94 PCM compatible with 95 cars? - TCCoA Forums
 
LinkBack Thread Tools
post #1 of 19 (permalink) Old 07-15-2017, 05:57 PM Thread Starter
1st Gear Poster
 
Join Date: Mar 2013
Location: Glendale AZ
Posts: 35
Garage
94 PCM compatible with 95 cars?

I have a 95 Cougar with what I am beginning to suspect is a fried PCM. I also Have a 94 thunderbird parts car standing by waiting to help test my theory out. Before I go swapping car brains all Willy nilly, are there any differences between these two cars that would make these PCMs different? Are there any hidden dangers lurking within my plan? I don't want to toss a transmission on a hunch, or buy a fresh 200$ non-returnable PCM without some kind of evidence. Noid lights sound fun, but a quick PCM swap is cheaper and requires no tool rentals.
fastrdinyu1138 is offline  
Sponsored Links
Advertisement
 
post #2 of 19 (permalink) Old 07-15-2017, 06:02 PM
PostWhore
 
ClintD's Avatar
 
Join Date: May 2007
Location: Parlin, New Jersey
Age: 45
Posts: 1,369
Garage
If remember correctly the 95 A5W0 is a better calibration but something has to be updated in the trans. You can use the 94 PCM in the 95 without a problem but it's not optimal.

I've come into this world with nothing and still manage to have some of it left.

ASE Master Technician and Advanced Level Specialist.
It's not what I know, It's knowing what I don't know.

1994 Thunderbird, 4.6 V8, PI heads, SVO Blower, 8# pulley, 2.5 duel exhaust, 4R70W, MarkVIII converter, Mark VIII differential, Trac-Loc, 3.73 gears, H&R 1.5 lowering springs, bilstien rear shocks and SC front struts.
ClintD is offline  
post #3 of 19 (permalink) Old 07-15-2017, 07:18 PM Thread Starter
1st Gear Poster
 
Join Date: Mar 2013
Location: Glendale AZ
Posts: 35
Garage
Thanks, the car is in the shop right now (and has been for 4 days without a diagnosis) because its hot is AZ and I got sick of sweating. But I'm going to get my keys back monday, make a noid light and get to testing. The LTFT bank 1 is -.8 while bank 2 is at 25. Timing advance is at 22 degrees at idle, so I'm thinking bad brains or a hanging injector.

Sent from my VS987 using Tapatalk
fastrdinyu1138 is offline  
Sponsored Links
Advertisement
 
post #4 of 19 (permalink) Old 07-15-2017, 07:56 PM
PostWhore
 
ClintD's Avatar
 
Join Date: May 2007
Location: Parlin, New Jersey
Age: 45
Posts: 1,369
Garage
I'm willing to bet its a bad injector rather then a bad PCM.

I've come into this world with nothing and still manage to have some of it left.

ASE Master Technician and Advanced Level Specialist.
It's not what I know, It's knowing what I don't know.

1994 Thunderbird, 4.6 V8, PI heads, SVO Blower, 8# pulley, 2.5 duel exhaust, 4R70W, MarkVIII converter, Mark VIII differential, Trac-Loc, 3.73 gears, H&R 1.5 lowering springs, bilstien rear shocks and SC front struts.
ClintD is offline  
post #5 of 19 (permalink) Old 07-15-2017, 07:59 PM Thread Starter
1st Gear Poster
 
Join Date: Mar 2013
Location: Glendale AZ
Posts: 35
Garage
I'm really starting to agree. The more I think about it the more sense the symptoms make

Sent from my VS987 using Tapatalk
fastrdinyu1138 is offline  
post #6 of 19 (permalink) Old 07-15-2017, 10:42 PM
Seasoned PostWhore
 
Join Date: May 2003
Location: Tinton Falls, NJ
Age: 36
Posts: 7,428
Garage
Send a message via AIM to MadMikeyL
94 PCMs were known for hanging an injector open, and the 95s have he same issue to a much lesser extent, but if that happens, your main complaint is going to be a misfire and raw fuel out the exhaust, not just a fuel trim issue. If you do have an injector hanging open, swap it out for one on another cylinder and see if the problem follows the injector or stays where it is. Also a cheap and easy test if you don't have a noid light is to hold the tip of a long flat-head screwdriver against the injector and put your ear to the end of the handle. If the injector is pulsing, you will hear the clicking of it going on and off through the screwdriver.

