Chevy v6 problems

[ka-titties]

ok, so im working on some piece of shit chevy lumina.

i replaced the head gaskets, manifold gaskets and plenum gaskets and put everything back together and what do yah know, its not starting.

it cranks fine with the throttle off, then when you put the throttle down it seems like one cylinder is going backwards because it ignites and sends the exhaust out the intake.

thanks, dimitri

[Benjamin]

sounds like the sparkplug wires are crossed up. this is a coil pack car ain't it?

[ka-titties]

i just went outside and a light went off! i think that is what it is.

yes, the car has coil packs. do you know which cylinders are numbered what?

like going from the passenger side of the engine (front) to the drivers side (trans side). is the front left 1, then front right 2 and so on?

[Benjamin]

what year and motor size?

[ka-titties]

3.1L '95 lumina

[Benjamin]

1995-2001 Lumina, Monte Carlo, and Impala (FWD)

cylinder location (engine--the part where you put the spark plugs) when looking from the front of the vehicle the cylinders are numbered from left to right 2-4-6 (front part of engine); 1-3-5 left to right (rear of engine). Firing order 1-2-3-4-5-6. At the other end of the spark plug wire you should find a "bank" of coils which matches the spark plug wire with the corresponding port. The "bank" from left to right when standing in front of the vehicle is 5-2-3-6-4-1. Spark plug wires should be from number 1 cylinder to number 1 on the bank. Then number 2 cylinder to number 2 on the bank, etc. Hope this helps.

[ka-titties]

yeah the coils are numbered lol. thanks for the help mang. ill go see if it fires up.

[ka-titties]

it definitely seems to want to start now, but every few revolutions it still fires backwards out of the TB. i checked and rechecked the wires. they were definitely wrong the first time but after your help they are right now. still not start though.

[NotoriousGreaseMonkey]

Is the exhaust stopped up per chance? That will make compression come out of the intake.

[Benjamin]

do the valve's have an adjustable rocker arm or is this an OHC motor? did you go through the proper valve lash adjustment when you re-installed the heads? could be a valve hanging open on the intake side

[ka-titties]

not that i know of. when i had everything out, it seemed to be clog free.

edit:

its pushrod. can you give an example of what adjusting the valve lash would be? to be honest, this is my fist time working on a pushrod motor. im used to DOHC motors.

[ka-titties]

well shit, it may just be a valve problem.

when i turn the key, it turns over, at one point it wants to start, then it gets a reverse exhaust at another point, then recycles the pattern.

the last time i tried to start it, it blew out the pcv breather on the front valve cover....

[ka-titties]

nothin?

[redmach1]

I think that engine has different length pushrods for the intake and exhaust. Could that be a problem?

[ka-titties]

it cant be that, because i put everything exactly where they came from. i think its because i didnt properly install the rockers. welp, looks like im taking the intake off, AGAIN lol. thanks for the help everyone.

[Benjamin]

someone please correct me if this is wrong.

Install the pushrods, making sure they seat properly in the lifter.

Install the rocker arms and bolts.

With all the rocker arms attached and the lower ends of the pushrods in the lifter seats, bring #1 cylinder to TDC (Top Dead Center) compression stroke.

Adjust the intake valves on cylinders #1, #5, #6. Adjustment is 1 1/2 turns past zero lash.

Adjust the exhaust valves on cylinders #1, #2, #3. Adjustment is 1 1/2 turns past zero lash

Next, bring #4 cylinder to TDC (Top dead Center) compression stroke.

Adjust the intake valves on cylinders #2, #3, #4. Adjustment is 1 1/2 turns past zero lash

Adjust the exhaust valves on cylinders #4, #5, #6. Adjustment is 1 1/2 turns past zero lash

Install the rocker arm (valve) cover(s).

Connect the negative battery cable.


also double check on the pushrods because i believe that they might be different lengths between the intake and exhaust.

[ka-titties]

thanks a lot for all of the help. i actually found the procedure for doing it, but yours takes MUCH less time lol. the one i found instructed to do them all individually. that would take forever.

again, thanks a lot.

[Benjamin]

cool deal i would have answered earlier but i was alseep. i got to catch a flight in less than 4 hours so i tried to get some sleep from 6 to 12 so i could wake up and get everything packed and not miss the flight.....

anywho let us know how it turns out.

[Sandman]

Sounds like you just misadjusted the rockers, I've been there before. For me after you find zero lash I only went 1/2 turn, anymore and the valves were over torqued.

[SATAN]

There is no need to set valve lash on a 3.1. I've been inside these engines about 200 times and all I do is put the push rods back in the correct spot, exhaust in exhaust, intake in intake, and tighten the rocker bolts, then you're done. Don't over complicate this.