PCM Pin Layout - CEG Archives

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Hey guys,

I did a search and couldn't come up with anything. I need a Pin layout of a pre-98 Zetec. I'm trying to see if I can make the homemade shift kit the ZX2 guy's are making, And I can't find a PCM layout so I know what wire i need to splice into.

Thanks,
-Josh

If you can receive a FAX, I'll send you the diagram.
Do you Need 1995 - OBO I
or 1997 - OBO II

Also: For Sale
1995 Contour and Mystique
Electrical and Vacuum Troubleshooting Guide
FCS-12253-95

Nope, I don't have a fax machine, Sorry.

I need it for a 96; OBD II

Actually, I just need to know where/what color the wire for the EPC is

Here you go...

http://home.wi.rr.com/buttonpuncher/Contour/Contour-Focus%20PCM%20Comparison.xls

Just ignore the Focus PCM stuff. I was trying to see if I could re-wire a Focus PCM so that I could swap out my CD4E and put in a 4F27E.

The data was copied right from my service manual. It should all be correct.

BTW, what are the ZX2 guys up to?

HTH,
BP

Originally posted by ButtonPuncher:
BTW, what are the ZX2 guys up to?

I'd like to know as well... A shift kit?? They must be doing something with a sensor input to raise line pressures is my guess.

Yup, basically they use a 10k ohm resistor on the EPC wire, it stiffens up the shifts and raises the shift points a little bit, you can even use a 20k ohm reistor to stifen them up even more. You can run a 10k ohm 24/7 20k ohm you use a switch and only use it when you have to.

all the zx2 owners that have done it have had great results, and most can chirp second reguardless of RPMs

Buttonpuncher, thanks alot man! I'll have to download a Excel veiwer to veiw it, doing so now. Thanks again though!

So they're putting it across the EPC solenoid wire? AFIK, the CD4E doesn't have a pressure sensor to trick, only the TSS (turbine shaft speed sensor). If it's the EPC solenoid, that's kinda dangerous. If you shorted it out accidentally, you would fry your PCM's output transistor(s) and possibly break your ATX. Runaway line pressure is one of the main causes for killing a CD4E.

If you don't find an Excel viewer... You are looking for Pin 81. The wire should be black with a red stripe. It would probably be easiest to tap into on the connector on the ATX instead of at the PCM.

HTH,
BP

Buttonpuncher, thank you so much! i just got that open. That's a HUGE help to me..

I can do this, its listed at 81 in the list, the black/red wire.

I'm also tempted to do the POTs mods, which basically tricks the ECT and IAT, dumps more fuel and advanced the tming (guy w/ auto zx2 went from 17.4 to 16.5 with JUST the pots mod)

Originally posted by ButtonPuncher:
Runaway line pressure is one of the main causes for killing a CD4E.

It would probably be easiest to tap into on the connector on the ATX instead of at the PCM.

Both of those thoughts came to mind for me as well... The ZX2 automatic is pretty tough. Application for application, much tougher than the Contour CD4E.

Keep us updated.

Not to be a nay sayer but people have tried the POTS mod on the Contour PCM and it causes alot of havoc. The PCM relearns very quickly. It still might work in a racing situation with limited use.

BTW, it would lean things out and add more timing. That's what the PCM does when it's getting really cold air. When its really hot out, it richens things up and pulls a bunch of timing to prevent detonation. That's why your car can be a real dog on 100 degree days.

Yeah after the line pressure comment I'm kind of weary on even doing this. Last thing I need is a blown transmission.

BP, The zx2 pcm will relearn them very quickly if you keep them also. You wire them up to a switch so that you can control it (switch it on/off) when you want to use it.

Ahhhhh, that makes sense. Kinda like the poor man's boost switch.

Basically, I'm probably going to try the POTs mod, then later down the line. Take off POTs and install a chip. Do it right, instead of half-a$$d, so to say.

That's cool. Do you know how long does it take from flipping the switch, for the effects to happen?

AFAIK its almost instant, though I can't say for sure.

Got to thinking, If they blow because of line pressure,... how do chips firm up the shifts?.. This is purely for information. because I want to get a chip sometime.

Good question. I'll be able to tell you more in a few days. I'm getting my SCT xcal2 and Pro Race software soon. In there you play with the shift points and line pressure.

I'm also wondering if the CD4E does have a pressure transducer somewhere. I wouldn't think that the TSS would be enough to regulate pressure reliably. Definitly a question for Unisys in the transmission forum.

**EDIT**
I just shot Unisys a PM. Hopefully he can help out.
**EDIT**

BP

Cool, let me know how that comes out man.

woops, those resistor values are off, its 10 ohm and 20ohm, not 10k ohm and 20k ohm

That makes more sense if it's placed across the EPC solenoid. It probably has an on resistance of about 10 ohms. 10-20k would only affect a sensors readings.

That must be a beefy resistor. 20ohms at 13.8volts must dissipate 9.5 watts of heat. That is HOT!

BP

Originally posted by ButtonPuncher:
I just shot Unisys a PM. Hopefully he can help out.

BP

Thanks for the heads up on this BP... nice to have a fun conversation `round here.

Now, down to the nitty gritty smelly ATF covered stuff.

The only info I have on the EPC is what I have listed in my FAQ's, in the tranny forum, but I will paste it in here as well because it can't hurt...

Electronic Pressure Control
The EPC solenoid is a variable force solenoid that controls line pressure in the transmission. The EPC solenoid
has a feedback circuit in the PCM that monitors EPC current. If the current indicates a short to ground (low
pressure), engine torque may be reduced to prevent damage to the transmission. (P0962, PCA)

No, for the mod of the EPC solenoid. A few people have talked about doing it, but were too afraid to do it. Mainly because none had 2G's laying around to rebuild their tranny. Would it work... Theroredically, yeah sure. As BP mentioned earlier, the CD4E is very sensitive when it comes to high pressure conditions. If you are not careful, you could wined up blowing a seal or two or even worse, cracking a drum. If you are going to do it, I would suggest only doing it if you have a way to monitor your pressure very closely. Cheapest way of doing this is with an old fashioned transmission pressure tester. Basically, it looks just like a compression tester with a nozzle that screws in the case of the tranny and a long tube that runs up to a measuring device. Might even been the same thing, but I have not actually seen one in person. Do a search on Summit or JEG's website, I think they have what I am talking about. You will also need to monitor the seperate shift circuits pressures as well.

To check these pressures - To check the main line pressure, you will find a plug on the driver side of the tranny case located by the pump housing. To check the circuit pressures, look down the left hand side of your valve body cover and you will see three small plugs sticking out of the case. That would be those.

Coming off your EPC, you will be affecting your overall line pressure, TV Pressure and the fluid flow to the TFT (transmission fluid temp sensor). Overally system line pressure runs within a range of 50-175 PSI in D,2 and 1. And 73-252 in P,N and R. Your TV pressure should always be within 0-90 PSI at all times.

Your TV pressure helps control the Line Modulator Valve and the Main Regulator Valve. From what I can tell in the oil schematic I have, it seems as though the TV pressure creates a balance against these two pistons when the higher main line pressures are applied to them, as well as helps with opening and closing the pistons.

Now... giving all this info I just layed out, I "personally" would not do it. The "bang" you get, for the risk you take doesn't seem to be enough to justify it to me. But again, I want to make it very clear - that is just me. Maybe I am getting old in my old age, so...

But since I bring up old age, it leads me to ask myself, "Why wouldn't it hurt to try?" I would have to answer nothing, as long as you know what your doing. If it doesn't work or seems the pressure is running out of control - shut the car off and take the mod out. If there are problems, running the car for an extremely short time would not hurt.

In other words, my advice is to monitor your line pressure. Install the mod in a way that it can quickly be removed. Perform the procedure in your drive way and not at a friends house.

If you do decide to do it though, feel free to shoot me a PM and I will be glad to answer any other questions or concerns you might have.

Uni,

Thank's alot for all the insight you've given me. I've decided against the mod, But rather decided I will be going with a chip instead.

I've never heard of the problem with the CD4E with a chip installed, And a chip.. In this case would net me more power than a simple pressure line trick would.

With my car going on 140,000, and being my only way of transportation. In my honest oppinion it's better to leave it alone (Or atleast in this situation do it right, with a chip.)

Again, I thank you for taking the time to post the post you have. Not many people would take the time you did to explain it to us.

Thanks,
-Josh

WOW! Thanks for all of the info!!

Originally posted by unisys12:
Basically, it looks just like a compression tester with a nozzle that screws in the case of the tranny and a long tube that runs up to a measuring device. Might even been the same thing, but I have not actually seen one in person. Do a search on Summit or JEG's website, I think they have what I am talking about. You will also need to monitor the seperate shift circuits pressures as well.

Couldn't you just use an oil pressure guage? That's what I was planning on using. (I want to be able to monitor it for my upcoming my turbo upgrade.) Something with a memory to record peaks.

BTW, what does TV stand for?

Thanks again.

Ben

Originally posted by ButtonPuncher:
WOW! Thanks for all of the info!!

No problem, that's what we're here for.

Originally posted by ButtonPuncher:

Originally posted by unisys12:
Basically, it looks just like a compression tester with a nozzle that screws in the case of the tranny and a long tube that runs up to a measuring device. Might even been the same thing, but I have not actually seen one in person. Do a search on Summit or JEG's website, I think they have what I am talking about. You will also need to monitor the seperate shift circuits pressures as well.

Couldn't you just use an oil pressure guage? That's what I was planning on using. (I want to be able to monitor it for my upcoming my turbo upgrade.) Something with a memory to record peaks.

Yeah, I'm betting it is the samething. Basically something that is able to measure fluid within a wide range of pressure.

And what does "TV" stand for? Hell... I don't know, but I will find out!

Alright... here's a link to an article about the AOD tranny, but covers TV pressure and what it is.

I stumbled across what TV stands for today too. Throttle Valve. It is an old reference when cars used to regulate the transmission pressure with a rod from the throttle. It's funny how that old stuff sticks.

BTW, ohhh sooo close to 1000 posts.