Code 12 Help Please

[sb]

Hey Guys n Gals,

93 Auto Fastback running like crap. I bought the car in this condition. So far I have:

Changed out the MAF with a known working oneChanged O2 sensor with a brand new oneChanged plugs with brand new NGK's ( copper )and gapped to .044Changed Air Filter with brand new one ( for good measure, no oil )The car had been sitting for a bit so I put in some octane booster, fuel system cleaner and a couple gallons of 93 Octane Gas.

I cheked the voltage on the MAF and got:4V on the white wire14.7V on the black/white stripeand black is obviously ground

All this and I still get the code 12 on the ECU. The car idles but stumbles from time to time. When I give it gas, it runs sich and blows black smoke.

Also when I give it gas it seems to have a hard time going up through the RPM band, when I get to about 3K RPM the engine starts shaking pretty bad. I havent taken it any higher than that.

Any solutions\ideas\suggestions welcome.

Thanks-

Shawn

[sb]

So I unhooked the MAF and fired her up just to see, gone is the black smoke.

But of course the car goes into gimp mode and wont rev above 2500.

Plugged the MAF back in, fired it up, white smoke, then black as I step on the gas. Rev'd it up to about 3k, let off the gas and the RPM's dive down to about 500 then steady out.

Reset the ECU and tested again. Code 12 remains.

Shawn

[sb]

Unhooked the battery and cleaned the terminals for good measure. No change.

Could a Vaccum Leak cause a code 12? Im not sure where all of the vaccum hoses are, if anyone could shine some light on where to look for some cracks that would be cool.

Shawn

[sb]

Forgot to mention the car has a brand new battery too.

Also the guy who sold me the car just let me know that he "may have messed up the timing" when he changed the cap/rotor/and plug wires. I dont really trust the guys mechanical knowledge so Im beginning to wonder if the wires are even in the right order. I guess I will have to check that, however I dont think that would have naything to do with the code 12.

Come on guys I need some suggestions here!

Thanks-

Shawn

[sb]

BUMP. No Suggestions? Im going to check the timing/cap/rotor tonight. Anyone know of some common vaccum leak locations?

Shawn

[240Guroo@ProtoMotoring]

check basics first. check timing. make sure the firing order is correct. check for vacuum leaks. check surroundings.

if you feel comfortable with all the basics, time to move to the heavy stuff.

remove distributor, set crank at tdc, and set line up points at distributor gear before putting back in.

you could also try to replace maf sensor. but first, make sure there are no leaks around intake pipe to rubber hose connector leading to thottle body. all after the maf sensor. it is a common that the car wont rev after 2000+ after disconnecting the maf. also check maf connection for unwanted residue. shine em up.

you could also check and make sure injector and injector plugs are ok. unplug unjector plugs, check for residue and clean out. it is common for the plugs to trip out causing bad connection.

it's gonna be a batlle. look me up if you wanna know what a code 12 is or if you have any other questions. let me know if some of my tricks worked for you.

[180fan]

check over the ground for the mafs, clean up the plug at the mafs along with the male connectors on the mafs.

[sb]

check over the ground for the mafs, clean up the plug at the mafs along with the male connectors on the mafs.

Yep turned out to be a bad stock ground on the MAFS. Spliced a ground wire in and hooked it to the neg. on the battery. No more code 12 and the car runs normal. I hate bad wires, what a pain.

Thanks for the resoponses guys, on to the next problem: brakes! lol.

Shawn