-91 Cougar LS, coming soon, complete overhaul with a 427" Windsor.
-90 XR7 5-speed black on black w/sunroof, MP2, coated rotors, double intercooler, 15%OD, ported heads, comp stage 1 cam, 85mm TB, 90MM LMAF, 80# injectors, and ported big valve heads
-98 Mark VIII LSC, Procharger P600b, TR3650 swap and 3.73s.
-90 SC Automatic rustbucket winter beater
-97 Tbird Sport 4.6 Nice weather daily driver
-"Your buddy Mike is INSANE!" -ClintD's dad
MadMikeyL is offline  
post #7 of 19 (permalink) Old 07-15-2017, 11:42 PM Thread Starter
1st Gear Poster
 
Join Date: Mar 2013
Location: Glendale AZ
Posts: 35
Garage
I will definitely give the screwdriver idea a shot if I can't get a noid light. There is a strong fuel and eggy smell and I can hear what I think is a miss in the exhaust. I have a parts car so when I head to the shop ill make sure to bring a few injectors, screwdriver, noid light, an ECM and the required tooling

Sent from my VS987 using Tapatalk
fastrdinyu1138 is offline  
post #8 of 19 (permalink) Old 07-15-2017, 11:52 PM Thread Starter
1st Gear Poster
 
Join Date: Mar 2013
Location: Glendale AZ
Posts: 35
Garage
Also, if the PCM does hang an injector, should I replace the injector as well? If so, is there an upgrade you would recommend for my humble stocker?

Sent from my VS987 using Tapatalk
fastrdinyu1138 is offline  
post #9 of 19 (permalink) Old 07-16-2017, 12:29 PM
1st Gear Poster
 
Join Date: Mar 2017
Posts: 58
You can test this. If the PCM is drawing the injector open you'll have ground on your 12V line all the time. The 12V holds the injector closed - ground opens it. My PCM shorted internally for cylinder 2 thus keeping the injector open constantly.

Also - the 95 PCM has a better tune for the transmission as the 94 trans tune backs off line pressure (eating 3rd gear and overdrive) in an effort to save fuel economy. There's a TSB on it. Search for: TSB 95-8-3

I have a 1994 SC with a 2003 Mustang 4R70W that does this. The previous trans died a horrible 3-4 death. I've been considering the '95 SC PCM for some time now. Finding one is the problem.
Attached Files
File Type: pdf tsb-95-8-3.pdf (18.6 KB, 4 views)
scottjohnston is offline  
post #10 of 19 (permalink) Old 07-16-2017, 01:17 PM
PostWhore
 
ClintD's Avatar
 
Join Date: May 2007
Location: Parlin, New Jersey
Age: 45
Posts: 1,369
Garage
Quote:
Originally Posted by scottjohnston View Post
You can test this. If the PCM is drawing the injector open you'll have ground on your 12V line all the time. The 12V holds the injector closed - ground opens it. My PCM shorted internally for cylinder 2 thus keeping the injector open constantly.

Also - the 95 PCM has a better tune for the transmission as the 94 trans tune backs off line pressure (eating 3rd gear and overdrive) in an effort to save fuel economy. There's a TSB on it. Search for: TSB 95-8-3

I have a 1994 SC with a 2003 Mustang 4R70W that does this. The previous trans died a horrible 3-4 death. I've been considering the '95 SC PCM for some time now. Finding one is the problem.
in the TSB is a very important warning.

"CAUTION:
THE PCM RECALIBRATION OR REPLACEMENT AND TRANSMISSION MAIN CONTROL ASSEMBLY CHANGES MUST BE DONE TOGETHER OR TRANSMISSION OVERDRIVE BAND DAMAGE WILL RESULT. DO NOT USE THE 1994 MAIN CONTROL ASSEMBLY WITH THE 1995 PCM CALIBRATION, OR THE 1994 PCM CALIBRATION WITH THE 1995 MAIN CONTROL ASSEMBLY."

I've come into this world with nothing and still manage to have some of it left.

ASE Master Technician and Advanced Level Specialist.
It's not what I know, It's knowing what I don't know.

