Crank but no start no fuel no spark

My 2000 tacoma 3.4 v6 will crank but no start ,no fuel, no spark and not seeing rpm on gauge crank censor tested good and cam was runninf great when turned truck off this happened once before a week ago but it finally started up but not this time been troubleshooting it for three days fuel pump is good also

 

EFI relay and fuses good outside in fuse box? Does the check engine light come on?

 

Yes, check any fuses related to the engine/computer. Also, check wiring.

Without spark the computer won't fire the injectors, so focus on the spark problem first. Computer needs input from crank and cam position sensor to fire the spark plugs. And without the spark plugs firing you don't have a tachometer signal, so that makes sense.

 

I have checked relays and fuses and all are good and the check engine light does not come on at all

 

did you verify there was no fuel or spark? or just because it wont start you think theres no fuel or spark?

 

Yes I did varify and tested coil packs and pulled fuel pump to test it both are good

 

ecu controls a lot of stuff...

 

I thought maybe it could be ecu going bad

 

does it turn over easily or is it struggling to turn over? I was thinking maybe a weak battery.

 

Turns over fast and the battery is new

 

This may seem like a bit of a WAG, but I would ensure the timing belt is not broken.

 

If the check engine light does not come on at all, I think that's your clue (provided, of course, that it did illuminate before this failure).

 

No CEL is a clue to what? This is difficult to troubleshoot. Have had a similar situation with a honda Crv . Cranked well, had spark but no juice. Turned oit to be the ignition switch. It would not allow injectors to ground and no opening of them.

 

The CEL not illuminating is an indicator of an ECU power problem, kind of. I have seen instances of the wiring to a CEL being bad, a bulb being out and one dude put a piece of tape across the inside of the instrument cluster(non-Toyota) to hide the light being on all the time.

Here is a wiring diagram for an 2003 3.4... it should be really close. Verify the power and grounds... especially the grounds. I would start with the grounds at the reinforcement rod that comes up on the drivers side of the upper intake to the block... there are 2 grounds there and they ground pretty much everything... they are kind of small diameter wires.

not being a jerk here... you do have and know how to use a digital volt ohm meter and have a test light? Along those lines, the igniter will only fire if there is more than 9.5 volts... I could be off on that, it has been a while since I had a non-opp toyota.

Is ther any signs of mice or rats under the hood... those little bastards can ruin your week with an over night snack on your wiring. fwiw, they used to make the wiring insulation out of a soy based component and those little guys think that it is edible.

 

Yeah, with key in ignition and turned to on, but engine not running, the MIL should be illuminated. If it isn't, then the ECU won't fire the coil packs or the injectors. A safety thing, I think.

 

Preach brotha, that's gospel right there

 

I am glad that someone caught that... the ineternet usually doesnt convey humor very well.

 

I do have a test light and a multimeter and can use them that's how I've been testing everything but so far all censors coil packs relays fuses connectors and grounds have been testing good

 

if all of the places that require power have power and all of the places the require grounding have a good ground then the highest probable replacement part is the ECU... disconnect the battery and unplug and replug the ECU connectors and see if whr starts then... sometimes, sometimes, the connections require a reseating. In all factory service manuals I have read the very last line on the component test proceedure is ... replace with known good unit. Yeah, like the parts department is going to keep $1k ECMs around for testing purposes...

 

Go thru and check all the power at the ECU for power and all the grounds for continuity to ground.