Ask the Toyota mechanic!

I will try that tomorrow morning, thank you!

 

Wow that is definitely the same issue, sorry I should have searched the site better before posting.

 

Nothing to be sorry about at all, its good these questions get re-asked from time to time, to keep everyone updated...

 

So, I pulled the harness, pulled back the loom, no corrosion that I could see; the wires are in really good shape. I jumped from the fuel pump module fuel pump output directly to the pump and get nothing with key on. I also checked the resistance of the red and blue wire for the fuel pump and it's zero resistance, so I think the wiring is good.

 

If I understand correctly. You did a resistance check between the red and blue wires while plugged into the fuel pump and get nothing, as in an open or infinite resistance? I'm assuming your testing at the module connector while its unplugged.

 

Resistance test red on both ends of the plugs and blue on both ends. Meter reads "OL" if no continuity, I get zero resistance through the 2 wires but have continuity. I took the red and blue wire out of the equation by jumping directly from the ECM to the pump (brand new pump that I know works) and the pump doesn't go on.

 

Zero resistance is an open do why do you think you have continuity?

For shits and giggles plug the harness into the pump. With the other end apply 12V from a battery. Red to + and blue to -. Verify the pump runs.

 

I'm sure there is some resistance, my meter only goes to tenths. Meter will read "OL" for an open circuit, it beeps and give you the ohms of resistance when the circuit is completed; continuity (see pics)

I did plug in the harness, no the pump doesnt run with key on. The new pump is outside of the tank, so i can access the soldered connections inside the pump. When I plug the harness into the pump, nothing happens, however, when I manually ground the negative side of the pump (red wire on connector/black wire in pic below), it runs.

.

 

Your mudding the waters a bit. Plug in the harness to the pump that is installed in the tank. Use two thin wires and insert them in the connector end that would go to the pump module. Use a separate 12V source (spare battery) and try to run the pump. If the pump runs the harness, connector on the pump and the fuel pump are all good. If the pump doesn't run then we will look at the harness and pump circuit. If the pump does run them the problem is from the pump module and back to the ecu. I'm just trying to isolate which end of the circuit the problem is.

 

Zero resistance is a closed/complete circuit, aka continuity. An open would be infinite resistance.

 

I got you 100%, i'll give that a try tomorrow. Power at the connection that plugs into the ECM. Thanks for your time tonight!

 

Oops, got my ass backwards.

 

Dude, your doing a spectacular job taking your valuable time patiently walking us through a complicated modern vehicle. PWM fuel system, who'da thunk.

Thank you.

 

Thanks but the pwm for pumps has been around for awhile. I'm actually off work for a while because I had surgery in both hands for carpal tunnel so lots of time to help.

 

I think that probably qualifies as a little known fact though. So you had surgery for carpal tunnel and you're spending your recovery time typing? Is that a PT approved activity?

 

Actually my doctor and physiotherapist want to keep the fingers and hands moving to remove scare tissue and improve dexterity so typing is the perfect exercise. That and video games.

 

Morning,

So I applied 12v to the pump through the harness, then tried directly to the pump, still doesn't turn on. I did check the resistance across the pump leads (see pic) and it was 140 ohms, also, across the sending unit circuit, it was 161 ohms. I compared that to the new pump I have, and it was about 6 ohms (see pic).

As a side question, see all that room I have? I know we aren't there yet, but if I end up having to, is It possible to get the pump out without dropping the tank? Ever seen that done?

Thanks, Eric

 

Good morning,

Now we are getting somewhere. You now know the problems is in the harness or the pump. Do one more thing. Plug your harness in the original Toyota pump that you have out. Apply voltage to the connector end. Does the pump work.


Unfortunately the tank has to come down if you have to change the pump or the truck box has to be lifted off.

I'm curious as to why the original pump was changed?

 

I have an issue with my automatic side mirrors. My passenger side folds in when I hit the button but the driver side only moves a little bit. Please help. Thanks in advance.

 

Hi Jeff..I'm looking to buy a current Toyota tundra with the standard oem 18 inch steel wheels. But I'm looking to upgrade to a 20 inch x 9 wheel with a 50+ offset..also going with a 305 /50 R20 tire. Will this tire fit ? I don't see it under the America's Tire(Discount Tire) list of recommended sizes. But the overall diameters matches up with the oem stock wheels.

 

Morning,

So I tested the new pump I have, out of the tank, when plugged into the harness and an external 12v is applied to the other end of the wire (connector that plugs into the ECM), it runs. So what's our next step?

Yea, I dropped the tank when I changed it last time, just curious.

So, when I bought the truck in December 2018 from a wholesaler in Philadelphia, it cranked, but no start. Replaced the fuel pump and that fixed the issue. It's been about 18 months and 8k miles since then.

Thanks, Eric

 

Good morning,

If you absolutely sure the harness is good then your putting the original fuel pump back in. It's the only thing left. Like I said before the Toyota fuel pumps are extremely reliable and removing that aftermarket pump would be a good idea. Sure hope your tank is almost empty.

 

The new fuel pump that is outside the take doesn't come on when it's connected to the wiring harness and the other end is plugged into the ECM. I did verify that the input side of the ECM is getting 12v with key on. I'm confused on why you think the new pump would work in the tank if it does work outside of it? So yo dont think it's the fuel pump ECM?

 

You said the pump that's in the tank doesn't run when you apply voltage to it through the harness. The pump should run. You used the same harness and connected it to the OE pump and it runs. If you know for sure that the harness is good then the problems has to be the pump.

 

There is no question the pump is bad; 12v to the pump in the tank and it doesn't run... that is getting replace regardless. ALSO, the brand new pump doesnt run when plugged into the ECM, so there is something else wrong, I say the ECM.

 

More testing would be required to determain that. I'm betting the aftemarket replacement pump.

 

I have 70K on my 2017 CM. I'm going to do the front and rear diff fluids , transfer case , and oil change this coming weekend.
I have read that the "toyota ticking" may be remedied by switching to a 5w 30 oil. Is there any reason to stick to the 0w 20 for eternity , or can a weight change be detrimental ?
Thank you

 

I think you would be fine using a 5W30 or 5W20. The older Tundras used 5W30 and the motor is the same but for winter you might want to switch back to the 0W20 if you live in a cold climate.

 

Thank you , kind sir

 

3 of my 4 door locks went bad. They don’t unlock with remote or switch. I pulled out all 4 actuators and replaced the motors. The one that worked still works, the other 3 don’t. Any suggestions?