Thinking about doing an efi swap

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Mar 30, 2013 | 08:10 PM

v6lightning

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Thinking about doing an efi swap

I have found an efi motor, computer and harness for sale locally. My question is would the fact that I have a cam in my motor now mean that I'd have to have the efi computer tuned?

Last edited by v6lightning; Mar 30, 2013 at 10:40 PM. Reason: Phone auto corrected title

Mar 30, 2013 | 10:04 PM

Gary Lewis

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From: Northeast, OK

Two questions: What is an "editor swap", and are you installing the "new" engine?

If you are just buying the engine to have all the parts then the next question will be how much of a "cam" do you have in the existing engine? And the question after that is what year and what vehicle is the EFI stuff from?

Mar 30, 2013 | 10:38 PM

v6lightning

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Quote:

Originally Posted by Gary Lewis

I just noticed the editor thing. It was the autocorrect on my phone. My plan would be to keep my current engine and put the efi stuff on it. I'm not sure hog big my cam is it was put in probably 10 years ago by my father in law and he can't remember. It's not a huge cam just enough for a small lope. The donor efi motor is out of an 86 f150.

Mar 31, 2013 | 07:40 AM

Gary Lewis

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From: Northeast, OK

Let's hope someone who really knows about these EFI systems comes along to answer, as I don't. But, from what I've read, these systems don't take kindly to change and aren't tunable. As they were 1st generation EFI systems they use a Manifold Absolute Pressure (MAP) sensor instead of the Mass Air Flow (MAF) sensor that EFI systems went to later. MAP sensors assume that with a given pressure difference between outside and inside there will be a given flow - since Ford knew the restriction of the heads, the characteristics of the cam, etc. But, change anything along the way and the system gets the wrong answer and can't cope.

Many have changed their systems over to use MAF. Search the forum for threads on that.

Mar 31, 2013 | 08:33 AM

85lebaront2

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From: Exmore, VA

I guess I need to comment on this. According to what Archion found, any cam with less that 115° lobe separation will not run well on a speed density system. The "lope" is the cam overlap, if you hook a vacuum gauge to it you will see that idle vacuum is low and pulsing. The speed density system is controlled partially by a Manifold Absolute Pressure sensor which equates low vacuum as engine load and enriches the mixture.

Since your truck never came with EFI you are going to have to rewire it anyway. I would go for a later system, such as a 1994-95 mass air sequential system. These are much more tolerant of different cams. You don't say what transmission you have, but if you have an AOD then you will need the AOD TV cable and all attaching parts for the EFI system.

As far as needing to "tune" the EEC, there are a number of options, Adam Marrer at Pops Racing has a lot of good information. There are different tuner hardware sources and tuning software. Clint Garrity's Binary editor is quite good and well supported, Mike Glover's TwEECer is ok, but support for a lot of the truck stuff is somewhat limited.

I have been fighting with an even more limited support issue on mine, the 460 systems are sort of "you want to do what?".

Good luck with it. If you need it, I think I have a complete 1986 EFI harness set.