almost but not quite
 

...driving to work at 1:45 am and just pull onto the highway when the engine dies! I coast to the shoulder. Like an idiot I didn't have a 'break-down kit' (emergency stuff in case of a breakdown). The truck was sitting a little too close to the highway so I crank the wheels to the right and give a push. My truck then rolls down an embankment into some brush and small scrub trees (remember it's early morning and I'm w/o a flash light). Well, I'll let AAA resolve that problem when I get off of work.

The truck turns over easily but it just won't run but for a few seconds. I figured I had a faulty fuel pump and/or filter. When I finally got around to it, I lifted the bed and pulled the pump. I hooked the pump to the battery and got nothing.Picked up a new pump, replaced the bed and fired her up. Runs for about 5 seconds. It would take me
forever driving to work in 5 second intervals so I replaced the filter. Stll NO change:-( I've got 13+ volts at the battery, the EFI relay meets specs and I'll check the the circuit opening relay when I find it:-/ I could use some guidance/ recommendations so I can get this truck ('99 Taco 4x4 w/5vzfe &
auto tranny) back on the road. Thanks

Pray tell just what are you working on here ??

Since it is in this section I am guessing A OBII vehicle??

Has your MIL turned on ?? Have you pulled any codes just in case ??

Most times if it starts and shuts off the ECM is not seeing a signal and shuts off fuel to a engine it thinks is not running

Some that come to mind are the Crank Cam sensors and Igniter circuits

It says at the end of the post. '99 V6 Taco.

Does it stall abruptly or does it stutter at all before it quits?

Does it restart fine, but only run briefly before stalling again?

Hey Pineapple

Can you briefly let us know if the starter cranks the engine? Also do you hear the fuel pump humming when you put the key in on ON?

So, from what I understand, sounds like you may have a broken ground/wire on one of the solenoids. I had a similar incident on a 4runner, also on the highway - the 4Runner engine stops running (no warning sign, just turns off) suddenly when cruising at regular speeds, then it came back on briefly...then again turned off. The starter cranks the engine fine.

Try gently pulling on the wire harnesses that are going to/away from the solenoids. It may allow the engine to run when you start it, but it wont actually fix the issue and most likely will happen again.
If you are ok working with wires, you can manually add a ground wire to the the solenoids' ground connection to see if it will work.
But do trace the problem with a volt meter for continuity.

Let us know.

Sorry for he delayed response. Had to go to FL to check up on my 91 yr old mom who still insist on doin' things like climbing ladders to paint trim, etc:-/

Got back last night and noticed I've got some mowing to do after a week of rain:-/ I did replace the fuel pump and relay before I left (both failed and/or weren't up to specs).

Truck cranks normally and will 'run' for 3-8 seconds before dying. Plan on lifting bed to see if I 'flubbed' the fuel lines some how as soon as I finish mowing. Thnx for responding.

the saga continues:-(
 

It's been a little over a week and finally got time to work on theTacoma. Lifted the bed again to access the fuel pump. It's operational. EFI relay (under the hood) was within specs. Replaced the circuit opening relay (located under dash near steering column) which was not within specs. Also replaced fuel filter (250 K miles on old filter) and it still turns over normally and RUNS for three to four seconds then dies. :-( All of the fuses checked out (not only visually but checked w/ meter also).

Question: shouldn't you be able to blow air through the fuel filter? I tried w/ new one but couldn't.

Question: I'm embarrassed and red faced, but the small end of the fuel filter should be pointing toward the front (engine)?
Any help/suggestions are appreciated. Thanks

I'll add my vote to @Wyoming9 for Crank or Cam sensor. The fuel pump does NOT run with key ON, as a post stated above. It only runs while the starter is cranking or the ECM sees that the engine is turning. If it doesn't get those crank/cam signals, it thinks the engine has died and cuts the fuel pump. Fits the case perfectly. I can't think what else does.

I'd hitch a test light to the Circuit Opening Relay and see if that is what is happening.

continuing saga
 

A month or so ago I had to cut off my alternator belt to gain access to the alternator's adjusting bolt which somehow seized to the alternator (the bolt head had 'snapped off'). I had to remove alternator bracket/s to remove it from the engine bay then take a sledge to hammer to tap out bolt that was seized in he alternator's lower hole. I am glad this isn't my DD. As per Wyomin9, checked cam and crank position sensors...were within spec. As per Durk I checked circuit opening relay...was out of spec so ordered the relay AND cam/crank sensors and fuel pressure regulator from RockAuto (Taco has 206K+ miles). The components they sent had Denso on them:-)

I'd just removed the plenum to access the fuel pressure regulator and injectors. I removed the wiring harness from the injectors and checked them w/ meter...all w/in spec. I didn't pull them out yet for a DIY cleaning. I placed noid light into the harnesses while wife cranked engine and the noid just barely lit up. The Fluke read below 1/2 volt at each harness. Plan on checking the ground/s.

What's next?...computer (ECM)? The Haynes manual doesn't offer much insight for the computer. Is there a way/method to check it w/ basic tools? Any suggestions are appreciated even if I have to back-track. THANKS

So I did some backtracking for ya, read Wyoming's suggestion on the igniter...Worth checking. Though after reading someone else's case very recently with similar symptoms as yours, I kind of doubt it (he replaced igniter and problems continued), but you never know.

KPV mentioned solenoids so that may be also something to look into. I doubt the ECM be giving you trouble, from reading it usually would give other issues aside from the engine shut-off.

Oh, may as well repeat, be wise to have a second vehicle for this issue, sure you can understand the danger, just to throw it out there.

Every saga has an ending, so we're all eager to know how it turns out for you. Good luck!

Here's a better link (though a bit troublesome to load) that may provide clues to what is going on if you still have issues after replacing the sensors, relay, and regulator...gotta say electrical is a PITA to troubleshoot --
http://www.pirate4x4.com/forum/toyot...t-down-me.html

Well, I finally got it "up and running" yesterday! I had sent the ECU to a shop to be checked and it came back w/ message 'no shorts or open circuits ...' so I reinstalled it. I inserted the key, not expecting anything to be different (crank/ no start), and VROOOM! The Taco came to life. Couldn't believe it.

As stated in posts above I replaced the cam and crank position sensors even though they were within specs because I broke the brittle plastic accessing and testing them.

Well, I can finally get some chores done w/o wrecking the family cars!