/87 5.7L TPI

Sorry about all the questions this week but I’m trying to get all the bugs out before the snow starts flying.

Is it true that the injectors can make a ticking or tapping sound that can sound like valves out of adjustment?

My motor was rebuilt (basically to stock) had 15,000 miles put on it and sat around for about 2 years before being transplanted into it’s new home. Now on heavy acceleration I am getting a ticking or tapping sound. I have read noisy injectors can sometimes cause this. Can anyone tell me if this is true or not?

I am thinking on adjust the valves to eliminate that possibility. Do the valve covers on the TPI motor come off easy, or will I have to get into pulling of the throttle body and everything else?

 

Should come off without much trouble. Could it be knocking/pinging or are you sure its a tick sound? How old is the gas thats in it?

Another possibility is an exhaust leak, mine would make noise under acceleration. Ended up being some loose manifold bolts.

The injectors are a possibility but I would think that'd make noise all of the time, even at idle. Same with a valve.

Could also be a lifter not pumping up all the way though...

 

Find a piece of metal rod, a mop handle, or long socket extension. Hold one end of it to your ear and put the other end on the object you're curious about. When you find the source of the noise you should hear it louder through the rod or extension. You're basically making a stethoscope out of whatever you use. Most likely you're hearing the injectors tick as they are kinda loud.

 

A chunk of heater hose works nicely as a automotive stethoscope.

But yep, injectors can make an audible tick, as can the valve train. And, as stated, the exhaust can leak, producing a ticking noise.

Just use something and probe around.

 

I tried a stethoscope but everything sounded normal. I had a friend stand on the bake and apply load while I listened under the hood with the stethoscope and it still sounded normal.

Only while driving does it make this noise, the transmission is on it’s way out, but the sound really seems to be coming from the top end of the motor, and I am more concerned about the motor than the transmission at this point because I am planning on paying a tranny shop to build a tranny for me (700R4).

The gas tank, lines, and pump are all new; I’m run premium gas. The exhaust is new from manifolds to bumper (true duels) {new manifold gaskets}

I set the base timing (8’ B.T.D.C). The noise really doesn’t sound like timing. I am thinking it must be valves or maybe a sticking lifter.

This is my first TPI motor, what type of lifters (stock) are used in these motors? And is it normal for TPI lifters to sometimes stick?

I have tried injector cleaner and many full throttle runs in an attempt to clean everything out, no luck.

Thanks again for all the helpful pointers.

 

The injectors on my TPI setup are pretty loud. You can hear them standing a few feet from the car.
Maybe you can record an audio clip so we can hear it.

 

If your engine sat for 2 years you can be sure that the lifters had NO oil anywhere near them when you put the engine in the car unless you took them out and gave them a good bath.

The injectors on a TPI can be heard at idle. If you are hearing a ticking sound that increases in frequency as the engine rev's you can pretty much bet you have a lifter going bad.

I know this because I just went through it myself. I first swapped out injectors (thinking it was the injectors) and I still heard the tapping as the engine rev'd. I even made sure I was not running my injectors at too high a duty cycle.

Do yourself a favor and just replace the lifters. Heck if your funds allow it you might as well consider a cam swap because you will have the engine pretty much torn apart anyway.