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Discussion Starter · #1 ·
Hey guys. I have been browsing this forum as a guest for the past couple weeks and finally decided to make an account. I couldnt quite get my answer just looking through existing threads. So here it is.

Recently I bought a 2001 Celica GT with 144,000 miles and drove it home from Nevada (1800 miles). Its a great runner and yes it consumes a little oil but not too bad considering the speed limits in Utah. Anyway, when I first bought the car, I noticed it had 5W-20 in it. That is what the oil change sticker indicated. The only problem during the entire trip was when it rained heavily near Mt. Rushmore it started sputtering. I have already resolved that this was hydrolock from the CAI and plan to create a better splashshield for it.

After it quickly burned up the 5W-20 cruising around Vegas I decided to switch it to 10W-40. Ever since I have had the car, though, there is a rattle in the top end of the engine between 2700RPMs and 3500RPMs. If I am light or hard on the gas it is much fainter. It seems like when the car is under heavy load it is fainter (up a hill etc.)

After browsing the forums here, I decided to clean the OCV filter really good. Before I put it back in it looked like new, no metal shavings, nothing. Virtually spotless. I did not pull the valve, but I can if necessary.

I did see a couple other people seemed to have the same problem on here but it went unresolved. The idle is almost perfect but it seems a little high when cold starting (holds at about 1500RPMs) Once down, it idles well but, on rare occasion stumbles from about 800RPMs to 650RPMs.

Keep in mind that the rattle is not as definite as some of the rod knock videos I have watched, nor does it rattle across all RPM ranges. This is the only issue with an otherwise flawless, clean southern car so its rather annoying.

Also, the car has a full DC exhaust and switched to 91 octane gas, did three bottles of injector cleaner (in three full tanks), and when I pulled and replaced the Autolite plugs that the previous owner had used, the plug tips where very white which usually indicates lean. I changed to NGK.

I might be forgetting details so feel free to ask questions.

P.S. does anyone else notice that third gear int he 5 speed manual is useless? LOL I just shift from 2nd to 4th now because 3rd isn´t even helpful unless your trying to pretend its a race car which I dont.

Thank you in advance for any help with this.
 

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Can't help much here about the rattle. But I can say that your idle is perfectly normal. You are over doing it with the fuel octane though. The GT only needs regular. And yes, 3rd gear has decent power, thankfully.
 

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I think the rattle around 2800 RPM is pretty normal for the 1ZZ-FE. I've had it on my engine since I dropped it in. I checked the valve clearances and they were all within spec. I also did a compression test a while ago and it was perfect. In conclusion, I'm not worried about the 2800 - 3500 RPM rattle.
 

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P.S. does anyone else notice that third gear int he 5 speed manual is useless? LOL I just shift from 2nd to 4th now because 3rd isn´t even helpful unless your trying to pretend its a race car which I dont.

Thank you in advance for any help with this.
I only just recently started skipping 3rd gear. But I find I only do it when I'm on a road with a 35 mph speed limit. I hit it kind pf hard in 1st and second and the drop it in 4th and cruise.
 

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Discussion Starter · #8 ·
Yep! Thats the same experience I have had. Except the speed limit is actually 30 but I go 35. lol. I decided using 3rd in uphill scenarios was appropriate but flat and downhill totally unnecessary. I am glad to hear others have the rattle. It is still very annoying....It has to be something. Other than that, a splashshield and she should be prime! Also, the 91 I know is overkill but it will help clean up some of the carbon so I am gonna keep running it. It gets superb mileage on 91 and slightly less on 87 so what the heck, might as well run it. I might even do the ocassional tank of non-ox until I feel the engine is nice and clean. At least to the extent it can be through fuel.:blah:

I also own a 96´ Talon TSi so this is kind of my nice D.D. that doesn´t need any mods so I am not looking to go GST because then I would want to go Lotus Supercharger and go all out....I dont have enough money for two major auto projects lol:money::money:
 

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Discussion Starter · #10 ·
Can't help much here about the rattle. But I can say that your idle is perfectly normal. You are over doing it with the fuel octane though. The GT only needs regular. And yes, 3rd gear has decent power, thankfully.
http://www.celicahobby.com/forums/u...ting-toyota-celica-recommended-fuel-type.html

I just came across this ^ which indicates that the 1ZZ peak efficiency is reached using 91 octane. For the 2ZZ peack efficiency is reached using 96 octane fuel. However, for the 1ZZ 87 is the MINIMUM allowable octane rating. For the 2ZZ it is 91.
 

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Watch your oil consumption closely.
 

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Fuel grades

I think if you do racing and need maximum engine performance, you would need the 91-Octane gas. But for normal driving, 87-Octane should do,as long as the engine is not knocking, the car is OK.

I have a 2002 GTS auto with 2ZZ engine, 220K mile, all original equip.

I buy 87-octane from major gas brands all along. Car runs fine. Occasionally I would have knocking when climbing hills. But it's random and cannot correlate to anything. I would just back off on the gas and the knocking is gone!

