OK, here's my sad story:
about a month ago I got a nice new-to-me bone-stock Z28 with 80K miles...

BACKGROUND INFO:

it drove good at low rpm range, but had a strange knocking/rattling at rpm above 4000... then it started stalling after driving through puddles, and then one day it got so bad i had to restart it a dozen times just to barely get it home, and since then it would not start any more... so I figured that opti has gone bad and it needed a good tune up... when i took it apart, opti had oil leaking in it, and moisture prolly too... oil was all over the engine compartment as well...
long story short, I ended up doing some work in the last few weeks:

- new Accel Opti spark
- new Accel SuperCoil
- new Accel 8mm wires
- new Autolite 106 plugs gapped at 0.045
- new ACDelco water pump with new temp sensor
- new Opti and WaterPump round gaskets inside timing cover
- new Serpentine Belt
- new PCV valve
- new Fuel Filter
- redone Intake Manifold gasket with Permatex UltraCopper and Felpro

when I put it all back together, I made a slight boo-boo and confsed the two vacuum ports that are one-above-the-other on the pass-side of manifold - one goes to Fuel Pressure Regulator, and the other goes to HVAC check-valve... I tried to start the car at least a dozen times like that, and of course, it backfired a lot, but would not start... it also made a strong air-suction sound and a loud metal ping a couple of times, whatever that was... (could i have damaged much by this???)
i re-checked the diagrams, connected the vacuum lines to FPR like they are supposed to be... at first crank it backfired a bunch, and then blew out the pass-side valve-cover vent hose and oil dipstick (why?)... now it just turns, no backfire or any sounds any more, but still no start either...

TROUBLESHOOTING performed so far:
- tripple checked all vacuum lines and connectors to make sure they are plugged in right
- all spark plug wires go to the correct plugs
- pulled #1 plug and grounded it - sparks every 2 seconds, not too strong, but i dont know how strong it is supposed to be
- tried spraying some Gumout Carb Cleaner in the intake elbow, as per someone's suggestion, it backfired and smoked through the air filter pretty bad aftrer 3 squirts (is my MAFS screwed now?)
- tested Knock Sensor - good, its resistance is 3800 and the connector voltage is around 5v
- tested Opti-to-Coil Pathway, get over 11vdc when grounding ICM harness' pins A or D, which means ICM is getting power, also i get around 2vac on pin B while cranking, which means pulses trigger the coil to fire (i am not sure if this completely rules out the opti harness)
- finally tested fuel... not sure here... for the first 2 seconds when the pump works i get around 47 psi, then immediately it dropps down to 39 psi and stayes there regardless if the key is left on or turned off... is that not good??? is FPR not working??? or do i have a leak somewhere else??? or is it ok???

so,
- should i test anything else?
- can it be the Opti harness itself?
- can i test the ICM itself?
- does IAC need testing and/or resetting?
- can i test MAP and TPS sensors somehow?
- should i de-screen my MAFS ??? is there a way to check its resistance?
- can EGR valve have smth to do with this since it controlls engine temp?
- can other temp sensors (IAT, coolant, etc) cause this?
- how about anything with A.I.R. pump related?
- can and should i check any vacuum anywhere?
- can oxygen sensor cause this? i hear bad ones sometimes make it run rich...

ANY OTHER IDEAS???

please save me from towing the sob to the dealer, i am on a college-student budget...

 

You changed everything except the ignition module, you may want o give it a try. The fuel pressure is working as it should. Your plugs are probably gas fouled from all the cranking with no start. Are you getting a spark? are the injectors being fired? If they are not, something may be wrong in the Opti and low voltage connections.
The big backfire was probably caused by raw fuel in the crankcase and thefumes blowing up inside the engine. The raw fuel in the cylinders will wash away all the oil from the cylinder walls and cause damage.
This is my personal opinion, but I always had bad luck with Accel parts.

 

so i just completed a compression test:
highest=170, lowest=135, prop=79%

drivers side:
1=135 , 3=160 , 5=145 , 7=155

pass side:
2=160 , 4=170 , 6=145 , 8=160

also, earlier today i have done the following:
- checked and got perfect 000 continuity on opti wiring harness
- cleaned MAFS with 99% alcohol - it was dirty and installed backwards
- reset the PCM by pulling the fuse and battery cables for 1 hour
- rechecked the grounds and spaced off the coil+icm assembly to keep cool

so now what???
looks like the timing chain and valves should be all right...
even if timing is ok, can it still be the opti-cam dowel misaligned???
how can i test the ICM (and should i?)

 

Dude.. Relax.

If its back firing an poping that means you have gas.

Your firing order is wrong. I know you hate to hear it but that has to be the problem.

Yes I know it sucks and yes I know they are had to check and yes I imagine you are tired of hearing it.

There are numbers on the OEM caps to show what goes where. All odd 1-3-5-7 cylinders I belive go on the drivers. All even 2-4-6-8 go on passengers.

If it is poping and such you must have the firing order wrong. The distributor only goes in one way.

You may have also fouled out your spark plugs. I hope you cleaned them up real good before you re-installed them. For future reffrence I would try to stick with an ACDelco plug. The ones you have now will work so you dont have to run out and buy more.

Really sounds like a timing issue. From what I read it sounded like a classic case of bad wires. From what I read after the work you have done I would say it sounds like another classic case of crossed wires.

Good luck. By the way, what are you using for a plug wire diagram?

 

The opti can be installed out of time, so you may want to check that out, also make sure you have the right opti for your engine.

 

sellc - i have checked the wire order, it is correct... i was going by the numbers stamped directly onto opti cap (same as stock)... besides, now it does not make ANY noise at all, no pinging or backfiring, just turns over and over....

i am seriously thinking about taking it all apart and seeing if the opti-cam dowel got misaligned somehow...

 

so, it took me about an hour to take it all apart (im getting good), with hand tools on the side of the street... dumped coolant all over my new opti, its good that ive sealed all cracks with silicone before installing...

yup... it was 90 degrees off... how the fvck that happened i have no clue, i tried to line it up properly the first time... so now its time for a short break, then putting it all back together again before it starts raining... maybe it will work better this time...

 

well, it just never gets any easier... one of the three bolts holding the opti in snapped at about 30-40 lbs of torque, so now i guess i have to take the timing cover off and it looks like it will be sticking out of the block by a mm or two... more fun and joyful times to come soon im sure...

i guess i might as well replace the timing chain now too... i am open to suggestions as to what to get... they dont make gear drives for lt1 do they? and i am almost waiting for someone to talk me into taking the damn intake off again and putting in a hot cam... problem is that i wont be able to afford the valve-end components for a while...

 

Good luck, don't give up the ship.I would not recomend a gear drive unless you want your friends to hear you coming a block away. Gear drives are noisy to the point of annoyance.

 

so, i guess i ruled out the gear drives due to knock sensor
what do people recommend for a nice mild cam ???