NEED ADVICE (Truck only runs right with set timing disconnected)

[lyfull]

1993 Chevrolet K1500 - 5.7
it recently has developed a constant issue where it only runs with the set timing connector disconnected (while I set it to 0 degrees of timing as indicated by the manufacturer)
It all started when I went to do some maintenance on the truck
I replaced the spark plugs and spark plug wires and also replaced the old exhaust manifold gaskets with a new copper set
went to go turn it on and at first it wouldn't even fire up (mind you i never loosened the distributor so i didn't rotate it)
found that it was way advanced so I disconnected the set timing connector and set timing to 0 degrees and it ran great
turned it off, plugged the connector back, turned it on, ran like hairy nuts again
went to go check the timing with the connector connected and it was wayyyyy advanced again
I'm talking like 20 degrees advanced so the truck spit and sputtered then eventually died
Here's a list of parts I have replaced so far
Distributor shaft (tried 2 of these)
Ignition Module (tried 2 of these)
Ignition Rotor (tried 3 of these)
Ignition Cap (tried 3 of these as well)
Ignition Coil
MAP Sensor
EGR Valve
IAC Valve
Rechecked the gap on plugs and made sure they were the right ones
Coolant temp sensor (Both of them)
Fuel Filter
And New Oxygen Sensor
It also has a refurbished engine from power torque with less than 5k miles on it
After all of this, the problem still persists and I have not noticed any improvement with any of the parts I have changed (timing still advances to 20+ degrees with set timing plugged in after all the changes)

 

[Schurkey]

I'd expect the timing to advance when the connector is plugged-in, but I'd say 12 degrees would be more likely than 20+.

Connect a scan tool, verify ALL the sensors. Maybe you knocked the vacuum hose off the MAP sensor, or broke a TPS sensor wire, or something.

Verify that the timing mark on the damper aligns with "0" on the timing pointer when #1 is at true TDC.

 

[Taz069]

Was having some of the same issues. Pulled the driver valve cover just to verify proper TDC. Need to find true TDC, please all correct if I am wrong. Had a cam cover for me not showing proper tdc. It was a pain!! If you do have proper tdc. By the book your supposed to unplug the unit time it and plug it back in?

 

[FrankieD61]

1993 Chevrolet K1500 - 5.7
it recently has developed a constant issue where it only runs with the set timing connector disconnected (while I set it to 0 degrees of timing as indicated by the manufacturer)
It all started when I went to do some maintenance on the truck
I replaced the spark plugs and spark plug wires and also replaced the old exhaust manifold gaskets with a new copper set
went to go turn it on and at first it wouldn't even fire up (mind you i never loosened the distributor so i didn't rotate it)
found that it was way advanced so I disconnected the set timing connector and set timing to 0 degrees and it ran great
turned it off, plugged the connector back, turned it on, ran like hairy nuts again
went to go check the timing with the connector connected and it was wayyyyy advanced again
I'm talking like 20 degrees advanced so the truck spit and sputtered then eventually died
Here's a list of parts I have replaced so far
Distributor shaft (tried 2 of these)
Ignition Module (tried 2 of these)
Ignition Rotor (tried 3 of these)
Ignition Cap (tried 3 of these as well)
Ignition Coil
MAP Sensor
EGR Valve
IAC Valve
Rechecked the gap on plugs and made sure they were the right ones
Coolant temp sensor (Both of them)
Fuel Filter
And New Oxygen Sensor
It also has a refurbished engine from power torque with less than 5k miles on it
After all of this, the problem still persists and I have not noticed any improvement with any of the parts I have changed (timing still advances to 20+ degrees with set timing plugged in after all the changes)

Underneath the dizzy cap, is the rotor, pull the rotor and look or even snap a picture of the magnet and post the results here. They get cracked and cause weird issues. Not a professional, I've delt with something similar... I'm still dealing with a "fishbite" miss on a cold start for the first few mins of running.. I've opted to just ignore it because it's not a big issue; not causing any harm.

 

[62barsoom]

I replaced the distributor on my 97 and couldn't get it right till I learned about the cam retard setting. Takes a good scan tool to read it though. Here's some info as well.

Chevrolet C/K 1500 Questions - setting timing marks on 97 Silverado w/5.7 - CarGurus

setting timing marks on 97 Silverado w/5.7 - I had my 5.7 rebuilt in a shop and installed it back into my truck a couple months back. Since then the servic...

www.cargurus.com

 

[Schurkey]

I replaced the distributor on my 97 and couldn't get it right till I learned about the cam retard setting. Takes a good scan tool to read it though.

Not an issue on a '93. There is no crank sensor, therefore no need to synch the cam sensor to the crank sensor.

 

[evilunclegrimace]

Bad EST Module?

 

[MrobsMan]

M

1993 Chevrolet K1500 - 5.7
it recently has developed a constant issue where it only runs with the set timing connector disconnected (while I set it to 0 degrees of timing as indicated by the manufacturer)
It all started when I went to do some maintenance on the truck
I replaced the spark plugs and spark plug wires and also replaced the old exhaust manifold gaskets with a new copper set
went to go turn it on and at first it wouldn't even fire up (mind you i never loosened the distributor so i didn't rotate it)
found that it was way advanced so I disconnected the set timing connector and set timing to 0 degrees and it ran great
turned it off, plugged the connector back, turned it on, ran like hairy nuts again
went to go check the timing with the connector connected and it was wayyyyy advanced again
I'm talking like 20 degrees advanced so the truck spit and sputtered then eventually died
Here's a list of parts I have replaced so far
Distributor shaft (tried 2 of these)
Ignition Module (tried 2 of these)
Ignition Rotor (tried 3 of these)
Ignition Cap (tried 3 of these as well)
Ignition Coil
MAP Sensor
EGR Valve
IAC Valve
Rechecked the gap on plugs and made sure they were the right ones
Coolant temp sensor (Both of them)
Fuel Filter
And New Oxygen Sensor
It also has a refurbished engine from power torque with less than 5k miles on it
After all of this, the problem still persists and I have not noticed any improvement with any of the parts I have changed (timing still advances to 20+ degrees with set timing plugged in after all the changes)

Make sure you didn’t put the plug wires on wrong I did that on mine by accident and it wouldn’t time right at all