NEED HELP BAD-NO CODES, CEL-on, Rough Idle, Hard to Crank

Thanks. I have done that, actually I just recently got a new battery because the old one would go dead so I would take it out to charge it for a few days and then put it back in after I made a repair to check if the repair fixed it. Yesterday after i put the ECT sensor on and got inside to crank it I had the scanner hooked up, and it started idling perfect and everything was communicating, the 02 was going up and down, the short term fuel trim was adjusting, no CEL, i thought well that was it, I revved the engine and it responded great, came back down to normal RPM's but about 10 seconds after that it started idling rough, and rich again, it is acting like it's getting way too much gas, like it's flooding the engine.

 

97 3.4 v6 4x4, no EGR..

 

Can you try the force it to pull a code? Pull battery for couple hours, then disconnect any sensor, scan before you even try to start it up. You should get the code for that sensor. And maybe other codes as well.
If you get any DTC, check freeze frame data for anything out of wack like IAT saying 50* and ECT way different as they should be relatively the same with engine cold.

 

That's what's strange too. I have disconnected all kinds of sensors on this thing, while it was off, while it was running, I can't get this scanner to read ANY codes on this truck, it reads them fine on my 08' Sequoia, and my daughters 09' honda fit. I will do it in the order your saying and see if that lets me pull a code, any sensor in particular? The MAF is easy to get to, also the IAC valve.

 

Hey Glamisman, didn't know if you saw my post about putting on the MAF sensor. No change. Wont stay in closed loop. Keeps going in closed loop for like 1 second then right back to open loop. wont read anything for the sensors if it's in open loop.

 

Glamisman told me how to unstick the ECU but advised it could brick newer ones so maybe he will chime in as to whether or not you could do it.

 

Not sure what that means. I bought a fuel pressure tester and a Infrared thermometer today. I'm going to try and test the fuel pressure at the rail on Saturday to see if I'm losing fuel pressure (maybe a leaking/open fuel injector) and the thermometer is to see what the temperature differential is on the catalytic converter to see if maybe it's causing some issues. Other than bad injector/s, bad cat, or bad ECM, I really have no clue what else it could be.

 

My terminology’s bad
It’s a hard reboot of the ECU
Understand that it comes with a risk of damaging the ECU
Disconnect the battery
With thin gauge wire connect pos and neg cables to each other and let it sit. This will drain all capacitors in the ECU and the rest of the vehicle as well.
Then after a day put battery back in then run scan.
It worked in my 95 and gave me code 115 without starting the motor.

 

I actually tried this yesterday. (I did it on my 08 sequoia a while back that was having weird issues with the radio and it actually worked.)

So I disconnected the battery terminals, and hooked the positive and negative cables together with a 10" 3/8 socket extension, but I only left it on for about an hour, not sure if that was enough time. Would love to hear if this is actually enough time or if I should do it again, or if it will mess up my ECU if I did it any longer.

 

I have googled and changed the search phrases to find out what is actually required for the Tacoma PCM to enter closed loop and I have come up with nothing. I have discoved that some people have an issue where the PCM stays in closed loop. I sure hope this isnt a crappy PCM.

 

Yes sir. I have been all over google and you tube. I know this much. It is running very rich, I think that is why when I punch the gas it tries to stall because it’s flooding the already rich engine, the symptoms have went away on 4 different occasions three of which I had disconnected the fuel line at some point in the system. I’m going to test the fuel pressure I hope on Saturday along with the temp differential on the cat conv. Do you think it would be a dirty fuel injector sticking open causing the rich/flooding condition and that may not allow it to go into closed loop?

 

Have you checked the plugs them selves? Are all showing as rich ( carbon fouled) on both banks?

 

Also, have you reseated the computer plugs? Not just at the box but there should be another set of master connectors. Mine were behind the glove box actually mounted off to the right hand side.
If rich is on all cylinders then that would rule out a sticking injector.
This is so much like what I went through, run good for a week or so the start hard missing and rich on all.

 

I pulled all the plugs to check the gap (I was told they didn’t need to be gapped at the store since they are dual electrode) and snapped a pic of one of the plugs. I have no idea if it’s good or bad. All of them looked like this and these are new they probably only have about 50 miles on them if that.
I did go behind the glove box and was jiggling the wires and harnesses gently to see if I could make anything change. Seemed almost like it at one point but after I continued I can be for sure. I also did this in the engine compartment looking for worn wire or something not connected well. Any thoughts on how this plug looks? They all looked like this. None of them were wet though.

 

Yep, looks like mine did. Erratic spark keeping fuel from burning. If it were injectors they would more likely clean and wet.
And if all are the same then the computer is getting mixed signals somewhere.

 

Damn
This is good one
I’m going to re read everything

Give an educated guess after trivia tonight

kiaser……do all plugs look the same?
that soot but white on electrode?

 

Yes all plugs looked exactly like that. None were wet. Once we get this figured out it will be a thread to save for all of history for anything 1st gen…I might even give the full story of this little truck I call Wally…

 

so should I disconnect battery cables and reconnect or jumper them for a longer period of time? Like 24 hours? Or should I just try to unplug every connector I see and plug it back in? Or both?

 

Not sure on time to drain caps. I did mine one evening and checked it the next eve after work. I have done this several times but my truck is older.
Like you, I am new to all this
These trucks are old and can be picky. Just the clip breaking off a sensor connector can cause these issues. I am more than 1000 miles since I changed out a few connector housings with only power steering issues .

 

In Summary kaiser
-4yrs sitting
-flashing CE
-no communication for codes to be read
-sporadically works/then same issue
-PCM resets(so far) no changes
-all plugs sooty, but the same

Bc of fired parts cannon to no avail, not mechanical

however
The 1st bullet point
Sitting 4yrs…….
Bc of the irregular on again/off again crap…..sounds like text book results if a mouse munched on some pretty GD important wires

I have seen lil mouse houses inside HVAC boxes/fan shrouds before
The PCM/harnesses are just below

I knew you said you ‘shook’ some wires back there
I would def dig deeper visually in that area
My 20min re-read and guess
GL