Junkyard Day...30APR24

Contrary to what the California air resource board may think of the rest of the country our cars do in fact run at stoichiometric fuel ratios too. Don’t overthink it, all CA spec means in modern terms is bureaucracy. There’s no real difference in 97 between 49 state and golden state in any component, earlier years yes.
 
So...let's assume I'm not just dreaming this: it has a smoother idle. What could possibly cause that benefit?

One thing I also noticed: when starting the engine (warm), there's a distinct 2-step rpm drop. Say I start the engine and do nothing ( = stay in Neutral): with the junkyard PCM, it first revs at 1,200 very briefly, then drops to 1,000, then drops to 800 or so. These two drops are very distinct.

With my original PCM, the drop after initial startup rpm was more of a gradual settling down. I also think that (with an already warm engine) it didn't stay above 1,000 for any duration.
 
First time starting the cold engine with the "new" PCM. It starts up remarkably quickly (compared to my personal norm which is usually at least twice as long).

This could be a total coincidence...but it's encouraging.

 
There's a sticker under the hood, at the hood gasket on the pass side. It's slightly under the gasket. it's a 4 digit alphanumeric code. Mine is mbe2.
 
I searched that name on Facebook and didn't find this.

Joe
 
Let's resurrect a thread from ages ago!

Remember this one? Quick recap: started as a junkyard crawl, ended up being a thread about PCMs, more specifically using a 49-state calibration in my car which was originally sold with a California calibration.

That was over a year ago, and my car has run without issue with the 49-state PCM installed. I pretty much just forgot about it.

Now I realized that I meant to obsess about whether or not a 49-state calibrated PCM could harm CA-specific catalytic converters. So I'm trying to figure out how the programming is actually different - and I find absolutely nothing. Google AI produces this useless blurb:

Screenshot_20250701_172307_Samsung Internet.jpg

No explanation what that "significant" difference would be.

An article not specific to my engine suggests that there may be a different warm-up idle strategy and different part-throttle strategy. But different how?


I know, I know, don't overthink it. I just like to understand everything, and there's no information to be found.
It appears to be agreed-upon that CA cars get different catalytic converters. Is it conceivable that they require a specific PCM calibration? That they could be harmed by a 49-state calibration?
 
I don’t think CA cars actually did get different cats, at least not on our cars. I do remember something about CA cars having a 3rd cat while 49 state just had a resonator, but I think that was only on 94/95 4.6 cars or something like that, and I know 94/95 3.8 cars with CA emissions got DIS whereas the 49 state cars got a distributor, but for 96/97 I’m pretty sure all the emissions hardware is exactly the same. Whatever changes there are to the PCM, I seriously doubt they are significant. The only way to know for sure though would be to use tuning software to pull the stock calibration from both PCMs, then you could compare them to see exactly what is different, but I don’t think it is worth all that trouble.
 
You should do it just to satisfy your curiosity.
 
MadMikeyL said:
I don’t think CA cars actually did get different cats, at least not on our cars. I do remember something about CA cars having a 3rd cat while 49 state just had a resonator, but I think that was only on 94/95 4.6 cars or something like that, and I know 94/95 3.8 cars with CA emissions got DIS whereas the 49 state cars got a distributor, but for 96/97 I’m pretty sure all the emissions hardware is exactly the same. Whatever changes there are to the PCM, I seriously doubt they are significant. The only way to know for sure though would be to use tuning software to pull the stock calibration from both PCMs, then you could compare them to see exactly what is different, but I don’t think it is worth all that trouble.
Click to expand...

94-95 4.6 cars have third cats, and a resonator behind it. actually it’s the same as the 96-97 4.6 exhaust other than the resonator being deleted.

I’m honestly doubting there’s a true 49 state/CA difference by 96-97. As a whole the 94-95 NA 3.8s that use DIS is the only true CA specific example in specification that I am certain is different from 49 state cars
 
1997ThunderbirdLXV6 said:
What's required? A 1990s laptop?
Click to expand...

One who already has the PRP could theoretically buy the database from a CA PCM, though I'm not sure if you'd need to show any kind of proof of ownership to get the database. From there, they could compare that database against their non-CA database to see the changes.
 
theterminator93 said:
One who already has the PRP could theoretically buy the database from a CA PCM, though I'm not sure if you'd need to show any kind of proof of ownership to get the database. From there, they could compare that database against their non-CA database to see the changes.
Click to expand...

I'm Jen in this:


Side note: The IT Crowd is the most hilarious show; you must watch it.
 
You must log in or register to reply here.

Similar threads

Back
Top