1994 Thunderbird, 4.6 V8, PI heads, SVO Blower, 8# pulley, 2.5 duel exhaust, 4R70W, MarkVIII converter, Mark VIII differential, Trac-Loc, 3.73 gears, H&R 1.5 lowering springs, bilstien rear shocks and SC front struts.
ClintD is offline  
post #11 of 19 (permalink) Old 07-16-2017, 02:03 PM
1st Gear Poster
 
Join Date: Mar 2017
Posts: 58
I read that too Clint. Need to do some research to find out what part they're referring to. As it is now the car only does it when driving in really warm summer conditions (90 degrees plus outside). Am thinking about a transmission cooler. It never does it on wide open throttle, just normal driving. I've learned to manage the throttle to minimize the slip/oddness that comes from it.
scottjohnston is offline  
post #12 of 19 (permalink) Old 07-16-2017, 04:06 PM Thread Starter
1st Gear Poster
 
Join Date: Mar 2013
Location: Glendale AZ
Posts: 35
Garage
So testing for PCM by swapping my 94 parts car unit into the 95 is probably not the best idea. Good to know! Luckily the Napa down the road rents Noid lights so I can check the PCM that way.

Sent from my VS987 using Tapatalk
fastrdinyu1138 is offline  
post #13 of 19 (permalink) Old 07-17-2017, 12:15 AM
1st Gear Poster
 
Join Date: Mar 2017
Posts: 58
I doubt it will be a fatality but why pull it when you can noid? In this case you don't want to avoid the noid?
scottjohnston is offline  
post #14 of 19 (permalink) Old 07-17-2017, 09:48 AM Thread Starter
1st Gear Poster
 
Join Date: Mar 2013
Location: Glendale AZ
Posts: 35
Garage
I love me some noid

Sent from my VS987 using Tapatalk
fastrdinyu1138 is offline  
post #15 of 19 (permalink) Old 07-17-2017, 10:08 PM Thread Starter
1st Gear Poster
 
Join Date: Mar 2013
Location: Glendale AZ
Posts: 35
Garage
Update: noid light test shows all injection connectors pulsing. I did not have enough time to swap injectors before the place closed. I could have just taken the car home, but I like the idea of something being done with it while I'm at work. I need this thing running quickly because i need to swap lifters on the wifes jeep before the semester starts

Sent from my VS987 using Tapatalk
fastrdinyu1138 is offline  
post #16 of 19 (permalink) Old 07-19-2017, 11:15 PM Thread Starter
1st Gear Poster
 
Join Date: Mar 2013
Location: Glendale AZ
Posts: 35
Garage
Shop says all the injectors are fine as well, they are at a loss. This is ridiculous, I'm swapping to 5.0L car the first chance I get. I never have this kind of trouble diagnosing the OHV engines.

Sent from my VS987 using Tapatalk
fastrdinyu1138 is offline  
post #17 of 19 (permalink) Old 07-20-2017, 06:30 AM
PostWhore
 
ClintD's Avatar
 
Join Date: May 2007
Location: Parlin, New Jersey
Age: 45
Posts: 1,369
Garage
there is a PCV hose that crosses under the intake at the back of the engine, check to make sure that didn't split and collapse. that would cause missing and fuel trim problems. My 94 I got because the guy gave up diognosing the problem which was the PCV line the whole time.

I've come into this world with nothing and still manage to have some of it left.

ASE Master Technician and Advanced Level Specialist.
It's not what I know, It's knowing what I don't know.

1994 Thunderbird, 4.6 V8, PI heads, SVO Blower, 8# pulley, 2.5 duel exhaust, 4R70W, MarkVIII converter, Mark VIII differential, Trac-Loc, 3.73 gears, H&R 1.5 lowering springs, bilstien rear shocks and SC front struts.
ClintD is offline  
post #18 of 19 (permalink) Old 07-20-2017, 07:58 PM Thread Starter
1st Gear Poster
 
Join Date: Mar 2013
Location: Glendale AZ
Posts: 35
Garage
Nice! I told the Aamco guys about it, they said they would smoke it again. It wouldn't show on an intake smoke would it?

Sent from my VS987 using Tapatalk
fastrdinyu1138 is offline  
post #19 of 19 (permalink) Old 07-30-2017, 01:10 PM Thread Starter
1st Gear Poster
 
Join Date: Mar 2013
Location: Glendale AZ
Posts: 35
Garage
Update: the Aamco guys have had the car for coming up on 3 weeks and aren't very good at listening to customers so I have no idea what happened with the PCV hose. They decided the only place left to look for problems is behind the timing cover (I've recently replaced the tensioners and guides but it had no effect on engine operation) , so They re-timed the cams and I'm SUPPOSED to get the car back tomorrow. But I was also SUPPOSED to get it back last Thursday. I have a feeling their timing theory didn't pan out.

Sent from my VS987 using Tapatalk
fastrdinyu1138 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the TCCoA Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome