I tried to upload my copy of the connector diagram for the 3.4, but the pdf file is too large for Yotatech.

 

i have seen a unpluged coolant temp sensor screw up iat readings

 

I see now I was off. Wiring diagrams aren't my strong point for sure.... as you will soon see.

What does the "noise filter" do? Mine has one Red/Black wire and one Brown wire going into it. From what I can see, all the RB wires on my 3.4 source from the IG2 connection on the ignition switch. And all my B wires are ground.

So... to make the noise filter work, does it just need a switched 12v source and a ground???

Hopefully this is not to off the original posters topic.

 

Okay... I am either starting to get the hang of this or so far off track I shouldn't be disturbed.

I broke out the "noise filter" from a wiring diagram I dug up. Maybe this will help.



Bit hard to read... but may be of some help... as to the mysterious gray plug at least.

 

So apperntly that plug is supposed to be there and when in open loop its supposed to be -40C...

Now I have no ideas where to go next

 

Some where between the ecu and the MAF you have a broken wire, or you have a bad MAF (unlikely). Check and make sure that you have a good connection at the MAF. If so, unplug it and unplug the ecu and ohm out the wires that go between the two.

 

I cleaned the MAf and reset the codes

Still runs the same but now I have no CEL at all

I actually was able to drive it around. I unplugged cyl3 and it stops backfiring
Well maybe once or twice for the drive it still backfired but way less often. Im pretty sure it isnt a bad valve because it backfires randomly not every cycle.

Also if i unplug cyl 1 and 3 it stops missing all together it runs mint with those unplugged. After I took my drive I look at my exaust and my cat is bright red hot along with some of the section before the muffler is red hot too. What would cause this?


and why do I have no codes?!?!

 

I would say you have a mess there , if the Cat is red then your motor is either breathing fire your Cat may be stopped up or running very rich and afterburning maybe all of which would cause it to run erractically .
I guess if I were to investigate that I would pull my timing belt and check the alignment , if that was good I would give the distributor a quick check (if you have ever removed it that is) for spark timing check , would then run a compression check on the motor if all that was good .
Finally after I rule out the motor I guess I would check my Cat ................if its flanged take it out and look at it , older ones are bad design and break and stop up quite often .

Hope its not your motor

 

The Cat is red hot because your running to rich You will shortly melt down your cat if you keep running it this way.

Yes check your timing but if your freeze frame still says its -40 then you have a problem. the reason its running so rich is because your ecu thinks that its -40 outside so its compensating with more fuel because it thinks the air is very very dense, Which it would be if it really was -40 outside.

There is No Distributor on your motor.


A compression test will help but what would tell you about the valves would be a leak down test. that will let you know if your rings and valves are seating correctly

Dont run this motor in this condition for any more time that a quick test YOU will BURN DOWN YOUR CAT. If you havent started to burn it down already.

 

X2, listen to this guy he's a Toyota trained master tech with 3.4 swap experence. You can't buy advice this good and yet you just ignore it.

 

If he is a master Tech then I would at least rule it out

 

Heres the thing guys... This motor has roughly 10k not 10000 actually 10 kilometers the rebuild was professionally done by a friend of mine I saw helped along the way

So I KNOW the timing marks are fine as i installed the belt and checked it twice (Had the old 3.0 skip a tooth on me)
As for the cat I dont know if this helps but when it was out I looked through it directly at the sun and I could see right through it, none of the catalyst was broken either
I dont thinks its the MAF anymore as I cleaned it, cleared the code and it has yet to come back. But I defiently will check it out again
For the IAT it did change once the vehicle warmed it and it was reading about 11C which was about right considers it was pretty cold outside

The only thing I dont understand is why when 1 and 3 are unplugged it runs like a top, minus the unburned fuel from them heating the cat up.

Also I sort of have a thought but I doubt it is the problem. While the motor was being rebuilt I saw the cam poistion sensor had a dent in it when the accident occured(from the prior vehicle) but wouldnt that makes all cylinders miss, not just 1 and 3?

 

I had the same problem with my truck running good while misfiring. i found it was backwards plug wires. Im still not sure why it ran and sounded great however i could see the jumps in the tack. i fixed the wires and it ran one day and now my motor keeps flooding and wont fire. it backfires every now and then while firing but i cant figure out why my motor dies if i give it any gas or just let it run for say 10 seconds.

 

Sounds like you have a maf problem like an air leak past the maf. it will quit running when you give it gas because its not senseing the increase in air flow with the change in TP.





as i remember mine missed cause i had wires mixed up as well but fixed it and ran fine.

 

might be i just worked a bit on it today until the rain and wind started so ill check on that tomorrow. hopefully i can figure it out i want to drive it again

 

Yeah I know its simple but I was thinking the same thing , do you think maybe you have the firing order messed up possibly ?

Kind of like when I was getting ready to get a Igntion Module for mine and it was EFI fuse blown lol

 

no thats not it cause i already fixed that thanks though

 

what did it end up was the problem ?

 

well im still not 100% sure i havent tried starting it for a bit now cause of time and weather so as soon as i can figure it out ill let you know

 

Ok , cool , just curious