Ok, new here just joined today. I bought a 95 maxima gle from a dealership for $500. Had a blown head gasket. I put blue devil in it and had no problems overheating anymore. Since then the gasket has been replace correctly. One day I drove a two hour one way trip and car ran a little hot well the exhaust was crackling. The cel light came on. The next day I drove a four hour one way trip. Upon heading back a hour from home the car didn't want to start. I thought maybe fuel pump issue. So I got it going and drove home. I ordered all parts bc once home it wouldn't start anymore. I installed new Ngk plugs, new iacv, the rear o2 sensor , didn't know it had three, ordered new struts and shocks not installed yet , new brakes all hour ,maf, fuel pump , knock sensor, coils. Everything I installed on my car into front yard but the struts and shocks. Car still wouldn't start. So, I checked the cel blinks and it said misfire in cylinder 3&4. Which explains the hot exhaust fuel entering into the pipe burning. I replaced then the uim gasket. Cars not overheating at all. I replaced the hoses. Still same issue no start.
Took it to a shop the way I got it running is I disconnected the maf have it a tiny bit of throttle and it started idled rough, then rev it to not stall or else it'll just die out. Once reconnected it ran higher rpm but still missing. Got it on a live scanner snap on tool. The o2 sensors bank 1&2 were reading rich but no signal was coming from them. We probed the back of the connections connected and not connected it had power was pulsing correctly but the ecu wasn't getting signal from them. They were stuck reason rich not alternating rich/lean. The rear one close to firewall was brand new after the issue. So what should I assume it is? The computer? I can't find how to remove it online or how to find my model. Any help?

 

Welcome to the Org.

When you say no start, does it at least crank?

Could be lots of things. A bad FPR, crank (ref) sensor, grounds etc etc

If the car is warm or hot and doesn't start, then it could be a bad ECTS or FPR.

Bad O2's will not prevent the Max from starting.

 

With 2 cyl. misfires i wonder what brand of coils u have in it, im not saying crappy coils would cause all ur probs..im just wondering.. cuz as have been proven before anything other than oem will most likely throw a code..if u ordered ebay 6 coils new for 100 bux, SENDEM BACK ASAP!..used oem on the otherhand...

 

I tried it again last night. The car is running on three cylinders,#4,5&6.
I pulled the plugs off the coils of 1,2,&3 one at a time and the car didn't change idle at all. So I left all three unplugged and the car idle was still as rough as it was before.
So, I'm now thinkin of changing the crank sensor on the engine on the passenger side. Maybe that is out? But that doesn't control the o2 sensors reading no signal to the ecu/ECM does it? It was driving fine, then the car just went bad??
It seems like I'm the only one to have had this problem.

 

Don't waste your time and money changing that crank sensor. It won't cause your problem, so it can't fix your problem.

You need to break out the voltmeter and start checking things. Let's start with the ignition coils.

Anignition coil has 3 wires going to it, a red wire, a black wire and some other color. All the coils have a red and black wire.

The black wire is ground - see if you have continuity between the engine block and the black wire.

The red wire has 12 volts on it when the ignition switch is on. The engine does not have to be running. Check and see if you have 12 volts on the red wire.

The 3rd wire is a different color on each of the ignition coils. This is the signal from the ECU to make the ignition coil fire. To check this wire, you will need to have the engine running. Since this is a quick pulse of a signal, change the voltmeter setting to AC volts. If the ECU is trying to fire the ignition coil, you will get some kind of a reading, the exact number will vary for each brand of meter.