okay guys, so I drive a 4g69 eclipse, but figured someone could give some info.

I blew a piston a couple months ago and did a rebuild, adding aftermarket parts. I finished up on Saturday and first start she idled and ran amazing. I let it idle for about 15 mins then turned her off. I then started it up again and the car started bogging like it wanted to stall out. I took her for a drive and she felt wonderful, but started stalling out at every stop sign. Over the past couple days it has been getting progressively worse, to the point it stalls even at cold start ups. I'm throwing a p0300 code that states random misfires in all cylinders. I feel this is a timing issue but all the marks are lined up, or were at least. I swapped back to my stock tune to see how it acts.

before the build engine mods:
Cai
bigger Tb
gutted cats
rre underdrive pulley
reflash
im resonator delete
Tb bypass

added during the build:
forged pistons..5mm overbore and dropped from 10:1 to 8.5:1 cr
eagle rods
ACL main and rod bearings (checked clearance 2/1000 for mains and .038mm for rods)
arp studs
EVO balance shaft delete
port and polish head and manifold
valve job

would
t he diff cr cause the timing marks to no linger be correct?

any ideas? thanks.


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hmm..maybe it's just the cold temperatures?
i never did an engine rebuild and i'm still running stock but when i start my engine when i come home from work, i let it idle for a bit while i'm getting ready to leave..
when i come back it's dead LOL..
only happens sometimes though especially when it's really cold..
does that seem normal?
hope this helps..
kinda answered a question with a question but i'm just trying to help out
take care man!

 

i think it's an AFR issue, are your spark plugs new? what's the gap? check them for fouling...

 

It could be a number of things , from the spark plugs like crans said, to a vacuum leak, tps sensor, crankshaft position sensor, MAF, leaking head gasket, or even just the lowered compression is making the fuel not burn completely.

What's your afr?

And the reflash wasn't for the lower compression NA was it?

 

i'm really leaning toward AFR being out to lunch...with the lower compression, there's no way to fuel it without proper tuning.

 

hmm..
i'm thinking of replacing my plugs soon..
i don't even know my AFR values so i'm at a loss here..
i'm all stock so maybe i don't need to touch on that lol..
plugs first for me then everything else when it comes to the engine..
ngk iridiums from CanTire here i come

 

to add to this with the polished heads and valve job and bigger TB and oversized bore and less compression, wont this really mess with the AFR and the reading that the MAf is trying to give

you might need to look into a tune for this now

and no compression wont effect the timing cause the crank still turns 2:1 if u changed the timing crank or cam gear then yes it would effect timing