HELP! Engine rattle/knock worsening since fuel additive/premium ga Options

[celicakitten]

Please help with any input as I'd like to get the knowledge of people who really know these cars! I just bought this car and am discovering some issues(as expected) that I'd like to sort out before going to the dealer or hopefully finding a good local mechanic to help me!

Here are some stats before I describe the main issue:

-97 Celica ST 5spd Stock-original engine/transmission
-192,xxx miles
Guy I bought it from recently replaced the:
-timing belt
-spark plugs/wires
-distributor(looks fairly new at least)

Everything works, passes emissions, shifts great, and idles perfect other then a little vibration when the air is turned off. What my main concern is that initially there was a slight rattle/knock on start up and occasionally at higher speeds(inaudiable if the radio was even slightly on). I tried to chalk it up to the bar that holds the hood up as the clip to hold it down in place was broke. 2 days ago I topped her off with 91 octane and a bottle of chevrons fuel system cleaner, and on day 1 the car seemed to respond quickly and perform even smoother.

BUT...

On day 2 the rattle/knocking noise became more apparent continually getting louder (although my paranoia/turning off the radio may also play a part), and is now almost constant! Only time I don't hear it is when the car is idling. I drove it 14 miles each way to work and back(mostly freeway) for 2 nights, and as of this morning I fear to drive it if there is a real issue with the engine. I put her in neutral and pulled the throttle to try and verify that the engine is making the noise...there's slight noise on the rev and then knock knock knock back down to a quiet idle. I had to replace the motor mounts on my old celica and this is nothing near the same noise, so I'm almost positive it's not that. When the engine cools off I will inspect the spark plugs/wires/wiring...maybe distributor? I'm afraid too many deposits have been loosened, but am curious if it could be anything else and what/if anything I can do to fix it!!! I know it's an old car and there's a good chance it may be the engines time...but I really hope not! I'd like to minimize my expenses until the time is right for an engine swap and still use this car as a daily driver around town. Any help or suggestions would be greatly appreciated!!! Thanks in advance!

This post has been edited by celicakitten: Jun 3, 2012 - 11:21 AM

[Xander_X]

Could be many things ... especially when we can't hear it. It could be ignition related, anything from timing down to a malfunctioning component. It could also be the obvious bad connecting rod, piston or bearing

[Galcobar]

Check for an oil leak.

Jamming that much cleaner through can loosen carbon deposits. Normally that's a good thing, but not if a deposit has built up around an oil leak and is plugging the leak. Remove the deposit and produce an oil leak; run the engine with low oil and you can spin a bearing or end up with rod knock.

[delusionz]

.... fuels have cleaners in them anyways???


is the sound inside the motor or outside the motor??? do u have a rattly exhaust?

does it rev properly??

[rave2n]

I swore my 7a knocked, but when I would let others hear it, they would claim I was crazy, or just looking for a reason to get rid of the engine. Not saying that is your case at all, but I would def check oil first to see whats going on, and tell us of any performance loss.

And or block explosions =)

[Special_Edy]

Step one-check oil level, refill if low

Step Two- drain oil into a clean container and check for metal at the bottom or a metallic sheen to your oil.


If the above two items are okay, perform a simple cylinder balance test. With the engine running carefully unplug one spark plug wire at a time and try to determine if unplugging any one cylinder drops the rpms less than the others.

[Smaay]

eryns car had a very slight knock to it. when i tore it down the bearings were all chewed up. i rebuilt it with new bearings and piston rings and it ran like a champ....

read this thread

http://www.6gc.net/forums/index.php?showtopic=72502&hl

[celicakitten]

I swore my 7a knocked, but when I would let others hear it, they would claim I was crazy, or just looking for a reason to get rid of the engine. Not saying that is your case at all, but I would def check oil first to see whats going on, and tell us of any performance loss.

And or block explosions =)

Haha! NO block explosions please!!! I do seem to have a bit of paranoia when it comes to these things, even when I shouldn't so I get what you mean

Step one-check oil level, refill if low

Step Two- drain oil into a clean container and check for metal at the bottom or a metallic sheen to your oil.


If the above two items are okay, perform a simple cylinder balance test. With the engine running carefully unplug one spark plug wire at a time and try to determine if unplugging any one cylinder drops the rpms less than the others.

Step one-checked
Step two-not done just yet, just had the oil changed two weeks ago(but a good idea none the less).
I was about to do a cylinder balance test, but upon checking the spark plugs and wires once the engine cooled I found that one wire(furthest from the distributor) had snapped off in the connector to the spark plug. I had to use pliers to pull the rest of it off the spark plug, the guy I bought the car from must have bought a really cheap set of wires so now I need to buy new ones...any suggestions?

I also discovered my exhaust manifold heat shield is missing bolts and some of the ones left were loose(slight rattling there), and upon closer inspection of the exhaust manifold itself there is a large crack. That would explain the slight exhaust leak/smell I get inside the car, so I will also be replacing that soon...again any suggestions on parts you guys recommend is greatly appreciated!

Hopefully once I get those wires replaced it will decrease, if not stop altogether, the knocking sound I'm getting. I does look as though I have a small leak in addition to the power steering one I knew about as the last couple days(since the knock started) the leak has increased. I'll have to keep an eye on it since there could be damage from the pressure building up from the spark plug not firing and like mentioned earlier the deposits that may have been preventing a leak being dissolved from the fuel additive.

