Engine Codes 511, 212, And 412. Do I Need An Exorcist Or A Mechanic?

rockandrollfrankie

Active User
May 5, 2017
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Tampa
Hi guys and gals! I've been trying to get my '95 GT back to running like a proper car, and now I'm deep into some ECC diagnosis. Can anybody help me with the codes below, specifically the 511, 212, and 412 ones?

Okay, so here's what I did last night:
  1. Reset the codes with the diag tool.
  2. Drove the car until it was normal running temp.
  3. Ran a KOEO test. Got 511 & 565 operational codes, and 172 & 212 continuous codes.
  4. Ran a KOER test and got 172 & 136 running codes.
  5. Ran a KOER test again (because I didn't RTFM), this time got a 412 running code and that's it.
  6. Ran the cylinder balance test. It shows cylinders 2, 3, 5, 6, 7, & 8 all throwing codes. Good thing 1 and 4 are still okay, huh? Ha!
511 - This car was "tuned" by a previous owner. Would that cause a 511?

212 - Somewhere along the way this car received a billet Accel distributor and coil. Just giving full disclosure to help the diagnostic process. Should I be chasing a wiring short?

412 - The IAB is new and not a lick of carbon on it. I set the idle routine Friday with a hard idle setting of ~700pm. Just above surging. The car sometimes idles at 900rpm and drives great, other times it'll idle at like 1500rpm, jump to 2500rpm in between gears, and then almost fall on its face at 600rpm. Do I need to call a priest?

Bonus points! Some coolant leaked onto my foot as I was driving. Heater core or head gasket?
 
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Bonus points! Some coolant leaked onto my foot as I was driving. Heater core or head gasket?

On your foot while driving? That's strange, as no coolant should be on that side of the dash. The heater core is on the passenger side, and if it's leaking, you'll see it dripping out of the AC condensation drain on the lower pass side of the firewall inside the engine bay. It usually drops on the exhaust and boils off, so it sometimes never makes it to the ground if it's a small leak.
 
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On your foot while driving? That's strange, as no coolant should be on that side of the dash. The heater core is on the passenger side, and if it's leaking, you'll see it dripping out of the AC condensation drain on the lower pass side of the firewall inside the engine bay. It usually drops on the exhaust and boils off, so it sometimes never makes it to the ground if it's a small leak.

Are we certain that this is coolant and not water from the evap? Whether it is or isn't, there is a drain that runs out to the firewall and drip onto the passenger side exhaust manifold. This is likely plugged or has been removed.

Just re-read the above post. The drain is probably plugged or has been removed at some point, if you're feet are getting wet.
 
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This water was hot! I was driving barefoot and all of a sudden my right foot was on fire. I wasn't even running the AC, but I did have it on all day the day prior so maybe the pan was full still? Maybe drain is clogged and the water heated up from the exhaust? It wasn't scalding so it might not have been heater core water, but it was certainly uncomfortably hot.
 
This water was hot! I was driving barefoot and all of a sudden my right foot was on fire. I wasn't even running the AC, but I did have it on all day the day prior so maybe the pan was full still? Maybe drain is clogged and the water heated up from the exhaust? It wasn't scalding so it might not have been heater core water, but it was certainly uncomfortably hot.


I think your A/C condenser drain is plugged and your heater core is leaking. Generally, both should be true if your feet are wet with hot water/coolant.
 
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Snake your drain on the passenger side, and see if it is in fact clogged.

You can bypass the core in the engine bay. Parts stores generally sell a heater-core bypass that's a fitting and two hose clamps.
 
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Looks like it's coming from there.

IMG_0097.JPG
 
Ah, looks like it's coming from the floor vent, which means the condensation drain is probably clogged. I'd try to clear it, and possibly bypass it. Do you even need heat in Florida?
 
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Yes, ah no, well maybe if your a skinny cracker.
Wait till your engine compartment has cooed down and you'll find a drain hole passenger firewall below the ac dryer, just stick a straw or something similar in there, I say straw because it's flexible and the opening will catch some of the filth that has accumulated and you will not poke anything. Notice too it should be just water/dirty junk and not sticky antifreeze.
 
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Blow a little air in there, as long as it was not antifreeze on your foot.
412 did you do a base idle reset? Whats it idle at?
212 did you clear the codes when you stuck your distributor in or after

Like with a compressor or with the straw? I smelled a faint smell of coolant I *think* but I'm not sure. I'll give it the nose check in a few.

Idles at whatever it feels like. Sometimes it behaves at 900rpm like it's supposed to. Sometimes 650rpm stumbling. Sometimes 1500rpm flying. In between gears sometimes the rpms drop right down, sometimes they'll spike up to 2500rpm while shifting.

When it's doing the 1500rpm idle thing it'll stay at 1500rpm while the car is rolling, even in neutral. When I come to a complete and total stop the idle will drop back down. It's possessed.

Cleared the codes before I did any of the diagnostics in the OP. Distributor was in the car when I got it. The eyeball test says there's a short in my ignition module/spout circuit. My buddy who sold me the car said this thing "likes to eat ignition modules" so I have to assume I have a bad wire in the circuit somewhere. I'm gonna have to get down and dirty with the Fluke and test it.
 
You can take a small hose and stick in there and just blow on it, don't need compressed air.
We may need a 94-5 specialist to jump in here but my money is on the computer but these sn95 5.0s are wired a little different than fox's so I may be in left field.
Eec, ecc, byob, naacp, no matter, as long as we know what we mean.