KA24E Misfiring problem Help!!!!!

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puerkone
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Hi I have a 240SX with 150000 miles in it. I just recently changed the water pump, thermostat, radiator hoses, belts, spark plugs, wires, distributor cap and rotor, fuel filter and o2 sensor and now I have this misfiring problem. When I first started driving the car with all this new stuff, the car was running pretty good then a day later the car started to misfire. The car runs fine below 3000 RPM when cold and when the engine is warm the engine starts to misfire at any random RPMS. So I removed the spark plugs and they were all burnt up with white dust on them and for some reason the electrodes on the spark were bent and broken. So what could possibly make this problem? any help please? By the way I tried NGK & Autolite XP Spark Plugs. Please someone help me. I need my car for school and commuting. Thanks.


Vegascorbin
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Photos would be a big help!

The only way for the electrods to be bent once the plug is installed in the engine is for the piston to hit it. I doubt that happened as you would hav eheard that right away and it never would have run well if at all.

double check any electrical connections you may have disturbed during your work and get us photos of the "bad" plugs.

Good Luck

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puerkone
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ok here are the pictures.

Note: These both sets were brand new NGKs today and when I drove it to school I removed them and thankfully I had a set with me so I replaced them overthere and when I was on my way back home it started misfiring again and when I pulled them out they came out burnt and regapped and the car sounds fine and runs really good when they are brand new why does it do that?I can't figure it out.



Is my timing ok to be all the way to the left on the distribuitor?

I just put these new spark plugs today and when it misfired today now they look burnt whats going on its like the plugs are running too lean or what? please help me. NGK Spark Plugs. Both sets of plugs gave up on the same day

Cylinder 4

Cylinder 3

Cylinder 2

Cylinder 1

Burnt Sparkplugs

the set before I put these plugs were worse they were burnt and broken





Same thing they were burnt any help? I gap them all at .044 and when i pull them out the gap changes below .020 why does it regap by itself? help!!!

Modified by puerkone at 3:43 AM 9/4/2008
Modified by puerkone at 4:15 PM 9/4/2008

sticky_steve
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Just something to try, I heard of an old trick. If you look at the base of the plug where the washer is, at the base of the treads, Try to add a washer from one of the old plugs so you have 2 washers at the base. What this will do is raise the plug that much out of the cyclinder, since it seems like the piston is hitting it. I hope this helps

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puerkone
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O wow thanks that solved my problem the car runs fine now no misfiring but the car is now burning oil it smokes blue does that mean the broken insulation that fell in the cylinder damaged the piston rings or the oil cylinder?

Here is the picture of what I bought at kragen auto; spark plug falters a set of 4 it stopped


Modified by puerkone at 3:21 AM 9/17/2008

sticky_steve
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It may be possible that a small piece of plug fell into the cyclinder causing the wall to get scratched up, or break a seal in the piston rings. try to do a compression test and see what you get.

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puerkone
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today I went to talk to a nissan mechanic and I told him about my situation. He told me that on nissans the crankshaft tends to wear out the connecting rods and make them to get loose. So in my case, since connecting rod caps have to be adjusted every 60000 miles the rod caps are right now loose. So I need to remove the oil pan and tighten the caps one by one and he also said that probably piston number 4 is the most important one because it is almost hitting the head and that is really not good because if I let it go then the head gasket would come loose and yeah it wouldn't be good. Anyways what do you think? I am still going to do a compression test and see what I get because the car started misfiring today.

sticky_steve
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That actuall makes sence, the bolts are loose causing the piston to rause just a little bit more that is should. Just remember to have the correct socket and torque ( step 1 torque all of the nuts starting from the inside and work your way out to 10-12 ft/lbs. Then do it a second time tq.ing them down to 28-33 ft/lbs) Just be ready to get a bit of oil on the ground so use some cardboard and find some concrete cleaner. Hope this helps

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martins_240sx
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sticky_steve wrote:That actuall makes sence, the bolts are loose causing the piston to rause just a little bit more that is should.
NO that DOESNT make sense. Have you ever seen the distance between the top of the piston and bottom of the plugs?If that where the case, and your connecting rods backed off that far, you would have bigger problems than backfiring.Sounds like the mechanic was just as baffled as you are. It probably wouldnt hurt to check but if they did actually back off that far post pics.make sure your getting the correct plugs for your car, if you havent already done it, try to get them at a different store.

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puerkone
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Oh wow really? well I I think that all of my cylinders are running really really hot and there is no sound of my engine hitting the head the car just runs and drives awesomely good when the plugs are new but except at the end of the day after a long time drive my spark plugs melt and starts misfiring.

