Same friend with the 2000 SE i asked about the latches for...
Turns out his car is a CARB car, and the pre-cat has melted.
In the interest of time, he's considering taking on a Federal emissions conversion. Found that Racing Beat has the extension harness(es) necessary for this, and if all goes well on my end, he can have the ECU out of my car. He'd just need to come up with an exhaust manifold (Either 01-05, or some cheap Ebay crap as a stop-gap until winter, when it gets a Racing Beat and a Megasquirt like mine).
Has anyone done this? DIY guide for the harness so he doesn't have to spend $90+shipping+waiting for the RB harnesses?
Or am i making this too complicated?
The red 2000 Base i had last year had this conversion done, but i didn't pay much attention to it since i wasn't keeping it. Kicking myself now.
No real comment except that the "pre cat" is actually the one that does 90% of the work. No idea why they labeled it as as a pre-cat, perhaps the person who wrote the book looked at old cars as examples.
Ok- real comment- can you find pins? As in connector pins? Using the harness from the old sensors (I'm sure you will replace the pair of O2 sensors, right?)- find the body side connector, and splice that into the wires that you cut off the original sensors. Use good crimps and not solder (it's wire that does not like solder, so don't bother trying). Should work fine using the wire from the old sensor as the extension harness.
And fix whatever caused the cat to melt.
Don't bother changing the ECU. Just swap out the hard parts and move the O2 sensor. Four lengths of wire and eight quality butt connectors and you're done.
alfadriver wrote:
No real comment except that the "pre cat" is actually the one that does 90% of the work. No idea why they labeled it as as a pre-cat, perhaps the person who wrote the book looked at old cars as examples.
Ok- real comment- can you find pins? As in connector pins? Using the harness from the old sensors (I'm sure you will replace the pair of O2 sensors, right?)- find the body side connector, and splice that into the wires that you cut off the original sensors. Use good crimps and not solder (it's wire that does not like solder, so don't bother trying). Should work fine using the wire from the old sensor as the extension harness.
And fix whatever caused the cat to melt.
Might have been a bad choice of words, the car is 8 hours away from me, i'm just going from what's being told to me. But it DOES have 280k miles on it, so who knows? 
Swank Force One wrote:
alfadriver wrote:
No real comment except that the "pre cat" is actually the one that does 90% of the work. No idea why they labeled it as as a pre-cat, perhaps the person who wrote the book looked at old cars as examples.
Ok- real comment- can you find pins? As in connector pins? Using the harness from the old sensors (I'm sure you will replace the pair of O2 sensors, right?)- find the body side connector, and splice that into the wires that you cut off the original sensors. Use good crimps and not solder (it's wire that does not like solder, so don't bother trying). Should work fine using the wire from the old sensor as the extension harness.
And fix whatever caused the cat to melt.
Might have been a bad choice of words, the car is 8 hours away from me, i'm just going from what's being told to me. But it DOES have 280k miles on it, so who knows?
280k will likely put enough oil on it to stop working, sure. Or shake it to death.
But not melt it. Very different failure modes.
Old cats will melt given the right misfire.
Just pointing that out as spending money on any catalyst is expensive. And having it get ruined quickly is not good money spent.
Might want to put your earmuffs on.
He'd be doing this to run a manifold without a cat in it like i think the Federal cars did. (I didn't look closely at mine when i took it off, but i don't remember there being a cat in the manifold.)
A cheap and fast "fix" to get the car roadworthy for MATG is to chuck a cheap ebay header at it and extend the wires.
In reply to Swank Force One:
I get the idea of not running a mani-cat set up. But doing the extension of the second sensor is kind of pointless without a catalyst of sometype in there. So that would imply that the second catalyst will stay. Which will die a quick death if there's a misfire.
With a 2000, the most likely cause of a melted cat is a coil failure.
alfadriver wrote:
In reply to Swank Force One:
I get the idea of not running a mani-cat set up. But doing the extension of the second sensor is kind of pointless without a catalyst of sometype in there. So that would imply that the second catalyst will stay. Which will die a quick death if there's a misfire.
Ohhhhh i follow now. 
No idea how long this thing has been messed up. Could be coil, could be something that was fixed a long time ago, could be still broken.
Keith Tanner wrote:
With a 2000, the most likely cause of a melted cat is a coil failure.
That's what i just told him to check. I'm going to try to get my hands on a spare for my own car before i head out.
I'm starting to be driven batty by all the little changes throughout these cars' run.
One of these days i'll spend enough time with ONE to actually become familiar with it.
Keith Tanner wrote:
With a 2000, the most likely cause of a melted cat is a coil failure.
That is what killed the cat on my 2000 CA Miata. Luckily it was a while ago and the cat was still covered at the time. The cat failed a few weeks after the coil was repaired. Apparently the amount of raw fuel that was dumped on the cat while the coil was misfiring was enough to completely jack the cat.
If it's a coil failure, there will almost definitely be a CEL for multiple misfires.
GTwannaB wrote:
Keith Tanner wrote:
With a 2000, the most likely cause of a melted cat is a coil failure.
That is what killed the cat on my 2000 CA Miata. Luckily it was a while ago and the cat was still covered at the time. The cat failed a few weeks after the coil was repaired. Apparently the amount of raw fuel that was dumped on the cat while the coil was misfiring was enough to completely jack the cat.
It doesn't take a lot to hit well over 2000F. And it's not just the fuel, but the fuel AND air in proper ratios.... 
Note that the CA-spec mid pipes do not have a bung after the main cat, so you'll either need to replace it or weld one in if you want to relocate the rearmost O2 sensor back there.
I have used the Racing Beat harness extension and it's a nice piece. More expensive than using butt splices, but simpler and probably more reliable. IIRC there are special considerations when splicing O2 sensor wires, but I don't know what they are.
