Misfire turns south. Need advice
06-16-2012, 07:49 PM
#1
Staging Lane
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Misfire turns south. Need advice Took my car (99 TA) to the drag strip last night. Ran great all night. On the way home passed another car and split the gears trying to go into fourth. Over revved it pretty good, and it acted like it had no power right after that, but it slowly came back on it own. clutch wasn't slipping and no ses light. once i parked it I could feel the misfire, car was shaking and there was a slight tick. Put the tuner on it to read the codes and got a cylinder 5 misfire code. Took the plug out and compared it to #3 and it was fine. swapped #3 and #5 plugs, and wires. Code still came on for #5. Took #5 plug out, hooked the coil wire to it and checked for spark. It sparked just fine. Did compression test on cylinder 5 and I could only get 60 psi. My car is pretty much fuc*** isn't it?
06-16-2012, 08:07 PM
#2
Maybe not too badly, assuming the valvetrain is stock you probably just bent a pushrod or two. Pull the driver-side valve cover and both #5 rockers, remove the pushrods, and roll them on a flat (glass is good) surface to see if they're bent. Easy fix if so.
The low compression is explainable if the intake pushrod is the bent one, can't make much pressure if little or no air is getting in.
The low compression is explainable if the intake pushrod is the bent one, can't make much pressure if little or no air is getting in.
06-17-2012, 12:53 PM
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Staging Lane
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well i'm waiting till monday, to tear it apart, when I go back to work, cuz one of my co workers has a really nice video scope in his tool box that im gonna borrow to look into my spark plug hole on #5 and try to see if I scored a piston or if i have valve kiss marks on the top of it. and I'll go from there. But if I do have bent valvetrain, this would seem to be the perfect time to upgrade it right? 
Hoping its just a bent pushrod, I would like to do rockers, and pushrods. And yes the motor itself is stock. My eventual plans are to run a small procharger on there (4-5 psi) so that way I can still keep it streetable. But now that I have issues here I'd like to do some valvetrain work that will work with a stock internal motor. What kind of rockers/pushrods should I use? As far as size is concerned, brand doesn't bother me so much.
Hoping its just a bent pushrod, I would like to do rockers, and pushrods. And yes the motor itself is stock. My eventual plans are to run a small procharger on there (4-5 psi) so that way I can still keep it streetable. But now that I have issues here I'd like to do some valvetrain work that will work with a stock internal motor. What kind of rockers/pushrods should I use? As far as size is concerned, brand doesn't bother me so much. 
06-17-2012, 01:22 PM
#6
Rockers: I'd just have the trunnions upgraded w/ Comp rollers. The factory rocker bodies are light where they need to be and plenty strong enough for what you're doing.
Pushrods...if you're staying w/ the stock cam, I'd get stock pushrods. They may have just saved your engine. It's good to have an easily-replaceable weak link in the system.
Springs: PAC 1518 or PSI Max Life. Beehive either way. And get a set of Manley valve locks. And while you're in there replace the valve stem seals w/ GM or Fel-Pro 1-piece stock replacements.
Pushrods...if you're staying w/ the stock cam, I'd get stock pushrods. They may have just saved your engine. It's good to have an easily-replaceable weak link in the system.
Springs: PAC 1518 or PSI Max Life. Beehive either way. And get a set of Manley valve locks. And while you're in there replace the valve stem seals w/ GM or Fel-Pro 1-piece stock replacements.
06-19-2012, 11:12 PM
#7
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Just got done striping her down, took # 5 rockers and pushrods out, checked the pushrods and yup they are bent (only a little but they're still bent). How much of a gain is higher ratio rockers on a motor like mine? worth doing, or just save my money? I'm definitly doing valve springs and obviously putting new pushrods in, which btw where can i get stock pushrods for a decent price?
