JHartlove

Short story: As I'm accelerating the engine makes a click sound and delays accelerating for about half a second. During that half second it sounds like the engine is shutting down then it comes right back up and runs like normal for a while.

More details: Hasn't done it as frequent since a recent oil change and upgrading to Premium Octane Gasoline. I just bought the car... the spark plug WIRES appear to be brand new, I wouldn't think anyone would replace the wires without the plugs, but I'll check that if you guys think thats what it is. I've owned the car since June 23rd and I've counted a total 5 times it's done it. I also used to get a delay in acceleration with no click before I put higher octane fuel in it and I would get small tugs forward and back as if the wind was hitting the front of the car (although I know that wasn't it).

As usual, any help is appreciated. Thanks in advance guys!

Car is a 1993 Camaro Z28 (with the LT1) and 128,000 miles.

Injuneer

Does the clicking sound like "marbles rattling in a tin can"? Was the noise worse with the low octane (exactly how low?) fuel? But the noise remains when you use higher octane (exactly how high?) fuel? Since you are most likely operating near sea level, the engine requires at least 91 octane fuel to reach it's full power potential. Using lower octane will cause knock retard, and loss of power, as the ECM responds to the knock and retards the timing to eliminate it.

The odd part, if its spark knock you are hearing, is that the ECM should pull timing before you can hear it.

Spark knock can be caused by running lean, too much spark advance, high coolant temp, high intake air temp, oil in the intake mixture, compression increase due to carbon buildup in the combustion chambers, and of course low octane fuel.

JHartlove

No it doesn't sound like marbles at all. It sounds like a click like when you go to ignite a grill or something similar to that, but it only does it once. I was using the lowest grade fuel and it seemed more frequent but it didn't make the situation worse or better for the car same effect when I drive it now but it's only done it once with premium fuel. It did it 5 times in the past couple weeks with regular fuel. So the answer to the second question is no, not worse, just less frequent and I used regular I'm guessing 87 octane.

When I switched from 87 octane to 92 octane (premium) I put a full bottle of lucas injector cleaner in with the fill up and I noticed a difference almost immediately. I put premium gas in it now wherever I go so I'm guessing thats at least 91 octane, correct?

Yeah it's a very odd sound. This will be my 5th car and 3rd fbody car and I've never heard anything even similar to it. Just a click then it sounds like the engine is gonna shut down for a half a second accompanied by a delay in acceleration then it just goes back to normal right after that half second.

The engine temp thermometer inside the car usually stays low actually because most of my trips are highway miles at 50+ mph, but it has done it a few times on the highway I believe, it's just not as noticeable as when I'm in town with the windows down. The temperature obviously is a good amount higher since I'm not forcing air through the radiator going 20 mph in town.

hopefully my description of the sound and conditions can narrow it down for us and sir I greatly appreciate your help. it means a lot that there is other camaro enthusiasts out there that wanna keep these things alive. I know I'm keeping this 93 and I'll probably get another 3rd gen in a few years.

mrmint69

I have a vehicle that when the AC gets low on freon, it will click like you describe. I think its the clutch going on and going off. The idle will change and it causes a blip in the rpm's. It will get worse as time goes by. I am able to unplug it and it stops. Very unlikely this is your problem, but you never know.

JHartlove

I'll give it a shot. Thanks

cthomson21

That may explain the tugging also. If the compressor is kicking in and out intermittently, that may cause the motor to bog a little.

JHartlove

Well I don't have a low pressure switch in right now because I found out the one in there was defective so it is removed and i'm waiting for the new one to arrive.

New problem: I'm getting a TERRIBLE SQUEAK. It's not a squeal. It's not the belts and I just had the transmission mount replaced so I thought it was that, but I doused it in WD-40 and it did nothing. It's not a polyurethane transmission mount. It sounds like it's coming from closer to the rear of the car. When I first start it it doesn't do it but I can especially hear it when I ride in the tunnel to work. It's louder than the exhaust! and I have magnaflows! The worst part is when the car is in idle the sound only briefly stays around because I guess the vibrations aren't enough to make it make the sound. It almost sounds like when you lean back in a computer chair and it squeaks but it does it so frequently. It's ridiculously annoying!

Sorry for being such a pain guys.

bw_hunter

The AC compressor turning on will not cause it to bog. Forget that completely.

The squeak may not be related to engine speed but to motion. Check all your rear suspension components....

mrmint69

The ignition switch when it starts to go out will cause the engine to cut out for a split second. It will get worse even causing stalling and turn your warning lights (air bag, check engine, etc) on like the car died and restarted suddenly.

cthomson21

Well I was saying that it will cause the motor to bog some what, from personal experience. Granted it was on a 4cyl s-10, which as you know are horsepower demons . Low pressure switch or something was out, I don't recall at the time, and cruising down the road it was like wind was hitting it. Just a thought.

JHartlove

A couple things and before you read on I just would like to say THANK YOU for all your help with this guys! I had no idea the LT1 had so much to it and I'm still learning.

I will have the ignition switch replaced. (My check engine and air bag lights are NOT on, but for some reason the left signal arrow light is always on when my headlights are on. Not sure if that has anything to do with it, but I'll still have the switch replaced.)

I hooked up my air conditioning today with a new switch and it works, but after riding down the road for a mile it shuts off and won't come back on unless I turn the car off and then back on............. UGH!

The squeaking still exists. When I go through a tunnel at 50-60 mph it's doing it constantly. When I go through it at 40mph it only does it when I go to accelerate... Maybe the vibrations? I have no idea, but I'm about to soak the entire car in WD-40...

Thanks again for the help keeping my car on the road. When I rule the world, you'll all get your choice of a camaro or firebird of any year.

mrmint69

I have given a few suggestions. Only to be taken at face value. It is possible that my problems in the past might be yours to, but there are tons of things it can be. It is worth a shot on the cheap ones and if you are like me, I want the problem solved and for as cheap and pain free as possible.

Gadget327

i am having all most the same problem with my 93. without the noise it is like its running out of fuel for a few seconds the last time it back fired.
there is no warning lights coming on and it doesnt stop running. i push the clutch in and the motor come back to live like nothing was wrong it has happened a hand full of time i have had the car about three months and about 1,100 miles i am hoping to get some ideas of what is going on with her. from your thread. i thought maybe it was your u-joint making the squeaking but you hear it at an idle so not u-joints

JHartlove

Just thought I'd let you guys know I took it to my uncle the mechanic today and he says there is a solenoid that I need to replace. He says when I unscrew the gas cap when after driving it to put more gas in it shouldn't make that "opening a new bottle of pepsi" sound and release fumes into the air. My 1986 Camaro Z28 did the same thing but he insists it isn't normal.

Also the squeaking is somewhere in the rear part of my car and I'm guessing the exhaust setup. I had my brother drive the car today and going about 20 mph it made the sound and I was close by to listen to it. I'm going to try to tighten everything and see how that goes.

The air conditioning still doesn't work and my uncle thinks I'll have to get someone who knows these cars a little better to take a look at it. I guess we'll have to wait and see on that one.

bw_hunter

Unfortunately, your uncle is wrong. The hissing sound is completely normal on these cars. Let him insist all he wants...just don't let him work on it....

As I mentioned before, check your rear suspension components. Sometimes the squeak can turn into a clunk...

Also check the rear brake pads for intermittent contact.

I can't think of a scenario when the exhaust system will squeak..