1. with MAF/SFI the injectors fire twice for every stroke as opposed to the once per that is the case with speed density; do the same 19 or 21lb/hr injectors work for both setups?

2. what is the best way to remove the old distributor to install the one with the hall effect sensor to detect cylinder one and keep the approximate postition so timing it is easy? my plan is mark the block in relation to both the rotors' position and something distinct on the distributor itself like the channel for cap alignment and then positioning the 94 distributor and rotor to those marks and going from there after the plug wires are rerouted for a H.O. firing order.

3. does the proximity of the sensor(IAT,BAP??) in the airbox after the air is filtered (before the MAF sensor) to the MAF sensor matter? the stock 94 airbox has that sensor 5-6" before the MAF sensor and my custom setup for the 92k&n filter (two outlets rather than one) will be 3-4" away.

4. should i use the tfi unit for the 94 computer and harness ive got (from a junkyard 94 bronco) or use my 92's?

5. lastly (and least important) the 94 maf harness that im swapping in has no plug for my cruise control. is there nothing i can do but say goodbye to it?

im damn near swapping in the newer harness but i cant get the big rectangular plug that is immediately next to the computer plug out. i keep loosing the plug bolt and it will not loosen at all. i dont wanna hack into the mess of wires to get the bolthead cutoff and try and pry it out (i doubt thatll work anyways.) i need the veterans and experts!

 

1. SEFI fires each injector once per engine cycle when the intake valve opens for each cylinder. The same injectors work on both batch fire and sequential injection. Batch injection fires the injector twice per cycle.

2. Your existing distributor should have the narrow tooth for cylinder 1 already. You can verify this without even taking the distributor out. Just pull the cap and rotor and the reluctor wheel is right there.

3. Depending on which year mass air computer (and what vehicle it is from) makes a big difference in placement. For example, the common 89-93 mustang computer has the air temp sensor mounted in the intake manifold like the truck does stock. The newer mass air trucks (OBD-II for sure, not so sure on the EEC-IV/pre-96 ones) mounts the temp sensor in the air filter housing. I recommend mounting it in the stock location for the computer you are using. If the temp sensor mounted in the air filter box, anywhere near by would work fine. It doesn't even have to be directly in the intake air stream. I used the stock truck MAP sensor as the BAP sensor and thus just left it mounted in the stock truck location. I might be able to give you a better idea on that if I knew what the MAF stuff was coming from. Are you y-ing the intake twice, once before and once after the MAF meter?

4. The stock TFI should work fine.

5. I'm not sure how the cruise control is wired on that new of a vehicle. To my knowledge, the '94 used an electronic control while the '92 used a vacuum servo. I think that is why you can't find cruise stuff. The '94 cruise uses a brake pressure switch mounted on the brake master cylinder, so it would be a lot of work to get that working correctly the way it was intended to. All this is assuming you are using a stock '94 truck mass air harness and computer.

I would go through the entire new harness and the old harness to make sure that all the wires serve the same purpose on each harness. Depending on how much of the '94 harness you have, the '92 is likely to not have the most important wires in it for the swap. It would have to be the whole underhood harness, and even then I would check very carefully to make sure all of the wiring is the same between the harness you take out and the one you are putting in. I would suggest doing this at every point where the swapped harness joins to all other harnesses in the truck. Take your time and it should work out well. You might find that it will be easier to add the wires you need for MAF (and move the wires that need to be moved) to your existing harness instead of trying to swap the entire harness from a newer truck.

 

haha. im removing the old one today, already got it completely loose. im going to use the newer dist and tfi (i made a duplicate post [my bad] and had someone suggest i should use the newer tfi. all of this stuff came from the perfect donor vehicle for my truck; a 1994 MAF/SFI 302/e40d bronco. the differences in systems between that truck and mine beyond the MAF FI is that it has 4 wheel ABS (rather than 2wheel like mine), auto locking hubs(i have warns), electronic cruise control (youre correct mine is vacuum diaphragm operated), and it had airbag impact sensors. i will retain the MAP sensor (there is no BAP in this harness). yes, i am double y-ing the intake tubes until i sell my 2tube k&n fipk to my friend and make an adapter for an even bigger filter. the one thing im worrying about now is the camshaft position sensor that seems to take place of the "distributor hall pigtail" (hall effect sensor?) in the electrical diagrams for 94 and 92. im hoping the camshaft position sensor theyre reffering to is in the 94's distributor. by the way, do you know how it is mechanically possible for a 302 to run fine in both the speed density/bank fire order (15426378) and the maf/sfI order (13726658) while using the same crank/camshaft. nobody has been able to explain that well. i will be putting the new harness/maf/pcm in today, probably sewing it back up late tonight/tomorrow.

