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Discussion Starter · #1 · (Edited)
Hi,

TL : DR

Car wouldn't start. Switched EFI/HORN relays and car would start, but horn still worked.
Car died a few days later and would not restart.
Shop determined it needed a fuel pump/filter/pressure regulator/ and relay. We replaced all. ($1266 after tax... oof!)
With new pump the car started and made it through the shops test drive, but wouldn't start when I went to pick it up.
Shop investigated and said it needed a new fuel pump resistor relay which no one makes so they installed a used one.
Car started but only ran for 1 minute and then would not restart, and they believe the used resistor we installed is no good.
Installed a second used resistor which also failed to allow the car to run.
Both resistors were tested at .2 ohms, rather than the .32 stated. I don't know if that is far enough out of spec to matter.

I'm wondering what is causing the resistor to fail. I do understand it could just be bad luck and the new (used) resistors I bought were no good, but the resistor doesn't seem to be a common failure, so much so that no one, Toyota or aftermarket, make a replacement part for it. I find it hard to believe that I have 3 bad ones. I will fully admit that I don't know much about the electrical side of a car.


WHOLE STORY

I'm driving an 04' Sportcross and recently the car would not start. It turned over strong, so I swapped the horn and efi relays and the car fired right up. Ten minutes later however, it died again. I swapped the relays back, and it fired up again... so clearly a relay wasn't the issue as the horn still worked in both cases, and the car would fire with me switching relays. I drove with no problems for a few days after this until it didn't and I couldn't get it to fire so it was towed to a shop (reputable 4.6 stars out of 400 review, well established), and they determined that there was power at the pump but couldn't get the pump to cycle even when applying 12v from a battery, so they installed a new fuel pump, relay, filter, and pressure regulator to a grand upsetting total of $1266. Seems obvious to me that the pump was the issue.

When arrived to pick the car up it wouldn't start. I gave them back the key, and they determined that the fuel pump resistor had failed but they can not order a new one, nor do any of their suppliers currently have a used one. So I bought two (to be extra safe) on eBay for $13 and $16 and just brought one to the shop (the other is still in transit to me). They installed it and the car fired right up... then died a minute later and won't restart. They are suggesting to me that the resistor I purchased was bad. I should be receiving the second one today in the mail and will try again...

I guess at this point my question is what would be causing this resistor to fail? Is it receiving too much current? If so, why and where should I look? While I know it is possible that the resistor I purchased used truly wasn't good, it was obviously good enough to allow the car to start. I find it hard to believe that I had 2 bad resistors when they are clearly not a common failure. If they were a common failure some company would surely be making replacements, but NO ONE does not even Toyota. I want to trust this shop, they've worked on several of my cars in the past, but I've been without a vehicle for 2 weeks, and If need to order another resistor from ebay I'm another 5 days minimum with shipping times... My emotions are not necessarily indicative of the situation, but I kind of feel like they "decided" it was the resistor and haven't looked further.

Would I just need a multi-meter plugged into the plug to determine if it is creating the proper resistance? Would the part need power for me to do that? I own a multi-meter but I don't think I've ever used it.

I might as well point out also that I had a new stereo and back up camera installed the day before these issues arose, but it wasn't like I added an amp or anything like that, just a new head unit and the rear view camera since my wife thinks the wagon is hard to see out of (it kind of is) The stereo shop insists (naturally) that they wouldn't have touched anything on this install that would affect currents in my fuel system. I wouldn't know on that front.

Anyway, if anyone has an ideas or has experienced something similar I'd really appreciate your input.

Thanks,

-Spencer
 

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They do make replacement pumps. If the called a regular parts store. You must buy the assembly. Which is the pump, regulator, and level sender. The ECU controls the voltage on a return-less system.
 

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Discussion Starter · #3 ·
They do make replacement pumps. If the called a regular parts store. You must buy the assembly. Which is the pump, regulator, and level sender. The ECU controls the voltage on a return-less system.
Yes, finding the pump wasn't the issue. It has been replaced with a new unit. The item that couldn't be purchased new is the Fuel Pump Resistor, Toyota part number 23080-46090. Honestly, I could probably take it apart and replace the resistor within the box itself. I don't know how, but I imagine that is an option, but buying the used ones was so affordable that I didn't bother moving past the consideration phase on that one.

135210


This guy located right in front of the igniter on the driver's side under the hood.
 

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Discussion Starter · #4 ·
Unfortunately the second used resistor I bought also failed to allow the car to start. The mechanic stated that it got very hot (which seems like maybe it is supposed to... it has a finned design and is attached to a small shield that separates it from the ECU, I would think because it is designed to get hot.) and that it was only testing at .2 ohms rather than the .3-.35 range that it is supposed to. They tested the second resistor and say the same ohm rating of .2. As of now, they're still trying to troubleshoot, but they seem hung up on it being a bad resistor. I've seen several forum posts about jumping the wires and bypassing the resistor entirely so I find it hard to believe that reduction in resistance (.2 from .32) would prevent it from running...

