LT1-LT4 Modifications - lt1 no start

Hey everyone i have a 1996 z28 i just finished putting back together, trouble is it won't start. The mods i have done are

new comp cam
le2 heads
longtubes
roller rockers
new opti, wires and plugs
58mm pp throttle body
ported intake
got rid of egr, air, evap, smog

anyways car has fuel i replaced fuel pump and were getting fuel, water pump was also replaced, i did troubleshooting procedure for spark everything checks out, i have spark all the way to the end of the coil wire. pulled off opti took it apart tested the cap coil connectors and have continuity, the rotor does not however, some genius painted the rotor tip so i put the old rotor in and gave it a whirl still nothing all i get is engine turns but doesn't really turn and rpms maybe 100rpms give it full throttle while cranking it turns to about 400 rpms and has small backfire out of the intake... i just have no idea what it could be anymore wasn't sure if anyone else knew?

any help is appreciated

Sounds like the timing for the opti is off. Did you put it back in right? It's really easy to get the cam gear dowel pin in one of the indentations for the bolts. And are the plug wires run correctly?

not to be mean but did you put the came in right? do you get spark at the plugs now that you did the opti again?

still no spark at the plugs, installed opti numerous times even took cap off and hand turned crank make sure there was no lag, cam was installed i followed shbox procedure lined the gears up at 12 and 6 spark goes from the coil just not recieving anything on the other side.... even after using my old cap and rotor

Check resistance on your plug wires.

hey guys i got it start, but it only starts under throttle and then dies.... its getting spark now i accidentally overtighted my roller rockers...i know i'm pretty stupid but tis my first build so no i know, but as state i can get it to start when im on the throttle as soon as i let off it dies and now it only starts then dies real quick

Did you tune it?

Check for vacuum leaks. Loose intake clamps after the maf to the TB, Intake manifold etc.

Any Codes?

i went to check for codes, but my obd2 scanner will not work anymore on the car it works on my daily driven impala though, its not tuned yet was hoping to get it running then to the dyno this weekend but i can't even get the thing going, i was looking for vaccuum leaks nothing noticableall holes have been blocked were the evap is no longer and smog pump hole on the cold air intake has been blocked off also

out of ideas at this point, could throttle position sensor casue this like i said it only cranks up when i give it throttle starts up to about 500 600 rpms then dies

by the way your trans am looks nice what color green is that?

anyone have any insight for me?

Loosen up all the rockers then adjust while the engine is on using the no more clacking +1/4 turn more routine. But that would be in the event it stays on of course.
They sell these rocker arm tip covers so the oil doesnt squirt at you...but otherwise you can lay down a wet towel over the headers as well for a little while.

Did you happen to ratchet crank the whole engine after you aligned to the 12 and 6 clock postion once over? This is important to do sometimes just to confirm the chain doesn't end up 1 tooth off after you take off the slack by spinning it over once.

Get a hold of another ICM altho u have spark and it tends to go out and not give spark....there are some rare instances it just acts up and acts this way.

You could be off by a tooth on the cam or you could be off 180 on the Opti install....I dont recall if that's possible as I have not done an opti in awhile...but it was possible on HEI....180 degrees off would mean you werent at proper TDC. Anyway I think the dowel pin might prevent this.....so your problem may just be the rocker arms too tight still.

when i did the timing chain i lined it up and there was no slack on the chain engines been rotated a few times, if its a tooth off that might be the case i guess, but the icm i took to autozone and it tested fine they tested it several times to allow it to get hot also, the rocker arms should be to tight still but i guess i can always just take a look at them again, i just figured it'd have something to do with the tps or iac since its a new throttle body i mean i know it wont run right because its not tuned but it should still start and idle right?

Loosen them all up.

