Just put the engine together and it has a slight miss when driving. Seems fine at idle, but not 100% sure as it does have a lope due to the cam.

Car ran fine wit the stock short block in the spring. I swapped the heads/cam into this engine.

I double checked my lash ( comp R lifters and magna rockers ), have them set 1/8. I used this lash on the engine before it spun a bearing, and again when I had the stock short block in when the stroker was rebuilt.

Changed plugs (TR6s gapped at 35). verified the wires are on properly, none swapped at the opti and none burnt etc. Wire (blue max) are 1 year old, about 200 miles,

Used a Noid and verified all injectors are getting a signal.


I'm thinking my next step is to ohm out the wires since there is no room to get a timing light pickup onto the wires?


Ign system is a acell 300+ system, injectors are are 3 years old and have about 1,000 miles on them. I also drained the gas and put 10 gallons of 93 octane in. The opti has about 30K on it.

What would a miss fire show on the O2s? Was thinking of stapping the injectors

I REALLY don't want to pull the opti! With the blower and billet hub it's even more of a pain!

Open to ideas! John

 

with the engine running get a water spray bottle and spray water on to each header tube if water evaporates immediately then that cyl is firing and working properly if not thats the cyl thats not working properly just an old diagnosis trick try it .

 

Or if you have a laser/infrared point and shoot thermometer, it will also pinpoint the cylinder by aiming it at the header tubes.

You can also wait until it's good and dark, start it, raise the hood and see if there are any fireworks anywhere.

 

Is it consistently missing or intermittent?
Does it miss only when cold(open loop) or only when hot (closed loop) or both?
Possible culprits...

Plug wire not fully on plug or opti.
Cracked insulator on sparkplug.
(most dreaded) Cap/rotor on opti. (are you getting any SES lights?)

If you can, put the car in a dark area(or wait till night time), open hood, start car, look in engine compartment to the degree you can and see if you see any sparks arcing from the plug wires.

 

The miss is consistent, just not sure if it is missing at idle or under load.

No SE light.

 

John....

Take it to Second Street Speed (short drive) and let them put it on the dyno with the ignition scope. Might be able to check your tune while they're doing the work.