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Discussion Starter #1
Okay, so over the Winter, the PCM on my 97 suddenly took a dump. I sourced out a good used one, and the car runs great with it.

The thing is, the catch code is LJC1, where the original was FTE1. I had talked to RobertP about it, and he claimed the differences were minor (shift tables), and that it should be compatible.

The issue is, my city gas mileage was 19, now it's 17.5 with the new PCM. Coincidently, I picked up a spare after getting the first one, and it is FTE1. I verified it worked, and threw it on the shelf.

Is it possible the lower mileage is caused by a different calibration in the PCM?

Thanks,
Al
 

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...Is it possible the lower mileage is caused by a different calibration in the PCM?

Thanks,
Al
Probably.

Most of the differences were somehow option based, and emission based.

The FTE1 is the common Tbird one. I replaced it with an MBE2 when it failed. :)

The EECs in my Cougars were both MBE2; no failures in those that I've seen.

Get RobertP to tune your car; that will probably not help the mileage, but you'll reeeally like it. :)
 

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Wow. I love search sometimes.

You hit nothing, change a few words and:

http://www.tccoa.com/forums/12-eec-tuning/49726-pcm-changeout.html#post433937

This is the important part:
Calif. emmisions PCM (F7SF-12A650-BB catch code LJC1)

That's a CA emissions eec; I'd bet that unless you have the rest of the CA emission-specific stuff on your engine, it's not totally happy.

A tune will fix all that. :)
 

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If you think it is calibration related and have a spare that matches the original why aren't you swapping that and checking? LJC1 is my PCM catch code, and I've never noticed any mileage discrepancies obviously mine is very tuned though.
 

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Discussion Starter #6
I just found another TCCoa article re: LJC1 being an CA emissions version. I got the thing from a junkyard in Georgia! The car runs perfectly fine with it, no differences, other than mileage apparently.

I am going to finally throw in the FTE1 tonight, it's been raining. Will take a few weeks to get good gas mileage data.

Why would I need a tune on a stock vehicle? Not looking to run 93 octane.

Al
 

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...Why would I need a tune on a stock vehicle? Not looking to run 93 octane.

Al
The tune I run all the time in the tbird is for 91 octane; it gets the best mileage, ~26mpg, and works well with the stock engine.

Lazarus, OTOH, has a PI intake, 24lb injectors, dual 2.5" exhaust w/X pipe, and mods to keep cyls 7&8 cool, improving the amount of timing you can use.

If I run it on premium, I get the best mileage anyway; I manage 24mpg in it, foot permitting.

My butt dyno says the tune woke the tbird up, with no mods. :)

All of them have 2002 transmissions, and need slight tuning to work best; my tune for them drives like a manual. :)
 

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Discussion Starter #8
Mine is 100% stock. It already gets 26 MPG hwy on 87 octane.

My old 95 used to get 28, sometimes 30. Actually got 24 city/ 31+ hwy when I had a code for "excessive EGR flow". Car did not ping either. There is definitely some mileage to be gained by increasing the EGR flow in the tune, if that's possible. As long as it doesn't throw a code.

Al
 

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Mine is 100% stock. It already gets 26 MPG hwy on 87 octane.

My old 95 used to get 28, sometimes 30. Actually got 24 city/ 31+ hwy when I had a code for "excessive EGR flow". Car did not ping either. There is definitely some mileage to be gained by increasing the EGR flow in the tune, if that's possible. As long as it doesn't throw a code.

Al
FWIH, eliminating the EGR pretty much equalizes the city/hwy mileage, but people here have reported worse. :)

My drive is 90% interstate, so EGR is a wonderful thing.
 

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Discussion Starter #10
I was talking about increasing the EGR flow, not eliminating it!

Al
 

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Discussion Starter #12
I used to get 30 quite often in my old 95. Probably averaged 28 hwy over the time I had the car. This is driving 75-80 with the cruise on.

Got a solid 31.5 when I had a code for "excessive EGR flow". I used to get it around once a year, then it would go away on it's own. The gas mileage stopped increasing though, I guess the EGR pipe was getting clogged at that point. Have no idea what caused the excessive flow.

The 95's with their 3.08's seem to get the best mileage. My new 97 got 26 hwy on the only long trip I have taken, so not too far off. Would be nice to get a tune to increase the EGR flow to increase mileage.

What happens if a PCM that is tuned takes a dump? Can you move the "tune" to a good PCM?

Al
 

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As long as it is on a chip, and the ECMs are the same catch code, then yes. If it is flashed through the OBD2 port, you will need to re-do that after replacing the ECM.
 

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For flash programming on the xcal2, I have the PRP, and the allowance to program MY cars; to do multiples, I had to send proof of vins and SN's of the xcals, iirc.

You have to have the EEC working enough to remove the tune from it, or you have to send the xcal back to SCT for a reflash to reset/remove the stock tune. And that's expensive.

I had a 97 bird with issues; I yanked the tune to see if it was the issue, and two days later it totally died; volcanoed the cpu.

(That's a highly technical term; the chip looks like it has a tiny volcano in the middle. This is a "non-recoverable error in the industry", lol.)

If I hadn't removed the tune, I would have probably have bought a new Xcal2; it would have been cheaper. :)

I lost a "Count" on the 5 VIN changes you're allowed to do, so that xcal reads 4 now.

It's a pain to change it out, and you don't want to go back and forth; there's only 5 tries. :)
 

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Discussion Starter #15
I never had an issue with the PCM on the high mileage 95 T-Bird and 96 Cougar we had. Had the 97 for two months before the 63k mile PCM suddenly took a dump. That, plus Grog6's, plus many others I have read about leads me to believe the 97 PCM's have issues.

I will look to either picking up either a spare FTE1, or have my 63k FTE1 rebuilt (and sell the LJC1 to someone from sunny CA, since finding out it's a CA emissions version).

Some irony to this: after topping off the tank to check the mileage on the "new" 200k mile FTE1, I discovered the LCJ1 put out 19.2 MPG on it's last partial tank! Makes no sense, as the temps and driving conditions were identical to the prior two full tanks where it put out it's typical sub-par 17.5 MPG. Especially since this 97 has been consistent as far as gas mileage is concerned.

Al
 

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Maybe the new ECM just needed some time for all the adaptive values to adjust to the vehicle, and that's why the mileage wasn't so good at first?
 

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2mpg is within the difference of a few % of alcohol in the gas; two different stations will show that much variation.
 

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Discussion Starter #18
I had the LJC1 in there for over 4 months. Many tanks of gas, though I wrote off a couple Winter one's that involved extensive defrosting to melt heavy snow.

Going by how the gauge is reading after 100 miles, I appears it is getting really good mileage with an FTE1 back in there.

Al
 

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For what it is worth I am completely interested in that LJC1 pcm as a spare catch code matching pcm if you are selling it, let me know a price shipped to 89129 via private message.
 
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