Autozone icm test is worth fukkel. best is to test w/ a known working one.

yes it should start without tune unless u maybe went with a gargantuan solid roller....but even then.......

no its the comp cams xfi280, i unplugged the iac valve and started it under throttle it ran for about a minute at 500-600rpms still under full throttle... i also swapped out traction control throttle cable and such witha non traction control throttle cable just incase that would mess with anything i don't think it would though

also my tps reading with throttle body untouched like it would be at idle is .8 which is higher then the .67 its suppose to be

http://www.youtube.com/watch?v=Y6GCiZXTgIo
the start is no throttle then i give it full throttle like a s3cond before it starts and then the second time is just full throttle

anyone? I don't think its the lifter because yesterday it wouldn't idle but would freely rev before i put waterpump and everything else back on, it was after i kept it revved about 2000 2500 for a few seconds that i let off the throttle and it died and this started happening think it could be fuel pressure regulator i primed the pump and pushed in the needle and got nothing

Check the spark plugs see how they look.
Then you'll be able to tell if it has something to do with fuel.

well i know i need to change the oil i checked it today and it smells like fuel but i believe thats from before it was starting when it wasn't igniting because of the compression but i'll pull a plug what am i looking for excessive fuel i forgot to mention i put bigger injectors on the car then stock also

alright just pulled out a plug looks fouled do to carbon buildup which makes sense with it being untuned, but also was slightly wet probably from fuel since it smelled like fuel also, hope thats enough infor for you, and thanks for responding but even with a fould plug why would it only start at wot and then only hold a 500-600 rpm idle for couple seconds then die even with WOT

Like RAMAIR sugessted me in the other thread just leave alone until you get your pcm tuned I'm pretty sure that will fix the problem..

i was gonna take the car to get dyno tuned though instead of a mail order...

well i know i need to change the oil i checked it today and it smells like fuel but i believe thats from before it was starting when it wasn't igniting because of the compression but i'll pull a plug what am i looking for excessive fuel i forgot to mention i put bigger injectors on the car then stock also

How much bigger? B/c it's gonna be dumping fuel and flooding the engine.

stock is 24 on a 3bar system these are 36 on a 4bar system so i figured they'd be around 30 on a 3bar system like the lt1 i could of been completley off with that too though... doh....

Yeah, they're gonna be spraying about 50% more fuel than the stockers. So for every 2 oz the stockers would spray, those things spray 3. Flooding. Probably fragged your O2s, too.

damn... well tomorrow imma throw the stock ones in and see how it goes, i mean it kind of makes sense to meto much fuel floods spark plugs not enough spark to ignite it all, but at the same time everything i try gets rejected so i feel like this would be way to easy a fix for it to work haha

I say check the stock injectors. If it runs, then use that to get to a dynotune, nothing else. Then get it tuned for the mods and the new injectors.

i wasn't planning on driving it at all except to take it to get dyno tuned didn't think injectors would hurt me so bad, but would that explain why it only starts at WOT? This is my first build so theres been a lot of learning and obviously somne mistakes so all the information i can get it great, its one thing to read something and another to do it so even though i've been stocking forums and getting all kinds of information i'm still no where near perfect

Perfection is the unattainable that we chase.

another quick question from it not idleing could that be from no adjustments made to the new throttle body i've read some things saying bigger cams need more air to idle wasn't sure if it was true or not

It'll start with the normal injectors.

You were definitely flooding.
Bad thing to omit that little detail. But you'll get it today. Good luck tho.

Swap the plugs out.

changed injectors today gave it a crank it sometimes tries to start without throttle and also starts with throttle same as yesterday going out later to get new plugs i'll giv ethat a try any plugs to try specifically the plugs i just put in are the ngk tr55gp are those pretty good?

