'92 K2500 5.7 TBI - Crank for days and no start after intake gaskets...

[tahoe.mkIII]

If you didn't remember to remove all the rags/towels you had stuffed into the intake&exhaust ports before reinstalling the manifold, that could be your issue...Ask my uncle how I know that

 

[Hipster]

I have never "seen" one "Jump" timing with the stock timing set. If you look at a TBI trucks timing chain and gears, it would take a huge amount of slack to be able to jump timing. It would be running very poorly long before it could possibly jump teeth. I've disassembled TBI motors with well over 200K miles, and while they had slack, it was far from being able to jump a tooth! If you've ever looked at a stock TBI timing set with the cover off, jumping a tooth "ain't happening"!

If it can cause issues long before it jumps sounds like another reason to check. It's anybody's guess to say if it's the original in there. Some offshore aftermarket sets are pretty light duty and leave a lot to be desired.

 

[VintageMetalMaine]

If it can cause issues long before it jumps sounds like another reason to check. It's anybody's guess to say if it's the original in there. Some offshore aftermarket sets are pretty light duty and leave a lot to be desired.

Following your logic and suggestions, here, I pulled the distributor cap and rocked on the nut holding the harmonic balancer. Interestingly, I could turn it clockwise (normal motor direction) and distributor responded immediately. However, the nut came loose when I tried to rock it counter-clock wise. Is that odd?

Sooo... I got on the nut that holds the alternator pulley and moved things a bit in both directions... Only a minuscule amount of "delay" in the distributor when changing directions on the motor. The rotor moves almost instantly when turning the pulley, indicating a reasonable connection between crank, timing chain, gears and distributor.

NOTES:

• There is, however, some "slop" in the new rotor/distributor shaft connection that I had not noticed... When gripping the rotor and turning gently, the rotor tip at O.D. moves about the distance of the thickness of the rotor tip, 4-5mm or so... A couple of mm in each direction... The distributor can move a tiny amount. The play seems to be at the rotor/shaft connection. Is this play considered "normal"?
• Coil wire fires out mighty bolts of blue light while cranking.
• Timing light indicates all 8 are getting signal at some point while cranking.
• No oil in coolant nor coolant in oil.

COMMENTS:

• When updating ground wires and connections a while back prior to IM gasket job that got us to this mess (see original post), I could not locate a ground wire at rear of head(s) as you and others have indicate exists on these trucks. It was non-existent. I added a new 4AWG ground strap from the manifold bolt near the T-stat back to a grounding stud on the cab behind the A/C evap canister. I cleaned and/or replaced every ground point and show 0.0 to 0.2 ohms in the ground system, depending on the connection being checked.
• I responded poorly "about running great until now"... What I should have said was that the truck would at least start right up and run consistently poorly until we reassembled it after the IM gasket job. Nothing we had attempted changed the rough idle/poor fuel economy/rich exhaust smell/backfiring-at-speed-when-hot conditions. Now, it will not start, at all.

Per your suggestions, I am on to checking spark quality at plug boots and fuel pressure at the TBI and will report back. Will provide pics and video next post.

THANK YOU ALL!

 

[PlayingWithTBI]

How about swapping in the ICM from the old distributor? It's in the distributor on the TBI trucks, right?

I don't see where you tried a different ICM? They are known to go bad, more often than one would think! When these go bad, they will cause stumbling. Try your old one or BUY AC DELCO (and use a high quality insulating compound)!

https://www.summitracing.com/parts/ado-d1984a

 

[VintageMetalMaine]

I don't see where you tried a different ICM? They are known to go bad, more often than one would think! When these go bad, they will cause stumbling. Try your old one or BUY AC DELCO (and use a high quality insulating compound)!

https://www.summitracing.com/parts/ado-d1984a

Would a new one that came with a new distributor go bad right away?!?!

 

[VintageMetalMaine]

If it can cause issues long before it jumps sounds like another reason to check. It's anybody's guess to say if it's the original in there. Some offshore aftermarket sets are pretty light duty and leave a lot to be desired.

See my response about checking rotor movement?

It seems like it is connected and has "minimal" play... I have no idea what the accepted "slop" in the system is but there is not much in this one.

 

[Schurkey]

Did you ever clean/replace the spark plugs?

 

[VintageMetalMaine]

Did you ever clean/replace the spark plugs?

They were new right before the intake manifold gasket job... literally 100 miles in them... had double checked gap a week ago and reported condition in my post... checking them all for spark quality and will clean them when I finish this post!

 

[Schurkey]

You "cranked for days" after the intake manifold work. If the injectors were squirting fuel, THOSE PLUGS ARE FOULED.

 

[VintageMetalMaine]

You "cranked for days" after the intake manifold work. If the injectors were squirting fuel, THOSE PLUGS ARE FOULED.

Thank you!! :-D