Spent a few $$$$ today on a few nice scan tools and a few more extras from a local snap-on route guy.

 

Well, if your scantool has data, find the ESC portion. It will probably say no under the data. 1 way to test it is to tap with a hammer on a metal bracket on the engine with it warmed up and idleing and watch the ESC. If you tap hard enough, you will see it change from no to yes. ESC is used for retarding spark a couple of degrees to help eliminate engine detonation. If it says yes all the time or will not retard, then a few possiblities. one is the knock sensor, the other is the ESC module, which is on the passenger side of the blower case. It is flat and has a 4 or 5 wire connector on it. You might have to remove the lower side panel to get at it. The other possibility is a bad ground on the ESC circuit. If the engine is staying in the retard mode, you are running a little late on the timing. My money is on either the knock sensor or the ESC module. Also, check power circuit to ESC module. [8D]

 

I'm on it now, will update ya later today man, next you need a PayPal donation button .

All the best!!!

 

Wherefore she's a 4 wire connector, checking the wire schematics, goes to the knock sensor then onto the distributor.

When you say bad ground on the ESC circuit, would this be the bracket to this module or one of the lines out of the four that are on the wire connector?

I think I'm staying in "retard mode" with this car, I've been through 5 cases of coronas since I started this project and surely going to Costco for more later today after I narrow it all down. I'll be going through all the wiring from the ESC to the distributor and testing if the knock sensor wire is in the proper sensor location.

This is one of the greatest forums for vette help ever!!! I'll be placing alot of links back to these forums from my sites!!!

All the best!!!

 

The ESC ground will be on the engine block, either on cylinder head, t-stat housing, or intake manifold bolt.

 

Code 42 could also be caused by wrong ignition module. Verify you have the right module and I would go with an A/C Delco. I know I sound like a salesman for Delco, but they have a time proven quality that has always worked for me.

 

Will check this out early AM as I spent the last 14 hours sanding, priming and prepping the car for paint by this weekend, as we are suppose to be in the 80's by Friday with "NO" rain in Seattle . Anyhow, I have bought a new ignition module the other day, so I'm not sure if it's bad if I check for continuity in it correct? As the ESC Module checked out fine today as a 7.5 on the meter and found I do have the KS plugged in but the pigtail on it is pretty cruddy so I'll be changing that out tomorrow to see if this helps as well.

So possibly the Ignition Module you say inside the distributor could be the culprit too huh? Well anyway to really check this module besides what's inside the Chiltons Book?

 

I forgot to ask, is your ignition system new, wires, cap, plugs, rotor? If so, I would suspect ESC module.

Also, your main problem is the Corona's. LOL. Need to stick with Miller Light or DOS Equis (XX)

 

New wires, cap, plugs, rotor... The ESC Module is no where to be found up here in the Seattle area checked on it, however seems to me also, if you have a faulty or loose pigtail to the Knock Sensor would this have any bearing on having a cruddy ground to it? (I'm veering more towards this now as everything this is fine until later when I'm out test driving it then there are sparatic jerks like it's starving for fuel again... However I have tested this ESC Module over and over and can't seem to find any faults within it.

HaHa well DOS Equis XX is the way to go but Miller Light I have to refute with you on, however if Costco keeps up selling me beer at the prices they have them cases for $22 then I'm a keep drinking till this is over with. Unless I wake up in the mornings to open the bottles then we have issues at 4:30AM [:-]

Dude I'm off to test more and will update you later on what I can find out, changing the pigtail connector to the knock sensor and double check the wiring all the way through and I'll update you of my findings... Not too sure how much a big role the knock plays but I'm a find out today.

All the best!!!!


(Great thread so far alot of options and hope others are learning as we go too)

 

Knock sensor is grounded through the body of sensor to the block. Have you tried the "tap" test I described earlier and watch scantool reading? If the ESC is on yes all the time, chances are the knock sensor might be bad, or the ESC. Knock sensor are made of quartz crystal and are tuned to certain frequencies as detonation produces a frequency that makes it generate a small voltage so the module can tell when your engine is detonating. [8D]