 

The distributors and TFI modules are probably the same parts (although the electrical connection on the distributor might be different. It would be easiest to swap the distributors in this case), so if you want to save some trouble, I'd leave the ones in the truck now. The MAP sensor will become a BAP sensor. It mounts in the same location, but does not connect to manifold vacuum - the port is open to the atmosphere. All the timing information should come from the distributor hall effect sensor for both systems.The crankshafts are the same for both firing orders. The only difference is the position of the lobes on the camshaft. The pistons go to TDC twice per cycle, the cam change just swaps the TDC of compression and TDC of exhaust on four cylinders, so it all works out fine. Good luck with swapping today .

 

okay i had some sensors confused. the MAP is the one near the firewall on the passengers side, and the IAT/ACT is in the front drivers side of the lower manifold, and i dont know what the hell the sensor in the 1994 airbox is(different style IAT/ACT?) but there is no connection in the 1994 harness for the IAT/ACT located in the manifold. haynes says nothing about a sensor in the airbox. I assume that the new airbox mounted sensor will replace the manifold mounted one.

in "How to Tune and Modify Ford Fuel Injection" im told the BAP is identical to the MAP in operation and output, and late model MAF systems have the BAP so i assume that by changing the harness the sensor will change roles. If i buy a BAP sensor new will that vacuum port thats on the MAP be deleted? btw, any particular reason i should unhook the vac port on the sensor?

 

The MAP is indeed the one on the passenger side firewall. The IAT/ACT was moved to the air filter box on mass air trucks, apparantly. You can just get an IAT sensor for a '94 and zip tie it near the air filter. You are correct in your assumption that the sensor in the airbox replaces the sensor in the intake manifold. BAP sensor senses Barometric pressure as opposed to manifold pressure, which is why you disconnect the vacuum line going to the MAP. The outputs are the same as you have found out. The only difference between the MAP and BAP physically is that on a BAP there is a small plastic ring that prevents the installation of a vacuum hose - the port is still there, it is just open to the atmosphere. Save the money and use the MAP sensor (those sensors are over 50 bucks new).

 

domo, Postmaster. these are definitely the best answers ive gotten to my conversion questions.

so im going to leave the port on the sensor open to sense atmospheric pressure and cap the corresponding line coming from the vacuum tree on the manifold. until i find a plug ill just leave the old ACT sensor in the manifold unconnected. I went the auto parts store and the part number for a 92 MAP was the same as a 94. The guy couldnt find an IAT or ACT sensor for a 94. On monday im gonna call ford and get a 94 IAT sensor priced, i dont really know about the durability of that particular sensor. The rest of the install should be easy, although im not quite sure of the proper timing on the 94 (its listed as 10 deg BTDC on my 92s emmision sticker) so i may have to go back to the junkyard to look at the sticker on the donor bronco. i installed the harness, computer, and got most everything plugged in except for upper manifold stuff. i removed the old dist and installed the 94's because im worried about the camshaft position sensor difference on the two different diagrams. im hoping that i got everything realigned close enough so it will run well enough to start and idle alright. ive never really set timing before. anyways im gonna get back to it, gotta install the upper and peice together my intake tube puzzle.

 

That sounds very good. I'd set the timing to 10° BTDC, same as the '92.

 

ack! why is there nothing in the 94 harness for a BP sensor? does the IAT/MAF make that sensor obsolete? i have one diagram for a SFI 5.0(not vehicle specific) with no MAP or BP shown and a 1994 5.0 e40d truck diagram that includes a BAP sensor, and a harness for a 94 without the connector.

also, how hard would it be, would there be any benefit to (in terms of optimal A/F ratio), trying to setup stereo HEGO sensors with a computer that uses only one currently? in the probst book it says "vtype engines usually have two oxgen sensors; one for each bank" and somewhere else it mentions how a stereo HEGO setup can allow the computer to estimate the amount of air coming from each cylinder based and a know time of travel between the open exhaust valve of the last fired cylinder and when those gases reach the sensor for that bank. it sound good to me, question is can i do it with my current computer, and if so what must i do?

