Help needed :/

Hey Ron, to :SNSign:

The A9* swap is typically frowned upon around these parts, but with good reason. I'll put together a list of pluses and minuses from the things that I know of for you.

Pluses (A9*):
1. More mod friendly, to a point (the Fox guys/gals aren't immune to surging/drivability issues)

Minuses (A9*):
1. Still a stock tune, no matter how you spin it
2. May still need a tune, at the same cost of tuning the stock EEC
3. Need to purchase an aftermarket fan controller (A9* doesn't have the capability)
4. Older, slower processor
5. Need to re-pin EEC harness for swap (or purchase adapter)

And the pluses/minuses of keeping the stock EEC:

Pluses (J4J1):
1. Newer, faster processor
2. No mods necessary to keep
3. Don't need an aftermarket fan controller
4. Any drivability issues can be overcome with a tune, the same as with the A9*

Minuses (J4J1):
1. Less mod friendly when stock

I'm personally a believer in tuning the existing EEC. The choice in how to do so is totally up to you. I went with a TwEECer RT to self-tune, but there are other options available, such as the Anderson PMS, having a shop do a dynotune, or mail order chips from a reputable tuner.

Now on to your next issue. A leakdown test would give you a better indication of where the issue may be with the number 8 cylinder. Were the results performed dry? How does the compression look in the number 8 cylinder if you squirt a little oil into the cylinder and repeat the test? How does the plug look on that cylinder when compared to the others? 20-30psi difference between the cylinders may be significant if there's some sort of mechanical issue like worn rings, cracked ring land on the piston, or a broken ring itself. What I would recommend, and personally do before anything else is to clean up the oil as best I could, install a new PCV valve, and probably install an oil separator to see if the oil burning issue persists.

Hi Ron

Mr. Matt has done a good job of laying it all out for you

I've fooled around with the pcm's in these cars a bit myself

So ... I would echo what he said

If you want to see more info about the 94-95 Fox pcm retro fit .....
you can do a search using A9L or PIH and be sure to focus the search
to the 94-95 tech and tuning forums.

Tons and Tons of info
and
Peeps opinions about why OR why not to do it

Grady

94 Mustang SVT said:

Hi, i have a 94 cobra, i have a e303 cam in it i heard i can get my cam to go straight to idle if i change the computer out to a 89 fox computer and a msd ignition, i just wanted to get a little more info on this or maybe someone could help more on this. when i stop, the car will idle high for maybe 5 seconds then finally the idle will drop, also my car is burning oil, thinking it may be the heads, thats what im hopeing it is, did a cylinder check on all 8... 1-7 were anywhere from 130 to 140 but #8 was 110 also i have oil in my intake tube all the way down to the Mass air flow, im hopeing its just the heads

thanks for your time and help
Ron

Click to expand...

Just went through the same thing. #8 was 100 psi with 1-7 in the 145-150 range. #8 leakdown test confirmed a ring issue. Hope yours are heads only, I wasn't so lucky. I'm wondering if this is a common problem and is somehow related to design as it's my understanding that #8 tends to run lean on our cars.