What is EST Low voltage Code

[IV Quattro]

Recently my Blazer has been throwing an EST Low voltage code, I've got a new ignition coil, I pulled the distributer cap and looked at the contacts and they looked clean, my spark plug wires run with some distance away from each other and are parallel, the truck will run but when the check engine light is on it falls on its face a little bit. But the light alternates with my 4wd light and then everything works fine, where is the ground for the instrument cluster and what am I still missing?

 

[Wes Harden]

what is the code number pls, year and type of fuel delivery of blazer

 

[IV Quattro]

43, 89 Gas, Holley aftermarket TBI, Not sniper EFI

 

[Blue85]

What year is this truck? It's a factory TBI system with an aftermarket throttle body? That code means the ECM is reading a low voltage from the knock sensor, something like less than 0.6V for 10 seconds. Most common cause is a bad knock sensor, but it could also be the wire shorting out somewhere. After visual inspection, a couple of quick checks are to unplug the sensor and measure it's resistance to ground. Then with power on, measure the voltage on the connector (coming from the ECM).

 

[IV Quattro]

I know for sure the knock sensor is good, I replaced it about 3 months ago so I'll try that fix,
It's and 89 that had a factory TBI till I recently upgraded, all other sensors and components are stock

 

[Blue85]

I know for sure the knock sensor is good, I replaced it about 3 months ago

Many new electrical parts are bad out of the box these days. What kind of sensor did you use and why did you decide to replace it? When did the problem start?

 

[Wes Harden]

Over torquing a knock sensor can cause codes, normally it will retard the timing. I forget which code that sets.