Hi everyone-

I have a question from my father in law- he is putting Mass Air EEC-IV fuel injection in his '72 F100. It's got a 302.

His question is this- is there a chip for sale or a company that will re-program his A9L or A9P EEC-IV to match the firing order of the 302? He is aware that a twEECer will do it, but that's an expensive solution.

Any good referrals?

Thanks-

Clay

 

An established Diablo or SCT dealer ought to be able to handle this.

 

the A9L is a 302(5.0) computer for a mustang. is ther a reason you want to change the firing order????

 

My understanding is that the firing order is different for HO 5.0's. Hence, if you put fuel injection on an old 302 (pre-1982) then you need to make sure the computer recognizes the different firing order.

There are two basic firing orders- it looks like the HO 5.0 and the 351 share the alternate order:

<table><tbody><tr><td>289</td><td>1-5-4-2-6-3-7-8</td></tr> <tr><td>302 (Pre-82)</td><td>1-5-4-2-6-3-7-8</td></tr> <tr><td>5.0</td><td>1-5-4-2-6-3-7-8</td></tr> <tr><td>5.0 HO</td><td>1-3-7-2-6-5-4-8</td></tr> <tr><td>5.0 Truck</td><td>1-5-4-2-6-3-7-8</td></tr> <tr><td>351</td><td>1-3-7-2-6-5-4-8</td></tr></tbody></table>

 

Why not just use a aftermarket camshaft with the later firing order?

 

Mitch... all you got to do is swap 4 pins in the harness connector at the computer... assuming you have the engine harness for sequential injectors. The wires for 5 & 4 get swapped with those for 3 & 7... problem solved.

 

Good call Conanski- thanks for the tip.

Clay

 

Hey guys-

Thanks for the suggestions- here is the response I got from my Father in law:

As for the EFI firing order. Swapping the 4 wires at the computer is how we were going to do it originally but as time as gone by and I have done alot more learning and getting more info it turns out this is not a good idea. Reason being is the O2 sensors are still reading/looking for the orig firing order. What happens by changing the firing order is the sensors read one bank lean and one rich thus they tell the computer to compensate and then one bank actually becomes lean and one rich and the engine gets runined. And I have cked into the cam swap and so far all I have come up with is all the 5.0s were a roller cam and all the 302a are a flat tappet cam. To use a roller cam in a tappet block means special lifters have to be used that hock together as there is nothing to anchor them to the block so to speak as there is in the 5.0 block. So as it is turning out I should of used a 5.0 block and not the 302 block. WHY Ford had to switch the firing order is beyond me but as you know Ford has a better idea, they just haven't found it yet.

 

You don't need to convert to a roller assembly to get the HO/351 firing order. If you missed it.. I just told you the 351 and 302 share the same cam journals and overall cam dimensions, so just select a 351 flat tappet cam and plug it into the 302 block.

 

Another thing too...the late 5.0's had the 13726548 firing order....same as the HO and the 351......Luck

JR

 

need 5L/351 fireing order for both ignition and fuel injectors and a matching cam.
Need to "fix up' an FI distributor that will fit the old block/oil pump rod length and correct metal cam gear for a flat tappet cam. Check and compare before you bolt in.
The block casting is different in the dist hole area so you have to be sure the dist-drive lenght is correct to drive the oil pump.
Need two ox sensors mounted approx the same distance from the heads as the original application so their control is correct. Out at some length in long tube headers often dosn't work as well. Use shorty headers and put them in the head pipes.
The only other way to handle the old cam in FI is to connect the OX sensors togather so they at least 'half' work and try to correct one bank and over fuel the other.
Other wise you get good starting, rough idle, poor ignition advance and good WOT running where the ox sensors are not used.
Been there 10 years ago.

 

Actually, there are no issues with longtube headers, mounting the sensor in the collector works great. And if the OP doesn't want to use 2 sensors for whatever reason, a single sensor that is Y'd into both sensor inputs at the computer will do the trick.. this is how the Ford MAF conversion kit handles it.

 

You may not percieve an issue with the ox sensor far away but I asure you there is a timing built in the EEC program that addresses this operation.
The distance/timing is based on a distance of close to 16 inches from the head port face unless the specific application has had the EEC program altered for a different distance.
Another problem with long tube Ox locations are the gas temps drops to much vs the distance and cause them to work lazy at lower rpm. The Ox sensors have to be at about 600 degrees min to operate correctly. The header collectors normally don't run that hot that far away from the head ports.
This is not my guessing or opinion but experience as well as known data on the subject.
If you doubt this, research it and find the answer in EEC tech data and programming.

 

I actually agree with you on this, if you were to stumble around to other exhaust system threads you'll see I have advised people to keep the sensors as close to the motor as possible when installing aftermarket exhaust components. My statement comes from my experience with longtubes, I have always placed the sensors in the longtube collector using only the factory wiring.. no extensions, and emissions sniffer tests indicate the motor is operating well withing design specs. I'd have to measure the header tube length but I'd be surprised if the sensor is more than 20" from the nearest exhaust port on my current vehicle.

 

I'm coming into this one a bit late but thought this would be a good place to ask this:
Suppose you had two cams of the same spec but one was ground with the 302 firing order, the other with the Windsor/HO firing order - Is there any difference in HP or Torque output between the two?
Obviously there must be some difference in exhaust tone.
This is one thing I keep wondering and maybe someone here can offer some input on this.
Mike