I am about to purchace a 97 Miata Limited Edition which has been sitting in a garage for some time. Seller has to smog and register it before sale.. well... it passed the smog test but the ODB2 computer failed ??? Seller claims it failed because he recently gave it a new battery and it needs to be driven a while before the ODB2 computer comes back up - is this just a minor issue or should stay away from this one ?
Another factor: it has 97K miles on it and he's asking $4K is that reasonable ??
It's true that a car will fail the smog test if the OBD computer hasn't gone through enough "drive cycles"
The only problem is though, that you don't know for sure that he didn't just clear the codes to sell the car, and a "check engine light" will pop up after a while.
It very well *could* be just what he says, but unless you trust him, or have some recourse you don't know for sure.
4k for a 97 sounds like a good price if the car is in nice shape.
You might try telling him you will hold back $500.00 until it can fully pass the inspection. If he has nothing to hide, he shouldn't have a problem with it.
Sounds a little strange to me. Where I live a smog test is not an issue. However, a smog test in the next city (where it's required) will fail if the ECU light is on, or does not work, regardless of a pass or fail at the tailpipe.
The computer will come back up as soon as ignition is turned on if it is not broke. The seller lied.
If you replace the ECU with an aftermarket one, it would fail OBD II. I just happen to know this. :) That car would be illegal to drive, at least here in the USA. But that would suggest a big turbo supercharger may have been installed on it in the past. Which would suggest lots of wear and tear.
Why not try calling the shop that did the test and ask in what way OBD II was failed? If there was no OBD II response, open the ECU box behind the passenger seat and have a look.
Of course the computer comes back up as soon as the battery is connected BUT...
the codes can be cleared, and the registers are in a zero state.
Many of the functions that the OBD computer monitors require several drive cycles before they can accurately register. Thats' why sometimes you can clear a code, and the light will come back on a day later, rather than right away.
Some states (like Nevada) REQUIRE that the computer has gone through enough drive cycles to register accurately. In past years they would allow an old-fashioned tailpipe sniff test, but no longer.
The reason why is that they don't *actually* test the car anymore.. they simply communicate with the car's computer and say "how are you running"... if the car responds "fine, everything is okay" then it passes.
If you notice, the smog cert on OBDII cars doesn't provide the specs for O2, CO, etc like they do with a manual test... it just says PASSED, or FAILED.
Anyway, like I said earlier... it's entirely possible that it's legit, but it's also possible that he just cleared the codes so it would't be lit when folks test drove it...
According to seller the smogstation was aware of this battery/computer problem.... so he has to re-smog it again next week after driving it for a while.
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