Fuel delivery problem
 

Fuel delivery problems. Not getting fuel, electric pump not kicking on when key is turned, no start. Suspect relay but can I test pump with jumper wire from battery? Motor is 502 , with Holley injection and merc mefi. Fuel pump I believe is Weldon. Was running good last week

Thanks

Padraig

I see you’re using an aftermarket pump, so the following presumes you’re still using the factory wiring harness. That said, the fuel pump relay is mounted on the ECU bracket. You can jump it there or go directly to the pump with a set of jumper wires. There’s also a fuse block with three fuses in it inside what looks like a data port connector, worth checking for a blown fuse.

However, you may want to check my thread from this past week, I had the same problem and it turned out to be a seized fuel pump that had gummed up. I was able to get it back up and running no prob.

https://www.offshoreonly.com/forums/...mp-seized.html

Thanks. Just jumped the fuel pump with a hot wire from battery so that is good.

Padraig

https://cimg3.ibsrv.net/gimg/www.off...71bc5aab6f.jpg
if you're running a factory harness check these fuses one is fro the fuel pump

Yes, factory harness, I'll check out those fuses.

Thanks, Speedy.

Padraig

The factory wiring and relay is only designed to handle about 10 amps. Most aftermarket pumps will draw quite a bit more amps.
A friend of mine had issues running an A1000 pump and using the factory wiring/relay. His worked fine for several years, then all of a sudden started loosing fuel pressure above 3000rpms.

Griff, this one does not kick on at all, when I turn the key,, unless I jump it from the battery. Not sure how to test the two relays. I may try replacing them this morning. If I recall they are not expensive. If I recall correctly one turns the pump on and one turns it off

Padraig

Relay
 

Pic of relay.
https://cimg1.ibsrv.net/gimg/www.off...166b039ef6.jpg

That doesn't seem right. One relay is all that should be needed for a motor that only has to run in one direction (an electric fuel pump). 2 relays would be needed for something like a trim pump, or a hatch lift, where running a motor in reverse is part of operation.

To test a relay, you need to rig up a little setup for providing 12V and ground to the primary coil of the relay (terminals 85/86), +12V to terminal 30, and a test light on terminal 87 (alternatively, ground to terminal 30, and +12V to the other end of the test light). If the light lights up when 12V and ground are applied to the primary side, then the relay is functioning correctly.

I am not an expert and I am old and have a bad but I am pretty sure that is what Eddie Young told me the two relays did. Motor was a crate motor built by Inovation for Factory 1 racing in 2005. Rebuilt by Eddie Young in 2013. Possibly the two relays were a Inovation thing?

Padraig

Just replaced swapped out a relay. The first one pump still didn't run. Tried the second one and pump activated. Started engine...all good.

Griff, Do you think the high draw eventually damages the relay???

Thanks all. I trust you guys more then my local seasonal mechanics and didn't want to haul it 2.5 hours to Buffalo! Plus I am heading next Friday to the Bwttleship Run on Seneca Lake.

Padraig

yes,the pump killed the relay.I had the same problem using the stock relay.what I did is use the stock relay to turnon a 30 amp relay w/ battery power going to the relay so when on,pump got all the power it needed.used heavy gauge wire and heavy duty spade lugs.

What did you get for replacement relays Padraig ? Where both the same ? If not which didn ‘t work and which did ?

Hey, SB, not sure whatyou are asking but replaced with a NAPA AR566. Do you think high draw from the pump caused failure. Had to replace the same relay about three years ago. Then again the relay was made in China. The new one is Tiwan. LOL. I bought another to keep in the boat tool bag.

Padraig

FWIW , I am also running a Weldon pump , but on a carb setup. I have a 30 amp relay. I think the pump only draws 7.5 amps.

Sometimes the relays just give up the ghost. I used relays to run fuel pumps and cooling fans in the S10 and they would crap out without any warning. they were rated and wired properly but would just give up the ghost. Figured more of a cheap Chinese manufacturing thing than anything else. I learned to keep spares with me.

Thanks Tom. They had to get another one in so I am picking up my spare today. Doing the Battleship Run on Seneca lake, Saturday so I am adding that to the onboard tools and spares. Also doing wheel bearings on trailer. Good thing I am retired.

In the sled world , this sucks and gets cold !!!. Our trick was changing out the fukUamerica branded chinese relays to Panasonics fully sealed from Japan. :)
On boats and trucks I have had several issues with Hella relays last few years. They where the go to before....but seems not anymore. I have my ears open for the suggested better ones.....

The Hella boat issue was a volvopenta efi that would try starting on it's own. Owner had put several batteries and starters on it and gave up. Luckily it was in my driveway instead of at work. Very quiet at home. Dirt roads and wild animals. :) Walked out in morning with coffee to my truck and I hear the boat trying to start it self. Shocker !!!!! The OE Hella relay was the issue.

Well the helle was what failed. NAPA on now. Wonder if Panasonic makes a replacement?

Padraig