MK4 with 4.6 2004 Mustang Efi engine

[rrbardsley]

Has anyone used a 2004 Mustang Gt 4.6 Efi engine in a Cobra roadster? I want to make a stock driver for
Sunday drives and don’I need to increase the horsepower. Has anyone trimmed the wiring harness and
Reprogrammed the ecm? I want to remove any unused wires and rewrap the harness to make it smaller and hide it. Does any one have any pictures of the engine compartment? Suggestions?
I want to get rid of plastic if possible.
Rand

[Shep]

I have a MK4 with a '99 4.6 2v. Had Art Cuesta at Wirediet.com cut down the harness and reprogram the PCM. Runs great, plenty of power and easily accepts superchargers if you get bored!

[edwardb]

Short answer to your question is absolutely yes. Lots of builds the Ford mod motor. I know it was pretty common to diet the wiring harness and reprogram the PCM. I don't have any personal experience, so can't offer much more. Hopefully those with experience will jump in. Since many of these builds pre-date this forum, you might do some searching on the other forum (FFCars.com) and find more information and pictures.

[rrbardsley]

I have a MK4 with a '99 4.6 2v. Had Art Cuesta at Wirediet.com cut down the harness and reprogram the PCM. Runs great, plenty of power and easily accepts superchargers if you get bored!

Thanks Shep. Do you have a current quote from Wirediet and a list of what he did? What sensors did you remove?

[walt mckenna]

I have a MK4 with a '99 4.6 2v. Had Art Cuesta at Wirediet.com cut down the harness and reprogram the PCM. Runs great, plenty of power and easily accepts superchargers if you get bored!

Art Cuesta modified my wiring and PCM as well. Started on the first try and flawless ever since.

[cfriedman67]

I have a 97 Cobra engine and Art modified my wiring harness as well. Art is great and very helpful. Be prepared that its not cheap but well worth it if electrical is not your strong suit.

[Shep]

His price is listed on the website. It will vary between customers a bit as not everyone needs the same diet. I'm in MA, so I needed full working emissions, which meant my harness didn't go on as much of a diet! It still came back perfectly wrapped, broken connectors replaced and like others have said, worked perfectly.

[FFinisher]

Has anyone used a 2004 Mustang Gt 4.6 Efi engine in a Cobra roadster? I want to make a stock driver for
Sunday drives and don’I need to increase the horsepower. Has anyone trimmed the wiring harness and
Reprogrammed the ecm? I want to remove any unused wires and rewrap the harness to make it smaller and hide it. Does any one have any pictures of the engine compartment? Suggestions?
I want to get rid of plastic if possible.
Rand

yes. its been done many times. I have done at least a half dozen of them. You end up with a great driving car and they run like a top.

If you open the hood the motor is uuuuugly, but they sure run great.


I would not get rid of any sensors, they are all there for a reason.


Art does a great job on the diets.

[Cobradavid]

I put a 2001 4.6L (2V) engine in my Mk 3.1. I did the wire diet myself and removed over 40 lbs of wire, connectors, etc from the harnesses. The diet was a tedious process, but not difficult. I had detailed wire diagrams and traced each wire in the harness and on the diagram before I cut them out. Every once in a while, I'd fire up the engine to make sure I didn't remove something important.

Like FFinisher said, the mod motors are not much to look at. I did some customization to make the engine compartment look a little nicer.
https://thefactoryfiveforum.com/show...Beautification

The driveability, reliability, and stock power/torque are great from the modular motors. Plenty of power for occasional spirited driving in this light car.

David

[Joel Hauser]

This seems like a good thread for me to jump into...because I could use some advice, too, with my 4.6 modular build. I built my Mk4 using a 1996 donor. I dieted the wiring myself, and it went pretty well. The car started, runs, passed inspection, and is on the road here in upstate New York.
But, it runs really poorly. Over 3000 RPM, the engine seems great. It is very strong. Under 3000, it is horrible. It misfires, stalls, and the exhaust smell signals a way way too rich mixture. I've changed the O2 sensors, MAF, TPS, IAT, IAC valve, crankshaft and camshaft sensors, put in new wires, coils and plugs, new intake manifold, double and triple checked for vacuum leaks, and tried getting a custom tune from BAMA/SCT. But it just doesn't get better.
I'm thinking of two more things I can throw money and time at. Maybe the ECU is just bad, and needs to be replaced. I can buy a new one from one of the ECU rebuild companies, and BAMA can do a PATS delete, and custom tune it for my specific mods.
Or, maybe I made a mistake when I installed the timing chain. The engine has the trickflow adjustable crankshaft gear. I thought I was careful when building the motor but maybe I made a careless, rookie mistake. It was my intention to use the stock setting on the gears, which I was told meant using the "0" keyway option.
So, if anyone has some advice or suggestions, I would sure appreciate it. By the way, I don't believe there are any local shops that custom tune the 1996 engine. I've contacted all of them, and none seem interested.
Thanks guys.
Joel