I put some really cheap spark plugs because I had to drive to school today; I tried autolite spark plugs and drove the car today. The car ran perfect and nothing happened until I came back home the car started misfiring again. Ah what a pain!!! I didn't even gone it. I drove slow and shifted on low RPMS all the time and guess what my car started misfiring again! So I put the car in my garage and removed the sparkplugs and the plugs melted to the sparkplug faulters. All of them melted.

So is there a way to cool down the combustion chamber? My sparkplugs bent and melted the electrodes and the gap changed alot it bent next to where the electrode is supposed to be but well they are not there because the electrodes melted and no pistons reached all the way up to the electrodes there is no way because the spark plug falters protect the plugs from being hit. Why is my combustion chamber running too hot I don't get it I fixed so much stuff brand new and it is still doing the misfiring but now its melting the sparkplugs. How can I make the combustion chamber to run cooler? do i need hotter sparkplugs or what do i need? help.

Firing order is good, timing is good, temperature needle points under the middle of the gauge, I'm using premium gas, I have a new K and N Filter, I have new cap and rotor, coil, no blue, black or white smoke, its just the sparkplugs melting. No smoke when it misfires.
Modified by puerkone at 11:35 AM 9/6/2008

sticky_steve
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Why are you using permium. From what i understand about different octane ratings, premium or 93 octane, burns longer and hotter than 87 or 89 octane. Permium gas is for more hi-end motors, 350z, supercharger and turbos. Just something to try, use regular. Thats what i use on my 93 dohc and all i have are intake, high flow cat 3in catback, and the car runs great. Just a suggestion. The higher the compression rate of the motor the higher the octane rating you need to use.

Try reading this

http://www.geocities.com/dtmcb....html

And just one more thing, try using some higher quality plugs and have a hotter burn rating, I know they are more expinsive, but u might save more money in the end instread of buying 2 or 3 set of plugs everyweek or 2.

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martins_240sx
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ok gas isnt going to make you backfire either. from the looks of it, the 3rd cylinders spark plug looks to be oil fowled. I could be wrong cause some of those pics arent very good. if they were white that would say they were getting to hot, maybe not enough fuel. but the darker color Im seeing tells me that there is either oil or way to much fuel getting in there. make sure you gap your plugs. get a timing light and find out where your at.

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puerkone
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ok so today I emptied my gas tank because the gas needle was almost to the E. So I'm going to put regular gas and going to try to buy hotter spark plugs. Note I did notice one thing, when I use cheap spark plugs they melt at the end of a long drive and when I use high brand spark plugs like NGK and Autolite XP the gap just changes and no melting. So I'm going to buy hotter sparkplugs today and see if that fixes my problems thanks. I will let you know what happened tonight.

sticky_steve
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just a stupid question, but (if you still have them) are the old plugs that you pulled out the same as the ones that you put back in. Or in other words, do the new plugs you bought just ilke the old ones. The reason that i ask is beacuse i was just wondering if the electrode is the same length or longer. Mabey the pervious owner bought some different plugs beacuse they were having the same problem.

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puerkone
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well the car has not misfired at all today. I bought some NGKs for a 90-93 240sx because the guy at Kragen said that 89 is different gap. So let me post a picture in the morning because maybe my engine came out of a 90-93 240SX and its not an 89. And the new NGKs feel awsomely good. Do you guys think that was the problem?

sticky_steve
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Well the 89 and 90 model 240's had sohc and the plugs went into the driver side of the motor sideways, and the 91 and up 240s's have dohc, and the plugs mound in the top of the motor. So if you have a 89 or 90 motor and your using the plugs from a dohc, the gaps may be different. I do remember that when i switched from my sohc to dohc the plugs were a little different. Do you know what year or if you have a sohc or dohc motor. And also how did the regulat gas work???

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martins_240sx
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post a pic of your motor...that definetly could be your problem though

sticky_steve
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Hows the car???

sticky_steve
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hello???

badintentions
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start from scratch and make sure u dont have any vacume leakes put a multimeter on every thing as for the oil burning its never good you could have stoped burning oil because u have none (witch is verry verry bad)

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puerkone
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Sorry for not replying soon it is because school has kept me busy. Now the car completely doesn't run. Last time I was telling you guys that my car was running very good and all of the sudden the next day, something blew inside the engine and was making this loud cranking sound pretty much a loud rod knock and the car just died. I tried turning the car on and it just clicks. the crank doesn't turn but you could still hear "moving marvels inside the engine" and just doesn't turn. R.I.P. SOHC KA24E.

sticky_steve
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DAMN, that sucks, I sorry for your loss. RIP

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puerkone
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yeah man I knew this was going to happen. So here is the good news since I knew that this was going to happen, today luckily I just bought this whole SR20DET swap. I'm going to get the whole clip tomorrow and start cleaning it up. Any suggestions so I can start doing them? before I start anything? I'll show pictures tomorrow. By the way its an SR20DET (bluetop) is that rare?

sticky_steve
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The blue top? I think the valve cover might just be painted blue. So you changeing the whole front end of the car to a sivlia front end or did you just buy the motor?

