I planning a MAF conversion on my 88 5.0, and I've found most of the info I need from searching the forum, but there's still a few things I need help with.

So far, I'm planning on grabbing some junkyard parts to make the swap as simple and painless as possible. I planning to pick up an a9l mustang computer, a wire harness and maf sensor off of a 94 or 95 maf equipped 5.0 f150. From what I've read, this should be a pretty straight forward swap. Will I have a compatibility issue running a mustang ecu with a truck maf sensor? I'm going with the mustang ecu because my truck has a 5-speed, and I can't seem to find any truck ecu's that come from a donor vehicle with a manual transmission.

I know the firing order is different, so I was planning on doing the swap at the time I do a rebuild on the motor. I'm leaving the stock TB, intake manifolds, and injetors, but I wanted to get ahold of some iron gt40 heads, and run the comp cams 35-243-4 cam. I went with this cam because it's hydraulic flat tappet, which is what I have now, and because it was made for the 351 which means it will have the 1-3-7-2-6-5-4-8 firing order, just like the mustang 5.0's. Plus, comp cams sells a nice kit that comes with new valve springs, retainers, and a timing set.

If anybody sees a mistake I've made along the way, please let me know now before I start buying parts lol.

Now here's where I'm left scratching my head...

My truck has the older style dual tank set-up with the two low-pressure in-tank pumps and one exterior hi-pressure pump mounted on the rail. Am I going to run into any problems with the mustang ecu controlling this fuel system?

Will the newer truck harness have any problems with the connectors that are on my 88 right now?

Will the mustang computer have a problem with the f150 emissions stuff? I'm thinking it might have a problem with the egr or something. Does anybody know if this stuff is compatible?

Thanks.

 

The fuel pumps are controlled the same way, with the computer energizing a relay, so there will be no problem there. The only issue you may have is a code for secondary fuel pump relay voltage if the truck was not originally wired to monitor this circuit.

The wiring changed substantially between '88 and the factory MAF trucks. The '88 used a dedicated engine wiring harness, which only interfaced with the chassis/underhood harness in a couple of places. The newer trucks used an engine sub-harness that runs from the fender to the engine, while the chassis harness carries the engine wiring between the fender and the computer. The newer trucks also used a remote-mounted TFI ignition module, while the A9L mustang computer and your '88 truck were set up for a distributor-mounted module. You'll probably be better off modifying your original harness rather than trying to integrate the newer harness into the older truck.

The mustang computer will operate the truck emissions equipment just fine, although if you end up modifying the original engine wiring harness, you'll have to move a few wires in the computer connector to match the mustang computer pinout. Have you seen this website?: custom air intake and MAF conversion for a 1988 Ford F150

 

Yeah, I actually saw that site posted on the forum when I was researching this project. I was hoping to avoid all the splicing and re-wiring, but it sounds like that may be the way to go.

What do you think about using the truck MAF with the mustang ecu? I wanted to use the truck maf so I could use a stock air box.

 

I'm not sure how the transfer functions of the two MAF meters compare. An aftermarket MAF manufacturer may be able to help with that question. I would think that the calibrations are pretty similar.

 

I just realized that even if I use my existing harness, I'll still need to pick up a MAF connector. If I can't find one at a junkyard Rock auto has them for about $20 shipped. Cheaper than my original plan.

I've never modified pins in an ecu connector. Do I need to buy a special type of connector or "pin" to crimp or solder onto the the new wires I'll need for the injectors and MAF signal?

I'm a little confused why this article says to leave the MAP sensor intact... The Corral Tech Why do I need the MAP sensor connected if I'm switching to MAF? I was planning on just pulling all the MAP stuff out of the harness for a complete removal.

 

I picked one up at the boneyard for $2. I got it off of a lincoln town car.

Yes you need special connectors. Go here to get them. That site has lots of good info and instructions on how to insert the pins.

Leave the MAP connected. Just remove the vacuum. The computer needs to know the outside barometric pressure.

 

Thanks a lot! I think I'm ready to start buying parts for this project.

