Yeah.. your truck should be 15426378, and all HO 302s(the computer you an I both have) and 351's use 13726548, so you need to swap pairs 5&4 with 3&7.

The reason I thought of this was because I was reading the 95 page long thread about all the problems Justin had with his 393 stroker, and one of those problems was he was using an SEFI MAF kit intended for a 5.0 truck on the 5.8 stroker, but he had not converted the injector order, so the motor was running lean on some cylinders and rich on others. It's hard to believe that is possible, but because the mustang computer also uses two O2 sensors, it has the ability to vary fuel delivery to individual cylinder banks. And because the injector banks were mixed up, it was alternating between rich and lean trying to compensate, but of couse it never gets there.

 

Paul,

I appreciate your help. Thank you.

I'll swap those injectors tomorrow afternoon 3<=>5; 4<=>7

pins 12<=>14; 13<=>42

I can't wait to see the result! With the four wires wrong it had more oomph than my old SD!

I may have bought that Air Aduster for nothing. We will see!

Thank you again,

 

Good catch...

 

I wouldn't get my hopes up that this will fix the pinging. My truck was right and it still pinged. I also tried something similar to the air adjuster that you are describing, and that didn't help either. I hope you have better luck with both, though.

 

I hear you. I read a couple of discouraging things on the web. I also found a couple more things about my truck.

1) According to Tom Cloud's documents ('97 and '98 versions) A "re-calibrated" Mustang PCM is needed. He continued that the PCMs sold with kits are re-calibrated, including a Ford one. He also said that if you use a PCM that is not re-calibrated, "you won't like the results"

I am counting on the Air Adjuster to make the A/F a little richer and eliminate the pinging. The company owner promised it would. He said that my pinging problem is very common in truck SD -> MAF conversions. If that does not work, I still have a couple of options: buy a "recalibrated" PCM or kit; recalibrate it myself; or get a custom chip.

2) From multiple sources, including Tom Cloud, there are two types of EFI distributors, an MPFI and a SEFI. SEFI dizzies are backward compatible with MPFI. One source, according to production dates would have my truck as having the SEFI. Tom Cloud's document hints that our trucks have the MPFI kind. The MPFI kind raises a signal that is converted to PIP by the TFI. There are eight EQUAL signals interrupted by eight EQUAL non-signal times. It is 50% on and 50% off. The leading edge of the high signal indicates that one cylinder is at 10*BTDC. We don't know which cylinder it is, but one is. That is OK for our MPFI SD bank fired injectors and timing advance/retard. The SEFI dizzy functions slightly different. It has a 35% on time signal to the TFI for the number one cylinder. All the other cylinders are still at 50%. That is to allow the PCM know how to sequence the injectors. There is a small device in the dizzy beneath the rotor the is the number mechanical signal.

Obviously most of our trucks must have the SEFI dizzy. The Ford kit works with them! Ford was making them for Mustangs and other cars. Why manufacture, document, and install two types of dizzies that cost the same when the newer more advanced one is backwardly compatible with the trucks. I can understand using up old stock and a few of us may be stuck with the wrong ones.

As for me, I changed the injection order from HO to match my non-HO cam order. I checked the location and quality of every connection. That change seems to have made the truck run slightly richer, but not significantly. I found an exhaust leak where the driver side manifold connects to the Y-pipe. There is a 1/4 inch wide black streak there. Could a small leak that far down cause a lean condition?

Still to do: check the dizzy for SEFI vs. MPFI; check the back booster for a vacuum; and check the cruise control for vacuum.

 

I don't know where all that talk about the distributors has come from, but I read the exact same thing as you when I did the swap several years ago and checked my distributor just to be sure. I have an 87, and the distributor in my 302 MPFI has a narrow tooth for cylinder 1. If my 87 has it, I don't see why it would even be an issue for any of the trucks these MAF swaps are marketed towards (mostly newer than my truck). As far as I know, even the batch injected setups had a narrow tooth for cylinder 1 -- even with batch injection, the computer needs to know the location of cylinder 1 TDC to keep all the timing events in sync. Tom Cloud's papers are awesome resources, regardless.