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puerkone
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Oh my bad I meant to say the swap as in the tranny, motor, turbo, harness, ecu, mounts and no intercooler. They want 1400 bux pretty cheap man!. But I'm still scared because they told me that I have to modify the wires. I don't know what to do if thats the situation. I'm still going to get it tomorrow I hope I can bring it hope too. I promis I'll post pictures of it.

sticky_steve
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Doing the swap if fairly easy, but the wiring harness is gonna be a pain, you might wanna search around for the wiring diagrams or check these people out. They will do the wiring for you

zerothread?id=329231

So while your swapping in your motor, they can do the harness.

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puerkone
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wow I didn't know they could do that for you. Well have you done an SR20DET Swap? or I can just simply buy it from ebay right?

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

do you think I can just simply use the SR20DET Harness brand new in my USDM 240SX? Or I must keep and modify my KA24E wire harness?

Modified by puerkone at 12:19 AM 9/16/2008
Modified by puerkone at 12:20 AM 9/16/2008

sticky_steve
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I have not done a swap, but i have researched it for the past 6 months, so it's like i already know hot to do it. You can't just keep the wiring harness, you have to modify it to fit usdm cause if not, you gauges will not read the engine speed properly.

Swap BasicsSwapping an S13 SR into an S13 chassis is about as simple as it gets. The motor is a direct bolt in, the motormounts are identical between the KA24 and SR20, and the driveshafts are interchangable.

Wiring wise, all that is needed to be done is to repin the big plug next to the battery that connects the EFI harness to the chassis, extend the O2 and MAF signal wires, and rewire a few wires for the ECU to dash plug. Be sure to check FRSport's Wiring FAQ for a detailed guide to wiring the motor in properly.

When using the US driveshaft, you will need to remove the dust cover from the end of the transmission, but the US driveshaft is the proper length and spline count. Just be sure to use a 5 speed driveshaft if your SR is a manual.

Be sure to remove the heatshield from the turbo and the AIV tube as both tend to make contact with the US steering column. Also, an SR downpipe will be needed but it will bolt to the US catalytic converter.

http://www.frsport.com/SR20DET....html

This is the wiring diagram

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puerkone
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wow man you are a great help man thanks alot for your great help. I had a quick question though, I'm I modifying the wire harness from my KA24E or the SR20DET harness just want to make sure, I have updated news for the engine too; It turns out that the engine that i suppose to get is missing a head stud and timing is off the guy just told me that today. What do you think man? I haven't closed the agreement yet should I get it and buy a new head stud and time it or just buy another SR20DET complete swap for 2100 bux which i would not prefer......

By the way thanks for that great website man it is a big help.

sticky_steve
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You are modifying both harnewsses. You are making the sr harness fit into the ka harness. The sr harness connectors don't fit the ka harness. So basically you are cutting off the sr harness connectors and replacing them with the ka connectors.

It's kinda hard to say, The question is why is it missing a headstud. I mean you can get a head stud but it take basically rebuilding the motor in which you would also have to reset the timing as well. It's kinda like killing 2 birds with one stone, but its a BIG stone to throw.This is how to basically take apart the sr motor down to the head studs.zerothread?id=259721

Make sure you get all of the old head gasket residue off the bottom of the head

So once you get to this point you get the old studs out or if the one stud is broken in the block then its gonna take some time to get it out. Your gonna need a bolt remover, (home depot) Then clean out the threads in the block to make sure that there is no gunk in them. Apply some assembly lube to the stud and hand tighten them into the block. and remember just hand tight.

Then install new head gasket, install head back on.Thread on the stud nuts and starting from the inside and working you way out (using a little oil on the nuts and threads) torque them down to 20ft/lbs. Then repeat the process starting from the inside and working out, 40ft/lbs. And then again to 60ft/lbs. And then 1 more time to 70-75 ft/lbs.

AND THEN install everything back on the motor(exhaust manifold, intake manifold and etc etc....)

SOOOOO there you go. If you think its worth all of that to you then grap a wrentch and get to it. The only good thing is that the motor won't be in the car which will make it easier to work on.


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