Cyl 1 mis-fire... at wits end...

D

d_rob1031

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So a couple of weeks ago my 4Runner kicked a CEL of knock sensor bank 1 and cyl 1 mis-fire. I put new plugs, plug wires and a new coil on cyl 1 and took it to the dealership for 2 new knock sensors and the wiring harness for them. The last couple of days it started missing again and CEL says the same thing... cyl 1 mis-fire. What else could it be? It's going back to the dealership in the morning unless you guys can point to something simple I can do this evening.

Thanks for the help...
 
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If the Cylinder 1 injector is not working properly, it won't shoot fuel into your cylinder, and thus create the misfire. You need both spark and fuel to make your fire in the combustion chamber.

I had the same CEL, changed my plugs, wires, coil pack, and it ended up being the #1 injector. I bought 6 off E-bay and just swapped all of them, but you could probably get away with just changing the one, if you don't want to buy all 6. I bought all 6 off E-bay, as it was the same price to buy 1 here locally!

Good luck with the repair! :)
 
If the injector is not correctly working (no fuel being dumped, or too much or too little), then the ECU will know it and throw a code.

You can use an ohm meter to check resistance at the connecter per the FSM or others have just warmed up the engine to operating temps and then pull the connector with the engine running at the injector. If nothing noticeable happens, then more than likely the injector has bought the farm and a new one is needed.

Toyota Tacoma/ 4Runner/ Tundra/ FJ Cruiser Factory Service Manual Page
 
fightman80 said:
If the Cylinder 1 injector is not working properly, it won't shoot fuel into your cylinder, and thus create the misfire. You need both spark and fuel to make your fire in the combustion chamber.

I had the same CEL, changed my plugs, wires, coil pack, and it ended up being the #1 injector. I bought 6 off E-bay and just swapped all of them, but you could probably get away with just changing the one, if you don't want to buy all 6. I bought all 6 off E-bay, as it was the same price to buy 1 here locally!

Good luck with the repair! :)
Click to expand...

I just now looked, I didn't realize the injectors were electronically controlled. Is there anyway to test them before tearing into the engine?

Edit: Thanks LittleCaesar. After the money I have recently put it it, it may be time for a trade/sell. My life doesn't afford me the time I need to do this job, sadly.
 
Hoping an injector is what my issue is. Not having many responsed on my thread, but I guess an injector is my next step. But mine only does it right at 1000 RPM's??
 
I'll probably get flamed for this one but is it even worth bothering with fuel injector cleaners on the off chance it's plugged up? If so, which one should I use?
 
Its worth a try, I've never heard anyone actually fixing their problem with it though. I personally like Seafoam int he tank for cleaning injectors.

Haven't seen it mentioned but the coil packs tend to go out fairly easily. Id check them as well.
 
Baja Runner said:
Its worth a try, I've never heard anyone actually fixing their problem with it though. I personally like Seafoam int he tank for cleaning injectors.

Haven't seen it mentioned but the coil packs tend to go out fairly easily. Id check them as well.
Click to expand...

Ok ill give seafoam a shot. I replaced the coil on cyl 1 and swapped them around. See the OP.
 
Seems like these misfire threads are pretty prevalent here lately. I've got one too...I'm currently experiencing a cylinder 5 misfire, and will be swapping coil packs, plugs & wires this week. Even if that's not my problem (which of course I hope it is), it's about time since I'm at 175k miles.

Many thanks to all you folks helping to diagnose these misfire issues! I really appreciate it, as I'm sure many others do as well.
 
i'm currently running seafoam through my tank now to try and clean it out. few months ago it was misfiring on the highway and i filled her up and stuck cleaner in the tank and it stopped until now it came back. so injector clean is worth a shot in my opinion.
 
hey man i just did the same thing as fightman and replaced my injectors, i also bought a set of refurbished ones off of ebay, it was around 170 for all 6, however, one of the ones they sent me ended up being bad as well so i had to put one of my old ones back in, it got rid of the misfire, mine is having trouble starting now though. :( but anyways id go ahead and change out the injector not really hard work, one person could do it in 2 hours or so
 
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