275k

Daughter's '03 V6 started and ran fine on Sunday and Monday.

Strong crank, no start this evening.

Threw knock sensor and cat efficiency codes

Fuel guage inop last six months or so.

Has been start and running fine otherwise

Could be a fuel pump.

Or may be out of gas.

Has oil? Or oil pressure sensor.

Does the tach move when cranking? If not, could be the crankshaft position sensor. Not too familiar with those engines but the camshaft position sensor is another usual candidate in a crank but no start scenario.

Timing belt intact?

Remove the air filter, spray starter fluid into air intake tube as someone cranks the vehicle. If it fires up and tries to run, it's going to be fuel pump relay or fuel pump.

Has fuel

I'm thinking (hoping fuel) pump or relay.

Knock sensors are an absolute pain to get to

Oil is good. Just changed. Checked on no start

akaggie05 said:

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Does the tach move when cranking? If not, could be the crankshaft position sensor. Not too familiar with those engines but the camshaft position sensor is another usual candidate in a crank but no start scenario.

Timing belt intact?

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'03 V6 has a chain, not a belt.. I'd definitely start with Buddy's idea and knock out all the easy things first. If it's not a fuel problem it's the ignition system :/

Ok fooled with it a little tonight. Didn't get s chance to grab any starting fluid, but my scan tool had a PID for fuel pump and relay.

Both came back "good" via the tool fwiw.

Will try the sf tomorrow

Had thermostat replaced a couple of weeks ago at the shop and had them do the upper intake gasket.

Wondering if the messed up something on the wiring for the knock sensors and now the e u won't fire the ignition since it can't see the sensors.

Will check spark tomorrow too.

I don't think knock sensors are usual culprits in no- starts. Cam and crankshaft position sensors are a different story.

If I remember correctly that year may have an external fuel filter. Has it ever been changed out. A clogged filter will also result in no start condition. The fuel pump will be good, but the clogged filter will stop flow to the engine.

Did you read akaggie05 post? Keep guessing, or check their recommendation.

Tach moving? That's the first thing you should check. C'mon, man.

Tach moves.

Registers <50 rpm

fuel and good fuel pressure from the tank.

no joy with starting fluid at the TB. Best place to start diagnosing spark?

Had a suggestion over the weekend to get a new key made as the chip may have dropped its code

Have you pulled a plug wire and put a new plug on the end and have someone spin the motor to see if it sparks ?

Next on the list.

I'm almost certain I won't get anything since the starting fluid was unsuccessful, but will try that before attempting to chase electrical gremlins that might be causing it.

spark. Still no start

Did you try a different key ?

Is there any kind of aftermarket antitheft on the vehicle ?


I had this issue once with a 2005 4runner and i disconnected the battery, reconnected, locked it from a different remote, and then unlocked from the remote. The person had locked it with a different remote, then the transmitter went dead so they used the key to unlock it and the vehicle would spin over but not start.
If you have a second transmitter, i would disconnect the battery, then use that fob to lock it, then unlock and try to start

Did you check all the ground connections?

Did the knock sensor code only show up after they worked on it ?

My hunch is the harness, plug or wiring may be damaged on the knock sensor, if not from the repair than from possible mice chewing on it.

JP76 said:

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Did you try a different key ?

Is there any kind of aftermarket antitheft on the vehicle ?


I had this issue once with a 2005 4runner and i disconnected the battery, reconnected, locked it from a different remote, and then unlocked from the remote. The person had locked it with a different remote, then the transmitter went dead so they used the key to unlock it and the vehicle would spin over but not start.
If you have a second transmitter, i would disconnect the battery, then use that fob to lock it, then unlock and try to start

Did you check all the ground connections?

Did the knock sensor code only show up after they worked on it ?

My hunch is the harness, plug or wiring may be damaged on the knock sensor, if not from the repair than from possible mice chewing on it.

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Wouldn't all those issues kill the spark? He's got spark. He's narrowed it down to a fuel problem.

Thought he had fuel and pressure too ?


"fuel and good fuel pressure from the tank.

no joy with starting fluid at the TB. Best place to start diagnosing spark? "

Knock sensor ******s the timing, perhaps it is too far ******ed to start ?