For now I'm lost.
 

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Problem with no resister is too much current. It will cause the pump to run harder than needed. Unless you are running boosted. I would not do it.
 

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Discussion Starter · #6 ·
Problem with no resister is too much current. It will cause the pump to run harder than needed. Unless you are running boosted. I would not do it.
Yeah, I am not interested in bypassing the resistor as a solution, but merely pointing out that if the resistance in the circuit is reduced (which should result in more current to the fuel pump) that the car should still run.
 

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People bypass the resistor all the time for boosted cars. As Tobias said, and what I would try, is to jump the resistor wires using 12awg wire at minimum. Then try and start the car up and see if it stays running. If it does, then you will need to try and find a good “known working” resistor from a running car that you can borrow to try in your car to make 100% sure that is the problem.

If it still won’t stay running, I would also jump the fuel pump relay temporarily and then try and start the car. This way you can Determine if the fuel pump relay is as fault or not. The fuel pump relay provides power to the fuel pump resistors as I recall.
 

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Discussion Starter · #9 ·
People bypass the resistor all the time for boosted cars. As Tobias said, and what I would try, is to jump the resistor wires using 12awg wire at minimum. Then try and start the car up and see if it stays running. If it does, then you will need to try and find a good “known working” resistor from a running car that you can borrow to try in your car to make 100% sure that is the problem.

If it still won’t stay running, I would also jump the fuel pump relay temporarily and then try and start the car. This way you can Determine if the fuel pump relay is as fault or not. The fuel pump relay provides power to the fuel pump resistors as I recall.

Thanks for your feedback! That all makes perfect sense and I actully suggested as much to the shop (though they didn't like the idea) As of now, the fuel pump has had power applied directly and does function in this manner, so the brand new pump is fine. Or at least that is what the shop tells me... (I want to believe them despite my frustration, but I'm at that point where I am becoming a conspiracy theorist on everything they say!) Since they currently have the car and I don't want to pay for a tow from them and potentially a tow back to them, I'm playing the waiting game for a BRAND NEW resistor that some warehouse in Japan had in stock. I'm told that they're looking into how to bypass the resistor safely, but since they're a large reputable local shop, they're not really the type to go outside the book on things so this has been moving slowly. I've convinced myself that if the resistor is operating out of spec with LESS resistance than it is rated for (.2ohm tested versus .32) that this should not affect the car's ability to start, frankly, even if it the resistor was applying extra resistance I would expect it would idle, but potentially stall out in lower rpm ranges as I applied throttle. But rather than take my half done project somewhere else and risk finger pointing and double the bills, I've elected to just let these guys roll with it for a while longer. Boy this is frustrating.

Thankfully (never thought I would say this) my wife and I are both currently laid off with this COVID business so we're fine with it just sitting at the shop for now. I'll update this when I have a resolution.
 

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Discussion Starter · #10 ·
Well, a resolution at last! I had to the car towed from my local shop to the Toyota dealer in town who actually diagnosed and fixed the problem for $250. To the embarrassment (and somehow credit, honestly) to the local shop, they had gotten hung up on the fuel pump resistor (and two replacements) all being faulty, a hard to believe situation. They were stuck on the wrong component, but barking up the right tree. The resistor was fine, however a simple electrical connection had come undone inside the left kick panel by the driver's feet. The dealer initially called me and told me that there was a resistance issue in the line between the FP resistor and the FP, where as my local guys got hung up on the resistor itself. Toyota said they would need to charge me a few more hours labor to dig into the wiring in the dash but found it pretty quickly and got it buttoned up.

I had a stereo installed recently and it had a problem so I even more recently had those guys replace some component involved in the install and at that point it wouldn't start (although it was having issues a few days prior, that were solved by the relay removal and re-installation). Those guys probably tugged on that harness while replacing the module that failed and messed it up. The Toyota tech noted that there was some "newly replaced" aftermarket connectors right in the area of the issue - clearly from the stereo.

I assume that the FP failure was just bad timing, and then the final failure of the car to drive was due that connection becoming disconnected instead of just loose. I wouldn't think the loose connection would short out the pump entirely, but who knows. There is no proving that anyway, so it isn't like I can get the stereo joint to cover the cost of the pump, but I will be taking the bill from Toyota to them and trying to get them to credit me back the $250.

All in all a frustrating situation. Where I'm out $1560 because a car stereo installer wasn't careful. Again, I kind of feel like the FP failure was related, but who knows for sure. Either way, I'm headed out to get my car and finally drive it again!

Thanks for your insights!
 

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Glad you got it sorted, despite the expense. TBH i hadn't even heard of a fuel pump resistor until this thread so learned something new, but obviously its not a common fault.

Shows a good troubleshooting electrical guy is worth his weight in gold, literally in this case. I hate electrical gremlins, would rather pay the money and pass them on to a pro.
 
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