Did have to replace Oxy sensor 1. But the CAT is OK. Car passed California SMOG tests.

But cheap gas like ARCO , even 91 octane, will cause a lot of knocking

The CAT still passes SMOG after 220K miles. Had to replace 1 front O2 sensor, only $25 on line. That's it. So 87-Octane is not that bad for high-compression engiines like the 2ZZ in my experiences.



http://www.celicahobby.com/forums/u...ting-toyota-celica-recommended-fuel-type.html

I just came across this ^ which indicates that the 1ZZ peak efficiency is reached using 91 octane. For the 2ZZ peack efficiency is reached using 96 octane fuel. However, for the 1ZZ 87 is the MINIMUM allowable octane rating. For the 2ZZ it is 91.
 

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:eek:mg: Just no!
The 1ZZ is designed for 87 (R+M)/2 Octane fuel. The ECU will vary the timing (advance/retard) to accommodate approx. 86-93 (R+M)/2 Octane fuel. However, the octane required to satisfy a non-force inducted 1ZZ is 87. Anything beyond that is not going to improve anything except, possibly, a very minor 1% increase from the heat factor in the higher octane fuel.

A non-FI 2ZZ has an octane requirement of 91 (R+M)/2. The ECU will vary timing(advance/retard) to accommodate approximately 89-93 (R+M)/2 octane.
 

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Discussion Starter · #16 ·
:eek:mg: Just no!
The 1ZZ is designed for 87 (R+M)/2 Octane fuel. The ECU will vary the timing (advance/retard) to accommodate approx. 86-93 (R+M)/2 Octane fuel. However, the octane required to satisfy a non-force inducted 1ZZ is 87. Anything beyond that is not going to improve anything except, possibly, a very minor 1% increase from the heat factor in the higher octane fuel.

A non-FI 2ZZ has an octane requirement of 91 (R+M)/2. The ECU will vary timing(advance/retard) to accommodate approximately 89-93 (R+M)/2 octane.
Just YES.

I hate to break it to you but I ran a dyno on it after members tried to dispute FACTORY recommendations. The 1ZZ IS more efficient and produces slightly more horsepower on 91. SInce that is the case, I would also stand by the assertions of the post I provided that the 2ZZ is likely more efficient on 96. Again, those are PEAK octanes. Just because YOU CAN run something doesnt mean it is OPTIMAL.
 

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SInce that is the case, I would also stand by the assertions of the post I provided that the 2ZZ is likely more efficient on 96.
You, obviously, do not comprehend the difference between RON and (RON+MON)/2 octane ratings.

but I ran a dyno on it after members tried to dispute FACTORY recommendations.
:bs:pictures? 87 (R+M)/2 is the factory recommended for a USDM 1ZZ and 91 (R+M)/2 is the factory recommended for a USDM 2ZZ. Who is disputing that?
produces slightly more horsepower on 91.
1%?

Not only that..... but, it takes about a tank of fuel for the ECU to nearly fully remap for a change in fuels (or other changes for that matter).
 

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Discussion Starter · #18 ·
You, obviously, do not comprehend the difference between RON and (RON+MON)/2 octane ratings.

:bs:pictures?1%?

Not only that..... but, it takes about a tank of fuel for the ECU to nearly fully remap for a change in fuels (or other changes for that matter).
Of course! I will post pictures after. I would disclaim for those that havent read the OP that I have minor mods, but that shouldnt significantly impact the results. The comparison is 87 octane v. 91 non-oxygenated. BOTH 2 FULL TANKS. I will redo the experiment and post screen shots. And yes I do. WHat you are alleging is there is no [increase] from 87 to 91 except that derived from the increased heat due to the fuel burning hotter.

I believe this to be false.

Even if it were true, there are obvious benefits to switching to 91 to clean out carbon and refresh the fuel system which is what the OP is about. It does help to throw in 91 from time to time in any vehicle. I dont care if you drive a Dodge Stratus. So recommending that people have the same attitude you do about 91 is ill-concieved.

A curious thing with regard to compression ratio, and this is unverified, but I believe the DSM has the same compression ratio as the 1ZZ. Granted it is forced induction versus naturally aspirated, but the DSM runs utterly poor on 87. Its cant even be ran.

Before I get the SS up, though, I would say that I personally feel an increase in responsiveness, the idle is more smooth (I have gone through all recommended maintainance) and it pulls harder, most noticably in 5th gear up hill.

Anyway, as far as I am concerned this is a discussion. I would hope other people who own a 1ZZ might chime in with their first-hand experience. Thanks all who have provided useful feedback.
 

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Happy to look at pics, plots, and facts. But I'll call BS unless you reset the ECU and ran on a clean tank of each octane rating for a couple of hundred miles before each was run.

If you're not running quality premium gasoline and aren't throwing in quality fuel system cleaner every oil change or two you're cheating yourself. Throwing in the occasional tank of 91 or whatever will never be as effective as a bottle of quality fuel system cleaner in a tank of 87 now and again...
 
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