1989 240SX KA24E Spark plug melting problem

[puerkone]

Hi guys I'm back again I just been having this problem over a month and I just can't believe my car still runs. I go to school every day with it about 20 miles every day and every time I drive I have to shift at 3000 RPM and keep the RPM under 3000 all the time. As soon as I go past 3000 RPM the car starts misfiring and dies. Then fortunately I always keep a spare of spark plugs with me and pull over replace them on the road. Then every every week I have to change them and I'm just getting tired of replacing damn spark plugs all the time because all four of them always come out melted on the electrodes. Now I use spark plug faulters where they are screwed in where the spark plugs go. The kind of save some life out of my spark plugs but is still not enough for a week. So I already replaced Distributor cap and rotor, spark plugs wires, thermostat, hoses, radiator, water pump, fuel filter, O2 Sensor, oil change 10W30, oil filter, belts, brand new coil, and did fuel injector cleaner and brand new air filter. So any more suggestions? I took it to 5 different nissan mechanics and they eventually charge me like 50 bux to say I think your spark is no good. All bs. So I been trying to look around and ask alot of people and I found out that my chamber is running too hot. Which device controls the temperature of the fuel air mixture or the chamber? thanks Oh by the way I also installed a brand new EGR and it fixed my RPM Idleing but still melts my spark plugs jusst letting you guys:redface
Modified by puerkone at 12:30 AM 10/20/2008

[puerkone]

please I know you guys are awesome to help people out like me

[the converted]

Lets see a picture of what they look like when they come out. Aside from the maintenace stuff have you replaced anything to do with the engine?

[puerkone]

here you go these are multiple sets every week.

1st set

2nd set

I adjusted my distributor timing already no difference found

These are the spark plug faulters that im using right now.

[the converted]

Photo bucket is blocked at work so I'll take a look when I get home.

[puerkone]

just wondering which sensor controls temperature in the chamber"?????

[the converted]

There is no sensor persay. Chamber temp is a function of that air fuel ratio. The only way you could be getting excessive temps is running to lean. I can't see your pictures to tell you right now though.

[puerkone]

interesting well when you have time let me know Ill be waiting for your resinse thanks fo your time.

[the converted]

So by looking at those I'm guessing that adjusting the timing didn't involve doing it with a timing light, and that your burning a quart or so of oil every.....i guess 500-700 miles? Looks like your running way too rich with too much timing. Also those spark plug extensions are probably only making things worse because the plug needs to be in the cylinder to help clean itself off.

So at the very least get rid of the extensions and make sure your timing is dead on.

Also are you having any issues with loosing coolant or overheating?

[modulation]

Have you unplugged your MAF and see if it runs better/worse the same?Since you can't rev over 3000 that's one possibility.

[rogoman]

The pictures are mostly out of focus but by the looks of them, it appears that the plugs are oil fouled rather then burned. How often do you add a quart of oil? If you're adding a quart every 200 mi or so, the motor is worn.

When you install a new set of plugs, are you able to rev beyond 3,000 rpm? If not, then there's a problem with the MAF.

[Vegascorbin]

One possable cause if it is running too lean is the fuel pressure regulator or the vacum valve that controls it.

I think you may have a combination of worn motor and running too lean.

I would recomend a compression and leakdown test and then see what that tells you.

[-RJ-]

sounds like a MAF problem. Maybe the MAF is sending the wrong amount of air to the ECU, which could cause the car to run too lean.

[modulation]

sounds like a MAF problem. Maybe the MAF is sending the wrong amount of air to the ECU, which could cause the car to run too lean.

I agree.He changed the o2 sensor.It isn't specific to any 1 cylinder...

[puerkone]

thank you guys for your comments. I am able to go past 3000 RPM all the time. The problem is that when I go past that the engine melts them so I try not to go above it. Therefore, I also tried disconnecting the MAF and it was still the same in fact the car idled hard when I disconnected it. Also, today that I started the car with brand new NGKs, the car was making this lound knocking when it was cold. As soon as it was warming up, the knocking was going away. So let me perform a compression test, check the fuel pressure regulator, and the vacumm valve. Im going to give it a new oil change 10W40 because the guy at kragen said that since I have 158000 miles it is better to have that oil rather than 10W30. Also Today I performed a diagnostic text and it said to replace engine temperature sensor, and replace O2 sensor. I rewired the O2 sensor and it fixed my idling. so let me do those things and see what happens. Thanks

[JOESCHMID26]

hey did u ever solve this problem? the only time i have ever seen spark plugs melt it i had a clogged fuel filter one time and it was letting junk get into the fuel and bridging the gap and melting the eletrode it also marred the ylinder walls when the electrode melted off and bounced around the cylinder before going out the exhaust so the car started to burn oil after that too. but usually a lean mixture will cause it to run hot but it would have to be really lean. those pics rnt so good to tell what the plug looks like. there is a fail safe that wont let the engine rev to high when ur airflow meter goes. very urious to see what the problem turns out to be please post it when u solve the problem. also if ur bearing r worn badly the engine will start to run hot. what does ur temp gauge read? maybe ur cat is clogged? is this the 12v or 16v?

[JOESCHMID26]

its a 12v sorry i didnt read close enough.

[JOESCHMID26]

have u checked ur timing? that could cause it too!!