I have a 2003 F150 Super Crew 2wd that i am putting a cummins 3.9 in place of the 4.6 ford engine. I am also using a dodge auto tranny. I'll have a tach signal, but i'm thinking my engine light may come on due to some sensors not beign hooked up. The O2 sensors will most likely throw a code. i am also looking at deleting the vacuum setup that is on the fuel tank and wondering what else may cause a code light. Further, how do i delete those things from the PCM so that there will be no code. My other concern is getting a speedo signal without the ford tranny?

 

I'm pretty sure you should just remove the stock computer entirely. I don't have a 2003, so I don't have the schematics, but I'm pretty sure the speedometer access the VSS directly. You shouldn't need the stock PCM since at that point it won't be controlling ANYTHING.

 

Just bringing up some points for you to consider.
On an 03 the dash has many input signals.
The fuel level is analoge to the dash where it's converted to digital.
The speedo and tach gets it's signals from the PCM and Vss.
The charge lamp seperate.
The CEL lamp is lighted by the dash electronics from a signals from the PCM.
It can light on it's own for other reasons.
The exhaust signals are in the PCM program so you can't do anything unless it's possible to get these turned off.
Your in a complex inter-action situation trying to re-engineer backwards.
Good luck.

 

Thanks, i appreciate your comments. I knew there would be no way to completely do away with the PCM. The tach will have signal from the crank postion sensor. I suppose the VSS was on the tranny so i'm not sure how to "trick" it or get signal to it. I may be able to find one that might read off of the drive shaft. I'll run stock alternator and stock fuel tank so those should be fine. I've seen some attachments that will fool the exhaust sensors to essentially delete them. I think i've got my info correct, but if i'm off on something let me know. Any suggestion on the VSS. If the VSS on the Ford is in the rearend, i make not have any problems with that either.

 

bump-- any more help????

 

If you're really doing a Diesel conversion then you're just need to get rid of the dash cluster all together anyway. If you don't have to worry about inspection or OBDII then it's easier to just gut it and start over with your new Drivetrain. Run standard aftermarket gauges and either build of buy a bezel for the dash.

Easy money. ...well, not easy money but easily done just the same.


Edit: To be clear, There is NO way you can make the ECU be in control of or monitor your engine.

 

I'm maintaining what i can from the gasser harness. There is nothing on the diesel engine that needs to be controlled. One wire with 12v to the fuel cut-off switch will allow it to operate. I'm running stock Alternator and stock AC compressor. I have to have a tach signal to the PCM in order to engage the AC clutch. I've fixed that by running my stock crank sensor on a tone wheel (36 tooth minus one) and fooling the cam sensor. SO, i will have stock Tach running. I'm not sure which signal makes the speedo work, but there is a VSS on the rearend of the f150 that is also stock. It may want signal from the tranny too, but i'm not sure. I'm adapting to the ford temp gauge and oil sending unit. I will also maintain the stock fuel level sending unit as well. The PCM will see the engine running for all practical purposes. I've read about folks tweaking the PCM and deleting certain things. If i can't, then i'll disconnect the CEL indicator and roll on. Any help with this would be appreciated.

 

That's going to be so fubar'd you're not going to be able to see straight. I get that the diesel doesn't need the ECU but the ECU needs the engine. Trying to get it to work should be the last thing on your mind.

The first thing I'd suggest is to do your swap, get it running and then see what you can use and can't use. The ECU shouldn't even be a thought in your mind. It simply wont work.

 

I'll just use what i can. I'm not so concerned with the ECU or PCM working as i was trying to allow it to function as normally as it could. I am concentrating on getting the engine to work as it should. I have that side figured out and well documented on another forum. I know have seen folks that have tweaked the PCM by deleting some signals. So, if anyone can help with that please chime in. If not, i'll be happy to disconnect the light and move on.

 

If you are running the diesel engine and trans, I see no reason why you would need the stock PCM at all.

Even if the instrument cluster gets signals from the PCM, you should be able to run without it. The speedometer should be able to read the VSS directly, and the tachometer should be able to read any standard tach signal.

You do not need the PCM to control the AC. Just engage the clutch when you want the AC to run, and let the pressure switches do their thing.

You are making this far more complicated than it needs to be. The PCM stands for Powertrain Control Module. You are running a powertrain that doesn't need it. So eliminate it.

 

Thanks for your replies, I digress.

 

Was it a 4x4 or 2wd? What transmission are you swapping in?

 

Its a 2wd and i am putting in a dodge 47rh Hydraulic tranny that only needs electric signal for OD and TC lock-up. BTW, the tach signal is necessary for the AC compressor clutch unless i want to run it with a manual switch.

 

I hate to get into this any longer but this guy has been displaying a 'hard head attitude' right from the beginning.
Comes an asks, then doesnot want to hear the replies as any help for his project.
He keep countering everything that is said.
From here on I would not do anymore replies because it seems to be of no help to him.
He has all the answers so let him work it out.
Good luck.

 

That is not the case. When i am offered info, i do counter it with what is known. I realize that some folks think that is "being hard headed", but that is not my intent. I do plan to use the PCM to control what it can control (not the engine or tranny). There are things like Reverse lights, Tach, Speedo, Oil pressure gauge etc. These all send signals to the PCM and then to the dash. So, to remain as stock as i can, the PCM is necessary. I would like to delete all of the "Junk" like O2 sensors, mass airflow, etc. I stumbled across someone who had been able to modify these things or delete them on a forum, but i have lost the link. When i reply to messages, i am simply sharing what i know to be true and what has been done by others who have done conversions. Most do not concern themselves with the PCM, but some do for functionality. That is all that I am trying to do. So if replying with data to comment is being hardheaded, please forgive me. I'm not trying to be difficult. Blugrass ticked over another thread i started and simply replied with info to him. No dis-respect was meant. If you think me hardheaded, please don't reply.