My 454 Rebuild

[ralmo94]

Might think it is wrong wiring at the ecu causing this but i don't think so

It's best to verify as much as you can, if something is supposed to be ground in the harness, check for continuity to ground, and check everything you can, if everything checks out, you can rule it out, if not, doesn't matter what you try, that's why you need to be certain, and if it is wrong at the pins, could take an awful lot of shop time and a "good" tech, to figure it out, and fix it.

 

[Spareparts]

Well after plugging/unplugging and and pulling/pushing on all the wires and ac system plugs it has stopped acting up. Got to be something in the harness but for now it is not doing it.

More weirdness though.
I was watching fuel trims as i was doing that seeing if it changed anything and for whatever reason i pulled the PVC valve out and the fuel trims went to almost a normal reading so i took the oil fill cap off also.
Idling in the driveway the fuel trims both STFT and LTFT read near 0. Has never done that sense new engine was first started. Still has the slight misfires though.
Driving it a few blocks that way the LTFT will climb to -13 and STFT will be around 0. Much better but not good.

So what does that mean? Lower intake gaskets leaking underneath for sure?
I know the top half is not leaking.

 

[Supercharged111]

It means your motor would be rich if the trims weren't leaning it back to stoich. You introduced a vacuum leak which leaned it out which helped knock the fuel trims down.

 

[Spareparts]

Thanks for explaining that.
Sucks though, thought i had stumbled on the fix.

 

[Spareparts]

Guess im done messing with the misfire issue. The 21st it goes to the shop to get a diagnosis. They have better equipment then i have, They are older duds that have every day experience + they both drive GMT 400s! Depending on what it is i'll either let them fix it or i will depending on cost and time.

So today i changed the outside DR door handle. Been broken for a few months but i have spent all my free time trying to fix the random misfires. What a little PITA that was!
Next weekend will be changing the rear diff fluid and drain the transmission pan and putting 5/6 qts of new fluid in that.

 

[ralmo94]

I hope they can figure it out for you.

 

[Spareparts]

Here is what's gonna happen.
I'm not chasing it anymore so im paying them to tell me what the problem is. This should hopefully solve the problem
If they can't give a definitive answer or fix i will bring it home, order some parts from summit. When i have everything i'll take a week off from work and take the entire top end off the engine including heads.
Examine everything and since it's so far apart at this point i will replace the cam with THIS one also new valve springs but i need to figure out what ones i need. and maybe shorty headers. Last will be a Black Bear in person black box tune.

 

[Mangonesailor]

I can't remember but the heads lack enough lift for some cams in the .500"-range.

Anyone remember what max lift is on our heads?

What about the ZZ502 cam? I also have some info on rocker studs and etc that I'll look up and post later

 

[Spareparts]

I have an adjustable valve train already not installed. I'll also need to order the tool for cutting down the valve guides.
I don't want a cam I need to tune for.
I don't know if the zz cam would work with out a tune.

 

[Supercharged111]

Mine is around .520/.530 with no modifications.