Anyone have an engine stethoscope I can borrow?

[Nitrousbird]

I am having a feeling that I might have an injector not firing, or only firing when it feels like it. I know you are "supposed" to be able to do it with a screwdriver against the injector and put your ear up to it, but my car is pretty loud and I don't think that trick will work.

 

So if anyone has one I can borrow I'd really appreciate it. smile.gif

[Guest nevarmore]

I've heard of lenghts of rubber tubing beign used for the same purpose, they channel the sound differently than a screwdriver and dont absorb so many extraneous vibrations.

[Renner]

With a loud car, I don't know if you would be able to hear the injector above all the other noise even with the stethoscope, unless you had some pretty loud injectors.

 

Probably a stupid question, but have you already tried the three main tests for an injector first? I usually try unplugging the injector in question to see if it makes a difference in how the car runs. Next I would test the resistance and make sure it is within spec. And last I would try hooking a noid light to the harness plug, to make sure that your signal to the injector is correct. If you have an injector firing sporadically, I would suspect the signal, not the injector itself, if the injector has the correct resistance value, you should be able to see this with the flashes of the noid light.

 

I am sure you already know this stuff, but I just figured I would try and offer some help. I don't think listening to an injector to see if it clicks is going to uncover something that the other tests wouldn't. Just my 2 cents.

[Joe]

Joe,

You can buy them at any Advance Auto for a couple bucks! smile.gif

Hope this helps

 

[ 04 September 2002, 07:40 PM: Message edited by: More Tools Than Columbus Racing ]

[Nitrousbird]

Actually, I've never really messed with injectors before, since I've never needed bigger ones until now. And sadly, I don't even know if that's my problem....I was just looking for a simple way to tell if they were all working or not. The car has a miss I just can't sort out, and I've pretty much went through everything ignition related. All I do know is my long term block learns are maxed out on the passenger side (at pretty much every cell I could get the PCM to go into), and the O2 values on that side tend to be lean....but not all the time. Grrrr.....

 

I guess I'll try just yanking a wire and seeing if that makes a difference on how the car runs. My cam lopes a lot, so it makes it REALLY hard to tell at idle...and hell, even at higher RPM's, unless the car is under load. I'm pretty sure the injectors themselves are fine (I've tried a couple sets, since the 24# SVO's I had were not going to be big enough anyway, so I tossed in 30's), but I have not checked resistances yet. I don't have a light, though I guess I could toss the multimeter on the injector wires and look at voltages. I guess I'll do that tomorrow.....I'd sure like to be able to drive the car again sometime!!

[ZYUL8TR]

Joe,

 

Use a long wooden dowel rod (hold the other end of the rod at your ear). It is not sound you will be looking for but rather the vibration of the pulsating injector. Even if your car is loud, you will still feel the vibration through the dowel rod and can detect if the injector is working. This is what I use on my car. You can also use this on the valve cover to detect rocker arm chatter.