Tbi backfire through intake

[Rustjunky67]

Hi all,
Ok I'm back working on my 94 k1500 5.7 tbi....NV4500tranny
I got it all put back together. Static timed. Didn't even turn key good and it fired off...
Rpm rose to about 1500 and stayed there didn't come down. I shut her off and, as it was late, went to bed. Next morning got up fired her off and again rpm to 1500 then about 30 second or so in, started dropping rpm and I thought cool she gonna settle down. Nope, went straight to 0. Cranked again, rpm to 1500 for about 30 seconds then straight to nothing.
Now for the past 2 days I can get nothing more than a spitting, sputtering barely running chunk of steel and aluminum.
It has backfire through the tbi twice.....
Any suggestions on where to start diagnosing? I don't have a scan tool or access to or money to acquire one....
Thanks in advance

 

[pressureangle]

What did you have apart?

 

[Schurkey]

First Suspect: Vacuum leak
Leads to high idle speed, causes lean running which accounts for backfire into the intake manifold, and decreasing idle until it stalls.

Could be other issue(s) though.

 

[Rustjunky67]

What did you have apart?

Intake manifold, valve covers, camshaft in and out, cleaned lifters, replaced all 12v and grounds, made new oil cooler lines, replace several harnesses that needed it(maybe),

 

[Rustjunky67]

First Suspect: Vacuum leak

Can't get it to run long enough to determine lol
However, the iac was stuck about halfway close, so there was that leak but it's been corrected

Could be other issue(s)

Yeah that's putting it lightly from all the reading and watching i've done

 

[Schurkey]

What is the cranking compression pressure of all eight?

 

[pressureangle]

Though there are many things to verify, my first thought is that your valves are too tight. First fire with empty lifters went ok, then disappeared- now no start or hard start/poor running.

 

[Rustjunky67]

Though there are many things to verify, my first thought is that your valves are too tight. First fire with empty lifters went ok, then disappeared- now no start or hard start/poor running.

That's quite possible. This was my first time even taking rocker covers off and after reading and watching everything i could find on it i followed what i thought to be the most sensible procedure. Basically set to TDC tightened all to zero lash, rotate 90 and again tighten to zero lash any that were loose, rotate 90 and repeat until all were at zero lash..... then tightened all 1/2 turn.......
Was that bad procedure? I sure hope tf not lol...

This is the procedure i followed to a TEE....

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[Rustjunky67]

What is the cranking compression pressure of all eight?

No clue....i know that is not a good answer but that's the truth of it..... never tested compression before

 

[pressureangle]

That's quite possible. This was my first time even taking rocker covers off and after reading and watching everything i could find on it i followed what i thought to be the most sensible procedure. Basically set to TDC tightened all to zero lash, rotate 90 and again tighten to zero lash any that were loose, rotate 90 and repeat until all were at zero lash..... then tightened all 1/2 turn.......
Was that bad procedure? I sure hope tf not lol...

This is the procedure i followed to a TEE....

xc_hide_links_from_guests_guests_error_hide_media

First timer, eh? lol Let the ol' guys tell you about adjusting rocker arms in the freezing cold uphill both ways.
There are a thousand ways to do it, all of them make it easier than all the rest. Personally, I use this method (with 3/4 turn instead of 1/2 on stock-ish motors)

SBC Valve Lash Adjustment on Hydraulic Lifters | 8 Steps

To get the longest life and most performance out of your engine, it's important to have the valve lash set correctly. Here we show you how to set valve lash on a Small Block Chevy using a hydraulic lift camshaft in just eight steps.

www.speedwaymotors.com

The real trick, no matter what method you use to find your cam position, is to find with precision the 'zero lash' adjustment. You have to feel the pushrod, rocker, and lifter pocket by rolling and wiggling the pushrod, and feeling the rocker arm until you know you have no slack, but it's critically important that you do not preload the lifter at all. Then get your 1/2-3/4 turn. Because I'm old, stupid, and never did have enough memory to find my own house on my own block, I clean a shoulder on the rocker arms and use a paint marker to dot the ones I've completed. Then when I'm finished, I roll the motor through 2 more turns to be certain I got them all.