Photomania

Thanks for the solid, practical tips. I'm sorry I'm just now responding. I was out of town yesterday and today. Got in late tonight. I will see if I can check out the distributor gear and the injector for cylinder # 7.

What's the procedure for disabling the injector? I've never done anything to injectors.

FICINJECTORS

just remove the electrical plug on the injevtor.. It has a spring clip with a high spot in the center. Push the high spot in and the sides go out releasing the connector off the injector.

Photomania

Thanks for the injector info. I will try that. I have a neighbor who has a wide range of experience in the repair of cars, tractors and heavy equipment. He said he will be glad to listen to the engine. He said it could be a wide range of things. It might even be a wrist pin at the bottom of the piston. Another mechanic said that also.

My neighbor suggested I get the engine warmed up, turn it off, disconnect the spark plug wire on No. 7 and see if the clicking noise diminishes or goes away.

DaNewmanator

Interesting thread, I know its a year later but did you ever get to the bottom of your Mystery Tapping?

Mike

JAKE

Words To The Wise: Be careful and selective on whose advice to follow. Some of the advice given in this thread is so old and outdated (and I don't mean just a year either) that it's surprising some can even remember it.

Over time, recommended procedures change and if you check, you'll see what was once recommended no longer is. It's important to remain abreast of current technology and procedures. Just because we use to start our engines by turning the crank in the area of the front bumper doesn't mean we still do.

My advice: Follow the current advice of the industry leaders.

Jake

Photomania

I'm sorry to take so long to get back to this thread for an update. A friend alerted me a few days ago that someone had asked for an update.

I finally took the Corvette to a mechanic and he hooked his high-dollar diagnostic equipment to my car's computer and my car's computer told his computer that cylinders four and seven were not firing after the engine warmed up.

So, I bought eight Bosch injectors from the nice guys at the Fuel Injector Connection for a fraction of what the auto parts stores were going to charge. The mechanic installed them for around $300. He installed a new distributor cap, which came as a surprise to me, and did some work on the fuel pump. The total bill was over $400. That was almost two years ago, and the car has been running well since then.

A mechanic at a Chevy dealership said certain fuel additives from auto parts stores are harsh on the original fuel injectors in certain older C4s. I used a lot of the fuel additives and that probably took its toll on my injectors.

So, that's my update.

cv67

When they were dropping out when warm the engine misses and Ill bet youre hearing the FW.

Sounds like you got it sorted out though.

Cliff Harris

To get an idea of whether or not you have a rocker arm nut that's out of adjustment, look at the number of threads sticking out of the top of the nut. If one is way different than the others, that's your problem.

You might try tightening your exhaust manifold bolts. For some reason I've never been able to figure out, mine get loose, but only on cylinders #6 and #7. Makes a ticking noise when the engine is hot... ;-)

Photomania

The engine runs fine now and has run fine for nearly two years because of the new fuel injectors. There are no longer any strange noises. I also changed the spark plugs about a year ago because the mechanic said Champion plugs aren't reliable. I've had the same computer in the car for five years. I wrapped some foam insulation around the computer to protect it from the engine heat and the hot summer days, especially lately when the heat index has been 115 degrees. Another Chevy mechanic told me that the computers in some of the C4s get too hot and melts the soldering on the wires. I also raise the hood when I get home and leave it up for hours so the engine can cool faster.