Misfire and voltage drop caused by instrument cluster

[Tanner Jacob Colbert]

Hello all, I have been chasing an issue on my 1993 C1500 5.7, engine and trans are out of a 1990 c1500.

New parts include:

Reman ECM, IAC, TPS, MAP, Ignition Coil, Plugs and wires, Coolant Temp Sensor, Oil Sensor., All grounds.

I have been having a misfire issue, and whenever the turn signals are activated the truck has a 400RPM Swing corresponding to the signals. Codes have been Code 43, Code 44.

Today I removed the instrument cluster to look for shorts and the problems all stopped. No misfire, truck runs great, no voltage drop with turn signals activated. If I plug in the cluster the problems return.

Ground under the dash, and fuses are good.

Are there any known issues with gauge cluster shorts? Or would I be chasing a short somewhere else?

 

[Tanner Jacob Colbert]

UPDATE: all voltage drop tests were within spec. Also with the cluster unplugged the battery reads around 12.5 volts and is not charging, with the cluster plugged in it reads 14.1 volts and charges.

 

[thinger2]

what happens if you have the cluster plugged in and run it with the distributor reference wire disconnected?
Do you get the same turn signal problem?

 

[someotherguy]

Also with the cluster unplugged the battery reads around 12.5 volts and is not charging, with the cluster plugged in it reads 14.1 volts and charges.

Normal. When you take the battery warning light out of circuit the alternator is not excited, so it's not charging, so you're going to read strictly battery voltage at the battery.

Richard