Fuel pump relay random click when driving

[Majindan]

Fuel pump primes as normal when starting, no starting issues, but sometimes when I'm driving I hear a singular tick from the engine bay, same click that relay makes after priming. Also, very slight surging when under heavy acceleration sometimes. Fuel filter was replaced a few months ago, WIX.

Thoughts?

edit; when I hear the tick while driving, it's always when I'm driving through a parking lot and or slow speeds.

 

[Majindan]

Is this the correct part to replace?

Denso Relay 567-0001: Advance Auto Parts

 

[Majindan]

Bump; Maybe the relay isn't the correct term...it's the part by the fire wall on driver side? Guess I'll youtube it or something.

 

[foxrider56]

if you are talking about the efi relay try swapping the relay with the rear taillights they are the same and see if the problem goes away

 

[the great him]

That relay provides power to the ECU as well, if there was a problem with it your rig would not run.

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[the great him]

And there is no way you are hearing the relay "click" or cycle while driving or with the motor running. Too much other noise to be able to hear suck a slight click, unless you are a dog

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[Majindan]

And there is no way you are hearing the relay "click" or cycle while driving or with the motor running. Too much other noise to be able to hear suck a slight click, unless you are a dog

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I can turn the key, get in front of open engine bay, the click is from the unit by/on the firewall by the brake controller. And yeah, I hear "a tick" from the engine while driving slow occasionally but the point of posting is that I'm unsure if it's the relay or what making the sound, ass.

 

[the great him]

that may be, i do not dispute that you are hearing a clicking sound, but it is not the EFI relay, nor is it the fuel circuit opening relay (fuel pump). a click from a relay is too quiet to hear while driving inside the vehicle unless the relay is someplace inside the truck itself.

 

[Majindan]

that may be, i do not dispute that you are hearing a clicking sound, but it is not the EFI relay, nor is it the fuel circuit opening relay (fuel pump). a click from a relay is too quiet to hear while driving inside the vehicle unless the relay is someplace inside the truck itself.

Any thoughts on what it is then? I was saying that with the hood open immediately after starting, it appeared to be coming from the part by the firewall left of the brake controller/reservoir.

Fuel pressure regulator is what I'm looking at after looking at this http://tacoma.site40.net/4Runner_96...2rmsour/2002/024runne/em5vzfe/cylhea/comp.pdf.

 

[the great him]

Any thoughts on what it is then? I was saying that with the hood open immediately after starting, it appeared to be coming from the part by the firewall left of the brake controller/reservoir.

Fuel pressure regulator is what I'm looking at after looking at this http://tacoma.site40.net/4Runner_96...2rmsour/2002/024runne/em5vzfe/cylhea/comp.pdf.

The FPR is just a valve with a spring... Nothing in there to be clicking and no electricity going to it. Without having the vehicle in front of me to hear and fallow the clicking it will be hard to say. It could be anyone's guess.

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[Majindan]

I had the windows down yesterday and I've noticed if I'm on the gas a bit then let off I hear the fuel pump priming again, so the click I'm hearing is the shutoff under the hood.

This is driving me nuts, is it normal for the fuel system to prime every other time you let of the gas at low speeds?

edit; I'm going to try and see if Torque will let me monitor fuel pressure at various speeds etc, normal pressure at idle is 45 from what I read online.

 

[TheDurk]

I had the windows down yesterday and I've noticed if I'm on the gas a bit then let off I hear the fuel pump priming again, so the click I'm hearing is the shutoff under the hood.

This is driving me nuts, is it normal for the fuel system to prime every other time you let of the gas at low speeds?

edit; I'm going to try and see if Torque will let me monitor fuel pressure at various speeds etc, normal pressure at idle is 45 from what I read online.

Pump should run whenever the starter is energized or the CPS says crank is turning. It does not cycle. The excess fuel gets returned to the tank via the return hose from the Fuel Pressure Regulator.

If you want any detailed electrical help, POST YOUR YEAR or better yet, put it in your sig with other details.(Pet peeve.)

 

[Majindan]

Pump should run whenever the starter is energized or the CPS says crank is turning. It does not cycle. The excess fuel gets returned to the tank via the return hose from the Fuel Pressure Regulator.

If you want any detailed electrical help, POST YOUR YEAR or better yet, put it in your sig with other details.(Pet peeve.)

I didn't realize the year or even the make would matter for what I thought a fairly universal fuel delivery system...but I did update my sig. 02 SR5 4WD. What would cause the fuel system to prime after starting? My Interstate battery looks pretty old, month and year were not stamped out before anyone asks and I've only had the truck about four months with no obvious battery related issues. Getting batt tested today.

 

[JRZEE2000TR4LTD]

I didn't realize the year or even the make would matter for what I thought a fairly universal fuel delivery system...but I did update my sig. 02 SR5 4WD. What would cause the fuel system to prime after starting? My Interstate battery looks pretty old, month and year were not stamped out before anyone asks and I've only had the truck about four months with no obvious battery related issues. Getting batt tested today.

I think the fuel injectors make a loud enough clicking noise to be heard while running. Maybe you have a bad injector?

