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Discussion Starter #1
Hi, I recently found out that I may have a bad computer. If that ends up being the case, I'm going to go all out and replace all the wiring in the car. I only want to do this once.
1: Does anyone know what the best computer is for a MAF system. I know that an a9l is good but is there anything better aftermarket? I think AEM makes one and others as well.
2: Does anyone know where I can get all new body and engine harnesses? I know places like Painless sell the engine harness but where can I get everything else other than a junkyard?
 

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Ford Fuel Injection

And I would stay with the A9L, unless you're going all out on a full race motor set up (do a DFI set-up), then you can run any tuner/programmer/burner to just about cover all your needs with the A9L.......
 

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Discussion Starter #3
Thanks for the link. Does anyone know how many volts I should see at each pin on the eec? Or is it 12V across the board? Can anyone offer advice on how to test a computer?
 

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It won't be 12v across the board. Some will have 12v, some will be grounds, and some will be varying voltages, and pulsed inputs/outputs. Tough to diagnose by checking it that way. Have you pulled it and checked under the capacitors?
 

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Discussion Starter #5
No, I haven't pulled the computer yet. That will be Friday or Saturdays task. Just trying to plan ahead if the caps look ok. Can I even test the computer with a DMM or would I have to pierce wires to test the circuits?
 

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You'd have to have a schematic to test it with a meter and I don't even know where to find one for an EEC. I'm sure there might be something somewhere if you dig for it, do you have any experience testing circuits? As far as I know the caps are the only problem these computers have. The easier thing to do would be to find another fox EEC that's the same as yours and swap the computers and see if your issues clear up and if the same issues appear in the other car.
 

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Discussion Starter #7
I do have experience testing circuits. I'm an electrician. I'm more experienced in residential/commercial/industrial, not really automotive though. Wouldn't the wiring diagrams in a haynes manual work to test circuits. I still wouldn't know what to look for voltage wise other than input voltage to ground.
 

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A wiring diagram will only get you so far. You can test 12v and grounds, and some 5v signals ect. If you really wanted to test the circuitry, you would need the schematic so you would know what kind of capacitors and transistors you have, and what values the resistors were. Plus, now that I think about it, you'll probably need an o-scope for the IC chip. That would be the more accurate test of the actual circuitry. Can't say I've ever put that much work into one of these computers because they're a dime a dozen, but it can be done if you really wanted it.

Here is a shitty one a quick google search turned up. I'm sure if you look for an EEC-IV schematic you can find something worth looking at.
 

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Discussion Starter #9
Ok I worded my question wrong. I don't want to get into the electronics repairing. I just wanted to make sure all my sensors and stuff had correct voltages without having to test at the sensor or relay itself. At work, if we find a bad PCB we just replace it. I hate electronics, unless its plug and play, its so tedious trying to solder and figure out the path of current on the board. Thanks for the input though. I'll visually inspect the computer and see whats up. I have a feeling I have another bad tfi module. Good thing for a lifetime warranty.
 

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Discussion Starter #10
Ok, so I found another problem with my car. The computer appears to have one burned tracer on the board along with 3 legs missing on the IC (the bigger one in the middle). One problem is that its not even the right one for the car. Its a E6SF-12A650-N1B. I read online its from an 86 thunderbird. What ecu should I get to replace it for speed density or an 88 mustang w/o cali emission? I do want to do a MAF system eventually but it's kind of expensive to go that route right now for me. Is the wiring harness from 88 and 89 mustangs the same except for the MAF pigtail? Oh and fogged306, I got the codes pulled finally using a test light without going right to ground. For some reason the check engine light wouldn't blink. I ended up with codes 21, 24, 67, and 11, the first time. Did the KOEO twice again and only 67 and 11 came up. Any ideas? I know its neutral safety switch but where is it and what's wrong with it?
 

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67 could be a few different things. If you don't want to diagnose it then you can just ground pin 30 at the EEC and it will eliminate it. I've actually just done a little research on this myself recently for my car and this is what I've found out. If you want to fix it, then you'll have to check the clutch switch, and I believe there's a neutral safety switch in the trans also and they're both tied in to the same pin on the EEC. 11 is a system pass which is good. If it's the wrong computer though, I don't know how much stock I would put in the codes until you get the right computer, but 21 is ECT and 24 is ACT.. not sure why they would be on if you have a system pass though so i would sort out the computer first.

I believe all you need to do is add the MAF harness to the 88 SD harness and you're done, but I've never done it myself so I've never really looked into it. Maybe someone else can verify that. The only other thing I know you'll want to do if you switch over to MAF is to pull and cap the vac line going to the MAP sensor. I'm pretty sure I have a stock MAF or two laying around if you want it. Just pay for shipping and it's yours. That way all you'll need is a MAF harness and an A9L. Should be cheap doing it that way.
 

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Discussion Starter #13
Yeah man it would be awesome if you could send me a maf sensor. I'll pay for shipping. As for the codes I pulled earlier, I don't really trust them because of I have smog delete and didn't even get any codes for it. I also couldn't run a KOER. It only revs up once, I waited five minutes and no codes. I'm def going maf if you have an extra sensor. Thanks for the link. How are the computers from autozone? Only reason I'm asking is because they have a 2 year warranty. Is there a better place like LRS?
 

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No clue on the autozone cumputers. I know there's been aftermarket replacement computers made, but if you plan on doing any tuning you may want to look into that and see if they use the exact same language and tables.

Yea I can send the sensor. I'm out of town until the 17th, but I can send it out when I get back. Just send me a PM on the 17th to remind me. I have a horrible memory and am guaranteed to forget by then lol.
 

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I think code 24 went away because your car got to normal operating temperature
 

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Discussion Starter #19
The harness appears to be ok. Not perfect but no splices that I have found yet. I do want to change it eventually because it looks like ass, but thats a $500 part.
 

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Discussion Starter #20
Ok, I have just done a full MAF conversion. That includes a used harness in pretty good condition, had some splices in it but they were done right, I rewrapped the harness in electrical tape and wire loom so it looks like new. I also put in an A9L. And a set of 24# objectors and a pro flow maf sensor calibrated for the injectors. Thanks fogged, but I won't be needing that sensor now. I scored all that stuff for only $300. Now, on to the problem. The car does the same **** as before, shuts down when it gets hot. I've tried so many things and I still cant find the culprit. What should I do now? Check fuel pressure? My dad says he thinks its the pcv valve but I can't even find the damn thing. Any idea where its located?
 
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