 

If you can get a harness from a MAF vehicle, you can use the MAF and injector wires and pins from that to add to your existing truck harness. The pins can be removed from the connector with a small (eyeglasses size) screwdriver. As Lance said, the MAP sensor becomes a BAP sensor when the vacuum hose is removed.

Make sure you have a wiring diagram for an 89-93 mustang so that you get everything in the right place. A couple of the emissions solenoids have a different pin location on the mustang computer, so those pins will need to be moved for those solenoids to work.

 

Here's a spreadsheet showing the computer pinout differences between the truck and Mustang computers. Those in color have to be moved and those in grey have to be added.

http://farm5.static.flickr.com/4017/...d936b8da_o.jpg


And here's a nice color wiring diagram for all devices connected to the Mustang computer...

http://farm5.static.flickr.com/4009/...35cfb419_o.gif

 

If you know the year of MAF and the associated truck computer number you could probably find a .bin file for the truck computer on the net and compare the A9L and truck computer MAF transfer functions to see how close they are. You can open the .bin files with free software like EEC Editor.

This is a good site for Fore EFI info/parts Ford Fuel Injection.

 

Well, my rebuild plans changed a little. Summit had a pretty good deal on the trick flow twisted wedge heads so I ordered a pair. Now my concern is fuel delivery. With these heads, I'll probably be making a bit more horsepower than with the gt-40's, so I don't think the stock 19lb injectors will be able to keep up. I've found a couple of websites that have indicated that the 19lb injectors are only good for up to ~258hp at 85% duty cycle or ~275hp at 90% duty cycle, 24lb injectors are good for up to ~326hp at 85% duty cycle or ~345hp at 90% duty cycle.

http://www.fordracingparts.com/downl...d_Adaptors.pdf

Fuel Injection Conversions 101 - Injector Size - Modified Mustangs & Fords

Can somebody with desktop dyno software give me a ball park figure of what kind of hp I might be making on this motor with the stock intake & TB, the comp cams 35-243-4 flat tappet camshaft, the tfs twisted wedge "fast as cast" 170cc heads, standard rocker arms, long tube headers, all on the stock displacement. Then run it again with 347 displacement, just in case I decide to completely throw my budget out the window. I just need to know what size injectors to buy. Thanks.

BTW, these are the heads I ordered Trick Flow Specialties TFS-51400002 - Trick Flow® Twisted Wedge® 170 Cylinder Heads for Small Block Ford - Overview - SummitRacing.com. I think it's a pretty nice set for less than a grand.

 

Couple things I'm going to suggest here one of which you may not be able to do anything about since you have already ordered the heads. I would have suggested you buy heads with 1.90" intake valves because 2.02's often require the pistons be flycut for clearance.. even if they already have valve eyebrows. On top of that the smaller valve heads tend to produce a bit more TQ which is a good thing with a street motor and a very good thing for a truck motor. If these heads haven't shipped yet maybe it's not too late to change your order.

Second thing I'm going to suggest is a different cam. The one you picked is most likely going to create P-V clearance problems with those big valves, and it pushes the powerband a bit high for a truck motor. I suggest the 35-234-3 which will greatly reduce the possibility of piston contact on the valves and it also boosts TQ while only sacrificing 9 peak horsepower.. which is a good tradeoff. The motor still makes 345hp which isn't at all shabby and yes that will require 24lb injectors. Here's the graph..

 

Well, the cam was the first thing I ordered lol. It's been sitting on the shelf for a couple weeks now. If I stroked it to 347, would the 35-243-4 cam that I have now be worth hanging on to, or would it still be better to swap to the 35-234-3?

 

A stroker would definitely make for a more truck worthy powerband but you will need dished pistons to keep compression reasonable.. something around 15cc total dish produce 9.5:1 CR with 347in displacement and those 61cc heads. Considering how little a flat tappet cam costs($119 at Summit) you could fix the issues without spending a bunch more cash on the stroker kit and block machining.

 

So if I stroke it to 347 I should keep the 35-243-4 cam, and if I stay with the stock 302 displacement I should get the 35-234-3 cam?

I wonder if comp cams would do an exchange for me.