Mechanics

ENGINE IS RUNNING ROUGH

2002 Saturn L100 • 97,000 miles

Just recently tackled a head gasket job, had the head machined shoped and needed exhaust vavles.I put a new chain, tensioner, along with guide kit. TDC, camshaft and crankshaft marks perfectly to the timing marks on the chain. New plugs, new ignition control module, tested coil all are perfect. I checked and tested for vaccum leaks, none. Tested and replaced throttle position sensor. The engine run (as before it was dead) but it is rough on idle. When I give it gas it sounds good but pulsates. I need some help
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Vsant76
March 30, 2012.




Engine Is Running Rough, Go to this walk thru link: http://www.2carpros.com/articles/engine-misfires-or-runs-rough

Tiny
Rasmataz
Mar 30, 2012.
Just to add to this one have you checked the compression of all the cylinders yet?Also post all replies here dont start new questions.

Saturntech9
Mar 31, 2012.
Ok so I was getting two cylinder 4 misfire codes, so I did a compression test. When I removed the coil pack cylinder 4spark plug was submerged in coolant (assuming not good) compression results c-1 195, c-2 205, c-3 205, and c-4 wet with coolant 215 I stopped there it was late. Can I torque the cylinder bolt a little more around cylinder 4

Tiny
Vsant76
Mar 31, 2012.
Was the coolant in the spark plug hole or outside the plug in the spark plug well?Also did you have the head pressure tested at the machine shop before putting it on?Did you tourqe the head down correctly with the correct tourqe and tourqe patteren?If you did you cant just tourqe it more there is something wrong thats why there is coolant.

Saturntech9
Mar 31, 2012.
There was both coolant in the plug well as well as in the cylinder itself when I removed the the plug, the others were dry. Yes it was pressure tested and exhaust valves were replaced I followed the torque pattern from the book used 45lbs of torque.

Tiny
Vsant76
Mar 31, 2012.
45 ftlbs?The main head bolts are 22 ftlbs then 155 degrees of tourqe angle. Then the front bolts in the timing chain area are 15 ftlbs of tourqe. Also if there is coolant leaking into the area where the spark plug boot/wire area there has to be a issue with the head how else could it get into there?

Saturntech9
Mar 31, 2012.
Thank you for the info, removed the head (back to the machine shop) the head was pressure tested at a higher psi and it was cracked around the spark plug hole. The head was replace with a remanufactured rebuild. (Free of charge, easy like pulling teeth) after re-installation the engine started right up (sweet!) But, Now it sounds like it needs a valve adjustment? Multiple valve ticks across the entire valve cover. Can they be adjusted on the engine? If so shouldnt this have been already done with the rebuild? If not any ideas? I have lost trust in the machine shop I used, they didnt want to warranty there service

Tiny
Vsant76
Apr 25, 2012.
That engine has self adjusting hydralic lifters no adjustment there. One thing comes to mind did you change the oil when you replaced the head?If so did you install the correct oil filter?You can actually install the V6 oil filter found on the L300 when that happens oil flow to the top end is lost and the lifters dont pump up and valves can be bent.

Saturntech9
Apr 26, 2012.
I replacent the filter again just for assurance. Purchased from dealer this time, no change. I checked the engine pressure and I think the pump is bad. At idle the pressure is 32 psi. With acceleration it increases to 77psi. The engine sounds good with acceleration. Could this have been the reason for the head failure to start with? Any thoughts before I pull the pump out.

Tiny
Vsant76
Apr 27, 2012.
Are we talking about oil pressure here?
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Saturntech9
Apr 27, 2012.

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