Re: [Amc-list] Wiring diagram for 4.0 head and EFI on 258? Or Clifford with 4 Bbl?

[Frank Swygert <farna@xxxxxxx>]

I just finished putting a 2000 4.0L head on my J-10 with 258. Also a Clifford intake with 390 4V. It runs great, finally! My main problem before the head swap was a leaking intake and exhaust manifold and a BBD (older non-feedback swapped on by PO) that would leak down after a couple days and require gas poured down it to start. Right now it has a little less power, but the secondaries aren't opening on the carb. Bought it used, expected problems. I just need to replace the vacuum diaphragm in the secondary servo. The carb looked rebuilt when I got it, but had been sitting up for 2-3 years according to the seller. No big deal -- it runs great after warm-up, it's a bit cold natured. It has "512" jets in it, which are Ford jets, I'm guessing. The "2" on the end has me baffled -- I checked the number twice on both jets to make sure I was seeing the right number. So I'm not sure about the jet size. Assuming it's a #51 I might be a bit lean. I think this carb was set up for a Ford
  200 six, I might need a much bigger jet. Will have to check the plugs, only been running it a couple days now. So I still have to tune the carb, and I haven't changed timing or anything from where it was before the head swap. No pinging, but I can probably turn timing up a bit. Sort of waiting to do a TFI upgrade before messing with that much or tuning the carb. Need to get that upgrade done soon!! Has stock Motorcraft electronic ignition now, so it's not bad.

You only have to have one wire to make a 4.0L engine run -- the ignition wire. That's assuming you lift the entire 4.0L harness and stick it in the car pretty much the same way it came from the Jeep. So you use the Jeep wiring for the alternator and starter, not the car wiring. Remove the car wiring. I cut my 63 Rambler harness about 2' from the firewall under the hood then cut the Jeep harness so I could splice it in. I took ALL the Rambler engine wiring out, even the power feeds to the dash. I spliced the Jeep power feeds to the Rambler power feeds, and matched all other wires. Most of the wires in the EFI harness are between the computer and engine sensors and relays, so there are few wires to splice. You only need to worry about the wires that go into the big firewall connector, those are the only ones that have to be spliced in. If you don't have AC, leave the ires disconnected. 

You'll find the fuel pump feeds in the Jeep harness somewhere, of course they have to be attached to a fuel pump. On the Renix system they are orange, and there should be two, depending on how the harness was cut out. One feeds straight 12V, the other only about 9V. Both go through a relay, you the two can be spliced together then one wire run back to the pump (when one is on the other is disconnected). On start-up and WOT the computer gives the pump 12V, for part throttle cruising it cuts to 9V. Extends the life of the pump. 

You'll like the EFI better doe a daily driver, I just went with a carb because I wanted to play with a carb again. Might not have been the greatest idea/reason! Make sure the Clifford intake is heated if this is to be a daily driver. I added a heating tube to mine, should work okay here in the more or less temperate south (mid South Carolina). If I were up north where it gets colder for longer I'd have waited to get a true water heated intake. 

---------------
Date: Sat, 12 Apr 2008 22:32:16 -0700 (PDT)
From: Jesse <j2sax@xxxxxxxxx>


I know, I could do a stroker and pick up .4 cu ltr,
however, I have a solid 258 with great compression and
I don't need a full rebuild.  I am dropping it in a
J10 Stepside with a 5 speed.   

I have a 93 4.0 head, and a complete 88 Renix head w
EFI as well.  Looking for a 99-02 intake 

I also have a Clifford 4 Bbl intake and Holley 390.  

This is going to be my cross country driver, no
off-roading and mainly for picking up stuff and towing
that is not too heavy, requiring the 401 4 Door J20.  

So, I am definetly dropping on the 93 H.O head.  I am
also doing a 2.25 dual exhaust (probably looking to
turbo in future) using a 4.0 header.  I am doing 3.54
gears...maybe 3.31's at the very least.  

Does anyone have a good wiring breakdown for running
the 4.0 EFI on an earlier vehicle?  I have heard many
times that it is only 6 wires, but having a little
more guidance that that would be helpful.  The
Strokers group site is great, but so far hard to find
specific info on.  

Or shold I forget the whole EFI thing and just modify
my Clifford to work on the head with a little Hly 390?
 

You're experienced answers are greatly appreciated!  

Have a great week, 

-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)


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