Engine shut off while driving?

[Zam15]

Two days in a row my engine has shut off when driving... I am not happy about that nor are the other drivers. Very dangerous

I have a very well maintained 3.4L V6 2004 Tacoma.

The truck gives me no sign that the engine is going to die until it shuts off completely. It leaves all the accessories functioning fine and the only way you can tell the engine is off is because you see the RPM drop and can no longer hear it running. I come to a complete stop after using my momentum to pull over (just whet through an intersection). I disconnect all my accessories and it seems to run fine until the next day it shuts off again when driving on the freeway.

Any ideas on what might be causing this?

My main thought are:
Alternator
Battery - Tested recently as "good"
Fuel pump


Thanks for the advise!

 

[Ryanmb21]

This just happened to my buddy with an '01 4runner. His shutdown on the highway going 65 mph. In his case the radiator had ruptured and this caused the engine to overheat. The towtruck diagnosed at as low fluid in radiator an added some water. He was able to drive 50 more miles by adding water.

He took it in had the radiator replaced. Two days later, check engine light. Blown head gasket, still in shop.

Be careful, good luck

 

[Louisd75]

I had something similar happen on my '02 Tacoma once on a road trip one night. Engine quit right after taking it out of cruise control. Could not get it started again though all of the accessories still worked. I checked the obvious, we had voltage and fuel pressure. The engine would turn over but not start. Finally had it towed to the nearest dealership. Talked with the dealership the next morning and they said it would be a short while before they could look at it. Just for giggles, I went outside and tried starting it, and it fired right up without any hesitation. They did a scan on it and it threw no codes. I've put another 30k miles on it without a recurrence.

 

[keezer37]

You need to call up your fault codes. I'd have it in the shop immediately. With it just shutting down while driving and you loosing your power brakes/steering, you could put yourself in a very regrettable situation.
My opinion is neither your batt, alt, or fuel pump would do this as you describe.

 

[corax]

you don't have an after-market alarm with the starter disable relay wired into the ignition / injection or anything silly like that, do you?

with the engine running in your driveway, pop the hood and start giving every bit of wire harness a gentle pull and a twist - if anything happens, make a note what you were touching at the time. You might also want to tap on parts with the plastic end of a screwdriver to see if anything drops out

 

[4x4x4doors]

Intermittent problems like this are a b**** to diagnose. You have my sysmpathies.

Modern engines are designed to protect themselves so an intermittent indication (not necessarily the fault) of overheating or loss of oil pressure would cause a shutdown but you you should be getting an idiot light or trouble code if that were the case. But I'd check the oil pressure and temp sensors to eliminate them.

A short in the ignition circuit to the keys would likely kill the accessories as well. This would also be true of the battery/alt.

I think I'd start by checking connections electrically, including the plug to the engine control computer. Be especially mindful of the battery terminals (is that a side connect? they can feel tight and not actually be so disconnect and reconnect).

A fuel problem seems most likely to me. Running out of gas (either through empty tank or disruption of flow) in a modern vehicle seldom gives any warning as was typical in a carb'd engine and will likely give no clue after the fact.

(I'll leave out snarky comments about the brand involved although I know that wouldn't stop some.)

 

[1911]

It's almost certainly a short somewhere; like Corax said start with everything that's ever been added - winch, stereo, off-road or fog lights, cb/ham radios, absolutely everything that's not bone stock from the factory. 99% chance that's where you'll find the problem. Last case like this I knew, it turned out to be the main power cable for the winch was not in conduit and the insulation had worn off, allowing it to short where it touched the body going into the engine bay (this on an FJ Cruiser).

 

[Zam15]

you don't have an after-market alarm with the starter disable relay wired into the ignition / injection or anything silly like that, do you?

with the engine running in your driveway, pop the hood and start giving every bit of wire harness a gentle pull and a twist - if anything happens, make a note what you were touching at the time. You might also want to tap on parts with the plastic end of a screwdriver to see if anything drops out

I do have a fuel pump cut off (Master Lock Starter Sentry) but it has never given me any problems.

It's almost certainly a short somewhere; like Corax said start with everything that's ever been added - winch, stereo, off-road or fog lights, cb/ham radios, absolutely everything that's not bone stock from the factory. 99% chance that's where you'll find the problem. Last case like this I knew, it turned out to be the main power cable for the winch was not in conduit and the insulation had worn off, allowing it to short where it touched the body going into the engine bay (this on an FJ Cruiser).

I disconnected all my positive leads going to everything but the stock equipment and it still happened. It's difficult as heck to figure out what item might be causing this problem.

No check engine light ever went off but I will have them check for codes.

Thanks for all the good input. I have never had a single problem with the truck so this breaking down thing is new to me... Guess I have to think like a Land Rover or Jeep owner :ylsmoke:

 

[1911]

If you've positively eliminated every single piece of aftermarket wire, then the first thing in the stock wiring harness I would check would be the fuel injection relay.

 

[Mattm94]

I do have a fuel pump cut off (Master Lock Starter Sentry) but it has never given me any problems.

This is the first place I'd look... I think it's likely it's given you problems exactly twice.

 

[Mr. Leary]

I had the exact same thing happen to me out near Tulsa, OK shortly after I bought my truck (99 4Runner). After combing through the truck at a local shop, we isolated a short in the fuel pump wiring (after dropping the tank). The truck never threw a code, just shut off and would not start again. We fixed the short... and i've been driving it ever since.

 

[Plannerman]

If you've positively eliminated every single piece of aftermarket wire, then the first thing in the stock wiring harness I would check would be the fuel injection relay.

This happened to me on an older Ranger I had. A few hundred bucks later, the mechanic traced the short the fuel injection system.

 

[teotwaki]

just to add to the swirl......

I had a 1996 Lexus (Toyota) that would shut down suddenly, especially on hot days. It became intermittent on start up too. Turned out to be a crankshaft sensor and a camshaft sensor messing up the the ECM. No codes were ever detected.

 

[Zam15]

Just got back from the dealer.... They have no idea... Guess I'll just keep driving and see if it happens again. :snorkel:

 

[go4aryd]

Make sure they check the MAF sensor -- I have heard of those getting dirty/damaged and it can cause a non-coded shutdown (IIRC). Others with more hands on experience may have more input.