Not sure why you're controlling the fuel pump w/o the ECU. Bad idea IMHO, fuel pump will keep running in the event of an accident. Engine off, fuel pump off.

Changing the injectors as you did should have no effect on your fuel pump draw.

Nor sure what you mean the fuel pump is grounded at the fuseblock? You ran the ground all the way back? To directly answer #2, yes you can ground the pump to the chassis, and probably should.

I cant help directly with #1, but what size wire are you running to the pump? Did you try another relay to see if it gets hot as well?

-Dave

 

Last night i ended up doing the "87 to 30 Pin" jump test with my multimeter and saw i was only puling slightly more than 10A from the pump - which is great. this was after i moved some ground components around and tighten down others at the chassis, battery etc just as a due diligence. i am going to take the car for a putt today and recheck.

wire size is 10g and runs about 10' from the rear stock fuel tank location to under the dash.

relay is now a 40A 5pin (87A left open) - the original issue occurred on a 30A 4-pin. i am starting to suspect the relay was possibly bad or i there was a poor crimp / wire job prior.

QUOTE="ChevelleFan70, post: 11666256, member: 24395"]
Not sure why you're controlling the fuel pump w/o the ECU. Bad idea IMHO, fuel pump will keep running in the event of an accident. Engine off, fuel pump off.
[/QUOTE]

that's a great call - my plan is to move it to the ECU once i sort this bug

Nor sure what you mean the fuel pump is grounded at the fuseblock? You ran the ground all the way back? To directly answer #2, yes you can ground the pump to the chassis, and probably should.

i have a fuse block with ground and 12v items going to it and from it. the fuel pump does ground to this block where other items are as well without issue. i will try and move it straight to chassis

Get one of these from hobo freight or any big box store and clamp it around the wire. (called a "digital clamp meter" or "amp meter")
Ensure your pump is pulling the rated amperage.

i have a Bosch multimeter that i did the 87 - 30 pin jump test on and showed slightly over 10A - but i will get one of these specific to "amp meter and retest"

 

...i am still feeling like the relay is getting hotter than normal/should.

1. how can i test the amperage the fuel pump is pulling being that it over the 10A max on mine?

Get one of these from hobo freight or any big box store and clamp it around the wire. (called a "digital clamp meter" or "amp meter")
Ensure your pump is pulling the rated amperage.
Ensure your hot/return wire and your relay are appropriately sized to handle the current draw.

 

What size gauge wiring do you have on pin 87, pin 30, and fuel pump ground? What are the lengths of those wires?

 

10g wire all around.

ground length is about 10' from stock fuel tank location to the dash where the relay is located. the 87 and 30 wires are also 10g

 

Ive had fuel pump relays really heat up when the fuel in the tank gets hot. The hot fuel will heat the pump up and put a ton of resistance in the circuit. If you’re still overloading the circuit with a 40amp relay and 10awg wire at that length after driving for 30minutes, check the temp of the fuel tank with one of those cheapo laser heat guns.

 

oh man - good to know and something i did not think of. did you ever find the cause of the tank heating up? jump ambient air temp? did you find a solve for keeping it cool?

 

Do you have a fuse protecting the wiring going to the relay ?

Are the relays a name brand or some off shore/no-name ?

One could try a test 10A fuse and see if it blows and then if it does maybe try a 20A ?.

Just keep in mind that the wire gauge relates to fuse sizing. My opinion is for 20A and less, use 14 gauge wire, 30A and less use 10 gauge wire, 60A or less use 8 gauge.

Maybe pull apart the first relay that was getting hot, hot, hot, and see what might be going on inside of it like melted contacts, burned contacts, or ??????

Jim

 

@GTO44 this is SUPER helpful, very much appreciated. my fuel lines are covered in protective heat DEI heat sheath from the pump all the way to the rails. when i was having the relay issue i was in bumper to bumper LA traffic for about 30mins.

i am using the Aeromotive Stealth 340gph P/N:18402 and have my fuel pressure regulator at the front of my fuel rails.

my next steps on this issue:

1. recheck the AMP current on the wire to the pump with a clamp meter to double check the draw
2. run the car as normal
3. recheck the AMP current again on the wire to the pump with a clamp meter to double check the draw to see if it has change after running
4. if the AMP has changed or the relay is getting hot, then test the tank for hot fuel:

if i understand the next steps in identifying hot fuel / tank potential issue:

1. run the car under normal driving conditions
2. use a thermo gun to see the heat of the FUEL TANK
3. @GTO44 what would a min / max fuel tank threshold be?

thank you all again!

 

@GTO44 this is SUPER helpful, very much appreciated. my fuel lines are covered in protective heat DEI heat sheath from the pump all the way to the rails. when i was having the relay issue i was in bumper to bumper LA traffic for about 30mins.

i am using the Aeromotive Stealth 340gph P/N:18402 and have my fuel pressure regulator at the front of my fuel rails.

my next steps on this issue:

1. recheck the AMP current on the wire to the pump with a clamp meter to double check the draw
2. run the car as normal
3. recheck the AMP current again on the wire to the pump with a clamp meter to double check the draw to see if it has change after running
4. if the AMP has changed or the relay is getting hot, then test the tank for hot fuel:

if i understand the next steps in identifying hot fuel / tank potential issue:

1. run the car under normal driving conditions
2. use a thermo gun to see the heat of the FUEL TANK
3. @GTO44 what would a min / max fuel tank threshold be?

thank you all again!

quick update - grabbed a clamp / amp meter from Harbor Freight and with the car running the AMP for the wire to the pump was 11.9A. with the car off and just the pump on it was about 10.8A. this was after i was driving around in the car for about 30mins as well.

that SEEMS to be in normal range, but welcome any thoughts.

 

Luckily, fuel pump relays are easy to test and replace on your own. Start by taking the fuel pump relay out of your vehicle so you can clean and inspect it. After that, you can use a multimeter to check the resistance going through the relay's circuit to see if it's faulty or not.
SPAM DELETED

 

Still trying to sort of some issues after my Holley Term X install with 42lb EV1 injectors. Prior I had the tuned stock PCM with stock 26lbs multec injectors.

Car has an LM7 with stage 2 BTR truck cam, BTR beehives, 102mm TB, long tube headers, sheet metal intake manifold.

Originally had the fuel pump relay issue that has been solved I believe. But I’m still getting the “sputter / stutter” sound in my exhaust after driving for about 30-45mins and when I am on side streets. Issue doesn’t not present itself when cold or first driving around.

There was some feedback here about fuel heating up, but my fuel tank is not warm.

The other issue I found was that my fuel tank was not vented at all, which I have corrected via the Aeromotive teams instructions. I am running their stealth setup with the 340gph pump.

Prior to swapping the term x and 42lb Holley injectors this issue wasn’t there - any feedback is welcomed.


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