[celicakitten]

eryns car had a very slight knock to it. when i tore it down the bearings were all chewed up. i rebuilt it with new bearings and piston rings and it ran like a champ....

read this thread

http://www.6gc.net/forums/index.php?showtopic=72502&hl

This is amazing!!! Very impressive you basically did all of that in just two days! Can I come to Cali and play too! You have all my favorite cars! Supra, celicas...especially the all-trac! I'd love to someday have a 5th gen all-trac, and I'm also curious how you like the turbo in the 7th gen?!

This post has been edited by celicakitten: Jun 5, 2012 - 12:41 AM

[Hanyo]

Upload a video of the knock and where it's coming from. Us 6gcer listen to our engines every day so we can Tell u if anything is out of the normal.

[Special_Edy]

Ok, the spark plug wire situation could very likely cause the knocking noise, and it could definately cause a misfire which would make smelly exhaust, loss of power and lots of vibrations at idle. You need to get them replaced. Spark plug wires for my '94 with a 5SFE cost me about $45 with a lifetime warranty at autozone.

The missing bolts on the manifold heat shield will cause it to rattle. The heat shield will rattle at random rpms and I dont know how to explain the sound other than it will sound like a cymbal from a drum set being hit very rapidly.

Finally the crack in the manifold will make a knocking sound. You may be able to get someone to weld it back together for cheap without needing to remove it.

[Xander_X]

Ok, the spark plug wire situation could very likely cause the knocking noise, and it could definately cause a misfire which would make smelly exhaust, loss of power and lots of vibrations at idle. You need to get them replaced. Spark plug wires for my '94 with a 5SFE cost me about $45 with a lifetime warranty at autozone.

The missing bolts on the manifold heat shield will cause it to rattle. The heat shield will rattle at random rpms and I dont know how to explain the sound other than it will sound like a cymbal from a drum set being hit very rapidly.

Finally the crack in the manifold will make a knocking sound. You may be able to get someone to weld it back together for cheap without needing to remove it.

What Edy said, except I'll add this:

I personally don't like aftermarket plug wires. After 12+ years of working on Imports (I also went to Toyota's mechanic school for 2 years), I found that vehicles like Honda and Subaru don't really like aftermarket plug wires all that much. They're very finicky. Of course T-Ten (toyota school) will teach you to ALWAYS use OEM parts. This is my first Toyota I've owned that I've really played with (I went straight to working at a Honda dealership out of T-Ten school and always tuned Honda's and Subaru's) so I don't have the experience with them as much as many on this forum, but they are designed very similar due to competition between makes, available technology and just plain physics. I would always buy OEM plug wires just due to past experiences. One of the reason Toyota, Honda and Subaru are so much better than most other makes is everything is mathematically precisioned and tolerances are tight. There isn't a lot of room for error. They're more expensive, but you'll never have a problem with them (the OEM wires I mean). Just my opinion. I know PLENTY of people have great success with aftermarket plug wires, it's just one of those parts I'm biased against the aftermarket.

With the crack, you can probably get it fixed. Or replace it with another one from a junk yard. If your planning on doing some mods, I would use the opportunity to get a performance header and exhaust. There are many post about these if you want more info. The consensus seems to be that most performance headers are "ebay specials" yet most reviews are positive so I wouldn't hesitate using one. And most people tend to get the rest of the exhaust custom made as the few companies that make full systems for the 6gc are quite pricey (over $1000). I would recommend a full 2" exhaust with a resonator. Magnaflow makes an inexpensive 2" cat. The 2" with give you enough flow to gain a little more flow without taking away too noticeably from your low end torque. I suggest a resonator just for the purposes of toning down the noise so it doesn't sound like a Ninja 10R driving down the street.

This post has been edited by Xander_X: Jun 5, 2012 - 11:39 AM

[rave2n]

Hmm sounds like the duralast autozone wires.

They suck bad for installing, just seems like they don't fit right without some major elbow grease, but they do work. As some said, OEM is best =)

[celicakitten]

Yeah I'm not sure what wires were used, there's printing on the side that says 'sumitomo' or something similar. I was thinking of either getting the NGK plugs and wires or OEM's to replace it all. Not sure I can trust the quality of work this guy put into the car being he only had it for a couple months to fix it up and then sold it. I'll keep you guys updated if I'm still having the same problem after the plug and wire change, and I have been looking into replacements for the manifold too...just not sure I can do the full exhaust yet. Thanks for the input!

[Galcobar]

.... fuels have cleaners in them anyways???

And meat has iron in it -- but you can overdose on supplements. A small amount fed constantly keeps things clean, prevents buildup, and removes some deposits. The bottle of cleaner he mentioned dumping into the fuel system could clean very well, because even added to a full tank it's much more concentrated than the amount you'd find any retail fuel.

This is why people often recommend against using cleaners such as Seafoam in the crankcase of older engines, especially if you're not looking to do major work. The removal of carbon deposits in the oil system can reveal existing leaks and elevate the repair from when-I-get-around-to-it to right-bloody-now.

That said, cheap or loose parts can easily be the source of the rattle. Denso or NGK wires are Toyota part suppliers and will be up to spec.