ECU woes

[240 Trainee]

Ok, heres a puzzle. I blew an ECU a while ago, when just begining to work on my car. Got another one, and was working fine. Finally traced a boost leak I was playing with las night when I fist started driving the car, and I was driving home from work. was enjoying the beginings of boost at 4,000 rpm, when I realized I was speeding, pushed in the clutch, and let it glide to the correct speed. Well, the engine cut off, and would not start again. The fuel pump stays on when the ignition is on, instead of turnign off after a couple seconds, and the ECU will not diagnose itself. I think I smoked my second ECU, but I don't know what is wrong. Any suggestions?

[boost_boy]

I have one, but you should definitely sort your electrical issues 1st.

Dee

[240 Trainee]

Yea, I know. lol. I am hoping someone has had this kind of problem before. Now I gotta get the thing towed.....

[pulsar gtr]

Well, first you gotta find out why you are burning ecus, one thing comes to mind is the Alternator is OVER CHARGING which resulting in burning the ecu.

when you install a new ecu and you get it running, measure the voltage of the battery as the car running and rev it up to 4-5K rpm and measure the voltage, make sure it doesn't go over 14.7-15volts max, if it goes over that your alternator is over charging resulting in frying the ecu, if you can find out the regulator inside the ecu and measure that could give you an idea if the alternator is over charging.

PULSAR GTRRafi

[240 Trainee]

Thats what iw as thinking. Because, I only burned out this ECU the first tiem i cleared 3500 rpm, I got up to about 4500 while accelerating. That might be it. hmmmm, is that just a problem with the alternator? If replaced, would that fix it you think? and, is the ECU repairable, because I already have 2, I don't really want a third. lol

[240 Trainee]

Oh yea, I als thought there was a fuse that would go out first. but, your reasons do make sense.

[Nismo1182]

OMG you blew my ecu up!

Do you have a turbo timer? Mine also measures voltages like most do. That way you can see if it over charges or not.

[240 Trainee]

No, I don't have a turbo timer. And yes Kevin, I blew yours up. Though how, I have not the slightest Idea. I have a frien who is a computer engineerign major, I'm going to ask him to take a look. I really hope I can fix these things....

[GotBoost4Yall]

Quote »but you should definitely sort your electrical issues 1st.[/quote]

:shocked

[biosehnsucht]

If it is being fried from runaway alternator power, then if you can get a 12-15 volt zener diode in a large enough wattage/amperage capacity for the ECU to operate you could slap that on the power line(s) into the ECU.. that would keep it from going over 12-15 (whatever you used).. anyone have an idea how much the ECU uses?

[Nismo_Freak]

ECU uses 12v but is fused for 15v IIRC.

[pulsar gtr]

Well, the ecu uses two voltage levels, +12v and +5v, it gotta built in regulator to get the 5volts, if you have another alternator I would replace it to be on the safe side. Or you can take out the alternator and take it to the place that rebuilds them, they will test it for you if its overcharging, this way you don't take any chances in burning a third ecu.

If you were close to my area, I would off trouble shoot it for you and fixed the ecus.

Good luck,PULSAR GTR

[240 Trainee]

well, what do I need to do to fix them? Because, I don't want to blow them again. If I replace the alternator, should that do it? I will have it tested, and see if that is it. Or, if I could send them to you pulsar, would you fix them?

[pulsar gtr]

Well, First, you have to take the alternator out and get it tested at a rebuilt alternator shop if you know any.

You can send me your ecus, and I will check them for you, but no guarantees I can 100% fix them for you, I will give it my best shot.

but first test the alternator to make sure that it is the problem.

PULSAR GTRRafi

[240 Trainee]

I am, I called Advance, they said they can check an alternator out of the car. anyone have an ECu circuit diagram? If My friend can't find it, I might be sending them to you, Rafi

[pulsar gtr]

no problem, let me know when you want to send them, you can email me at [email protected] if you decided you want to mail them, I will give you my home address.

Thanks,

Rafi

[240 Trainee]

Ok, well, might be a ground problem. I was unaware that the Alternator has a post near the plug to be groudned as well. I was told that this might cause that problem I was experiancing. Now, Gotta get a workign ECU to test the theory... I wish I could figure out how to fix them.

[Spectre_240sx]

Depends how they're broken. Care to take the cover off one and give us a decent resolution pic? A friend of mine blew an ECU bad enough that it fried 3 IC's and scored half the board. That was easy to figure out what went wrong, lol.

[240 Trainee]

Nah, nothing looks burnt. I'll try to get ahold of a digital camera

[240 Trainee]

ou know, I just noticed that the little saying udner my avatar says I/H/E, cams, and ECU!!! lol, kinda ironic. No one has a scematic? Pulsar should be gettign my ECU, so I hope to be able to know how to fix these problesm. I have a sneaking suspiciton I might blow another or 2 before I finally figure out the problem, If I haven't already.

[GotBoost4Yall]

:youwon :fried:

[gore]

dont waste our precious ECU's

[Nismo1182]

You mean MY precious ECU.

[240 Trainee]

Darnit, I forgot again.