New here, first post. I was reading all kinds of threads on here first about this but the end never really verified the fix. So I joined to ask again. I am a retired mechanic but never worked on/for Toyota but I don't really think that matters. Anyhow, I bought this truck used with 441,000 miles on it and it was a daily driver. Needs a syncro unless I want to keep double clutching but I was going to do that later. So I hadn't drove the truck that much but tried to start and run it here and there. I knew the battery was going as I had to put it on the charger if I waited too long in between starting it. The I guess everything happened at once. The clutch pedal went so I bought a new master and slave cylinder and a new battery. Then it wouldn't start. So I pushed it over to the drive and figured it was likely the fuel pump. I replaced the master /slave and dropped the tank and replaced the fuel pump. I put a Delphi fuel pump figuring it's at least a known brand. I also did the electrolysis cleaning to remove the rust. When finished it started right up! So I bought a new fuel filter and lost a few years off my life I am sure as replacing it on a 2.4L is a royal pain. Especially that the previous fuel filter changer had the old one in the wrong place by the firewall and I put it back where it belongs. Lots of swearing. Now it won't start. I can't ever hear the fuel pump run, but that doesn't mean it's not running. So I pull the hose from the fuel pressure regulator and crank it and it sprays fuel, so I know the pump is working. Still won't start. So I pull the vacuum hose for the brake booster from the intake and spray some brake parts cleaner in there to check for spark and it starts up and stays running! I figure I must have just bled the fuel line or something. I go back 3-4 hours later and it won't start again. I use the brakes parts cleaner again and it starts and stays running. Not being a Toyota tech and not having a manual, I am going to change the fuel pressure regulator first. My second idea is a crank sensor but not really sure if that would do it. Am I on the right track?
Thanks,
Volatge

 

Followup. I put a clamp on the exit line from the FPR and it didn't start. But with it on there and 30-40 cycles of the key I was able to start it. And once it started the pressure from the fuel pump made the clamped off hose leak past the clamp. I found a few other things by googling that I will try... I am going to try and find my OBDII reader that I used on here when I first got it to see if there are any codes.

 

Welcome! I hope we can be of great help to you as this goes on.

From the sound of things, I would say that your COR (Circuit Opening Relay) is bad. The part that runs the fuel pump when the key is in STArt position.
The COR is a 2 part relay, used to mainly shut off the fuel in case of an accident. One Part of it, as I said, runs the fuel pump during the start cycle. Then, once air flows through the AFM, opening the vane even slightly, the other half takes over and runs the fuel pump as long as there is air flowing into the engine.
The COR is located just above the ECU, under the passenger side kick panel. Just forward of the door, under the dash. Very easy to remove, both the kick panel AND the COR. Just one bolt holds the relay in.

A COR is about $65.00 at a dealership.

Having said that, you would do your self better to get an OEM fuel pump. Look how long the old one lasted?
Also, a lot of people move the fuel filter over to the sidewall, which makes it a lot easier to put in. Make sure you get the fuel filter in in the right direction. When it's mounted "correctly", it looks backwards. It's just the way the built the hoses for it.
Last, never EVER reuse crush washers. ALWAYS replace them, even if you just tightened down onto them a little bit.

Let us know how it goes for you!
Pat☺

 

Hi Pat, Sounds like you know your Toyota stuff. When I worked for Dodge, Chrysler, Plymouth, we had ASD relays (automatic shutdown) that by the looks of it does the same thing on a Toyota. Makes perfect sense that could be my issue. I am glad to start with changing that part as opposed to ending changing that part. When this fuel pump goes I will use a factory part. I thought Delphi was a good one when I missed it by this much: Denso. I will go find a place to order the relay and let you know how it turns out. Thanks for letting me know where it is located too. And lastly, thanks for your service.
Voltage

 

Thanks!
The dealer, and RockAuto are two good sources. Once again, try for OEM parts. Maybe a bit more, but like I say, how long did the original last!

Yes, sounds like the COR is a Toyota version of the ASD, or vice-versa

Glad I could be a little help
Pat☺

 

I had already ordered one from Rock Auto as I use them quite a bit for my other vehicles. They sure are proud of that relay with dealer prices varying from $80-$140 after a quick search. Also, I looked for the relay on my truck and it wasn't behind the passenger kick panel or the drivers kick panel. But after a search I found it under the dash on the left side of the steering column. I just wanted to know where it was so when my part arrives it will be a quick swap. All good. Mine is a 1996 Tacoma 2.4L.
Voltage

Added: Well I put in the new relay today and it still won't start. I got a new ODBII scanner and it shows a coolant temp circuit code. I found that the sensor is located on the back of the head. I am going to order one after checking the wiring etc...

Added: Fixed it! Apparently when I was trying to install the fuel rail banjo bolt in an area with -10% visibility, I decided to remove the one bolt that holds the wire harness to the back of the cylinder head to gain more access. That likely caused me to inadvertently unplug the coolant temp sensor (ECT) as that is what I found when I read the real-time data and the ECT showed -40 degrees. That got me trying to locate the ECT and am am sure glad I didn't have to change it. I couldn't even see it with a mirror and a flashlight but that was partly to blame on the bright sun. I saw some wires on the left rear side of the head and pulled on them a little and lo and behold it was the plug for the sensor. After some brief struggling with my oversized hands I got it plugged in with only two cuts across the top of my wrist. Glad it's running as it cranks up instantly. I put the original COR relay back in and now I have a spare for possible future reference.

 

RZ engines have a hot wire mass air meter with no moving parts. It has no control over the fuel pump power circuit like on a 22-RE with a mechanical vane air meter. The RZ ECU controls the fuel pump relay and shuts it off when it detects zero engine RPM from the crank position sensor.

Not really. Doing all the diagnostic investigation before throwing parts it will save time, money, and aggravation. On a side note, there's nothing wrong with Delphi parts. They're an OEM for big car companies just like Bosch, Denso, NGK, Hitachi, etc.