ECU problems- Please help
 

I am having trouble getting a pettit upgraded computer to work in my 93. Over the past few months, pettit has sent me 3 computers none of which will work properly in my car. The problem is that I always get a check engine light once the computer is installed. I currently have a stock N3A1 computer which is working perfectly and gives no check engine light, but with the mods I have, it is not safe to be running on such lean maps.

After installing the 1st computer I recieved, I started the car and the car starts fine, but the check engine light immediately comes on. I tried to check the code but when I jump the TEN and GND terminals no codes will flash, the light just stays on. I had driven the car around the block and it seemed to be running in limp mode and bogged during acceleration.

I sent that one back and they sent me a 2nd computer. This one was clearly not the right model for my car. I plugged in the computer, started the car, and the check engine light came on. Again I attempted to check the code, and it gave me code number 16 which is the EGR sensor. My car is a 93 non cali and does not have the EGR sensor, so obviously this was the wrong computer and I sent it back.

Now currently I have the 3rd computer they have sent me. It took them almost 2 months to get this one to me, and they assured me this was the right one and Cam had tested it in his own car for 200 miles. Well when I plugged it in, it still brings up a check engine light and does not allow me to check the code, much like the first computer did. I drove around and again it seems like its running in limp mode and bogged when I tried to accelerate.

I would like to know if anyone knows why these pettit computers keep giving a check engine light, but will not allow me to check the code. I am very certain that there are not any problems with my car, since I am able to install a stock computer and the car will run flawlessly. I know the check engine circuit is working fine since I can check codes with the stock computer, and the 2nd computer they had sent me, and the light will flash with the codes. I can only assume they keep sending me bad computers which do not operate properly. This is getting pretty frustrating since I have been trying to get a working computer from pettit for 4 months and each time they assure me its going work and it doesnt. Also their customer service leaves something to be desired. Anyways please let me know if you have any advice for me at this point. Thanks

Aneel
93 touring
orlando, fl

I cannot see them sending you 3 different bunk ECUs, especially after the last one was tested by them before sending it out.

It's not the ECU.

Also, you might want to provide some pertinent background history, such as your other posts on the same subject:

https://www.rx7club.com/showthread.p...gine+light+ecu

My guess is that there is something still wrong with the wiring. You mentioned further down about your passenger side harness being damaged by wheel through the fender. I suggest you look in the FSM for all sensors that take that route and check voltage.

Thanks for your replys. Yes previously there was a wiring problem that caused some shorts, and it has all been fixed since then. I have been running on a stock computer and have paid pettit to have my previous pettit computer replaced. The car is currently running perfectly, and does not give any codes on the stock computer. This leads me to believe that any past electrical problems are no longer present.

One prior symptom that does arise is that when I had fried the pettit computer, it had stopped outputting engine codes and the car would not start. When I plug in the current computer pettit has sent me, it also does not give a check engine code. Is there something that could cause the light to come on that the computer does not have a code for? My previous wiring problem had caused some problems in the fan circuit, but I had fixed it by removing the fan control module, along with the harness for the fan recall. Would this have anything to do with it? I assumed not, since I do not get any codes with the stock computer that is currently in the car.

and the stock ecu will run the car without cel's ?

funny its the first time i hear of the pettit ecu giving problems ,i used mine without any problem whatsoever
altough i have heard about check engine lights with no codes,dont know how they fixed it though

Do you have someone local with another stock ECU you can test? I'm curious if a different stock ECU will also have a problem.

However, as clayne has mentioned, I seriously doubt if the Pettit ECU's are at fault.

I think maybe the Petit ECU has some sort of built in feature that turns your check engine light into a shift light or something, Theres an EPROM chip for the DSM that does that, my friend bought it and he thought his car was going crazy, he didn't know it had the feature. Might be worth a shot.

I did test another stock ecu in my car with no problems. Pettit had requested I send them a stock computer as a core, so I had purchased an extra one and had tested it in my car before I sent it to them. I had paid to change the eeproms from the bad computer to the stock computer I had sent them. Well they have kept that stock computer and sent 3 different ones none of which have worked.

I am certain that the check engine light should be off. Pettit doesn't convert the check engine light to a shift light, since it is pretty important to have it to read the codes.

To ressurect an old post, I'm having the same problem. Throws a code about a minute after start-up. Code can't be diagnosed; the light just stays on. Anyone have any idea why?

possibly a 93-94 descrepency?

Yeah, that's what I thought until I read this post.... Looking into it now but I think the previous owner had a 93.

Sorry
but what I can do to see my error codes to my car too?
What wires I have to short?and what light I have to look?
Sorry twinturboy for out of thread question.

Read this:
http://www.fd3s.net/engine_codes.html

Or check this, it explains the long and short flashes a little better.

http://www.rx7city.com/ecucodes.htm