Hello,

This is my first post, to say hello and post a question. There is so much material to study and learn here, and I am so grateful to members who contribute with their answers and comments.

And here is my situation. I bought in California a new 1994 Ford F150 XL 4.9L, L6 with manual transmission, 5 speeds, 300 cu. in., GAS, OHV.

Years later, in 2015, in Washington State, due to a fault indicated by the Check Engine light, a mechanic foolishly installed in my truck a substitute ECU with Federal Emissions, instead of one with California Emissions. As a result, the behavior of the engine changed considerably. The smooth running of the engine is gone.

This is the ECU they installed:
A1-Cardone P/N: 78-5754 (F3TF-XA, XB) - Federal Emissions, manual transmission.

This is the ECU I believe they should have installed:
A1-Cardone P/N: 78-6550 (F3TF-VB) - California Emissions, manual transmission.

I would like to buy the California Emissions ECU, but apparently, from what I see, all Internet stores ask for the truck’s VIN and the OEM number of the original ECU, but I do not have such OEM number because I do not have the original ECU any more.

The calibration number label on the driver door post of my 1994 F150 is 3-51F-R10 (F3AE-6E061-HHD).

Can please anybody tell me whether Cardone P/N 78-6550 (F3TF-VB) is the right ECU and, if so, what other number (other than the VIN) to give the store? Or, what would the right OEM number be for the needed ECU?

My beloved F150 has only 64,000 miles on it and I want to keep it for a long time.

Thank you for any help!

EDIT: I later found out, as I explain below in this thread, that my F150 ECU/PCM is Federal Emissions, not California. So, my apologies to the unnamed mechanic I mentioned above, since he correctly installed a Federal Emissions ECU/PCM.

 

I suspect something else is going on. I doubt you'd be able to tell any difference between those two PCM's. Unless of course, the new one is failed in some way. Have you tried pulling error codes?

 

I would agree with the previous post. I cannot believe a Federal versus Cali. emission PCM would make the truck run any better or worse. Something else has to be amiss, IMHO.


To answer your direct question, Calibration Code 3-51F-R10 translates to Engineering Number: F3TF 12A650-NB Ford Part Number: F3TZ 12A650-NB



Thanks to Subford for the info in an older thread: https://www.ford-trucks.com/forums/1...l#post14035869

 

Thank you, DPDISXR4Ti, for your comment.

Thank you, rla2005, for your response and for the ECU/PCM part number!

There is a story behind this situation with my F150.

In December 2015 I took my truck to a big chain tire and repair shop (FIxxxxNE) because the Check Engine light was lit (STEADY, not blinking). Everything seemed to be working properly and the engine was running smoothly.

First, they replaced: 1) the EGR Control Valve, 2) the EGR Control Solenoid and 3) the Vapor Canister Valve. After those new parts were installed, the Check Engine light remained on STEADY. Then they said that the ECU/PCM was bad, so they replaced it (it took a few days for them to get it). As an aside, I read somewhere that when the ECU/PCM, the Check Engine light lights steady (not blinking), it means that the ECU/PCM itself is bad.

After they replaced the ECU/PCM, the Check Engine light didn’t light any more, but my truck’s engine didn’t run smoothly anymore. I noticed this right after they replaced the ECU/PCM when I took the truck for a test ride after the repair. It did not happen a few hours, days or weeks later.

The engine's behavior is that it intermittently hesitates and then overcorrects. Like it is starving and then gets too much fuel. It never acted that way with the old ECU/PCM.

Thank you, guys!

 

Most likely that Cardone fuse they installed is bad. Unfortunately they are just about the only "rebuilder" out there anymore. I suspect a replacement Federal PCM would probably fix the issue(s), but if you are sourcing a replacement, you might as well get the right one.

I would also highly suggest to run your own Key On Engine Off (KOEO) tests and Stored Code display just to see if there is more to this story before replacing the computer again.

 

Thank you, rla2005,
Regarding replacing the Cardone ECU/PCM, so, calibration Code 3-51F-R10 indicates Federal (F3TF 12A650-NB) as opposed to California (F3TF 12A650-VB)? This, in spite of the fact that i bought my 1994 F150 new in California? I thought there were physical differences between an engine set up for Federal Emissions and one set up for California emissions.
I will get the Ford OBD1 Code Reader. By the way, the Check Engine light is not showing any faults.
Thanks again.

 

Looks like someone slipped in a Federal emission vehicle into Cali. back in the dark days. That Calibration sticker is the evidence of what the truck was setup with from the factory. In this time period there were typically no differences in the physical emission equipment, only the tune programmed into the PCM. Starting in later 1994 the California emission light duty trucks started to get MAF, the Federal trucks stayed with Speed Density.1995 started even more differences. Then in 1996 you start to see Cali. emission F250HD/350 that were OBD-II versus the Federal truck staying with OBD-I and Speed Density.

FYI...you can have an issue that would flag a failure in the KOEO tests without triggering an active Check Engine Light. You can also have a stored code with no CEL.

 

Thank you, rla2005, for all that information! Man, it is right on track!

I just checked under the hood, and yes, my California-bought F150 is Federal Emissions! The label reads "... conforms to U.S. EPA regulations... OBD1 certified". So, my doubt between the two emissions standards has been solved.

Thank you so much for quoting the right ECU/PCM part number, originally provided by Subford. Thank you, Subford, in case you are reading this.

EDIT to add: And you might be right that the PCM I have right now may be defective.

 

The parts list:
Attachment 284867
/

 

Thank you, Subford!

 

A little update.

Well, having the right piece number for the PCM thanks to the information provided by Subford, I ordered it from an Ebay vendor ($200), and received it. So, in order to install it I removed the the "old" one, and big surprise! The mechanic, opposite to what I though, actually had installed the right PCM!

So, how come I thought he hadn't installed the right PCM? Well, because I checked the work order from their repair shop and the PCM number they put on the order says P/N: 78-5754 which, in the Cardone numbering system, corresponds to OEM piece F3TF-12A650-XA, XB. According to the table provided by Subord above, the right OEM P/N is F3TF-12A650-NB, which corresponds to Cardone P/N 78-5751. At the repair shop they made an error; they put the wrong P/N number on the order, but they installed the right piece. That "little" error cost me $200.

I have been driving around with this "new" PCM from Ebay, and my engine's behavior is pretty much the same (which, of course, I kind of expected) with the jerking at cruising speeds. It is not terrible, just annoying because it was not there before, and I miss the smooth running of my 1994 F150, of which I was so proud.

Something was messed up by this big chain repair shop mechanic, but what? Was any of the 3 pieces he replaced first: 1) the EGR Control Valve, 2) the EGR Control Solenoid or 3) the Vapor Canister Valve? I am planning to take my truck to a Ford dealer for a diagnosis.

Any ideas of what the problem might be?

Thanks for reading this!

 

 

 

CamoF-250,

Man, you are saying exactly what I have been reading regarding vacuum, fuel filter and codes, thank you!

At least, the Check Engine light is OFF, thank God, but I am about to buy the Innova Ford OBD1 Code Reader.

And last, but not least, I swapped the PCMs, which I found easy, but to be honest, I am an absolute ignorant when it comes to auto mechanics, so the steps you recommend will be taken by a qualified auto mechanic, most probably at a Ford dealership.

Thanks again, CamoF-250.

 

I have a 1994 Ford F-150 with an e4od transmission and a straight 6 4.6 L 300 my speedometer just went out truck is giving me problems shifting and interior lights are not working what just happened