Engine Misfire.. Please Help
10-03-2009, 02:39 PM
#1
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Engine Misfire.. Please Help
Hello.. I'm so frustrated. My 98 4Runner is throwing 2 misfire codes. One is random misfire and the other is cylinder 2 and 5 misfire. Heres what i've checked/replaced: New Plugs, New wires, New coil pack on cyl. 5, New fuel filter, Fuel inject. cleaned/pressure checked, compression 165psi, good coolant temp sensor, cleaned maf sensor, and checked for vac. leaks. Along with the misfire i often get hard starts.. Thinking a valve adjustment or ECU but i'm lost at this point. Any ideas would be greatly appreciated. Thank You
10-03-2009, 03:31 PM
#2
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Cyl. #2 and 5 are both on the same coil pack. Are you still getting codes for 2 and 5 after changing the coil pack or is it just a random misfire code now? Which cyl. had 165psi compression? Did you test the rest of them?
10-03-2009, 03:46 PM
#4
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Ignitor? more likely A bad connection between there and the coil try Di-electric grease on the connection from the ignitor and also in the drop tube to the spark plugs.
This will usually fix the issue if you have not used it already.
This will usually fix the issue if you have not used it already.
10-03-2009, 03:55 PM
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I would also try swapping the coil pack on Cyl 5 with one on another cylinder and see if the CEL changes ... maybe the new coil pack is bad? Either way it's free and worth a try
10-03-2009, 04:23 PM
#6
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Yes, di-electric grease should always be used on the coil connectors and the wires/boots going to the plugs. It might just take care of the problem if you didn't use any (actually, I've seen Eddie give this same advice for this problem before and he's right, it can make a big difference).
It could be a faulty new coil pack. It's actually happened to me before w/ a crappy Autozone one. Come to think of it, I think I've gotten more wrong or faulty parts from that place than good ones (sorry to those of you who work there - nothing against you). Point is, do what nc994run said.
It could be a faulty new coil pack. It's actually happened to me before w/ a crappy Autozone one. Come to think of it, I think I've gotten more wrong or faulty parts from that place than good ones (sorry to those of you who work there - nothing against you). Point is, do what nc994run said.
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10-04-2009, 05:57 AM
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The igniter is in the engine bay on the passenger side of the truck. It's underneath the cruise control. Small square metal device with a black connector. Also how do u test the igniter?
10-04-2009, 07:16 AM
#13
NO, DO NOT TRY THAT! This is a prime example of not doing everything you hear on the internet!
Di-electric grease is an INSULATOR, by definition, and using it on electrical connections would be the opposite of what you really want to do.
10-04-2009, 07:40 AM
#14
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dielectric grease
[edit]English
[edit]Noun
dielectric grease (plural dielectric greases)
Any insulating grease that prevents corrosion of electrical connectors (and spark plugs etc) by preventing access by water
this equals good it will still allow the metal to make contact yet not allow corrosion. And it is used in the drop tubes on factory install. It is the only thing that stopped my misfires.
What do you suggest otherwise?????
http://en.wikipedia.org/wiki/Dielectric
Please read and understand fully...
the fact that a Di-electric is an insulator is in this case a positive and ideal it not only prevents corrosion but stops arking between two separate contacts. This is especially good when it comes to the plug, which is why the factory uses it in the drop tubes.
10-04-2009, 08:11 AM
#15
What's more funny is that you found an encyclopedia entry for di-electric, and still don't understand that applying non-conductive grease to electrical connections is about a bad idea as it gets.
Di-electric grease is used in auto application to make electrical connectors water tight. It is NOT applied to the metal connection points themselves, but rather to the mating surfaces of the connector. Reason why di-electric grease is used, is because it's rather easy to accidentally get grease on the metal connection points. And because some greases are electrically conductive, which would obviously cause a short, a non-conductive grease just for that purpose is prescribed.
If you want to improve electrical conductivity between metal connection points, you get CONDUCTIVE grease, like this:
http://www.altex.com/MG-Chemicals-Ca...G-P144963.aspx
Di-electric grease is used in auto application to make electrical connectors water tight. It is NOT applied to the metal connection points themselves, but rather to the mating surfaces of the connector. Reason why di-electric grease is used, is because it's rather easy to accidentally get grease on the metal connection points. And because some greases are electrically conductive, which would obviously cause a short, a non-conductive grease just for that purpose is prescribed.
If you want to improve electrical conductivity between metal connection points, you get CONDUCTIVE grease, like this:
http://www.altex.com/MG-Chemicals-Ca...G-P144963.aspx
Carbon Conductive Grease lubricates and improves electrical and thermal connections between sliding surfaces, while providing protection from moisture & corrosion.
10-04-2009, 08:44 AM
#16
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what if i want to inhibit corrosion and not allow an ark between the two contacts from the ignitor??? do I do as you suggested and increase the chances???
I do understand what you are saying but that stuff would increase the chances of arking across to the tubes in the drop tubes as well loosing spark.
I do understand what you are saying but that stuff would increase the chances of arking across to the tubes in the drop tubes as well loosing spark.
Last edited by eddieleephd; 10-04-2009 at 08:46 AM.
10-04-2009, 08:58 AM
#17
Di-electric grease is used in the drop tubes, so the tube is more water tight, and does not stick to the spark plug. But it is not used on the electrical contact itself, inside the drop tube. Corrosion protection comes from air sealing the drop tube. If you want to directly apply corrosion protection to electrical points, then a corrosion inhibiting and conductive grease/paste should be used.
10-04-2009, 09:20 AM
#18
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Di-electric grease is used in the drop tubes, so the tube is more water tight, and does not stick to the spark plug. But it is not used on the electrical contact itself, inside the drop tube. Corrosion protection comes from air sealing the drop tube. If you want to directly apply corrosion protection to electrical points, then a corrosion inhibiting and conductive grease/paste should be used.
when you plug this in the two sharp points will cut in to the flat metal contact making good connection.
Where would you get a tube locally???
10-04-2009, 09:28 AM
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first there is nothing wrong with di-electric grease. i only use it if im replacing a PCM or BCM or if the connection is already corroded, then ill clean it or replace then apply di-eletric. Also di-electric is a preventive measure it doesnt fix anything. Second i need to know how bad of misfire is it. is at low or high rpms. what gear are in when it occurs. is the engine loaded up when i occurs. How is the idle? how many miles are on it? And yes u need to check all the cylinders compression and do a wet and dry test (if u dont know what a wet and dry test is then u shouldnt be doing the test). Next make sure u have the correct OEM plugs in the truck. some toyotas will only run rite with NGK platnium plugs in it some people may disagree with me abt that. Check firing order and check again. i may not know as much abt toyotas as some of u do. but i do know alot abt car and truck repair. give me more info and we can fix it.
10-04-2009, 10:13 AM
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The misfire is really bad when vehicle is cold and when warm better at mid range but no low end power. Ac on makes it worse. Idle was fine but now at 750 and rough. 120k miles on it. How do I test the igniter?
