molnarzack

i have an 85 trans am 305 tpi runs great starts right up everytime.the only code it shows is code 42, i replaced the ignition module and the light still comes on even when i reset it so its a hard code. all the wires coming and goes from the distrubtor and ignition module look fine any sugestions? please help! also my tach does not work. does this have anything to do with the code 42?

Ozz1967

iTrader: (4)

42. Fault at electronic spark timing circuit OR Fault at direct ignition system OR Fault at fuel cutoff relay circuit

I am pretty sure this could be a knock sensor issue. I would replace your knock sensor, then check the routing on the wires to make sure it's away from your spark plug wires.

The reason I say knock sensor is because when the knock sensor detects engine ping, it sends a signal to the ECM to retard the timing up to 20* so you don't wreck your pistons. If the sensor is bad, it could be sending an inproper signal.

However, in my case, I was getting a false signal because the wire the ran from the knock sensor to the ECS module, was running over top of my plug wires. This has the effect of a conducted "false" signal generated by the energy of the plug wires, making the ECM think it was getting a code from the knock sensor (I had previously replaced the knock sensor to no avail). I re-routed the wire around the back of the motor away from the plug wires and my code went away. It was pure happenstance that I did that to fix it but now that I look back on it, it actually makes perfect sense. Hope this helps!

molnarzack

i really dont think my plug wires are routed correctly i never have since i installed them is there any picture or or instructions to follow when routing them?

Ozz1967

iTrader: (4)

DId you buy a set from autozone that are supposed to go under the exhaust manifold of did you buy a set of "over the head" type? I thought I had a picture of mine but don't. I bought a set of "over the head" style 90* boots from MSD. I then bought a loom set to help route the wires. I just like stuff to look neat and professional, can't stand it when wires are going all over the place.

molnarzack

i got them from auto zone a bosch set

molnarzack

i got a bosch set from autozone

Ozz1967

iTrader: (4)

Do they all have 90* boots or are some of them strait? In the description it will tell you how they are "supposed" to be routed. Mine come off the dizzy, over the valve cover in neat lines and "down" to the spark plugs (Think of a highway with off ramps).

molnarzack

i was looking at my knock sensor to notice it wasent even plugged in.. when i found the wire i plugged it in and it still have code 42.

Ozz1967

iTrader: (4)

You'll have to reset the codes by disconnecting the battery. Then you'll have to drive the car for a bit to see if it comes back. If it does, try moving the wire that plugs into the knock sensor away from any other wires (you may need to splice in longer wire like I did to do it). If that still doesn't work, try replacing the knock sensor. After that...we'll need to find someone with more experience.

molnarzack

okay update and now i really need help haha after i plugged in the knock sensor the car will start and either stall imediatly or go to an extremly rough idle it never used to do this infact the car has never stalled till now, im pretty sure its cuz my timing is off? any sugestions?

KnightmareCS

iTrader: (7)

Clear codes and see why it lights up again.