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HELP DEAD MISS on 4th Cylinder

1K views 10 replies 8 participants last post by  crusty shadow 
#1 ·
Just got my car back from the shop and It has a dead mis on 4th cyl
I brought the car to get the head gasket changed! and Bought a remaned head from cylinder heads international and a Mopar Performance head gasket and the rest of gasket are felpro including the head bolts. So they got that all done and started it up and it missed so they checked the compression and it was 45 but it seams to run fine besides idleing I cant tell if its missing when driving but it seams to run smooth so I dont know.
I know it might have been alittle hard to read but if you have any ideas please help....they say it might have somthing imbetween one of the valve so its not closing all the way and to drive it and it might stop.....any other ideas or also think that could be it?

THANKS JOHN
 
#3 ·
take it back to the shop and have them fix it right 45psi way to low could be a bad valve, but you said it's new so it cant be the prob. could be a bad lash adjuster pumped up holding the valve open a little bit. could be a bad piston as suggested or bad rings. no matter what, u need to see about having the engine redone.
 
#5 ·
Pop the valve cover off and see if the valves are closing all the way. do a leakdown test and see if you can tell where the air is coming out of. My guess is if air is gushing out the pvc, then its the piston/rings or if it is coming out the intake or exhaust (w/valves closed)then its the head. Maybe they did a quick slip and slide job on the hg and charged you for a full head removal that may have caught the issue.
 
#6 ·
"Ever since I worked on my car, it got worse" Maybe the spark plug is bad, Maybe the plug wire is bad. Maybe the valve is hanging open. Maybe the piston is bad, Maybe the rings are bad, Maybe the gauge wasn't screwed in properly on that cylinder. Maybe the spark plug hole threads are cross threaded. Maybe, I think I'm about out of maybe's. No matter what, if it ran good before you "fixed" it, it seems that it didn't get fixed properly and that issue needs to be addressed with the quality mechanics that worked on it.
 
#7 ·
MAYBE the mechanic went a little hairy on the "post-repair test drive" and #4 cyl.s' ring lands took a shit? Then he didn't tell you, figureing you'd dog the car and break it worse and need another "repair" job. Wouldn't put it past a
shady mechanic during slow times to trump up more work from "one of those turbo guys who wouldn't know the difference anyway".
MAYBE that's just my $.02 (two cents).
 
#9 ·
putting some air pressure in that cyl will tell u right away if its a valve prob. as someone in the replies clearly stated.

so what do u need to do, u need an air compressor, a hose adapter that screws into the spark plug hole, have #4 at tdc, so look thru the spark plug hole and see if you can see the piston. turn engine by hand until you get the piston right on top. pull off dist cap, see if dist rotor is pointing toward the rad. if it's pointing to #1 cyl, u need to turn the motor 1 full rev 360° put about 30 psi air pressure in spark plug hole and listen for leaks. more than 30 psi and all u do is push the piston to bdc and a valve will open then u will have a leak.
 
#11 ·
dude you got taken for a ride is what happened. if it didnt miss before it was worked on it definately shouldnt miss afterwards.
raced an N/A 2.2 back in the day? you live in springfield, which means to him racing is just bolting on a cherry bomb and driving around town in second gear all night.
45 psi is less than half of what compression should be- at least 110 preferable around 135 or so. either they got a crap head thats not sealing, , reused the headbolts, or blew the rings out of it after they put it back together. take it back and tell em to fix it right or give you your money back.
if this guy knows how to work on cars then he shouldve known that it wasnt right with a dead miss, and had no buisness telling you the car was done when it really wasnt.
the engine feels ok when the car is going down the road because boost is making up for a lack of static compression in the cylinder.
 
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