How do they know?

[GRUNT]

This week hopefully I will be going to by a 4.0 HO out of a 91xj. I plan on rebuilding it(stroker) and have already made a list/skematic of parts needed etc... Yet, in my research on motor swaps I find a common rule. It is said that you must replace your current motor with an equal year or newer. Is this to ensure you keep with emissions standards? OBD-1 guys stay OBD-1 and 2 guys stay 2?! :eek: This 4.0L is multiport and so is my lil 2.5L, does this mean they are same generation of emissions compliance or not?
And to the question at hand.... How does DMV know what you have going? When I go to get emissions, what are they looking for? Sure they may notice it went from a 4cyl to a 6cyl but how do they know if the motor is "newer?" Are they only concerned if it does not pass?

How frustrating to get this far and prepared to be snubbed by something like this. I could use any help one may have. I got passed around on the phone with AZDMV the other day....:banghead:

[My Green Jeep]

I would have to say they are only concerned about is if it passes
or not and if it has the required equipment it needs to pass..

We had a 78 Chevy Blazer 4x4 the engine was not the original
one that came out of it...

they didn't care...

just my 3 cents worth :em19:

[GRUNT]

Bump...
Any ideas? I know you motor heads out there have an answer for this!

[ecamp55]

I don't know the rule in AZ. I do know however, that in most states that require emissions testing that you may change out your engine for the same year or newer and the vehicle is smogged based on the year of the engine.

[rubicontrail]

If it is a 91 then it is not OBD II. OBD II cars are typically built in 1996 and later.

I am not sure on a pre-OBD II vehicles. But on an OBD II vehicles they don't check anything with whether your engine matches the vehicle. They just record your VIN number and plug in the computer to the OBD II port. The OBD II spits back whether all is okay with the emissions (if you have an OBD scanner you can see the status before you even go in), and you go on your merry little way.

[Markos]

The key is the engine management system. Like Rubi said, you need and OBDII system. If I dropped a stroked 91 block into my XJ and changed nothing else, nobody would be the wiser. While technically it's an older engine, all emissions controls stayed the same.

I think the law is meant to prevent people from dropping a carburated 350 into their chevy S10...

[rubicontrail]

Well, Allen has a YJ so I think the 91 XJ block should work fine.

It's a silly law anyway... you need to pass emissions one way or another based on the year of the car, not the engine so I am not sure why it matters.

[GRUNT]

Talked to a lady at DMV and she said there is no provision that states you must use a newer year engine in you vehicle when you replace it. She said the only thing is it gets(forgive me I am at work and forgot the exact verbage) title-C...?! She said it is something that states to the effect that the mileage cannot be verified... I will call again tomorrow to double check with another representative before I go pick up my motor. Just an FYI for you guys... :D