It's good to hear from someone that Ford recalibrated their MAF kit computers. That may help to explain why we have had the pinging issues, but still makes me wonder about the folks who have swapped using this method and have not experienced any issues. The mustangs featured about 42 degrees of total timing advance, while the trucks were a much more conservative in the mid 30's. Perhaps Ford altered the timing curve in their MAF kit computers to keep them from pinging at the factory 10° base advance. By retarding the base timing, the total timing is reduced, but idle timing and low range timing may possibly be adversely affected, killing combustion efficiency by incorrect injection timing and spark advance.

Please keep us (at least me) up to date with your progress and what you find out. It might help me swap over to MAF again, with better results this time around. As it is now, I keep putting off investing in a tuning setup that would allow me to alter the ignition advance curve and monitor every computer input as well to check for any problems I might have missed in my previous diagnosis.

 

It works!

I put the Air Adjuster in the MAS lead, spent some time and miles adjusting it and viola! NO PINGING!

It now runs the slightest bit rich. It is about .05vdc (out of 0-1vdc) richer than 14.7:1. Before the adjustment it ran very lean, about .25vdc too lean. I will try to fine tune it to perfect after about another 100 miles.

In my testing I tried to lug the engine at all speeds, uphill, and on flat stretches. My timing is set between 10*-10.5* BTDC.

A little bit down the road, I will write up what I did, my pin-outs, my parts, and my pitfalls.

THANKS FOR ALL THE HELP!

 

It works!

I put the Air Adjuster in the MAS lead, spent some time and miles adjusting it and viola! NO PINGING!

It now runs the slightest bit rich. It is about .05vdc (out of 0-1vdc) richer than 14.7:1. Before the adjustment it ran very lean, about .25vdc too lean. I will try to fine tune it to perfect after about another 100 miles.

In my testing I tried to lug the engine at all speeds, uphill, and on flat stretches. My timing is set between 10*-10.5* BTDC.

A little bit down the road, I will write up what I did, my pin-outs, my parts, and my pitfalls.

THANKS FOR ALL THE HELP!

 

Great to hear! Maybe the air adjuster that you have is different than the one I have from Pro-M.

 

I hope u find out the pinging problem, havin the same problem, w/ a MAF swap, 94 F250.......

 

Wayne,

The pinging problem is from the air/fuel mixture being to lean.

I solved that by installing the Air Adjuster on the MAF sensor, slightly raising the signal, making the PCM think there was more air than in reality. This caused the PCM to increase the amount of fuel.

 

And the reason you needed this was because the computer was not properly set up to match the application. Correct?

How much did this set up cost? What was the installation like? Pics? Where did you by it?

 

Eco,

Documentation that I found on the web, stated that most MAF kits sold, for manual or AOD trannies, are "re-calibrated" for our trucks. Tom Cloud in his documents said, "you won't like the results" if you don't use a "re-calibrated" PCM for a truck conversion. I used a C3W PCM from a '93 Mustang LX 302.

I did not recalibrate it. I just popped it in my truck (with harness and ducting changes). Now that I have installed the Air Adjuster and read the voltages off of its DVM display, I could take a shot at calibrating the PCM if I had the tools. I was an assembly language and machine code programmer for over a quarter century. I'd feel comfortable disassembling the code, following linked lists, and reading the tables.

The Air Adjuster cost $179. It has a plug and socket on it. It fits between the MAF sensor and the MAF sensor harness connection. It takes a few seconds to install it.

The unit has three items on it: a three digit DVM showing the altered/unaltered MAF sensor output voltage; an adjustment screw that biases the output voltage up or down; and a switch that invokes or bypasses the unit.

It took me a little over one hour clock time to setup the unit. I spent only about 15 minutes of real work time however. My setup involved reading the voltage and adjusting the screw, taking one minute. This was followed by 15 minutes of waiting with the battery disconnected. The battery was reconnected followed by a two minute test drive, listening for ping and watching the A/F gauge. That process was repeated a total of four times to "zero-in" on the proper value.

I have not yet affixed the unit to its final location. I will do that after I driven through a couple tanks of gas from different vendors and done some fine tuning.

I'll take a picture of my setup when the rain clears this weekend.

Here is a photo and description from the manufacturer's site: click.

 

Eric,

What was the voltage at the MAF at idle? It should be about .8vdc. Mine was .57 to .71vdc. After the Air Adjuster tuning it is .81vdc (.76-.86vdc)

 

It's been a while so I don't remember exactly, but I think I tried anywhere from .6 to .9 volts at idle. My adjuster has analog ***** to adjust high and low range, how does your digital one work? Does it just offset the voltage curve all the way through the MAF sensing range?