302 EFI conversion questions

[tj]

4 questions about adding 90-93 Mustang EFI to a 1970 302.

1. The fuel injection harness has a ground wire with a big ring connector.

Where does the ring connector connect? Looks like a bolt head somewhere.

2. The right rear bolt securing the upper manifold to the lower manifold has a threaded stud at the top of the bolt. There appears to be a rod connected to the stud that goes down behind the engine towards the left side. What is this about?

3. This may be a biggie. I have a 1970 302 with stock cam. The HO EFI system is sequential injection and the HO 302 has a different firing order. What issues and side effects may I see with missmatched cam and sequential injector firing order?

4. With the 1970 stock cam and 1992 EFI distributor is there any issues regarding the distributor gear?

Thanks for your help on this.

TJ

 

[mxpaz]

This is just my opinion. Dont do it. I added it to my stock motor and its more trouble than its worth.

I put a 351 cam in mine to take care of the firing order problem. You will have to change gears on the dizzy too.

 

[COBlu77]

I just did it to my 77 302, and the current concensus is to change the cam to a 351w cam so that the O2 sensors are sending the right signals regarding the fuel air mixture. That's what I did to mine. That part is fairly easy. Yes, you definately need to put an iron distributer gear on the Mustang distributor. It's Ford Motor Sports p/n M-12390-D and Summit sells them for about $30. You might be better of just getting a rebuilt distributor with the iron gear already on it. When you ask the parts store for a distributor one they should ask you if you want an iron or steel gear. I bought the gear and you have to carefully press it on a drill a 1/8" hole for the pin. Remember to save the pin from the one you took off. I didn't and try asking an Autozone guy for that part.

I just attached that grounding wire you're taking about to one of the upper plenum bolts.

There's alot more involved than you will initially think and although I bought the Upper/lower intake, computer, wiring harness, distributor and coil for $300, I've spent at least $600-700 more on everything else. I'm now just trying to sort out all the final gremlins and get it going. Read my post about "EFI Won't Start". Now is not a fair time to ask me if I'd do it again. I'd probably tell you to buy a complete Mustang 5.0, it would be cheaper and easier.

 

[Socal Tom]

4 questions about adding 90-93 Mustang EFI to a 1970 302.

1. The fuel injection harness has a ground wire with a big ring connector.

Where does the ring connector connect? Looks like a bolt head somewhere.

2. The right rear bolt securing the upper manifold to the lower manifold has a threaded stud at the top of the bolt. There appears to be a rod connected to the stud that goes down behind the engine towards the left side. What is this about?

3. This may be a biggie. I have a 1970 302 with stock cam. The HO EFI system is sequential injection and the HO 302 has a different firing order. What issues and side effects may I see with missmatched cam and sequential injector firing order?

4. With the 1970 stock cam and 1992 EFI distributor is there any issues regarding the distributor gear?

Thanks for your help on this.

TJ

1) That should be grounded to the battery I believe.
2) Not sure
3) It doesn't matter. It idles a little funny, that's all. I ran one like that for over a year. It's not worth swapping the cam.
4) Yes you need a cast iron gear, the 92 HO will have a steel gear. You can either swap the gear yourself or buy a rebuilt that has the right gear. Option #3 is to get a junk yard dizzy from a non-ho car.

Tom

 

[67EB_in_619]

yeah.. what tom said.

grounds are very important to EFI... ground the body to the frame to the engine to the battery... that strap can then go any ground.. best to get it to the engine or battery though.. you want a solid ground for the harness grounds.

yeah.. no idea about that rod...

dont sweat the firing order thing... 66horse has been running his with the mismatched firing order for over a year and hasnt noticed even an idle problem.

If you have the money... buy ryan mccormick's harness BC sells it or you can get it at fordfuelinjection.com... lots of other great infotidbits there too.

It is a pain while you set it up... but you will love it.

 

[tj]

grounds are very important to EFI... ground the body to the frame to the engine to the battery... that strap can then go any ground.. best to get it to the engine or battery though.. you want a solid ground for the harness grounds.

I currently have the battery ground strap going to the frame and a ground strap going from a starter motor mounting bolt to frame. I need to look to see what I did with the body. Previous dreaded owners cut up my harness plus I added enough changes that I ended up ripping out the harness from the dash board forward and making my own back in '96. So I guess I'll run the ground lug to a convienent manifold bolt so the sensors & injectors get a good pathway.

no idea about that rod...

I've looked in wrecking yards but all I can see is this rod disapearing down between the back of the engine and fire wall. Either way with all the conversions people in this group have made, I guess it it were importnt somone would know.

If you have the money... buy ryan mccormick's harness BC sells it or you can get it at fordfuelinjection.com... lots of other great infotidbits there too.

I know my way around schematics, a soldering iron and can ring out circuits. I have the fuel injection sub harness and plan to use it as is with the addition of a resistor across the leads going to the canister solinoid to simulate it being in the circuit. Current plan is to pull a main harness out of a Mustang, strip out wires I don't use and add resistors to leads that would normally go between the ECU and solinoids. The main harness should be reduced down to wires going to the EFI sub harness, ignition coil, MAF, distributor, test plug and barometer.

It is a pain while you set it up... but you will love it.

I hope so. Looks like a lot of guys are trying the conversion right now and and having all kinds of problems getting everything to work. I have faith in my wiring and circuit reading skills and I have been studying Charles Probst's EFI book but there seems to be a lot that can go wrong in the conversion.

Tj

With fingers crossed, trying to think of as many gotchas as possible before turning the first wrench.

 

[Socal Tom]

The injectors are grounded through the computer. I believe the ground cable by the ECU connector is the important spot for that ground. That's why a good ground to the body is important.
Tom

 

[BabyBlue69]

I have the entire 5.0 engine out of a mustang that I will shortly be putting in my 69. I took that rod off a about a month ago when I was stripping the motor to freshen it up and do some painting. I remember looking at the rod and asking myself what the purpose might be. I suppose it is some form of brace. My memory sucks but I believe it went from the stud on the lower intake you mentioned to the back of the drivers side head. I will be reinstalling my lower intake and the rod this weekend so if I find out I am wrong I will write again.

Also, there were a number of ground wires that were bolted to the rear of the drivers side head.