1992 5.7 TBI crank, fuel and spark no start

[phatphuck]

Kinda says it all here. Helping brother troubleshoot.

All ignition is now new he's been replacing stuff willy nilly (unfortunately).

I reset timing today and still same situation. Spark at #1 wire for sure. Injectors are pulsing and dumping fuel into the TB. Won't start with starter fluid either.

He keeps being told jumped timing but I think that's one of those things that is stated often but super rare.

Supposedly it's a 30k mile crate motor replacement. Ran fine but died while idling from cold about 15 minutes one evening.

Any ideas.

New components

- distributor assembly
- cap and rotor
- ignition coil
- wires

Any insights appreciated!

 

[Supercharged111]

When it ran, where was the timing set? What's the fuel pressure? I was gonna suggest it was 180 out, but if it ran that can't be it. Was the distributor tight when it ran? Can you advance it until it doesn't want to turn over? That's at least tell you the fuel and spark are doing their thing to some extent.

 

[phatphuck]

When it ran, where was the timing set? What's the fuel pressure? I was gonna suggest it was 180 out, but if it ran that can't be it. Was the distributor tight when it ran? Can you advance it until it doesn't want to turn over? That's at least tell you the fuel and spark are doing their thing to some extent.

Not sure on fuel pressure actually..

it could be that they had it 180 out before i reset it today. TDC and rotor at cyl 1.

he told me he and a friend old almost get it to start by having the dist loose and advancing it by hand but I was not able to replicate this feedback today.

 

[Supercharged111]

Not sure on fuel pressure actually..

it could be that they had it 180 out before i reset it today. TDC and rotor at cyl 1.

he told me he and a friend old almost get it to start by having the dist loose and advancing it by hand but I was not able to replicate this feedback today.

So they did or did not have it running at one point?

 

[phatphuck]

No not since the original break down that occurred while idling at warmup.

 

[Supercharged111]

No not since the original break down that occurred while idling at warmup.

That breakdown was on the new engine, right?

 

[phatphuck]

Yar. He bought it with the supposedly "new" ish crate motor a couple years back. So this is the same engine

 

[Supercharged111]

So was your brother present when it ran those 15 minutes or was that part of the story he bought it with?

 

[phatphuck]

Yes he was present but in a co-workers car a few parking spaces over while his truck warmed up. And his truck just stops running after about 15 min from time of startup.

Couldn't get it to turn back over. Been in that condition since (+/- 1 month)

 

[thinger2]

That really sounds like a timing problem to me.
Chain skip is kinda rare on a sbc but it does happen.
I dont think that is the problem but the only way to find out is make absolutely sure that you are at tdc on the compression stroke.
Pull the coil wire, disconnect both injectors,
You really dont want it to start while doing this.
pull the number 1 plug and hold your thumb over the plug hole.
Dont even look at the distributor or the timing marks on the balancer.
Have somebody crank it a little at a time.
When it blows your thumb off of the hole.
It is compressing.
Stop cranking the second that happens.
You dont want it to go past TDC.
You just want to make sure it is on compression stroke.
Now you want a homemade feeler of some type. A welding rod with all of the flux knocked off works great.
Disconect the battery.
From here on everything is done by hand.
Pull the rest of the plugs so you arent fighting compression and so you dont break the crank bolt.
Stick the rod in the hole on top of the piston and put a breaker bar on the crank bolt and rock it back and forth untill you get a feel for when it actuall hits TDC.
Do not use a stick. Nothing worse than finding out its great and then breaking a stick off in the cylinder.
Now look at the balancer and the dist.
Many reman engines do not come with a balancer. So you reuse the old one.
The engine might have 30k but the balancer might have 300k.
And they are known to slip and make timing a real pain.
The balancer would not cause the original failure.
But it can make stabbing a new distributor impossible and leed to chasing a problem that is purely timing related.
When you hold your thumb over the hole the compression should agressively blow you thumb off.
If it doesnt or is really feeble. Ask if this thing made a bunch of valve noise when it ran.
It may have no compression at all from lack of valve adjustment on a reman engine.
I suspect the stall and no start was due to something else and that timing and the newly installed distributor are keeping you from finding the real cause.
Its a bit of a pain to do but it is the only surefire way to completely eliminate timing as a problem before you move on.