Hello all!

New here and after lurking for advice I'd figured I'd reach out to see if I can fix the issue myself.

My 2008 Scion xB with aorund 140k miles suddenly lost acceleration power while I was driving. Got it towed and automatically thought it was an alternator or battery issue since the car never really showed any signs of fuel pump issues or engine struggling. Car always performed very well mechanically. New alternator. New sparks. Battery is fine. Connectors are clean. Fuses in the engine and under the steering wheel haven't fried.

Still no start. Sprayed some starter fluid in the air box and the car started up for maybe a few seconds and then just went back out. So it was fuel related. Assumed it was a fuel pump but with the fuel and acceleration never being an issue, I was trying to determine if possibly it could still be relay related since it was all so very abrupt.

Any help would be appreciated. Thank you!

 

Problem is 99.99% electrical. Parts typically don't die immediately all of a sudden. They wear out, you'll experience gradual degradation.

Do you have multimeter and know how to use it to measure voltage?

This is 5-minute fix with multimeter:

1. measure fuel-pump signal coming out of ECM when cranking.

2. measure power/voltage at fuel-pump itself when cranking.

 

I bought a 5 dollar volt needle reader the other day while I was getting a new battery. Would that be able to read sufficiently?

The ECM is the cartridge looking fuse in the engine bay underneath the smaller fuses correct? I read in a diagram that a relay could exist there but I never understood why it covered a wide area as I was looking for a smaller boxy fuse so I never thought to check that fuse.

Thanks for the response!

EDIT: The reader that I bought is just a light reader I'm not sure if it's entirely helpful in this case. Took off the plastic covering on the ECM and it just lights up.

 

ECM is computer that controls everything. Should be located inside under console. ECM will only turn on fuel-pump when it sees engine spinning.
You'll want to get service manual to get test-procedures to follow along with wiring-diagram so you'll know which terminal on ECM to probe.

So we want to test:

1. That ECM is turning ON fuel-pump relay when cranking
2. That fuel-pump relay and wiring sends power to fuel-pump

It's usually these intermediate stages with corroded or broken wiring that's problematic, rather than actual components at ends.

Here's basic multimeter that you can use to measure voltages, current and resistance.

https://harborfreight.com/electrical...ter-63759.html

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UPDATE: Used the starter fluid to try to see if the car starts up and it managed to stay alive for about a second enough to throw a Code at me. P0010.

When I cranked the car and stopped, I could hear the pump make a priming noise so I believe the pump should be fine.

___

 

Good job! Now we've narrowed it down to fuel-problem.

Fuel-pump prime is blind automatic function when key is turn ON. But it still doesn't guarantee that ECM will turn on pump when you crank starter. We are testing for proper ECM functionality.

Let's look up that code in proper manual for your car. These are typically specific for each model.

 

P0010 is an issue with cam position circuit...

Scion P0010

 

Would a bad solenoid cause the car to suddenly stall on the road or prevent the car from starting up again? If I can find the location and just pull it out and clean it then maybe that can fix an issue.

 

 

You probably have multiple issues. Bad solenoid will just give you low power. But won't cause running engine to just die and shouldn't interfere with starting car.

This is 5-minute fix with multimeter! you've wasted way more time than this wandering around in your head. Get official service manual, pull out multimeter, and follow test procedures in manual.