Yes the FMS people are wrong, all MAF Mustangs used sequential injection so both the plug and injector sequences MUST match the engine firing order if you want any respectable idle quality and power. The best way to accomplish this is to move the 4 wires at the EEC connector on the overlay harness, just buzz out and label the wires for injector pairs 3,7 and 5,4 and swap them using a soldering iron, that way at the engine end the injector plugs will remain in sequence with the cylinder numbers.

 

k i got that noted. i still need to try and get this engine running. im trying to determine if the injectors are spraying or not. i do not have a noid light. i know that when i ground to the motor and test one side of the injector plug it reads 12v when u crank it drops to about 9v. with a ground to the engine and a tester to the other prong of the injector plug was getting a low reading and when cranking it goes up to about 1.5v.

initially i took the black and stuck it in one side of the plug and the red in the other side of the plug and got a reading of .8 key on to surges of 3.49v when cranking. i hope i cleared some of this up lol
any ideas?

 

Anyone????
None?

 

You're gonna have to rewire the injectors it's as simple as that, it'll be a beast to get running if those aren't in sequence.

 

Rewired or not they should still be spraying gas into the cylinder now.

 

Yes that's right. In a nutshell the way this is done is 12v is applied constantly to the injectors and the computer grounds them one at a time to open them, but it's not an all or nothing ground the computer uses pulse width modulation so you won't see 0v or consistent numbers even with a simple voltmeter.. you need an oscilloscope by rights, but in any event if you see any number significantly lower than 12v you can assume the injector was activated.

 

I was just trolling over your thread and have done what your attempting to a 351w powered 89' Bronco and have many happy miles under it's tires since so this is not mission impossible.

the sequintial fire on the Mustang style computer (Mine was a A9L) supplies a single signal to every cylinder injector. The batch fire system fire one bank of 4 Then the other bank of 4 the harness has to be repinned and wires added jumpers deleted to accomplish this.

Look up itacrazyasian over on FSB that is the instruction I followed

Now have you tried to see if you have spark by using a shot of ether to get it to at least crack off?

Kemicalburns I read over this and was told by many not to attempt matching the firing order for the HO engine it would be of no benfit and actually make thing run worse I think Gackner was one of the ones who warned me of it and I think Ford actually says the same thing in their racing harness instructions.

 

In your case the engine and computer already have the same firing order so nothing needed to change.


No.. when Ford produced MAF conversion kits for these trucks they made different versions for each firing order, why would they bother if injector firing order didn't matter?

 

Your argument is valid conanski

I was only offering words of encouragement and trying to help him along if he has a HO firing order ECM then the paper you scannned is not really relvant unless he is willing to search and purchase the correct one for his application.

This was the explanation I was given for the HO/non HO injector firing order swap.
"You cannot swap the injector wires. There are 2 ways to fix this.
1. swap cams for the right fire order
2. buy a chip, and change the firing order in the ecu by reprogramming.


The reason you can't change the injector wires around is because the 'learning' that the ecu does is based on the computer assuming that the right side injectors are on the same cylinders as the right side O2 sensor.

If you move an injector wire from the right to the left bank, then you will have the left O2 making fuel corrections to 3 injectors on the left and one injector on the right.
The mismatch will result in WILD fluctuations in AFR as soon as the adaptive starts to function."

 

Yes that is exactly right if we were talking about a dual sensor setup, but these MAF kits are based around a single O2 sensor in the stock truck location which sees both banks so there is no learning problem with either firing order. The non-ho firing order is accomadated by simply rearranging 4 wires at the EEC overaly connector.

 

Ah I was unaware of that kit but since were on the subject I have been running with the o2 sensor circuts joined so I guess a guy could run like that and make due. I'm running that way and have been for a while and not really feeling any ill affects to date.

 

Do you mean a single sensor connected to both computer inputs? If so that's exactly what is done with the kits and it worlks just fine. I have experimented with dual sensors on my truck since the mustang EEC has the capability to use two, but it made no noticable difference to engine operation from the drivers seat and analysing the data from my TweecerRT I could see that the fuel trims for each bank were also running in near perfect parallel with each other, so my conclusion was that this simply isn't needed on a engine that performs well and has clean injectors.

 

Yes both o2 inputs are picking up the signal off my one and only o2 sensor I was planning on splitting it, but the thing runs so good the way it is I am reluctant to touch it. Up until I changed the tire size from 35" I was getting 13mpg on the intersate with no OD and 4:10's.