Help, I've got problems

DMX

Registered User
Cam install was pretty easy. However since I put the engine back in i've had some issues. I'm getting a misfire from #3 for no reason, the plugs and wires are brand new and are working properly,(saw the spark plug fire and checked wires with timing light)

The misfire only occurs when the engine is cold though, it mysteriously disappears when the temps get in the normal range. However it runs hot (???)

Autozone temp guage says its reaching 230*, even higher if i let it run long enough - thats scary, but whats puzzling is the temp will steadily drop from that 230* to about 180ish about 5 minutes after shutting off (???) That has to be air in the system, but I know for a fact i purged it and opened the vent tube when filling and eliminated damn near all of the trapped air.

Whats the deal? I pulled the engine to drop in the SC crank and the RPM 216/225 cam with good strong springs. The signs are kinda pointing to HG failure, but the heads werent touched, the engine was running perfectly fine on the 11 month old felpros I put in july 02.

I'm scrating my head on this one, throw me a bone here please? I'm about to try swapping injectors on #3 tomorrow to see if that helps pinpoint the problem.

Anyone here have any ideas? I'm lost on this one.
 
sounds like an intake leak. would take off your lower manifold and replace the intake gaskets. Sounds like its getting air in somewhere around there and maybe at the # 3 cylinder. A failed gasket could be causing it to run lean, therefor hot and misfiring. Just a thought, because your lower intake was off to change the cam.
 
Part of your problem could be the engine is lean with your new cam set up. Dont know for sure. Check the plugs that are easy to get to and see if its running lean.
Its always been my experiance that when changing cams you need to tune fuel mixtures and ignition timing curves to get things to work properly.
Of course eleminate the simple things first like vac leaks and clogged or dirty rad. Is your rad fan kicking on?
Does it cool the engine down when it comes on?:)
 
I replaced the lower intake gaskets yesterday hoping it would make a difference but it didnt.

I swapped the #3 injector for one of the spares I got from supercoupeKuhn and it still didnt help, I should have expected that because the old (and new) injectors clicked when I applied 12V.

I've been purging the system but still seem to get air in there somehow, i havent had this much trouble before. I just dont understand why the misfire is intermittent, it was misfiring off and on when cold OR hot today.

I'm only getting about 10inHg in park/Neutral and I dies if you dont give a little gas when putting in gear. I cant think of any other places where I could be leaking, i've checked everything, and if i was, why affect only #3?


???? confused.
 
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