I have a 1970 automatic Ford Bronco and am looking to convert ot EFI. A friend of mine just gave me the parts off of a 1991 or 1992 Mustang without the computer, but I have a couple concerns and am hoping someone else out there has been through it.

I rebuilt this engine 15,000 miles ago and don't really want to scrap it and start over. When I built it I used Chrome molly rings, RV cam and looked to achieve a 9:1 compression ratio.

I have been told the Mustang in these years used a sequential firing order from the 351, therfore I cannot just bolt it up, I may need to change the cam or change the order of the EFI. I also have been told that the mass air on the mustang requires more sensors than a desity type one. I am not subject to any smog laws so my ideal goal here would be as few sensors as possible

Could anyone out there please help with some advice or web sites etc.

Thank you very much.

George

 

Oo OO!

I know this one!

Mass air does take more sensors than the speed density system. The word around the campfire, however, is that Mass Air is the way to go as it's far more compatible with motor mods. Things like cams, intakes, etc don't work well on speed density because it doesn't read the increased flow.

I just KNOW there's a way around it with speed density, as you can't tell me that all the 94+ Mustang owners convert back before they cam their motors... but I don't know what the solution is. Maybe re-flash the ECU, which is kind of spendy, I hear.

I can't answer your other questions, I have just gleaned this much from other EFI threads on the boards. If you have an hour or so you may want to search through the old posts on this board. There are a few really nice ones that go through everything you could possibly ask and then some.

You could also try the search feature, but I don't have much luck with it.

-Dawg

 

The newer 5.0 motors are Sequential Electronic Fuel injection, and the firing order is the same as the 351 Windsor. Some people have merely changed the engine harness connections to the injectors around to make it match the older 302 firing order. I have never done this, but have heard it works allright. Or, you could swap the cam to give you the 5.0 firing order, probably a better solution. If you have the parts from a 91 or 92 Mustang you have Mass air already. There are tons of write ups about this conversion on the net. Go to classicbroncos.com and click on the web links and go to the SEFI conversions, there are probably 15 different web sites listed there. Also, you need to make sure your cam and distributor gears are compatible. You would have to use the distributor out of the Mustang to work with the Thick film ignition that is stock on the mass air mustangs. If you end up swapping cams, just make sure it is compatible with the SEFI TFI dizzy gear. Good luck.

 

Thanks Utahbronco. I have been doing a lot of searching on the net and I guess I was looking for the step by step thing so I done screw it up. One thing that really concerns me is the computer for the SEFI. is there a better computer to get or do they all do pretty much the same thing. Also I am looking for some direction on the sensors, can they be bypasesed or should they for that matter. I don't care to have them if not needed.

Thanks again to anyone who can help.

 

OK! here the drill; Get the Ford SVO efi booklet $5.00 from Ford. Also call Helm publications and get the wiring diagrams from the year of Mustang the engine is out of. The harness has a tag taped to it with the part #. If you do not have a harness you can get the harness from SVO/Ford racing. This harness is VERY similar to a stock Mustang.
Or you can get one off of ebay. That is what I did. Make sure it has the oval 4 pin connector for the MAF. 89-93 Mustang, also get the computer off of ebay I have one marked A9P 1990 Automatic and one marked A9L 1991 manual transmission. You will want to mount the computer above the heater, passing the harness through the firewall and using the rubber mustang plug that is on the harness. The cutting diminsions are in the SVO booklet. I have this booklet if it is out of print. I cut down a Fedex truck tank for my Bronco and got a in tank pump and a big tank. I still have 3 of these tanks with pumps that I plan to cut like mine pressure test them and list on ebay. Go the the salvage yard and get stainless braded hoses off of a truck. You will need to take the fuel line tool along with you along with your basic dimensions for the length you need. I did not use the high pressure plastic that Ford also uses.
Don't swap the cam! Don't cut the harness up at the engine! Just swap the pins at the 60 pin connector at the computer. Take your time and plan when you do this. Remove the red retaining bar and release one pin at a time. The holes are numbered 1-20 21-40 41-60. Good luck and search the internet. Lots of folks have put their labors up for us to look at. Some list part numbers and wiring color codes. If you don't do anything else get the Ford racing booklet. And use the Rollover switch!
Have fun.