The crank was at tdc in those pics


Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust

This is what my timing advance was reading at idle the last time i scannned it.Im hoping the cams being off caused these readings.I read on the quad4 forums that each tooth your off on the cam gear is 10*.That sound about right?



Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust

If its not your timing then check your fuel pump, or your cat. I had a bad fuel pump that did this once and a bad cat in a different car that did it.

Do you have dowl pins for the gear holes? Put some dowl pins or long bolts that are close to the size of the holes so you can be absolutley sure its timed correclty. You know when its correct when the crank is at TDC and you can put the dowel pins(or bolts of same size) in the gear holes and pull them out with ease.











~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ

not sure this is the best way to check it...ive timed a quad/tc a hundred times and with the pins in the cam gears right the crank is always alittle past tdc. so if he has the crank at tdc now i would bet a nut thatthe gears wont line up.
whenever i time my 2.4s i line up the pins on gears, line up tdc on the crank, set the chain and theres always a little slackon the right sideof the chain. i have to turn the crank justa degree or two to remove the slack...and it has always worked out right. Im willingto bet the cam gears look like this because the crank is perfect tdc.
If it was my car i would simply set it to TDC, take the timing chain off and reset the timing from scratch the right way to be sure...wouldnt even have to buy anything. takes like 15 minutes. Then you could eliminate that part...which may in fact be the problem

So i got the new timing set today.Put everything together,bolts in the cam sprockets in the timed position,crank at tdc.Started with the exhaust cam,around the water pump to the crank and up to the intake cam.Took the bolt out of the intake sprocket,turn it counter clockwise to engage the chain.The last time i did the timing,i would rotate the intake cam counter clockwise and the sprocket would return to the timed position.When i did it today,the sprocket wouldnt return to the timed position to tighten the chain.Its like there was no resistance at all.Any ideas?Im thinking it has to do with something in the valve train.I guess im taking the head off this weekend.


Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust

This is how it was before i removed everything.I ordered a new timing set cause the top chain guide was broken.When i compaired the new chain to the old,the old one looked like it was a link or so longer.

[IMG]
Maybe ill just remove the cam covers first and check everything out.I have a rebuilt head to throw on there.The only reason i was gonna swap it out was because one or two of the cam cover bolts are stripped and i get a slight amount of oil coming through the bolt holes every so often


Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust

So,i put on my remanufactured head today.Put the towers and cams in.I cant rotate the intake cam sprocket.The exhaust rotates fine.The crank is at 90 degrees past tdc so i know its not caught up on a piston.Any ideas?Could the springs be that stiff?I didnt wanna turn the cam bolt too hard cause i didnt wanna snap it.Would a cam holder tool work so i can turn it?Im at a loss here.I installed the cam with the dowel pin at 12 oclock.


Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust

if the cam is that far off just simply from install there is a chance that one of the lobes has a valve jammed in the piston, not hurting anything, but not allowing you to rotate the cam.

he said the crank was at 90*..so no way a valve is hitting it.
ive had this happen before, when after assembly a cam wouldnt turn at all when doing timing. was due to a bad spot on the cam..guess someone dropped it or something

Yea,the valves def arent hitting the pistons.The cam looked good when i put it in,didnt notice any dented lobes or anything like that.Im gonna take it apart tommorow and take a look at it.If anythhing,ill put the cam in that was originally in there back in.The cams and housings i have in there now i got on ebay.I hate tightening the bolts on the cam housings.The book calls for 16 lb ft + 90*.Feels like its gonna strip if i go another 90* .I just tourqued it down to 16.The head i took off had 2 bolts stripped on it,Im not stripping them this time.


Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust

if it feels like they're gonna strip thats probably because they will. lol. the bolts dont thread that far into the head and the steel bolts weaken the aluminum threads in the head and then the threads tend to break. especially if the towers have been removed a few times. i've had to helicoil about 7 or 8 holes on my head over time, just from tearing it apart a lot. if youre worried about it leaking throw a thin bead of rtv on either side of the lower tower gasket to help it seal. just dont clog the oil ports and itll be fine.

on the cam thing, definately make sure it spins freely by hand in the tower before putting it on the motor, i had an engine skip timing like that because the exhaust cam would stick at a certain point in the rotation and cause slack. smashed every single one of my exhaust valves.

Oh, i know.I stripped my fair share of them lol.Thats why im just gonna snug them down lol.


Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust

Well,i got the car running.At idle,my boost/vac gauge is reading 20".Before it was reading between 15 and 16 " at idle.So,that fixed that problem.also,when i scanned the car with hpt,the timing was pretty stable unlike the graph above.But the car still runs like crap.Has no power whatsoever.Im getting my spare rail tapped for a fuel pressure gauge tommorow and see what kind of readings im getting.The pump isnt that old either.Its not the cat,cause thats brand new.Maybe a bad pump, fuel regulator or injector?I found no vacuum leaks.When i pinch the return return line on the fuel rail,theres no change at all in engine speed.If the pump was weak,it should make the engine run smoother right?Or maybe the screen on the fuel regulator is clogged,and theres max pressure in the rail already,thats why theres no change when i pinch the return line.Theres no fuel coming out of the vacuum line when i take it off the regulator.The fuel filter is brand new.I gotta look under the car.Maybe theres a pinched line somewhere.Once i get the readings from the rail,ill start diagnosing it.


Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust

Any updates? I'm just curious.

No,not yet.When i get some free time im gonna work on it.I tapped my fuel rail for the gauge today.Once i get the rail on,ill have some updates.


Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust

So,i put in the fuel pressure gauge and swapped out the fpr with a known good one(that i know of).These are the readings im getting.

With engine running vacuum hose on:36 psi


With vacuum hose off:45 psi


When i pinch the return line,it shoots up to 60 psi.Fuel filter is brand new.Weak pump?




Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust

Those readings seem about right. Isn't your long term fuel trim maxed out at -25? Would this indicate you're running too rich?


- Your not-so-local, untrained, uncertified, backyard mechanic. But my @!#$ runs

I thought you always check fuel pressure with the key on/engine off ???

Well,i finally worked on the car again after 3 months.When i put everything back together,i noticed an oil leak.The car sat since then.I took everything apart again a couple of days ago.Stupid me put the gasket between the timing chain cover and the exhaust cam tower backwards.Everything is back together with no leaks.Im gonna have to change the fuel pump though.The pressure readings are all over the place.Now it reads 30 psi at idle.Im hoping this fixes all the problems im having with this car.


Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust