Hi everyone, got a new one for you after changing the middle front ignition coil and turning on the engine white smoke started to come out from the top part the plastic really melted, it was one of those Duralast bought at autozone, I think some of the dielectric grease that I put in the boot got beetween the spring and the spark and cuased a short circuit, but I´m not sure and dont want to plug in the new exchange coil until I hear your suggestions.

Is a 2001 Nissan Maxima SE 3.0 engine with 97k miles

Also, should I change them all our just that one? I noticed that the one from autozone is not the same manufacturer from Nissan.

People I need your help really!!! Went to Autozone got a replacement coil and I put brand new spark plugs in and put the new duralast coil with the nissan coils (front pack) and it burned again, it literally melted where the electronic ciruit is. Need your help anybody outhere.

Also when the car is cold the iddle speed races to 2000 rpm and as it heats up like 10 minutes it goes back to normal. Thats after the coil went bad the first time. Had a new MAF installed, throtle body plate put back in original place and ecu reset by the dealer.

 

Aside from coils being of low quality (internal transistor doesn't sustain the flyback voltage and shortens) or incompatible with the engine (wrong connector pinout) the only possibility I can see is fried ECU output - it keeps ignition signal high which turns the transistor inside the coil on and keeps it on. This will cause the effect you're describing in a matter of seconds.

 

Hi thanks for the reply, I just went to autozone and the guy told me the samething about the quality and ordered another brand lets see how it plays out. I hooked up to the scanner just to make sure nnothing else was bad and only came out 1032 and the #4 cylinder miss fire. How would I know if the ECU is fried?

 

Try the simple route first if it doesn't cost too much. If it works you won't have to bother with anything else. If it doesn't - come back with results and we'll see what can be done. You 'd need a multimeter and 1kOhm resistor to continue at that moment.

 

Update, at Autozone they gave me another coil, think the brand was namishi and it had a nascar performance logo on it but it was half an inch shorter than the oem ones, put it didn´t notice a difference on the engine. Took it out and saw that one of the sides bulged I dont know if the bulge was there when I put it in also it didn´t smell like burnt plastic like the other ones at least there was no white smoke. But this one I didn´t even felt when it made cotac with the spark plug. I got refund from them, thinking of going to dealer tomorrow and buying a oem one from them.

 

The Duralast coilpack I bought for my #4 on my 2000.5 (same part as the 2001) actually was an OEM part - you could plainly see where the cast Nissan logo had been ground off of the part. I've had no problems with mine since replacement.

 

If you look closely then Nissan logo has been sanded off, they used and original nissan oem coil to do the plastic mold. Also you can see in the quality of the plastic as in the nissan coil when they go bad it doesn´t melt but kind of bulges while the duralast actually ignites inside melting even the plastic outside and creating a fire hazzard.

 

Update went to the dealer and got the oem one it was only 30 dollars more than the autozone one. But not gonna risk frying it cuz they told me the electronic parts have no return so gonna wait for Max 5gen to tell me how to test the ecu, got the multimeter and the resistor already.

 

Waiting on anybody on how to test if the ecu is the culprit in frying the coils.

 

Any ignition items that melted when I was a full time automotive tech was due to a loose fit or not quite plugged fully condition. So the arc is not in the combustion chamber but in the spark plug tube or between the spark plug and coil end!

 

When I replace the spark plug for cylinder 4 it was completely loose. Gonna try now with the oem coil with the new spark plug to see if it doesn´t melt this time.

 

Wow I don´t know what to do I replaced the coil with the oem it seem to work fine for about 40 seconds the the car shut off and when I went to the engine bay the coil was squirting out melted plastic, the car wont turn on now not even with the other coil that it was turning on with no problem. It cranks but no go. HELP!!!!!!!

I took a pic of the coil but don´t know how to post them in here.

 

Sorry, I missed your yesterday's post. Could you connect resistor in parallel to the multimeter contacts and then measure voltage on the connector going into coil:

1. First check battery voltage as on this picture from FSM
2. Then check voltage on the contact 1 relatively to the ground, must be close to 0.
3. Check voltage on the contact 2 relatively to the contact 1. Must be close to 0 as well (below 0.3V). If you see any voltage above this on this contact do not connect your new coil, it will be melted as well.

 

Oops, I was too late, sorry one more time. You did the check albeit in the brutal way. Looks like ECU fries your coils. Check your fuses first - I bet at least one of them is open. It takes some current to melt a coil like that and most likely your ignition fuse prevented the fire. Replace the fuse, and do those measurements I suggested in my previous post. Do not connect any new coils on your #4 coil connector.

 

Hey thanks, how do I connect the resistor in parallel to the multimeter contact and wich one positive or negative?

 

If it is difficult due to multimeter contact arrangement you can connect it later between leads directly or use some thin copper wire to connect resistor ends to multimiter leads. This is one time event, so any way will do.

Resistor doesn't have polarity, so it doesn't matter which way you connect it. Its only role to ensure corectness of your measurements, otherwise you might measure some leak current effects instead. This matters only for case 3 in my previous post and only if you see voltage above 0.3V - then connect the resistor and check again if it helps to bring it down.

Good way to check if your #4 ignition channel is at fault is to compare your results with #2 or #6.

Multimeter itself usually has polarity, '*' symbol on one of the lead contacts usually means '-' and something like 'VIR-' mean '+'. Make sure it is in DC voltmeter mode with range to allow you measure 12V voltages. You can check it by measuring battery voltage. Just make sure it is not in ampermeter/ohmmeter mode.

Have you found the blown fuse? If not - make sure you check those in Fuse & Fusible Link Box which is located in the engine bay on the driver side:

 

looking for the blown fuse

 

found it eng cont 1, 15 blue

 

The car turns on fine. Going to do the volt tests.

 

Ok here are the results of the volt test.

Battery: 12.55v (with the car off)
13v then 12.35v when the car turn on with ac radio and all lights

#2 cylinder coil plug pin 3: 12.31v pin 2: 0.00v pin 1: 0.01v

#4 cylinder coil plug pin 3: 12.31v pin 2: 0.00v pin 1: 5.08v <----- This is the cylinder that keeps melting the coils, 4 so far.

#6 cylinder coil plug pin 3: 12.31v pin 2: 0.00v pin 1: 0.01v

Ok done with the test, let me know your dianosis

 

Well, it looks like ECU channel #4 always outputs full internal driver voltage. This almost certainly means that internal output driver in the ECU itself on channel #4 shortened to internal 5V power supply. Standard way to fix it is to replace ECU with dealer reprogramming all your keys. More creative way is to repair internal ECU driver on channel #4 but it takes skills/experience/tools. Any sound TV/VCR repair shop should be able to do this. I'm sorry but this is how it looks like.

Just to make sure I'd disconnect ECU from its connector and repeat the measurement on pin 1 channel #4. It should be 0V. If it will be anything else please post it here, it would mean that this is not ECU who drives this pin up but I have not much hope for it.

BTW: Do not waste money on new coils, they'll go the same path. They contain power transistor which is supposed to be turned on for spark only. In your case fried ECU output turns it ON continuously and never turns it OFF which leads to overheating, melting etc. I started to suspect this after your second coil but didn't want to bring bad news without solid reason.

 

Is there a procedure in disconnecting the ECU or just unplug the battery, disconnect the wiring harness on the passenger side and reconnect battery and do the test again? Also I´m quite handing fixing motherboards and stuff so if you have the directions I feel confortable doing it.

 

To be honest, I've never seen ECU of my 5 gen max. If you're sure about connector then the procedure you mentioned will do. I'd depress brake pedal before disconnecting ECU to discharge capacitors in the system but this is pure paranoia.

If you tell me ECU location and how to remove it I'll do it tomorrow, open it up, trace #4 channel to its driver and then I'll be able to tell if it can be repaired or not. I'm curious creature so I'll do it just for fun.

 

Check your ignition fuses and fusible link

 

Ok did the final test, disconnected the ecu from the wiring harness as described above, reconnected the battery again put the ignition at the on position and did the volt on the coil plug all came out 0 volts. Disconnected the battery again, reconnected the ecu and reconnected the battery car turn on no prob.

To remove the ECU there are 4 5/6 bolts, 2 on each corner of the bracket that holds the ECU. To remove the ECU after disconnecting the battery and removing all the bolts, disconnect the wiring harness on the passenger side by depressing the white tab and pulling up the black handle to the top that would pop out the harness, then slide out the ECU.

 

Thanks CMax03 found the fuse for ing cont #1 burn after the incident.

 

OK ECU ignition driver #4 is dead for sure, no harness problem whatsoever.

Sounds like I have to remove both kick panels first, right? I mean is ECU in the central console below climate control? This was actually the question: what do I have to remove first to get to ECU?

 

The ECU is on the floor to the right of the acceletor pedal, is open on both sides.

 

Here is your driver:
. I circled it with red line and marked the pin driving #4 coil.

The markings on the chip say:
9M2T
151007

I don't know if you will be able to find one: I couldn't find datasheet on it, only for HD151005 which is 8- channel version.

Another way to get this chip is to get ECU from junk yard or from another orger here who replaced it recently and remove the chip from donor ECU. Donor ECU does not have to be operational, you just need the chip. Chip is very often used as ignition driver in other cars as well.

 

Wow you are the man!!! Gonna hit those Junkyards in Newark NJ to find a ECU so I could swap the chip. By the way could a bad ignition relay cause this? Will post when done fixing it. Thanks again.

 

No, nothing outside that channel driver and coil could cause this. I'd say short from driver output to +12V could do but this can only happen if someone accidently shorts pins #3 & #1 on the coil connector for example. I found on other sites that this happens often on its own due to faulty chip. Watch orientation of the chip when putting it back, I've seen/done more then once chips soldered turned 180 degrees. Sometimes some smoke comes out of the chip sometimes - from a new place altogether .

 

Almost forgot - if you decide to take chip replacement route please disconnect all the coils before connecting the battery back and check pin #1
voltages on all of them - they should be close to 0, like your #2 & #6 used to be. You don't want to melt more coils due to another failty chip/soldering mistake.

 

hii...
most of maxima 2000, 2001 ecu problem are, injector all wayes open or one of the coils all the time working.. so how u can check thes ..
buy led light and counect the led light wire to the coil fushed if u see the led light waring on and off its okay
if it alwayes on ther are problem with the ecu..
hope u understand what i mean

 

Let's see:

Most of 2000/2001 Maxima problems are related to an injector driver always on or ignition driver always on. To check this you can take a led and connect it between pins 1 & 2 (+ of the led to pin 1) of the ignition coil connector. If you see the led blinking then the channel is working OK if it is continuously on then your ECU has a problem.

Well, interesting method, it will most likely work. Looks like most of ECUs can be actually repaired. Wonder what do you replace faulty driver chips with?

 

Hi guys thanks for all the imput, what you think about this two places?

http://www.autocomputerexchange.com/...ts.asp?cat=152

http://www.solopcms.com/Links/nissan.html

 

If you're going to chicken out and replace the whole ECU may be the one from the local j/y + reprogramming keys by dealer is a way to go. You can bring the car to their lot, swap ECUs right there and cry for help .

 

Is just that the junk yard is chargin about the same for a used ECU and this places have it for about the same plus the vin programming. To change the chip do I have to get the exact year or a 96+ used ecu ignition driver chip will do?

 

You know your situation better, so it's up to you I was just kidding.

You need a replacement chip wherever you can get it from. I have strong suspicion that any Japanese 6 cylinder ECU would have one inside. I read somewhere that some Suzuki model had one. The chip is made by Hitachi and contains 6 n- channel MOSFETs which are normally open and keep pin 1 at the ground level. In your case ch 4 one got 'tired' and lost its contact so there's nothing left to drive that pin to the ground anymore. Some people in other parts of the world just put piggy back external MOSFET over the broken channel and call it a day but it requires some extra knowledge and looks ugly at the end.

 

Hey I found the chip on the net but they were selling it in volumes, otherwise it only costs 1 dollar, gonna keep searching to see who in the us my sell it.
Ignition Driver: 151007
Application: Suzuki ECU
By: Hitachi
Parts: ECUSA1502ECU500$1.00 Alt #:
Packaging:
Application: Suzuki ECU

Order#: SA1502

 

Also this site, contacting them to see if they can sell a small quantity like 20 or so.

http://www.sacer.com.cn/ArticleShow.asp?ArticleID=107