Multiple misfires after rebuild ** FIXED **

Thanks so much. I have a plan: I ordered a new ECU, it was fairly cheap, and a new wiring harness, also pretty cheap. I figure, I plan on keeping the truck forever so it might be good to have some spare parts if my ECU and harness are good. I am going to disconnect the alternator and swap the ECU, the easiest thing to try first. Then I will go with the wiring harness.

I really appreciate all you guys help and suggestions. This has been a journey, hopefully I am getting to the end, but I will get there at some point.

 

I'm sorry you have this mess. I never cease to be amazed by the solidarity that members here have.

Good luck, sorry, I have no suggestions.

 

I just turned the ignition on with the engine off and the battery light was on, with the alternator connected. Should the battery light turn off with the ign on and the engine off?

 

With the alternator connected, IGN ON/ENG OFF, it's normal for the Batt light to be on, along with a few other indicator lights.

Under normal conditions, the second I turn the key to IGN ON, all the below lights are lit.....after 3 beeps?, the ABS goes out and after 5 beeps?, the AIR BAG goes out. The SEAT BELT simply continues flashing and BATT, A/T OIL TEMP, CHECK ENG stay on steady !

from my 04 IGN ON/ENG OFF....

 

Ok, I unplugged the alternator and the battery light was not on with ign on eng off. It still has the same misfire though with the alternator disconnected.

 

What’s odd is when I run the truck without the alternator plugged in the battery light doesn’t come on. Shouldn’t the ECU notify me somehow the alternator isn’t working?

 

It may only come on once the voltage in the battery drops.

 

My experience in the '06 supports this theory.

The alternator shorted, was 100% not working. I noticed battery was lower than normal a few blocks into my ride, and continued getting lower as I drove to work. Batt light didn't come on until it dropped below like 8v-9v, and at that point I was pulling into the LAPS (NAPA) to get a new battery.

After installing the new battery, the added voltage caused something in the alternator to get red hot and catch fire. That was a fun day.

 

I have the connectors to the ECU out in the engine bay. I want to test for continuity between the ignition coil and the ECU. Which pin do I use to test? Which pin should go to the coils?

 

Just did some checking and looking at the EWD. I was wrong earlier with this statement....

The warning light will not work with alternator not plugged in, it needs pin 1(yel-grn) to even work.

While checking the backside of the Instrument Cluster and IGN ON/ENG OFF, one side of the charging light bulb is 12vdc and other side sees a GND, light on. With ENG ON, altenator working, one side of bulb is still 12 volts but other side instead of a gnd, it's 12vdc also....2 hots, no current flow.

I'm pretty sure that's why I have seen some folks saying we can not change our incandescent charging light with an LED.

 

It’s normal. The internal regulator is the alternator is what turns the battery light on or off. The ECU does not control the alternator on your truck.

 

So here are the actual spark tests:

https://youtu.be/uDHM98B8l78
https://youtu.be/ovCU0pvmTKA
https://youtu.be/ZWoEUolKGeU
https://youtu.be/W7XJHJR6Fpg

 

They seem good to me. The only thing I didn’t do was swap all the injectors from one bank to the other. Should I do that?

 

So I swapped all the injectors, same issue. While I was in there I checked the intake manifold bolts. They were a little loose so I was hoping that was the issue. Apparently not. What is odd is that while I am driving it there are no misfires in the live data. Only at idle or when I am stopped. And now it is just a couple. I am still quite baffled by this. I am back to my thought about driving it more. But I just don’t know.

Oh, and my speedometer and odometer don’t work. Any suggestions on what to check?

 

Idle air control valve, maybe? Is there one on the 2UZ-FE?

 

So I took it for another drive and now I am getting a P0100-MAF error. Do you think this could all be because my maf died?

 

Nevermind. I just took it around the block again and the only code I have is a P0330 knock sensor. Probably because the idle is so low it is shaking the engine and car and the sensor thinks it’s knock.

How do I get it to idle higher?

 

Well, I cleared the codes and took it around the block again. I got the knock sensor code but no misfire codes. Could the knock sensor be confused because I have open pipes and it is LOUD when I drive?

 

One thing to remember is that the codes are the ecu’s best guess at the cause of what it is seeing. I would get the fsm procedure to check the MAF and the throttle position sensor as well.

 

Take it out of drive and put the vehicle in neutral when you come to a stop. Won’t increase rpms, but it’ll take the load off the drivetrain.

I would also recommend a bottle of dry gas.

 

Thinking outside the box, does your truck have an EGR valve? If so start the truck and let it idle and smack the egr with a dead blow hammer or like item. Old trick from years ago.

My gut says your issue is something that was removed and reinstalled in the rebuild. Not that my gut has not been wrong. But I keep thinking that’s where the issue is.

 

Anything that measures air (MAF), meters air (throttle body, IAC), measures combustion on the back side (O2) could be the culprit.

 

The maf code is gone. I disconnected the maf while the truck was running to see what happened and it died. I’m sure that’s why the code came up. I cleared it and it’s not back.

One question, how important is it to tighten the crank bolt to the correct torque settings? I only used a little impact gun on it and forgot to tighten it all the way. Could that be affecting the timing gear at the crank?

 

I don’t believe it has an EGR valve, but good suggestion. I agree with you, but I don’t know what it could be.

 

Its important that it not come off...but the keyway will keep it in time until that happens.

 

I can’t find an idle air control valve. I found an idle control valve but it is expensive and I don’t know where it lives.

 

Just following up, I drove it to the muffler place today and I got 2 codes, knock sensor (I hope it will go away once I get an exhaust) and P0500 - VSS fault (which makes sense since my speedometer and odometer are not working. No misfires which is great. I wonder if tightening up the intake manifold did the trick.

 

So where do I find the VSS? Is it the one in the wheel hub or is there one in the transmission?

 

This is a little like performing surgery on someone that took an ass-full of #9 shot out of a 10 gauge.

 

It does feel a little like that. Hopefully the issues are almost all gone.