OK. Ive been posting about a no spark issue on my 95 maxima. I have replaced all sensors and did the harness check with voltage and ohms. All good. New plugs and the whole 9 yards....grounds, ect. ect. When the car was running a few yaers back I had replaced the MAF due to how it was running. I have checked everything like 3-4 times. Im not getting spark. So when I was finally able to get codes(due to my stupidity) I got flash code 12 and 82. Out of bordum I took out the MAF and took off the cover since I had heard about the solder points going bad. Under the cover was a sheet of copper covering the circuit boards and I noticed an X type of crease in it. Kind of like what the cover looks like if you were to put it on up side down. the copper cover was pressed against a terminal pin and when I peeled it back it looked to have a hot spot stain on the copper. i think it got shorted out. Now, when I changed the MAF before it still ran like crap. I parked the car as I was able to drive something else. Code 12 staes that there could be rationally incorrect voltage entered into ECM, compared with the calculated value by crankshaft position sensor POS signal and throttle position sensor signal. Is it possible that the MAF shorted and the POS signal was misdirected or misunderstood by ECM? Gonna try to change MAF soon. Will post results but please feel free to comment or suggest something.

 

I am not sure if I read the post correct, it was a fustercluck of words.

It sounds like you're well off on your way to diagnosing it but let me drop a few helpful tips.

The 4th gen Maxima does not need the following to start and idle:

TPS
O2 Sensors
MAF
IAT
EGR
all 6 coil packs and injectors (Bare minimum to keep idle is 4)
MAP/Baro sensor

Now, what is extremely crucial to the car running is below:
CPS
CKPS (Ref and Position)
IACV (needed to keep an idle, but it the car WILL fire over and die w/o it, you can get around using a IACV though, so this isn't really crucial either....)
Fuel and Spark on at least 4 cylinders (I've ran one on 3, but you need to keep your foot on the throttle to keep it alive, which is something you can't really do w/o a TPS sensor anyways....)

If I'm diagnosing a problem removing the first section above has been EXTREMELY helpful in identifying what the problem is w/ a VQ30DE

I don't know what a code 12 is (maybe using the flashing light method i think?) buut.....

If i'm reading correctly you think your maf may have shorted out the CPS or CKPS sensors? I find that hard to believe, any tomfoolery going on with those sensors and it will blow the ECU fuse, learned this the hard way by shorting out my CKPS Pos wire doing headers on my red car.

Good thing is those sensors rarely go bad, since they're just hall effect (i think, right?) magnetic sensors. Just goto a local junkyard, find some nissans and yank those sensors out for your car and replace them all.

 

A code 12 is a flash code. Its actually a P0100. I am not getting spark. New sensors are....3 O2, knock, crank REF, crank POS, ect, egr and tube. New plugs, timing chain, water pump all belts and hoses, new ignition switch. Yes, the timing is correct. It ran after chains put on. Like crap, but it ran. No fuses were blown. Ignition relay at interior fuse panel works. All relays under hood work. Put grounds from battery to block, trans, and crank POS sensor. Cleaned all other grounds even at the upper manifold. Getting fuel from pump and injectors. Starter works fine. No aftermarket alarm or remote start. IAC and manifold is clean. TPS adjusted to specs and works in all parameters. Like I said, the MAF is supposed to get signal from crank POS. If it is not getting it or it is not getting it properly there might be a starting problem. I opened the MAF and found the copper plate touching a solder pin sticking up from circuit board and it looked like it had a burn mark on it. This MAF was replaced with a reman one and its possible the lid was pushed on the wrong way forcing the copper plate onto pin terminal. I drove the car for a few months like that but it ran horribly. Could it be that the system shorted out for so long that the circuit between the POS and MAF is fried? I would hate to buy a new MAF and it still not start. All I need is spark for it to fire up. The rest I can figure out(I hope). Power is at coils as it should. When I tested the POS while plugged in with key on I get over 5V and passing or touching screwdriver across magnet changes nothing. All wires from all sensors are good with volts as required or ohms as per FSM. Before I replaced MAF the car ran with classic MAF failure problems. Bad idle, shaking, stalling, ect. ect. If the copper plate is not supposed to touch anything but the soldered area it is attached to but it does hit a terminal, wouldnt it make car act like the MAF is failing? Again.....all I want is spark.

 

I'm sorry not to be an ******* or anything but PLEASE. PLEASE. PLEASE!! Use breaks in long post to help ease reading it.

Before I go on helping you I don't want my brain to bleed out of my nose.

Here is my post above in fustercluck style, compare it see which one is easier.

Which one is easier to read? The above? Or my first reply?

Just be friendly with the "enter" key, it makes reading things WAY easier on forums.

I do want to help, just extremely hard to read a blob of text w/o getting a noose bleed.

 

No I understand you. There was an issue I found inside my MAF and understanding the cicuits of the MAF in relation to the crank POS. I am not getting spark. Once I get it and the car fires up the rest I can handle. What dont you understand about the post? Ask away and I will answer so that you might be able to help me with this.

 

Maybe I'm missing something, have you tried running the car w/o a maf?

Or wait, maybe you did run the car w/o a maf, and once you plug it in you get no spark?

 

I agree completely with aackshun. It's not a question of understanding, it's a question of willingness to wade through all that and figure it out. It's much easier to comprehend text if it's broken up into multiple paragraphs.

We get way too many long posts that consist of a single paragraph, or worse yet a single run-on sentence. It's a matter of self-interest. If you want your post to be read by as many people as possible, you need to make it as easy to read as possible.

 

I appreciate all the willingness to help me out but I figured the more information about what I did to the car already would help you all know what was already checked. Bottom line is that I have NO SPARK. All sensors are new but noticed a problem with the MAF.
I know the car will run with out one but ......it wont run due to no spark. What I am looking for is to see if anybody knows the relationship between the MAF and the crank POS.

 

Well you know there are the 2 sensors, one at the front of the engine, another on the bell housing. If you are not getting power voltage and signal voltage at the coils and the sensors are good, the next thing to check is the continuity of the wires from the sensors all the way to the ecu. I would probe the wires from the sensors to where they enter the firewall to check if there are any breaks up to that point, the next would be to check from there to the ecu. If all is good then the next culprit would be the ecu. You already replaced the maf with the same results so.. on to the next components.

Also the fact that the ecu is reporting weird voltage from those sensors it could be a break or short in a wire somewhere.

 

Replaced MAF and cleared the codes. No spark. Checked codes and got flash 47 and 82. Cleaned the pulley and cleared codes again. Now only getting code 82 P0335. Gonna check for like 5th time continuity and voltage in harness. STILL NO SPARK. Also going to check the pins at the ECU. If all is good then I guess its time for another ECU. Anybody have any recommendations on getting another ECU? Junk yard? Ebay?

 

Replaced MAF and that code cleared. Found out that the "new" part I bought from AZ was no good. it was the crank sensor POS. Took it back and they replaced with another one. Went and replaced the REF sensor too. Got my spark back but cranked forever. Burned up starter and replaced that. Replaced orings on injectors. Now one is leaking. Gonna change it out tomorrow. Seems to be sucking air somewhere. Going to change all the vacuum lines too and see if it works. she wants to run but is backfiring through exhaust.