On/Off Misfires and CEL 1999 4runner

[hardiek]

One more thing...how big of a job is it to replace an injector? Thanks.

 

[brian2sun]

brian2sun,

Great information.

I moved the coil packs and the problem stayed on cylinder 4 so I was thinking its the fuel injector. I don't think I have ever had a miss except on cylinder 4.

Everything you noted makes sense except that it never starts running again again until the car cools all the way off once the problem arises. This normally takes a couple hours and then its fine. Maybe once it gets warm its just leaking heavily into the cylinder and it can't operate properly again until it cools all the way back down?

Thanks again.

Kevin

Hmm.. since the truck won't run at all when you try to restart it when it's still warm, that could be something other than the injector. Mine always started back up when it was warm, it would just miss. Maybe the plug is getting fouled with fuel??

One more thing...how big of a job is it to replace an injector? Thanks.

Unfortunately, #4 is the middle hole on the driver's side so it's under the intake plenum. It's not too bad, but the plenum will need to come off. It's a half a day job. You could listen with a mechanic's stethescope while the miss is happening and listen to see if the injector is clicking like the other ones. If not then at least you know it's bad before you go tearing everything apart.

I'm just not sure about why it doesn't start at all when warm. If it was just one bad injector, it should start with the other 5 cyls and just miss on #4.

 

[hardiek]

thanks brian2sun. Let me clarify; sorry for the confusion.

It starts fine when warm, just runs rough and misses when warm. Once it cools back down it runs normal and doesn't miss at all until it heats back up and I turn it off. Then its back to running rough again when I start it back up.

Thanks again. I am thinking its the injector as it makes sense.

 

[hardiek]

fyi...rebuilt injector cost $40 on amazon.

 

[brian2sun]

thanks brian2sun. Let me clarify; sorry for the confusion.

It starts fine when warm, just runs rough and misses when warm. Once it cools back down it runs normal and doesn't miss at all until it heats back up and I turn it off. Then its back to running rough again when I start it back up.

Thanks again. I am thinking its the injector as it makes sense.

Ok, that's what I originally thought that it was doing. Then I thought you meant it wouldn't run at all when warm. So yeah, knowing this, the injector would be my best guess.

If you do replace it, get a new o-ring kit for all the injectors on that side (3 uppers and 3 lowers). I recommend putting a little bit of Vaseline on the o-rings before you reinstall them too, it'll help prevent tearing the o-rings and also help ensure a good seal. You might as well clean the other 2 injectors on that side when you remove the fuel rail to make sure they don't have any gunk or clogs. Good luck!

 

[hardiek]

sounds like a plan. how do you clean the injectors once removed?

 

[MONTYMTB]

Not sure if this applies here, but several years ago I had the exact same symptoms on a different vehicle (ran fine when cold, like crap when warm) and right away my mechanic said "it's the plug wires". He replaced them and it fixed the problem.

 

[brian2sun]

sounds like a plan. how do you clean the injectors once removed?

You can actually send them out to get properly cleaned and bench tested (search witchhunter on yotatech), but I just meant visually inspect them for gunk and spray them out with some carb cleaner. If you don't need to drive the truck for a couple weeks, removing all the injectors and sending them out to get cleaned wouldn't be a bad idea, but if you need the truck back and running ASAP, I would just replace the #4 and clean #2 and 6 the best you can while they're out. The other 5 injectors are probably fine since they aren't throwing any miss codes.

I hope I'm right, it's always hard to diagnose a problem over the internet, but I really do think it's the injector on yours. The symptoms fit.

 

[hardiek]

montyMTB,

good thinking and the plug wires were replaced yesterday with no luck. Now its time to try the injectors.

 

[hardiek]

thanks for all your help brian2sun. I am putting my money on the injector as it makes sense.

 

[brian2sun]

No problem hardiek, I'd bet $$ that it's the injector also, especially since you ruled out plugs, wires and coils. I put a Beck-Arnley rebuilt injector in mine and have had no issues with it since. My bad injector/miss was on #4 as well.

 

[hardiek]

great. the one i bought was an AUS that had a great reviews.

 

[hardiek]

replaced the injector and all seemed to go well. put it all back together and now its leaking fuel. Any easy ways to see where its leaking easily before taking it back apart?

if I have to take the air intake and plenum back off can i start the 4runner with it removed so I can see what is happening?

Also, replaced the orings on the injectors that were not missing so all the orings are new. I placed the injectors in the rail first then seated all the injectors at the same time and it seemed to go well.

Thanks and fun fun.

 

[hardiek]

i took everything back apart and reseated everything and it still is leaking. when I took it back apart again I noticed that its the lower fatter part of the injector that is leaking.

its not the new injector i installed; instead its one of the older injectors. Anyone ever see that before?

Should I just replace the other 2 and hopefully that fixes the issue?

Any other ideas?

Thanks.

 

[hardiek]

well I replaced the other two and no more leaks at the fuel injectors.

But...now i have a leak at the bolt connected to the fuel rail. The bolt is tight. Any ideas what it could be?