yotarunner87

bought an old beat up yota this winter and am just getting around to messing with it

guy said it needed piston rings and didnt run

said he just had a bunch of work done to it

-new timing cover
-new chain, gear, tensioners, cam
- head bolts

those things are new among many more

it was siezed up so i pulled it and have the head tore off it right now.

ill attach a picture of the under side of the head.

looks like two cyl were running LEEAANN

and two were running RIICCHH

i use capitals because the damn plug ground strap was turned to almost 100% ash on one of the cylinders haha

there is very slight scoreing on one of the cylinders, nothing i cant hone out

so now that you kind of have the histroy of whats going on, here are my three questions

1) what would cause #2 and #4 to be so rich and #1 and #3 to be so lean?

I should have checked the timing before pulling the head but it was 3 am and i guess i didnt think about it

2) looking at the fsm it said there are 3 sizes of STOCK pistons

This seems to have all 3 sizes in the motor.... i do not have the crank pulled out or anything yet.

cyl #1 is size 1, #2 and #3 are size 2 and #4 is size 3

wtf?

the tolerances for each size seem to overlap but would that cause the seizure?

3) whats a good way to get these pistons out they are locked up tighetr that fu*k

wyoming9

iTrader: (1)

If it is seized let it soak with Kroil for awhile or what is your favorite penetrating oil.

After you remove the crank just drive the pistons out using lots of penetrating oil as you go.

Is it the pistons that are seized or is it the crank??

It is possible that engine had a very bad head gasket failure and the two cylinders you think were lean just had lots of coolant run through.

Really hard call to make without being up close and personal.

Terrys87

iTrader: (1)

I dont know what would cause it to run rich. Lean..., maybe a partially clogged injector. Sounds like it has set for a long time. I would go thru the fuel system, starting at the tank all the way to the injectors. Most likely you have a nasty fuel system. I would bet your fuel return line is clogged as well. Pretty common. I would also check the crimps in the injector harness. They can get really corroded and might be part of your problem. All three of my builds below, one of the first things I have worked on is the fuel system and posted it to show how bad they are and each one was.

As far as the block work, I would have to rely on my local machine shop for his guidance.

yotarunner87

All of those are great ideas

The motor has been freshly gone thru

Head is brand new and can we the HG was not leaking

Fuel system is a good place to look.

As far as I can tell right now the only issues with it were a couple cracked injector nozzles


I'm just parting this engine out and saving the block.

Just wanted to know if the 3 size pistons was a big deal and make sure I don't save junk parts that will cause this on another build.

Just seems odd that two cyl are so far rich and two are so far lean

yotarunner87

Just answering this because yota tech is so flooded with absolute nonsense it makes it impossible to find any useful info in the search function

Keywords: injector harness, lean, rich, burn down, carbon, ash