Tested everything as you suggested. Yes there's 12V at every injector on the B-R wire and I believe I just figured out why I wasn't getting 12V at the ECM. I went off of the original picture I posted to determine which pins but just realized there are more plugs in the picture than there are on my actual ECM. I went back to the service manual and found a wiring diagram from the injectors to the ECM, finding the pins with the wire colors given on the wiring diagram and I am getting the correct 12V at the injector pins ECM as well. ����


Yes the battery was disconnected when the work was being done.

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It's been a couple years since I popped the hood on this project. I know I replaced the plugs at the beginning but pulling them today, they look pretty bad and even though they're said to work, I can't figure out for the life of me why I would've gotten platinum. I usually stick to oem with all of my Toyotas. I even have record of using ngk BKR5EKB-11. I'm going to swap them out for peace of mind.

I was able to get it into closed loop and get the fuel trims. I attached screen shots of the various readings I was getting. The CEL was flashing because of the misfires and once it stayed illuminated the fuel system would stay in open loop.

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Finally being able to get the fuel trims makes it obvious what I originally posted is not the issue. If it's been over compensating the fuel,I now know how the plugs got to looking that way. I'm mostly certain it's not the MAF due to having tried multiple, new and off of a working vehicle. Even though I've replaced all vacuum lines, took the intake manifold down to the heads to assure everything was sealed and have done spray test for vacuum leak, I haven't done a smoke test so I'm thinking that would be my next best step to take. Any other input from those of you that are knowledgeable on troubleshooting?

I've never had any issues with fixing the mechanical side of the known problem, it's the troubleshooting that I'd like to gain more knowledge on.

Since the black on those plugs goes up the threads, that hints at an oil issue, not a running rich issue (though maybe it still is just running rich). The correct Denso plugs work just as well as the correct NGK plugs. Most 5vz's came from the factory with 3 of each...

What year is the truck? Since you talked about the wrong ECU pinout, I'm assuming you have a '96-'98.

Interesting to see such bad short term trims - but I guess the long term trims just haven't had a chance to adjust yet since it hasn't spent much time in close loop.

It is easy to miss the air assist hose, so maybe that's where your air leak is coming from (if that is the issue!). I suppose it could also be a bad O2 sensor always reading lean, so the engine over-fuels? Stuck injector(s)?

-Charlie

It's a 98.

I did a smoke test yesterday and I have smoke coming from the iac valve and slightly out of the PCv grommet.
It's not coming from where the iac valve meets the throttle body but from where the plastic piece with the plug meets the body of the iac valve.
Not sure if it's related but if I have the vehicle over 1300rpms either by using the pedal or adjusting my throttle cable to increase the idle, the misfire seems non existent and I don't have a flashing cel at higher rpm. I am going to run some test on the iac valve that I found from Timmy the tool man and if everything checks out, see about resealing where the smoke was coming from to rule that out. I'm not sure if the iac is as sensitive as the MAF sensor but I did take the iac valve off and clean it when I was doing all the original work.

I've confirmed it's not the injectors through swapping them around and also having the ones I have on sent off and cleaned and tested.

What's the best way to test the O2 sensor? Can I tell from the readings on my obd data?

I've confirmed all the vacuum lines are plugged in multiple times and I'm sure of that. However, even though I labeled everything, I have questioned if I accidentally hooked a hose up wrong. I feel like they only way I can confirm this is by having someone with the same vehicle come by to compare. I haven't found any diagrams that have been very helpful.

I appreciate your input

And OBD-II reader that does live data should be able to read the ECU's version of the O2 reading for the main and sub O2 sensors. That will be a start. You may still need to break out the multimeter to be 100% sure.

The sticker on the hood should cover *most* of the vacuum lines, though not all...

-Charlie

If the upstream sensor hasn’t been replaced in a long time, or if you don’t know the last time it was replaced, I would just put a new one in as part of preventative maintenance. Denso p/n 234-4162 (or 234-4161 if manual transmission, different length wiring harness on the sensor).

I'm going to give this a go when I get back to it, since it's past due anyway. I've been told that wouldn't cause it by more than one person but also the one thing I haven't tried. I'm not coming across any record of testing the O2 sensor and don't recall if I did either. Now, being able to get my fuel trims and doing some research I'm learning the O2 sensor could cause the exact issues I'm having but seems I should be getting codes for more cylinders. I didn't check my pending codes to see if maybe there were other cylinders pending.
Appreciate your input.