 

http://fordfuelinjection.com/files/EFI_harness3.gif

That diagram doesn't show a BAP sensor, so maybe it is correct that there isn't anywhere to plug in one. The '94-'95 mustang 5.0's (mass air) didn't use a BAP either, whereas the 89-93 did (they were also mass air).

The dual O2 sensor setup would be ideal since that is what the MAF computer is wired for, but in terms of practicality, it is going to be a little bit of a pain. You will have to drill and tap the exhaust manifolds (or weld in bungs just after the manifolds) for each O2 sensor and plug the hole where the O2 sensor is now. I don't think that the O2 sensors are accurate enough or switch fast enough for the computer to adjust individual clinder air/fuel ratios. I used the stock single O2 sensor and split the signal from the one O2 sensor to both input pins on the computer plug. The signal is just a voltage, so that voltage will be the same on both wires. This will keep the computer from throwing codes.

 

"SFI allows control of injection pulse times of each individual cylinder. Under some engine conditions, the control unit program calculates the individualcylinder air/fuel ratio by reading the oxygen sensor, knowing the time required for the exhaust gas from that cylinder to reach the sensor at that rpm. In V-type engines. two oxygen sensors are used, one for each bank. Metering is improved in what Ford Electronics engineers call "Stereo HEGO". " - How to understand service and modify ford fuel injection and electronic engine control, Charles Probst

If i could determine whether my computer was capable of making that calculation and accordingly adjusting a/f for individual cylinders, as well as how to wire both sensors (one already existing....), my assumption is more efficiency would result at the least, perhaps more power/response. i've heard the distance between the farthest rearward exhaust valve and the 02 sensors is supposed to be something like 18" on these sytems. welding in 02 bungs is no problem. im thinking i might do the one on the pass side (longer header) right at or past the collector and the other side (shorter header) equidistant down the stream. im wondering how critical that distance and/or the exhaust tube volume/shape might be... or who would know.

 

What I've read is that the O2 sensors should be no less that 3 inches downstream from the point where the tubes come together in the collector, so that the gasses from all 4 cylinders are well mixed by that point.

 

i imagine 3 inches past the collector on the stock exhaust manifolds is about 18". but with my longtubes ill be lucky to get as close as 24 inches. ( ive also heard that the 4 wire HEGO[not the 3 wire] will adapt to placement farther down the stream, although not sure how) i just dont know where to go/who to ask to figure out how to rig a stereo hego setup (in terms of wiring to the computer) with a 94 302 e40d CA bronco's computer. id really like to add that finishing SFI touch.

 

As long as the O2 sensors are heated sensors, the distance from the engine isn't quite as critical. I mean, you can't put it at the muffler, but the distance is more forgiving over a non-heated (one wire) sensor. I would use the configuration used in the '94, which I believe is a four wire sensor. I'm not sure if the '94 used two O2 sensors of if it used one like the older trucks. If it only used one, there isn't any need to install two because the input isn't there in the computer.

As for the adjustment, the twin O2 setup can make adjustments from bank to bank, but I don't believe it is advanced enough to be able to control individual cylinder fuel/air balance. I've got that book too, and it's a great book, but I'm not sure about the individual cylinder control...

 

"SFI allows control of injection pulse times of each individual cylinder"
i believe (but im not sure either) the computer can simply adjust injector pulse widths for the individual cylinders based on the sensors input, not really air flow to individual cylinders. (what i qouted is on page 153 of the book). maybe only later SFI systems have that capability.

however, the 94 bronco only had one sensor, and youre most likely correct that it doesnt have an input for a second. i was just kinda hoping i might be able to take advantage of more precise a/f measurement. i wonder if a CA 95 is the same. oh well. ill deal with only one for now i suppose.

i just wonder if incorporating things like a second O2 sensor and maybe a BAP sensor into an ECU that didnt have it originally is a huge undertaking. would it require new processors/cicuitry, or does the computer already have the hardware/prgramming for those sensors?

i still havent gotten it started yet. i need to set the distributor gear to have the rotor pointing near terminal 1 when im on the right TDC cylinder one stroke, and havent really been able to get good help. maybe tomorrow....