JonnyO78

I am at my wits end with this.

I have replaced the cam sensors with some salvaged and they all test at ~1035. Cleaned out the sensor plugs. New rotors and caps. Replaced the capacitors in the ecu. Put the motor to TDC and verified the timing.

This code 12 keeps disappearing and then coming back and killing my car. Please help!

AlaskanLS

Check harness and connector between engine & ECT ECU and each sensor. Inspect sensor installation and teeth of signal plate.

AlaskanLS

Also check the crank sensor that is located close to crank pully.

JonnyO78

The teeth on the sensor? The cam pulley? The crank sensor too? Looks like I'm pulling it apart again.

AWWWWW MAN. I don't want to do the continuity testing. What do I need like 15 foot leads?

AlaskanLS

Reaching Crank position sensor is easier than cam position sensor. I don't know the year of your car but if it is 1st gen, you can remove engine splash shield and diagnose it from getting under the car, or the most easiest way is to reach it is from the top and remove it from it's housing and unplug the harness, it has one 12mm bolt. But if you have to count the teeth of the crank signal plate then that is going to be a bit challenging.

AlaskanLS

Resistance of left and right cam position sensor and crank position sensor should be from 950 to 1250 ohms. Crank position sensor is also called engine speed sensor.

AlaskanLS

Please read page IN-27 and IN-28. If everything checked good then maybe it's a corroded harness pin. Do you have salty roads where you live?

Nad1370

Possible OCV valve on Bank 1.
This will chug or even kill your motor at idle if stuck in the RETARD position.

Also might be a jumped tooth on the timing belt on bank 1.

What was prior work done before having the 12 issue?

JonnyO78

Oh man. I went to check the crank sensor today. I decided to pull it because the pins were hard to get to and it looked like a simple single bolt. It IS a simple single bolt. However, when I started to pull it I fount it well stuck to the housing. A couple of taps with a long screwdriver from the top and it seemed to be coming out. THAT WAS NOT THE CASE. It broke the plastic body away from the metal sensor housing. So with a little drilling, screwing, and digging at it with a pair of needle-nose I pulled the rest of the sensor out. It was disgusting. There was so much caked dirt and salt and other mess up in and around the sensor. I cleaned it all out and ran a bore brush around in it and it looks a lot better now. Sitting open waiting for the new part.

While I was in the bay, I figured I'd check the plugs, they are all rather fouled looking. So I guess I'll be getting some new plugs along with the crank sensor. Some new wires as well, since these were off another older car that now has fresh new wires (but needs serious steering and suspension help).

This leads me into another question: OEM or nah? I know some folks are OEM only types, but for a sensor like this, it's about $150 compared to as little as $15. Is this a place where it really matters? Is a tested good used one better than an aftermarket?

JonnyO78

Replaced the crank sensor. No change. I'm going to have to test the damn harness.

AlaskanLS

Do you get any other code beside code 12? Usually most of the time it shows 2 or 3 codes, couple of which are false positive. Like for example if your getting EGR code, which is 71, it will start showing couple of codes that in lower in number with EGR code. Those other two codes are usually false positive.

JonnyO78

Full story of 12: I got it and it was running. Drove it about 10 miles and had to park overnight because of a flat. Drove it home. Was starting it regularly keep the battery charged and get oil moving while waiting on capacitors and other parts. Stopped starting, found code 12. Re-capped the ECU; no change. Replaced the caps and rotors with some from a parts rig. Started, ran fine for a while and I drove it 32 miles daily commute. ied on my way home. New caps and rotors. Up and running for a few weeks; there was a regular code 13 and some hard stuttering starts, but otherwise nothing noticeable. Until I drive about 1'30" and then went to an eye doctor for ~2 hours; failed to start. Started next day, drove home. Keeps wanting 12+ hours of cool-down between 1+ hours of driving. Now it's back to a 12 and will start after a disassembling and reassembling the ignition system until I push it and it dies again. I figured it was the cam/crank sensors, but I have replaced all of them and it's still not starting.

I have inspected my harness around the front near the sensors and found that the LH coil plug clip is broken off. I don't think any of the other plugs are making poor connections. I will say that the deposits on the point in the caps and rotors look abnormally heavy. I should probably change out my plug wires, and my plugs looks a little fouled. However, I don't think these are related to the 12 or 13. I'm down to testing out the harness, which seems to be a seriously painful task.

AlaskanLS

Maybe it's a faulty ECU, if every thing checked good. recapping ECU does not assure that it will fix malfunctioning chip inside the ECU.

JonnyO78

I already did the re-cap.

I've been systematically pulling it apart. Disassembled the RH cap and rotor for inspection and put them back together. I got the crank pulley off and inspected the entire timing assembly. I pulled a lot of greasy dirt and bits of my idler pulley that had failed a few months back; one of the bearing plates and several bearings had fallen inside. Also found my LH coil pack has a broken connector, and the RH has a poorly spliced connector on that side. I used liquid electric tape on the crappy splice, but I think I'll go back and replace the cheap splices with some butt connectors and heat-shrink. Plugged everything back together and it fired up. Going to button it all up tomorrow and run a block test and see if I'll be pulling the motor to replace the head gaskets.

In other news I picked up my 5th LS today. A 97 with hemorrhaging cam seals. $400. Hopefully I can get the 94 out of the way now.

AlaskanLS

Sorry I meant recapping ECU doesn't assure that it will fix malfunctioning chip inside the ECU.