ish volts. From the tan/white wire. Mike in Sydney JUN 15, 05:01 AM quote Originally posted by saving_rossi: Hoses and filter and everything are all brand new. Battery is solid. Which pin should I be seeing 12 V from? I know there’s a voltage drop due to the length of the circuit, I only saw 8.5 ish volts. From the tan/white wire. You should see at least 11.5 volts between the tan/white wire and the black wire. If you don’t then there is a strong possibility that you have a bad ground somewhere or the battery is bad. Check your battery if it’s more than a year old. A battery can show 12 volts at the terminals but still be bad or on the way out. Check the voltage while cranking. If you don’t see at least 10.5 volts while cranking, consider replacing it. GodSend JUN 16, 08:50 AM quote Originally posted by saving_rossi: I’m nearing the end of my LG8/F23 swap. The pump was priming and it was cranking but not getting spark—now it’s getting spark but the fuel pump isn’t even priming. the tan/white wire gets 8 volts when the key is in the on position. The pink wire gets 0V but is continuous throughout the circuit (I have just been checking continuity as I go to check for breaks), and the black wire I assume is a ground, but I don’t know how to check for a faulty ground. And I haven’t messed with grounds recently. I tried unplugging the connector and giving tan/white 12V, and it still didn’t prime. This pump is a couple months old but it has been sitting for most of those months. How can I know for sure that this is a pump issue and not a wiring issue? Thanks To check for a bad ground.. unplug the relay... put your multimeter in continuity mode (tips of leads will beep when they touch each other). Place once lead on the ground terminal of the relay, and touch the other one a good piece of bare metal on the frame/engnie (or negative terminal of batter if close enough). If it beeps, your ground is good, or at least existent. If you want to know if its a QUALITY ground, than the same thing but OHMS (resistance). It should be low (almost zero).. for this one you want to ty to get as close so there you think the fuel pump relay ground is attached the chassis.. maybe the starter bolts?