I would think the battery has nothing to do with your problem. Doesn't hurt to have an old battery tested though.

 

[TheDurk]

I didn't realize the year or even the make would matter for what I thought a fairly universal fuel delivery system...but I did update my sig. 02 SR5 4WD. What would cause the fuel system to prime after starting? My Interstate battery looks pretty old, month and year were not stamped out before anyone asks and I've only had the truck about four months with no obvious battery related issues. Getting batt tested today.

The whole fuel pump switching system got redesigned along the way from hot-switched to ground switched and wire colors are always changing. Using the wrong year EWD is just asking for trouble.

This is a weird one. I've never heard that complaint before. If I were there, I'd first rig a test light from the contact side of the COR (fuel pump relay) that I could see inside the cab as I drove. This would allow you to confirm your diagnosis of a pump-cut-out.

Is it in anyway related to how much fuel in the tank?

As to standard for all years, now that I took a quick look at the '02 EWD, I see the COR is energized at key on, unlike the earlier years. But, since you didn't give your year, I won't apologize for the bad info.

http://tacoma.site40.net/4Runner_96-02_Repair&Wiring/techinfo.toyota.com/ileaf/ewdtmc2/ewdtmpdf/ewdsourc/2002/024runne/systemci/015ecs.pdf

I hear weirdness, I think grounds. The fuel pump grounds through the BH ground, located inside the left rear quarter panel, see p. 42 here:

http://tacoma.site40.net/4Runner_96-02_Repair&Wiring/techinfo.toyota.com/ileaf/ewdtmc2/ewdtmpdf/ewdsourc/2002/024runne/electric/connecto.pdf

Since it's an intermittent problem, the only thing you can do is access that ground, remove it, clean the terminal and the area it contacts, and reattach.

If the light does confirm your diagnosis, then you can swap the COR relay with the power window relay on the back of the fuse panel by driver's knee (another thing I could not say with confidence without knowing your year).
Then swap the test light wire to the coil side and see what happens then.

 

[gamefreakgc]

The FPR is just a valve with a spring... Nothing in there to be clicking and no electricity going to it. Without having the vehicle in front of me to hear and fallow the clicking it will be hard to say. It could be anyone's guess.

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Toyota FPR's do tick, incessantly sometimes. Ask anyone who has owned a 2nd gen.

It could very well be the FPR but it is totally harmless.

 

[Majindan]

Borderline necro update:

Found this in another thread, the sound I've been hearing is the brake booster clicking off and on! I was over analyzing because my 00' Limited I had before didn't have the same braking setup, therefore didn't make that sound. Figured I'd add this in case anyone else came looking.

 

[El dondo]

Rapidly cycling EFI Relay solved!

Thanks to this thread and similar, I was able to troubleshoot and solve a similar strange problem where my 4Runner was drivable, but every couple minutes the engine would lose power down to idle rpm. I'd quickly shift into neutral and coast, until the engine would rev back up again and then I'd pop her into "D" to accelerate back up again.

Background - Thursday after a heavy rainband from Hurr Dorian passes by and skies clear, I jump in 4R to go check on my mom, who lives about 4m away. Pull out of the drive way and engine intermittently loses power. So I pull a U-turn and head back to the house and turn off the ignition. I notice a little bit of water leaking from the roof liner down onto the passenger dash.
I jump out and retract the sunroof to find small berries & debris has clogged the drains on either side of the sunroof. Easy enough fix before the next rain band hits with a pic and air compressor to blow out the drain lines.

As I'm heading back to the garage, I hear a tiny ticking noise coming from the engine bay and discover that the EFI relay in the engine fuse box is rapidly cycling, almost like Morse code (3x per sec). Pull the very warm relay, so the battery won't die, and head inside to do a little online research. Unfortunately I can't find anything about a rapidly cycling EFI relay.

Friday morn I plug in the EFI relay and the truck fires up, so I hope the mystery problem has cleared. Nope - starts losing power in 1/2 a mile, but I make it across town to work using the shift to "N" when the engine loses power trick. Once at work, I pull out the relay; annnnd plug it back in when it's time to go home.

So this morn (Saturday) spend a couple hours learning about the EFI and COR relays along with the ECM.

I start by swapping out the EFI & COR relays with a spare, but dang if the spare EFI relay starts ticking away as soon as it's plugged in too.

Next stop is the ECM to see if maybe some of the leads got wet or shorted. I dig it out from in back of the glovebox and disappointingly all the leads look fine & dry - until I pull it out of the truck, turn it over and it takes a pee on the driveway!

20 minutes later, I've flushed it down with alcohol and lightly scrubbed with an old toothbrush and the ECM is drying in the sun. Once installed back in the dash, the old 4Runner fires right up and it's off to the brewery!

First, I can't believe the truck ran as well as it did with the bottom of the ECM sitting in water

Second, many thanks to folks like TheDurk & The Great Him for the valuable insight.
Next weekend the old gal gets new rear coils and shocks!

1999 4Runner SR5 3.4l 230k miles 16" wheels

 

[pluton]

Good problem solving story.