well guys update for today, swapped in stock injectors and new plugs and guess what?!?!?! still not running right its improved a little bit in the it sometimes pops and fires under no throttle now but still only starts under WOT. Sometimes it will stay alive and and "idle" at 500-600rpm, by idle i mean i have to be at WOT to keep it alive at that, there were a few moments were it would surge down to about 400 and such and then back up and there was definetley raw unburnt fuel burning in the exhaust and some from swapping the injectors in the engine bay today.... Everytime i let off the throttle it dies again, i'm just confused when i re adjusted the valves without waterpump on, and everything else involved with an opti swap off the car it firedup under WOT again and revved freely even though i only had it up to 5000 rpm as i tryed to keep a sustained idle but as soon as i let off the gas it died again.... just so confused, most the sensors on the car are new waterpump, coolant temp, oil pressure, o2 sensors, oil level

also gonna give the readjsut lifters again tomorrow..... i'm out of options and last time it cranked up and actually reved freely was when i did them

hey guys, swapped plugs injectors readjusted the valves again blah still no start unless under full throttle this time it revs up to about 2k then dies if i let off the gas also

anyone?

another update, got the code reader to finally work tryed running car as long as possible to let the computer try to do its cycles still didn't go good enough though for none of the emissions did there cycle and only code that musters up every so often is po100 which is mass air flow i've unplugged it and tryed starting same thing, any ideas, also gonna replace fuel filter to

The popping threw the intake is Timing Triple check that & make sure the lil dot lookin slot is the one on the dowel Spin it over to make sure the lifters are pumped up & the do em one buy one set all of em to zero lash & tighten a 1/4 turn As far as tps voltage search the sticky on how to set it Might need to enlarge the slots Ya really need a base tune! Please go to Oreillys or Napa Autozone aint a real parts house LoL

i was going to oriellys, theres no popping through intake anymore that was from me over tightening the valves, there re adjust for the 3rd time can get the car started under WOT and keep it alive with wide open throttle but i can't control revs, sometimes it slowly jumps up sometimes it just sits at 500-600 rpms, or sometimes just dies out even at WOT. I'm gonna replace fuel filter see if thats any better i'm not sure if its bad gas or what maybe even bad fuel pressure regulator?

on another note i usually go to orielly but after having a shit ton of sensor exchanges there causethey gave me the wrong parts i started going to autozone for tool rentals also and i can see what they're doing on the computer with how its set up... also if i can even get the car to idle and drive im gonna get it dynoed, at this point though i might just send the pcm off or give the whole tuning thing a try myself so i can atleast learn how to tune and adjust myself

ready to rip my hair out i can't even get it to stay alive for any period of time it only trys to fire up at about half throttle now so confused, tps checked out fine IAT would probably be my next bet but i just don't know....

dude you've got some setbacks here and its usually best to ease back from a project when it gets this complicated. try a week or two+ off of it.
This could be your optispark at this point. Im not sure if you were able to swap in another ICM like I told u to before.
Also your readjusting the valves....but how.? I told you that textbook bullchit is just that it never works out....you can leave them fairly loose then once it gets started and it will start loose (as oppposed to NOT start too tight)then adjust them with engine running. (you could still be too tight...you've mentioned its been too tight twice already....the worst part about all this is you could throw a lobe...it's not common but I would guess its possible)

I dont think this is your problem anymore tho. Try another ICM and if not its your opti.

well ill be going back to work tomorrow might have some free time this weekend to maybe look at it, don't have an extra icm to throw on the car, the one on it tested fine at autozone but i know how the feelings are on that, i got a scanner on the car, thought that themap sensor isn't reading right causeing a rich fuel condition because i don't have leaking injectors nor i the fpr leaking but yet im still getting excess fuel

Hey 96z28_lt1 have u figured out what ur problem was because I have the same exact symptoms. I think I just can't get my rockers set correctly. Do I need to set on compression stroke an how loose can the rockers be to just get the motor to start and idle. Any help would be greatly appreciated thanks guys. Don't mean to hijack but I'm stuck

Also forgot to AD that I'm able to get the car to stay running at 5-600 rpm while my girlfriend hold at 1/4 throttle and when I play with the rockers the RPMs do get faster or slower depending on witch way I twist the poly locks. That's the man reason I think I'm not setting the rockers correctly. I have never adjusted roller rockers.

Anyone have an answer I'm stumped I've tried setting my rockers so many ways and still can't get it to idle. I have fuel pressure and spark. I just can't get these rockers right any pointers would be great. Thanks