Alright, been following the board for years and just got back into the 3rd gen game. Found my old 89 Camaro and bought it back after 9 years.

First up, i did a quick tune-up, Jegs distributor, plugs, wires, coil, timing and pulled the Stealth Ram of and BBK and went through them and cleaned them up, as well as pulled the injectors and cleaned them up. Once i completed that, i jumped into a T56 swap and just finished it up. The car did not have this issue prior to me doing the tune up or swap.

Took it out to try it out and i have a horrible misfire under load. I have checked my vacuum and seems to be good, re-checked the timing and set it to 6 degree advanced, and put a different set up wires on, but still have the problem. I bought and set a new TPS and set it off voltage.

I am kinda at a loss on what is going on. The car shows no codes, i don't think this has anything to do with the T56 swap.

Does the coil have to be grounded through the bracket? The reason i ask is because i forgot to put the bracket on prior to putting the distributor in and plenum and now can get to the bolts to mount it.

Anybody have any input? Thanks

Current setup - 383, Stealthram, mild cam, stock heads, stock injectors

 

i know this may sound silly but easy to do by mistake..do you have the wires from plugs to distrub correctly? i was off by one wire an it did run ..till i got at high speed..
id check that..just to be sure.

 

Doesnt sound silly at all, checked the wire and they are good, just changed the fuel filter as i was only getting about 30PSI with the key on but not started. That seem to help a lot as the old filter had a lot of blackish settlement drain out. But it is still missing but not as much.

I also just ran a vacuum test and it was reading around 14-18 on the brake booster vacuum from the intake. Think that is a little low as i have read it suppose to be around 20-22 i think. My gauge says that at 14-18 it means the timing is to retarded.

 

I am going to hookup my Actron ScanTool up today and pull readings from it running and post to see if that helps.

 

Okay i got the car up to operating temperature in neutral and recorded the data from my Scantool:

3rd Gear SW - ON
4th Gear SW - ON
AC Clutch - OFF
AC Enabled - NO
AC Request - OFF
Air Divrt Sol - NORM
Air SW Sol - CONV
Battery - 13.8
BLM Cell - 0
BLM Enabled - NO
CCP Solenoid - OFF
CLNT Start (F) - 87
Coolant (F) - 167
EGR Duty - 0
Engine RPM - 800-825
Exhaust 02 - LEAN
Fan Request - ON
IAC Position - 83
Idle REQ RPM - 800
Loop Status - Open
MAP (V) - 2.49
MAT (F) - 131
O2S (MV) - 200
Overdrivve En - NO
P/N Switch - R/DL
Prom ID - 4131
Spark Advance - 24/25 ish
TCC Lockup - NO
TCC Solenoid - OFF
TPS Sensor (V) - OFF

So I sure there is plenty of you that can run through these readings and and tell if anything is out of whack.

I dont have an EGR valve as i am running the stealth ram and the prom was reprogrammed years back when i did the engine rebuild and stealthram swap, still running the stock injectors.

 

One correction the TPS Senor (V) - 0 not OFF

 

Anybody have any ideas from reading through the data i posted? Going to test injector wiring tonight, check plugs and take compression readings.

Any thoughts on if the coil need a better ground? Or if the spark advance looks off? I did some research but wasnt able to find a lot on what the spark advance should read off the scantool. Also any thought on the vacuum being a little low? Doesn't seem like i have a bad vacuum/intake leak?

 

misfire under load for me has historically been either wires, cap, or especially coil. i know you mentioned you changed all those but i'd double check the coil as i've had same issue on multiple cars that turned out to be the coil

 

Just did an ohms test on the coil and everything checked out. Removing the distributor tonight and going to mount the coil as it should be, then re-install distributor and re-set the timing and give that a try. Don't think having the coil installed correctly will make a difference but worth a shot. Figure if that how it come for the factor there some kind of a reason. still don't know if the coil grounds through the bracket.

 

according to some google searches it doesn't need to be grounded...whatever that's worth.

just curious why you would test the resistance (ohms) why tht means it's good and not the actual voltage it's giving off.

when you timed it did you unplug the pigtail for the advance up by where the AC compressor is? (EST?) i think it's called

are you watching your fuel pressure gauge when you rev the engine for drops in the PSI? it should snap back quickly if working properly

 

if i recall when you pull a distrubter out, u cant just put it back in an set timing
because say the first time u pull it out the rotor is sitting on plug 4 on the cap
when u put that distrib back in u want it placed same exact spot or set the piston 1 to TOP dead center on compression stroke, set distrib in rotor should be facing #1 on cap, set timing from there..


else u will never get it right



http://www.wikihow.com/Install-a-Distributor

 

Just installed the distributor, pulled the valve cover and determined that i was TDC on intake stroke, adjusted the oil pump gear and aligned the distributor back a hair for the distributor gear, point cap to tower #1 and snugged up distributor, fired right up just too late to fire it up and get to operating temp to set timing (neighbors would not think that was to cool!). As far as testing the coil, i tested the resistance per the Chiltons manual and all checked out, not really sure what you would gain from testing voltage output as long as it was around 12V with car off.

Is it possible that i could have been notch off on the distributor before? Would the engine run? Or could this cause misfire underload? From the original Scantool reports it showed spark advance at 24/24ish which i think is high.

Also would there be any correlation to the T56 swap and the misfire? I had a ECM programmed for my previous stall and lockout? Dont think this is likely but at this point just trying to look at all item changed.

Also the vacuum was a bit low but not like there was a big intake leak or vacuum line unplugged.

Is grounding a possibility?

Sorry to keep rambling, think its the 4 Monster/Vodkas!!!

 

Definitely verify fuel pressure under load. May need to tape the gauge to the windshield while you drive.

Need to KV test the coil and the wires at the plug ends. You can use a cheapy KV tester like the one Thexton sells, or just use a phillips screwdriver in the wire end and hold it one inch from engine ground while a helper cranks the engine. The e-core coil should jump a one inch gap. New wires cap and rotor, it's doubtful you're leaking KV anywhere but double check by testing at least two plug wires the same way as the coil.

Be sure you set timing with the EST connector unplugged. Then double check to be sure you get advance when you rev the motor.