blinking CEL, engine stalls. Works fine a few minutes later

I am having engine stalls that seem to only happen after the truck is warmed up. It is a 2004 4-cylinder Tacoma with 220,000 miles.
When it happens the engine stalls completely while driving. The check engine light blinks while it dies and when it is dead there are no codes or check engine light. The engine will turn over but wont start until it has been a few minutes, then it starts up fine and drives like normal until it happens again.
I checked the plugs, tested the fuel pressure (45 lbs steady) and replaced the fuel filter. After that I drove it for almost 30 minutes before it stalled again.
I have been doing some reading and it sounds like there are a million things that could be causing it. I don't know where to start. Any help is appreciated!

 

Usually a blinking CEL means a misfire and unburned fuel is going to hit the catalytic converter and overheat it (damage/melt). Blinking means stop and turn off engine as soon as is safely possible.

I can't diagnosis your problem, but likely ignition or low fuel pressure is causing misfires and then stall.

Someone else with a 2004 repair manual might be able to tell you if blinking CEL could mean something else.

 

This just started so did anything happen??

More Water then normal ?? A really hard landing ?? Do any work to the truck??

So after this happens there are no stored codes??

This is not good.



Most often the blinking light will shut the fuel off that being why the engine quits .

The blinking light being The Danger Will Robinson trouble code

I would look at the ECM ground and ECM itself

The Igniter circuit

The Cam and Crank sensors

A problem in any of these areas will shut the engine down because the ECM is not seeing the feed back telling it the engine is running

Sounds like a loose connection if it was heat related it might take longer to restart

 

Thanks for taking time to respond! Replies in red

 

I've had these same symptoms before where it only happens intermittently after car and engine is nice and warm and also on hot days, although not on a Toyota.

It was on my old 93 Civic where the fuel pump relay would occasional crap out because of the dry solder joints. It would usually start back up after letting it sit anywhere from 5-10 minutes.

The fix was to open up the relay and just add some new solder to all the joints.

Since @Wyoming09 mentioned that the blinking CEL light means fuel has been shut off, I think my theory could be feasible.

Might check the relay which should be above your knee area, green colored relay I believe.

 

There is a CIRCUIT OPENING RELAY located in that area. I can test it with an ohm meter. Did your relay show bad even though your problem was intermittent?

 

At the time, I stumbled upon this page which described my issue pretty well.

http://www.diymyhonda.com/civic/hard-starts-main-relay-repair/

I used that as a guide to pull out the relay, open it up to visually inspect and confirm that the solder joints had cracked.

Took a few minutes to resolder them and issue never came back.

 

there should be a code stored in the "pending" catagory that is viewable with an ODBII scanner. If nothing is there this is going to be tough to figure out. When it happens again you are going to have to check for spark immediatly. If you have spark that leaves fuel and like mentioned above if the pump is on the way out and fuel pressure drops while driving it will go to lean and that flags the CEL.

 

I checked the EFI and CIRCUIT OPENING relays and they both seem fine. I am thinking of shorting out the FP and B+ terminals on the CIRCUIT OPENING Relay socket to see if that makes a difference. I tried to check the ECM ground but couldn't find it. I reseated the connectors to it.
Does the mass air flow sensor control the CIRCUIT OPENING RELAY? If not what does?

 

ECM ground on the 2RZ is on the coil bracket.

 

You do have a Code reader ??

The fact you have no pending Codes even though The ECM caused the light to blink does not bode well .

A no fuel or low fuel pressure should not trip the blinking light.

 

the only other thing I can think of is if the PCM is loosing its power while driving, rare, unless the wiring in your truck has been butched up. A OBDII scanner will tell you if the PCM has been reset by a P1000 code. To verify this theory, create a fault, unplug the MAF and fire her up and the CEL should pop on. Verify that a code has been created before you turn the key off. Shut her down, hook up the MAF and drive her. When she stops next time scan her. if there is no code then she is loosing power and is self "resetting" and you should see another P1000... hope this makes sense to you.

 

That is why I suggested checking the Ground of the ECM they can be a little touchy.

In the past I have run a #4 wire from the negative battery terminal to the Ecm ground to cure issues

 

The car has four coil packs. I don't think the ECM ground is there.
I also cleaned the throttle body and the MAS airflow sensor.

I can try that.

 

This might be it. Passenger side fender well. In the service manual is says EC ground.

 

So I cleaned the ground in the picture above and the chassis ground. disconnected the MAS, started the truck, got the P100 and P110 codes. turned off the truck and reconnected the MAS and drove around for 10 minutes until it stalled again. Afterward the P100 and P110 codes remained. Got it to started drove home and the CEL light is still on.

 

Tried running it with the circuit opening relay bypassed and no change. I called my local shop and they said they were too busy to look at it right now, but based on what I am seeing they wouldn't know what to fix...
Any other ideas?

 

It seems like all the circuit opening relays Toyota uses from this era work like this. They are always on while cranking the engine. They are on when the ECU supplies a signal (grounds a terminal of the relay from FC terminal on ECU). The ECU only supplies that ground signal while the ignition is sparking. If that signal is shut off the relay will stay on for about 1 aecond then shut off.

The trick of jumping Fp and +B and the check connector doesn't always work. It seems like Toyota took that wiring out of the harness even those you might still see the metal terminals in Fp and +B.

Another way to turn the fuel pump on is to pull the starter relay then turn key to START. This will turn the fuel pump on without the noise of the engine cranking.

I'm wonder if the fuel pump is just getting weak and you're losing fuel pressure. I had an old Honda that would sometimes stall out and after waiting a few minutes I could start and continue on. A new fuel pump solved the problem.

 

On an old truck I had it would stall out when hot. Turned out it was a bad egr valve.

 

No, Toyota just labels the ground points with 2 letters. First letter, E=Engine compartment, I=Interior, B=Body. EA, EB, EC, etc.

I would guess the ECU ground is brown(?) and attached to the engine block somewhere, maybe under the intake manifold.