Guys,

My engine has developed a very loud ticking under load. It can be heard at idle with my head under the hood but gets worse with load. Other than the ticking the engine is running strong. The sound is loud enough that it is easily heard from the drivers seat while driving.

I have checked for exhaust leaks and didn't find any, however I replaced the header donut gaskets anyway.

If I unplug #7 injector while the engine is running the sound goes away.

That would make me think it was the injector, however the sound is so loud that I'm not convinced.

So I bought an automotive stethoscope to do some listening. I found with the engine running the #7 injector sounds different than the other 7. Other than that I couldn't hear anything funny with the engine. I could not seem to specifically locate the ticking.

I'm guessing its the #7 injector that went bad. But could it possible be that bad?

 

Cracked or warped exhaust manifold?

 

could even be an arcing wire, they can be very loud, much much louder than ticking injectors.

 

Thing is the ticking goes away as soon as the #7 injector wire is unplugged.

 

I have to admit, I only read the topic title

It could very well be the injector

 

leave the injector plugged in and pull off the plug wire, if the noise is still there it could be the injector. if the noise is gone it might be a wrist pin noise

 

I have the SAME issue . I just ordered new injectors and should have them in by the weekend . I will post up any info if this resolves my problem .

 

I ran the engine with the #7 spark plug wire disconnected and the ticking remained. With the spark plug wire disconnected I disconnected the injector wire and the noise went away.

So an overview

-Engine ticks louder than normal at idle and very loud under load.
-Unplugging #7 injector makes noise go away (could be injector ticking or possibly something on the #7 rotating assembly that goes away when cylinder pressure goes away)
-Unplugging #7 spark plug only and the noise remains (suggests injector is the problem not rotating assembly)
-#7 injector sounds different with a stethoscope than the other 7

So I think its the injector that is broke. Typical Camaro, 12,000 mile Ford 24lb injectors broken.

 

Ohm the injector when its hot and see if it reads correctly?

 

try swapping the injector with another cylinder

 

I checked after I had the motor running a while, probably close to operating temperature, it read 14.9ohm IIRC. I think that is in spec. One of the other injectors read 15.1ohm I think.

 

Easier said than done on a TPI motor.

If I'm pulling injectors they are getting replaced.