If A Injector Is Faulty, What Are The Symptoms?

[the_josh]

have a feeling that i may have a faulty injector(s), what would be the symptoms i would notice if thats the case?

when my truck is at idle its seems like intermitently a injector is failing, i dont think its a spark plug because in the past if there is a spark plug misfire my computer detects it and the check engine light comes on, now this only happens as idle, never above 1000rpm and it doesnt matter whether the a/c in on or not.

it feels like a slights little tug on the engine, but the engine still runs smoothly and it you have the hood lifted and looking at the engine you cant even notice it, you only notice it when your in the truck or have your hand on the engine cover, its like a slight bump every so often, its almost like a misfire but i dont think its that, can someone help?

 

[eskimochaos]

have a feeling that i may have a faulty injector(s), what would be the symptoms i would notice if thats the case?

when my truck is at idle its seems like intermitently a injector is failing, i dont think its a spark plug because in the past if there is a spark plug misfire my computer detects it and the check engine light comes on, now this only happens as idle, never above 1000rpm and it doesnt matter whether the a/c in on or not.

it feels like a slights little tug on the engine, but the engine still runs smoothly and it you have the hood lifted and looking at the engine you cant even notice it, you only notice it when your in the truck or have your hand on the engine cover, its like a slight bump every so often, its almost like a misfire but i dont think its that, can someone help?

I just read that your engine swap engine had 40k on it.

Were the plugs ever replaced? They are 30k plus as you know.

 

[the_josh]

Yeah we put in brand new plugs, the old ones looked good but we put in new Toyota ones anyway

 

[eskimochaos]

What about a stuck EGR valve? Does it happen after running on the highway etc or right when you start it. I feel like a faulty injector would definitely throw a code either for a sensor for the injector itself or a misfire code.

 

[CJ3Flyr]

A faulty injector may be the culprit but it's odd it's only at idle. IMHO, while an injector, spark plug or coil pack is on the verge of failing you may pick up the symptoms you describe without a check engine light. At some point the issue becomes big enough it'll trip the light but there's a 'grey area' where you'll have an issue but no light.

If it were mine I would be looking more closely at the electrical aspects based on the symptoms you descibe.

The cheapest thing to do is go get a set of NGK's or Denso's, cheap ones, and put them in there. It's possible one of the new plugs you put in is faulty. If that fails then I'd have it put on a scope to watch, live, each cylinders firing looking for an intermittent coil.

The thing about plugs/coils is that at idle, the signal voltage is reduced and the spark is weaker on purpose. At higher RPM/power settings the signal voltage (and coil output voltage) goes up. It may go up just enough to make that weak plug/coil fire properly.

I guess one could make the same argument for a faulty/sticky injector...

That's my 2cents. Good luck and let us know what you find.
:cheers: