big engine troubles

so ill start off by saying hello...now to my problem, a friend of mine brought over his 07 chevy aveo for me to work on, it had a blown head gasket, car has 31k miles, obviously still ran when it arrived. i dug into it but it took about a month to get all the free time to fix it, i replaced the head gasket and ran into a problem...it wont start. it will turn over and run extremely rough (sounds like a harley) for about 10 seconds before it stalls out, wont pass 1500 rpm even with the gas to the floor and wont under any circumstances idle on its own free will. now for the list of things ive checked. first though was the timing, i checked it again and its dead on, not the problem, i checked for fuel pressure via the relief valve near the intake manifold, plenty of pressure, replaced the plugs and checked for spark, all is well there, double checked and triple checked all vacuum lines/hoses/electrical wiring, all seems to be well but i fear my problem is here somewhere. any sugestions? i cant test for intake vacuum cause im illequiped, could it be some sort of secondary component like an egr valve? and for the record if it matters the entire intake manifold was caked in peanut butter looking goop from the head gasket mixing the coolant with the oil. and i am no noob to cars, i just own a honda and things are easy on those. suggestions would be great thank you

oh and while its running for the brief period of time there are no cel lights so its not throwing codes

:shock: damn i wish i new. hondas are easy. i work on mine usually.

hmm i kno someone on here bought a used aveo with motor problems.

maybe rabbit will kno, he's got alota knowledge. good luck. and welcome to the site

Did you have the head resurfaced or at least checked while you had it out?

we did not resurface the head but everything looked fine when i had it apart

this could be a lot of things..

the goop it going to be the thing i will go with, pull out the primary o2 and see if it runs at all better.

I bet your cat is clogged.


if not that, i'll try again.

on this car is the primary cat directly connected to the header? cause if its on the exhaust farther down the pipe i disconnected the exhaust pipe where it bends under the engine and tried it that way and no luck but if it is connected to the header then would i have to disconnet the header? is it safe to start the car (assuming it will) without a header?

I wouldn't run it long, you'll start to burn valves.

But just pulling the o2 will work. Why replace another gasket?

Oh. Edit. Yes the cat is directly under the header.

pulled the o2 and its black but seems ok, the cat is nasty with chunks in it but i think its normal.. maybe not

did you start it?

the cat sould be able to be seen through if you shine a light... or hold up to a light.. its either square or honeycomb..