2010 Tacoma no start/ sometimes start.

My 2010 Tacoma started on spray, changed the fuel pump, checked all fuses and relays are good as well.got it to start twice by disconnecting battery and Reconnecting.im lost at this point.2.7 liter manual trans

 

Many places to start.
But I will tell you, these trucks won't fire the injectors (fuel pump) without a crank signal.

Does the tach move when you crank the engine?

 

Crank no start? Security light not enabled? Check fuel pressure at the rail, clogged filter possibly. No engine codes for cam crank signals?

 

No it does not.there is no tach bounce or movement at all. Also vehicle has no codes present in computer and the security is not enabled

 

If there is no tach bounce ,would that be an igniter or something similar? Not extremely in tune with Toyota electrical.i do mostly heavy line work and have done so for 40+ years. Also I don't hear fuel pump when key on or cranking

 

No tach would be crank/ cam signal. But if it fires on starting fluid, then more likely a fuel issue. You don’t hear fuel pump when key in run position, I would start there. Briefly looking on internet tach should move when cranking and fuel pump should run when key in run position. Maybe a more central issue, power to ECM, major ground issue etc. is the truck rusty?

 

Unless it is a Canadian truck, and was shipped with that option, it won't have an immobilizer.
2.7 American market trucks didn't have the immobilizer.

 

If you have a scan tool, look at live data.
See if it shows RPM while cranking.

The tach can be used in "most" cases. But it's not exact.
It can be off by enough to not register, especially if the battery is weak(er).
Or you have a slow(er) crank.

You could also, see if you are getting power to the fuel pump on cranking.

But, that doesn't mean "a lot" until we verify a crank signal. (since we have no tach movement)

 

Might want to check Connector IB1 Pin 8 (Black/Red) behind the left kick panel for a burnt pin.

 

To be clear...
When it won't start, does the starter crank?

I recently had no start issues, but it wouldn't crank and kept stalling. After getting stranded a few times it finally threw a crankshaft position sensor code.

 

He says it starts on spray. So we can assume it does crank.

 

Interesting to come across this thread. As my 2013 TRD Sport just did the same thing.

Cranks over, But will not fire. No engine light. No Codes.
Will only fire with starter fluid.
Garage thought it was the full pump. Replaced it. No change.
Thought maybe the MASS sensor. Cleaned it. No change.
Eventually a Throttle body position sensor code came up.
They put a new throttle body in. No change.

They chased the wiring harness looking for anything.. nothing.
Their best guessing finger points to the PCM/ECM. So now we are waiting for a new one and that to be programed to my truck and arrive.

So while I hear this... and wait. I quickly go and ask the good ol' "DR. GOOGLE" research Lab.
"What could cause a PCM/ECM failure?"
One interesting point was brought up.
"High current, Power spikes or voltage inconsistency could cause failure"

I say interesting. Because a week before this issue came up. I had a muffler shop weld on a new muffler and tail pipe section.
Now in my mind, that could be a decent power spike.. possibly? . and, if I was to weld on my truck. Wouldn't one think to disconnect the battery first?

I imagine hard to point fingers.. but it is an interesting thought.


Hope you were able to find the weakest link in your truck and back rolling.

 

I'd bet it's not the ECM, sounds like they are just guessing instead of doing proper testing.

 

We'd be happy to help you.
But it's not worth our time (or yours) if it's still at the shop.
The same shop that is "guessing".

Step 1. Does the Security light stop flashing when the key is inserted in to the ignition?

Creating steps by throwing parts at it, isn't the correct way to diagnose it.

 

Correct. Truck is still at the shop.
Can’t answer if the security light stops flashings. Can’t say i ever saw it.

if that was the culprit. Then why would the truck run on starter fluid? The ignition shouldn’t work at all.. no?

 

Correct. But it's step one. (Not throwing parts at it.)
Next would be checking for power at the fuel pump, the fuel pump relay, the EFI relay, and power to the injectors. (Super easy too)
Find the missing. If all powers are there, move to the control side.

There is a bit more than I listed, but finding the missing shouldn't be "too hard".......Not for a shop. (A good shop)

 

Sorry I didn’t relay an absolute play by play for you.

When the truck first got to the garage. We couldn’t hear the fuel pump at all. But would run with starter fluid. We all had made the guess it was fuel pump. And went ahead to put a new one in.

but then soon found out the issue was still there. The boys checked and confirmed the fuel was getting to the fuel rail. Plugs are in good shape. Air filter was good. Checked for good measure.

Keep in mind. This whole time. There has been no engine codes. After checking relays and fuses. The truck then threw a throttle body position code. They checked the throttle body and the mass sensor was getting proper power. But in the process they noticed the throttle body wasn’t responding to the gas peddle position either. Theres other stuff they were checking in correspondence to that. I wasn’t there at the time so I can’t say. But we felt a new throttle body was it. They tried a new one. Didn’t fix the issue. So we sent the new part back and put my original one back in. They disconnected the battery and reconnected, tried the “reset throttle body position” procedure too. Nada.
They then checked power continuity throughout the wiring harness. So far. All was checking out.
I know they got help from a Toyota Tech at some point this week whom somehow determine the PCM/ECM was not responding property and was suspicious.

so here we are, waiting for a new brain.

 

Not necessarily, most Immobilizer systems just disable fuel not spark and on some vehicles the starter as well but not on these.

Hopefully that's it but we see very few ECM failures on these and I get skeptical real quick when I see a bunch of parts were already replaced based on assumptions.

 

I understand why you didn't think the "Play by Play" part was very important at first.
There are a few of us here on TW that have/do put a lot of time and effort into helping others.
And time, and time again, we get halfway into a 3 day diagnosis, only to find out "other stuff has been done".
And often times, replacing parts just makes it harder to diagnose. Even more so when the parts are aftermarket.

If the shop got with a Toyota Tech, and the process of elimination, and diagnosis was done.
Then sure, the next step is an ECM.

But I/we didn't know how you arrived at the ECM being bad.
Hopefully that is it. And you get the truck back up and running.

Let us know the outcome.