MAFS or Ecu?

[MarlboroLights]

I have a 1991 240sx hatchback, ka24de, automatic, with Idle problems. The car idles at around 500 rpms when I stop and the engine also shakes vigorously and then sometimes it will die out. I took it to the dealership and and the mechanic told me it was the Ecu/Ecm that i needed to replace. At first I thought it was the MAFS but it turns out thats not the case. Can anyone give me parts/info on this problem? It is much appreicated.

[dareo]

of all the things that control idle on a 240sx i'd blame the ECU last. Of all the things that cost money and control idle i'd say the ECU is the most expensive and the most profitable for a dealer to replace.

[MarlboroLights]

Is it a ECM or ECU ? whats the difference between them? And does anyone know anything about Emission codes? "California and Canada" why does the ecu matter where its from?

[SeVa-S13]

Probabaly emissions, seeing as California is the emissions Nazi state. Replacing the ECU seems over the top. Maybe try to take a MAFS from a DOHC S13 at a local junk yard and try it out. If that doesn't fix it, do a search for EGR and AIV here on the tech forums. I think people have had similar problems dealing with these devices and possible fixes may have been discussed.Good luck.

[SeVa-S13]

I got your IMs, Marlboro.I think you need the MAFS from a 91-94. The one you borrowed from an '89 is different I'm pretty sure. Try to get a newer one and go from there. Also, have you disconnected the AIV? It's the little black tube coming off your intake box and going to an odd-looking valve/box thing, then continuing on to your exhaust. Disconnect that all from your intake box and plug the whole with something temporarily. If the AIV is bad, it will be letting exhaust gas back into your intake = bad.Good luck.

[NISTECH]

ECU and ECM mean the same thing. Its just the confusion from different manufacters calling them different things. What codes do you have stored?

[MikeMurphy]

You should have asked him why he thought it was the ECU.

[MarlboroLights]

I just recieved the trouble code 12. Which means its the MAF sensor is the problem like I suspected. What was weird is I have 2 ECU's and 2 MAF sensors. 1 orig MAF and 1 orig ECU, The other MAF is a 89 and the other ECU is a 93. I have mixed matched all of them and started the engine up, and i still get the same result . The problem was still there. And yeah the ECU wasnt the problem. As of now, ALL of my ORIGINAL parts are now inside my car. . Anyways, Im looking to buy this MAF since this small puny island has NO GOOD JUNKYARDS click here

http://cgi.ebay.com/ebaymotors...19855

Do you think this MAF will solve the problem ? I am uncertain about it because of the fact that I already used my friends 89 MAF. I am also thinking it is the wires connecting to the MAF that could be bad also. I did read on about the proper Volts for the wires and i think i might have to check on that soon. But if it is the wires thats bad, Would the car even run? And would it make that much of a difference if the wires are changed? Thanks for your time and effort, Im glad somebody out there enjoys Nissan's as much as I do.

[MarlboroLights]

Oh yeah BTW my local nissan dealership told me it was not only the ECU but the MAF also. They guy told me the ECU wasnt working correctly to read the MAF codes. Thats why i thought the ECU was bad all this time. But then again i I think what Dareo posted on this forum is also true. I WONT GIVE UP ON THE KA !