Real time help--code 12

[KliersLC]

Howdy,

I was up in Doug's neck of the woods a few weeks back, and the 80 threw a code 12 at me. I called Doug and he found that it was some sort of problem with the ignition circuit. However, there were no other symptoms and the code went away after about 5 min.

Sooo,
This evening the wife headed off to the movie store and noticed a lack of power and the CEL, so she came home (yup, I'm proud ). Anyway, it is throwing a code 12 again and there seems to be a noticeable drag or reduction in power. It feels like it is only in third gear when I let of the acc, but I have verified that it shifts into all four gears.

The rig has about 145k, AFAIK stock ignition components.

Any ideas and a definition for code 12 would be very helpful.
Thanks,
Dan

off to excercise jedi search powers....

 

[IdahoDoug]

Trouble Code 12 reads: "Owner of a vehicle displaying Code 1-2 should be advised several expensive and complicated SFI components are malfunctioning and need to be diagnosed with a diagnosticator modulator extremis. Said owner should drive north about 2 hours and offer the title of said vehicle to DougM in order to restore said owner's Cruiser Karma."

Here's what my 93 FSM says:

System - RPM signal
Diagnosis - No "NE or "G1", "G2" signal to ECM within 2 seconds after cranking the engine.
Trouble area(s) - Distributor circuit. Distributor. Starter signal circuit. ECM.

So, do you think the drag is your imagination, or is it because it's getting cold at night and the engine did not warm to the point the torque converter will lock up. If it's not locking up you'll have a few hundred extra RPMs and possibly some extra engine braking as a result. This should go away when the engine is warm per standard tranny programming.

DougM

 

[KliersLC]

Very funny....


I'll take it around the block a couple more times to make sure, but Jess already drove it 3-4 miles, and it is still well above freezing here.....

So, in reference to the diagnoses/trouble areas, what should I check on???
That there is engineer speak and all it says to me is pull the cap and look at it to see if it grew horns....

Thanks,
Dan

 

[IdahoDoug]

The NE, G1 and G2 wires are Red, White and Green (not necc in that order - just giving the colors of the wires you should check) coming off the distributor heading to the ECM. You might check these wires to see there's no obvious connection problems interfering with a signal. These eventually change color and end up at the ECM above the glovebox. Others have found obvious fraying issues above the glove box, and the more common area behind the valve cover where the thick bundle has heat insulation that crumbles off. Check for heat damaged wires there, and fray damage by the glove box. A search on these might turn up more info as to specifics.

DougM

 

[KliersLC]

Alrighty,
I just returned from a 10 mile or so drive and things are looking better. I traced the lack of power and engine drag to a rash of driving my T100......it coasts better....

Anyway, In my pokings around I found that the wring harness behind the valve cover is in pristine condition with all of the heat wrap in place and in good condition. The section by the firewall also checked out.

I did find that I had a very loose, but non corroded battery cable that I subsequently tightened down.

So. Ten miles at hwy and street speeds, and no code.

It rained today. It rained last time it happened as well

Question: Could moisture at the battery terminal cause this code??

Thanks,
Dan

 

[CJF]

It rained today. It rained last time it happened as well

Moisture likes to mess with distributor caps/rotors. Replace 'em if they're anywhere near due.

Curtis

 

[RavenTai]

a poor battery connection can do goofy things, hard to say,

there was a thread not long ago about a physically damaged pickup in the distributor, I cannot find that thread now for the details, If I remember correctly there is a pickup at the base of the rotor that provides cam position info to the computer be used to calculate ignition timing,

the lesser power may indicate the computer was un able to calculate advance timing and just reverted to base timing instead, making for a loss of power,

the pickup in the other thread was damaged, I forget how it got damaged worn distributor bearing? but he was able to repair it IIRC


maybe pop the distributor cap and take a close look at the pickup at the base of the rotor see if you can see anything apparent, also give the rotor a grab and wiggle see if the shaft has any slop.