wolverine8490

So,

I think I may have fired my ECC in my 91 GT, causing all of my mystery problems. The question that I have is the ECC in my car has the following numbers:

8914-1020
E9AF 14A624 AA
E4LB 14A459 B
073 ECM

When I do a search on those numbers, I really do not see much about it. Autozone was not able to cross reference any of those numbers. So what I think I want to do is get an ECC out of a 93 cobra, since I have 24lb injectors, and a C&L MAF. There are four different cobra model numbers, and I was wondering if someone could tell me which to get.

F3zf-Da
E9zf-Aa
F3zf-Db
F3zf-Ca

AdderMk2

you should just get a stock A9L/P and slap it in there.. call it a day

samseed101

Why do you want to put a cobra computer in there? What benefits are you expecting to gain?

I'm also curious what your mods are and what the mystery problems are. I've seen a lot of people say they fried the computer because they couldn't figure out what the problem was. 99% of the time, the problem isn't with the computer. At least half the time, the people who said they fried the computer never even pulled codes to see what was wrong.

1fastzook

x1

wolverine8490

Well, I just figured that while I was replacing the computer, then I would go ahead and get the one that was calibrated for the 24lb injectors. I mean, both the computers are the same price.

As for why I am thinking my ECC is fried, it is a little hard to explain. I am doing a V6 to 5.0 swap in my SN95. I bought a 91 Gt parts car, and swapped everything over. I have it running, but the TPS is sending 4.9v to the ECC no matter what I do. Here are the engine codes I am getting:

22 X X X MAP/BP sensor out of self test range.

35 X X PFE or EVP circuit above the maximum limit of 4.81 volts.
X PFE or EVP circuit has intermittently failed above the maximum limit of 4.81 volts.

51 X X ECT sensor signal is greater than the Self-Test maximum of 4.6 volts.

52 X X X Power steering pressure switch always open or closed.

54 X X ACT sensor signal is greater than the Self-Test maximum of 4.6 volts.

67 X X Neutral safety circuit failure.
X A/C circuit was on during KOER Self-Test.

85 X X Canister Purge Solenoid circuit failure.

53 X TPS circuit above maximum 4.5 volts.
X TPS circuit has intermittently failed above maximum 4.5 volts.

25 X Knock not sensed during dynamic test.

I have completely re-wire3d the whole sensor wiring harness straight off the sensors down to the ECC. I am thinking the ECC is back feeding the system somehow.

One mistake I made, when I was wiring up the ECC, I sent 12v to Pin 30 on the ECM. On manual ECC’s that wire sends out 4.9v, on an auto, it receives 12v. So I think when I sent it 12 volts, I fired something. But no matter what I do, the TPS will only send 4.9v back to the ECC at idle, and not .9v.

samseed101

It sounds like you're running a 91GT engine (electronics, sensors, etc) but using an SN95 computer and then tried to rewire everything yourself. I think that is going to cause some issues there, but it may not be a fried computer.

The SN95s use different strategies and the pinouts are slightly different. So that can and will cause problems right there. Rather than try to rewire the SN95 stock computer, the easier solution would have been to simply grab the correct computer to begin with so the harness would already be correct

But either way, the computer is probably not fried. I guess it's possible but I lean more towards an incirrect wire (or a few.)

If you have a calibrated MAF and hte injectors already, you're not going to gain anything by using the cobra computer. I'd just stick with an ordinary GT computer.

wolverine8490

I stripped all the engine wiring out of the SN95, and am using the wiring and ECC from the 91. The ECC for the 95 is in the back seat . As for the wiring, I just dont get it. Ill attach the diagram, I mean it is really easy, Pin 47 on the ECU should be recieving .9v from the TPS, but when the sensors are plugged in, the ECC recieves 4.9v. I replaced the TPS already, but no dice. Also, pin 46 which is supopsed to read .1v off the ECC, is reading 4.9v.

[IMG]local://upfiles/70634/55FB6785B1CD490B8AC9B320E57A711A.jpg[/IMG]

samseed101

I'm thinknig you have a wire crossed or something somewhere. The wire that runs to pin 46 runs to a lot of different locations. If you get a line crossed anywhere along the line then it could send the voltage back through that line.

Are you sure all your grounds are connected properly (including the ground for the EEC that is right next to it.) I'd disconnect the sensors one by one (any sensor that connects to the return line on pin 46) and then test the rest of the line with a multimeter to see if you're still getting any voltage on it.

Did you do any physical splicing or did you just directly bolt the 60 pin harness to the ECU and call it a day? I guess I'm confused on how you got a wire crossed or what you mean when you said you rewired it. I just had to mess around iwth my wiring harness to splice in a narrowband emulator, so it's kind of fresh in my mind. I had to physically splice into teh wires.

This image may be a bit more confusing, but I found it to be VERY helpful.

samseed101

But like I said, I'm betting that one wire is crosses or placed incorrectly somewhere. It only takes one instance. And then it will send the voltage down the line and into each and every other sensor that relies on pin 46. The you'll get a host of problems.

wolverine8490

Thanks for all the help so far.

At first, I used all of the factory wiring. I did not splice anything to anywhere. THe only thing I had to splice in was the EEC power relay, and the fuel pump relay since the SN's use the CCRM. Also, my car WAS an auto originally, so I had originally bypassed the nuetral sensing switch by running pin 30 straight to the BAP (which is what would have originally caused my 4.9v issue). I took that wire back off. Ran pin 30 to the nuetral sensing switch under the pedals, then out of that to the BAP. I left all of the senors from the tranny unplugged for now, but they have nothing to do with any of that for now.

I did do the sensor test. I set my volt meter on pin 46, which is supposed to have .1 volts. Mine is reading 4.9v. If I unplug all of the sensors on the circuit, I get .01 volts. Then I started by plugging in one, taking it back out, and plugging in another. Everytime I plugged in 1 sensor, the volts jumped back to 4.9.

So then I thought maybe somehow I had something wrong with the original wiring. So I chopped off all of the senors, and re-wired them straigh tto the ECM as the diagram described. And I still have the same results.

Pin 30, has voltage as if the clutch was pushed in all the time. If I cut off the wire that goes to the BAP, then it only has power when the clutch is pushed in. So something is back feeding power threw the whole system, and I really just dont understand what or how at this point. I just really dont get it. I will go over the wiring again from pin 30, but I know I have checked it about 5 times .