P0304 Code and Rough idle

[USAFAVIATOR]

Hello. I'm new to the forum and have a problem with my daughter's 99SC2. My daughter drove it until the head gasket gave out a couple of weeks ago. After doing all the work to it, It idles rough and is hard to keep started. This is what I did to it:
New head, intake, exhaust and valve cover gaskets
New timing set
Had head machined/milled
new water pump
new hoses/belts
new coolant temp sensor

I had replaced the plugs and wires about 6 months ago.

So, when I try to get it going, it starts but runs real rough and I have to feather the throttle just to keep it running at all. About 3 minutes in, the check engine soon light blinks, and the car will run without me on the throttle, but it's real rough. I get code P0304 when I test it. I pulled the plugs and all 4 are black sooty.

Any ideas? The fact that it has been well below zero here for a long time doesn't make matters easier. Thanks in advance for help. I've searched the forums and can't find the exact situation I'm facing.

[rc1488]

Thats a missfire code. Compression numbers?
New head bolts also were put in correct?

[USAFAVIATOR]

Sorry, forgot to mention that I did replace the head bolts as well. Didn't get compression numbers because I can't get the engine hot to do it.

[USAFAVIATOR]

Well, I fixed it. Went out and pulled the valve cover again to recheck that the timing was right (f on camshaft pulley aligned with gasket surface and pips at 12 o'clock) and it was. So, I went back to check each rocker/lifter combo and found the rocker on #4 was cockeyed on the lifter. Took a screwdriver and easily popped it back on even and it started right up, runs great! Took it to the gas station and back, no issues. No oil leaks and had lots of power. Hopefully everything remains good.

[rc1488]

Very nice! Good job.

[saturn94v]

Originally Posted by USAFAVIATOR

Well, I fixed it. Went out and pulled the valve cover again to recheck that the timing was right (f on camshaft pulley aligned with gasket surface and pips at 12 o'clock) and it was. So, I went back to check each rocker/lifter combo and found the rocker on #4 was cockeyed on the lifter. Took a screwdriver and easily popped it back on even and it started right up, runs great! Took it to the gas station and back, no issues. No oil leaks and had lots of power. Hopefully everything remains good.

Nice job, good catch. Hope it is a good machine for ya!

[madpogue]

Originally Posted by usafaviator

my daughter's 99sc2.

...

Originally Posted by usafaviator

found the rocker on #4 was cockeyed on the lifter.

???

[USAFAVIATOR]

Quote:
Originally Posted by usafaviator
my daughter's 99sc2.

...

Quote:
Originally Posted by usafaviator
found the rocker on #4 was cockeyed on the lifter.

???


I don't understand what you mean by ???

To better explain, the rocker was cockeyed on the lifter when I tightened it down after replacing the cams/head/head gasket. This, obviously, was affecting the way the valves on #4 were opening and closing, thus causing the P0304 (misfire on #4). I popped the rocker back flush onto the lifter and retorqued the bolts. Runs great, can barely hear it run and has good power and no leaks.

[madpogue]

A DOHC engine doesn't have rockers.

[OldNuc]

99 and up do in an odd sort of way. They are very similar to the system that is used in the SOHC.

[rc1488]

Originally Posted by madpogue

...
???

'99 uses the third generation head. They made the ports smaller and changed the way the cams interact with the head. I saw some pictures of it around here somewhere. I never really opened up my old '99, even though I should of.

[madpogue]

Y'learn something new every day: http://www.saturnfans.com/photos/sho...29210/size/big . Bears little resemblance to the topside rockers on the SOHC. I can see the need for this; when they moved the cams inward, they couldn't relocate the valves for "real estate" reasons, so they came up with this.

[OldNuc]

The only thing that hold that rocker in there is the hydraulic lifter and the end of the valve stem. Several have been found to be out of position.

The roller cam followers are a result of the impending loss of ZDP from engine oil scheduled for 99. That did not materialize but Saturn spent the $$$$ to redesign the head. This was another expense the company could ill afford. I believe GM did this redesign to several other engines also.