Engine knock/rattle vs. fuel injectors??? Any help?, Video and description... Options

[celicakitten]

So I've had my car for three months now and still cannot figure out what this noise is! I'm by no means a mechanic but have common sense around cars, celicas inparticular. It's a mostly stock 7a-fe with 194k and 5 spd tranny. The car runs fine, and since I've had her changed the oil, spark plugs/wires, exhaust manifold/down pipe(original was cracked), and have had no other problems...not even a check engine light. I can't find anything loose that would rattle, but there is a significant power steering fluid leak.

http://youtu.be/FOrH0HC7l5w

Please see the video I put on youtube to hear the noise, which is most notable on a cold start and anytime I'm constantly holding revs over 2500rpms, but will stop if I floor the gas or let off it completely...It's very annoying on the freeway(but isn't noticable with the radio on! ha!). I'm thinking maybe a bad piston ring, or possibly something in the fuel injectors??? I should also say the noise does seem to emit from the passanger side of the engine bay. I'm worried it may be time for a rebuild as I do not know how the previous owners treated her. If that is the case my biggest challenge would be finding someone I trust to do the work, but I'm sure you guys can help point me in the right direction for that!

[mkernz22]

When you first started it up it sounded like a rod knock, but when the same noise came back it actually sounds like it's a cam shaft (under your valve cover). Take the valve cover off and see if anything is loose underneath there.
If it was a rod knock, I doubt your engine would be running right now.

Try getting a video where you go close up to different areas on the engine.

[Special_Edy]

Without seeing it in first person I would want to guess that something is loose, an engine mount for example, that is rattling when the engine reaches a certain harmonic or RPM. I once had a very bad knock on my pickup truck and after maybe 15-20 "expert" opinions it was determined to be the crankshaft. I pulled all the main bearing caps and plastigauged them just to find out it was the three bolts that hold the torque converter to the flexplate that were loose. Moral of the story is that its usually the simplist fix, not the hardest one.

If you want to doublecheck the injectors-
With the engine idling pull one spark plug wire at a time and listen for a drop in rpm. The cylinder that causes the rpms to drop the least has the potentially bad injector. Make sure to use a rag to pull the wires so you dont get shocked.
Now that youve located a possible bad injector you can remove the two bolts attaching the injector rail to the cylinder head. Remove the bad injector and swap it with one of the good injectors. Reattach the fuel rail and retest for dead cylinders. The dead/weak cylinder will have moved to the same location as the bad injector if the injector is indeed bad.

Hope this helps...

[Box]

I find it easier to just unplug the injectors. It's not hard to get down to the fuel rail though, I recently took the injectors out and flushed them. It sounds like valve-train noise to me. If you or anyone you know has a stethoscope, can use that to isolate the location of the noise.

[celicakitten]

When you first started it up it sounded like a rod knock, but when the same noise came back it actually sounds like it's a cam shaft (under your valve cover). Take the valve cover off and see if anything is loose underneath there.
If it was a rod knock, I doubt your engine would be running right now.

Try getting a video where you go close up to different areas on the engine.

Yeah, it's been doing this since I got it, highly doubt rod knock at this point. I'll look into checking the cam shaft if it's something easy I can do on my own.

Without seeing it in first person I would want to guess that something is loose, an engine mount for example, that is rattling when the engine reaches a certain harmonic or RPM. I once had a very bad knock on my pickup truck and after maybe 15-20 "expert" opinions it was determined to be the crankshaft. I pulled all the main bearing caps and plastigauged them just to find out it was the three bolts that hold the torque converter to the flexplate that were loose. Moral of the story is that its usually the simplist fix, not the hardest one.

If you want to doublecheck the injectors-
With the engine idling pull one spark plug wire at a time and listen for a drop in rpm. The cylinder that causes the rpms to drop the least has the potentially bad injector. Make sure to use a rag to pull the wires so you dont get shocked.
Now that youve located a possible bad injector you can remove the two bolts attaching the injector rail to the cylinder head. Remove the bad injector and swap it with one of the good injectors. Reattach the fuel rail and retest for dead cylinders. The dead/weak cylinder will have moved to the same location as the bad injector if the injector is indeed bad.

Hope this helps...

I'm really hoping it's a simple fix! I'm almost positive it's not an engine mount, had that problem with the last celica so I know the difference. I will check the injectors...but it's most likely an engine issue

I find it easier to just unplug the injectors. It's not hard to get down to the fuel rail though, I recently took the injectors out and flushed them. It sounds like valve-train noise to me. If you or anyone you know has a stethoscope, can use that to isolate the location of the noise.

Stethoscope you say? I can get a cheapo one from work, good plan thanks!

[celicakitten]

I should also add that I just changed the oil and filter today, I used 1 quart Lucas and 3 quarts Castrol gtx high mileage with a K & N filter and the sound is almost inaudible at high speeds now. It's still there at lower speeds, but not nearly as loud? It had just been changed when I bought the car (still clear fluid on the dipstick) and over the last three months the noise had got worse, but now with new oil again it's better??? It had burned off maybe a little more then a quarter in that time also (3 months), so not sure if that's typical.

[Box]

Definitely sounds like valve-train. I had a 3000GT that had valve-train issues and made a similar sound to yours. Though with my 3000GT the noise was constant. I found using Rislone made it quiet again. Odds are what happened to your car with it burning oil, the previous owner let it get low and the top of the engine was starved of oil. Best you can hope for is a stuck lifter. If not it's something with the camshafts, or valves. The 7A-FE engine is notorious for stuck oil rings, and therefore oil burn. Most likely is the cause of your oil burning.

[Bitter]

I doubt it's the same issue with your 3KGT since the 7A has solid 'lifters' and you had oil filled ones notorious for collapsing.

[celicakitten]

Thanks for the feedback so far guys, when I get a chance to check some of these things out I will (school/work sort of consumes my life!). I just wish I had a trustworthy mechanic nearby that I could take the car to, but the best I can do for now is learn from all of you and make some educated guesses before finding a mechanic or going to toyota(and getting ripped off). Fortunately the car runs absolutely great aside from the noise so at least I still have my dd!

[Box]

I doubt it's the same issue with your 3KGT since the 7A has solid 'lifters' and you had oil filled ones notorious for collapsing.

Ahh ok. Just looked it up and the 7A-FE uses mechanical lifters, where as the 6G72 uses hydraulic lifters. Still, willing to bet it's a valve-train issue she's having.

This post has been edited by Box: Aug 30, 2012 - 2:27 PM

[mkernz22]

Thanks for the feedback so far guys, when I get a chance to check some of these things out I will (school/work sort of consumes my life!). I just wish I had a trustworthy mechanic nearby that I could take the car to, but the best I can do for now is learn from all of you and make some educated guesses before finding a mechanic or going to toyota(and getting ripped off). Fortunately the car runs absolutely great aside from the noise so at least I still have my dd!

Just try digging in and doing stuff on your own! That's what I did and I can replace almost anything on my car and I know it inside and out (to the most part).

[Bitter]

Try to listen and determine if it sounds like it's louder on top or on bottom. The fact that it knocks initially as oil pressure builds makes me think it's a bearing issue since none of the valve train needs oil pressure, top end bearings are part of the head I think. I'd drop the lower oil pan and check the oil pan for debris and check the oil pickup for blockage, then check actual oil pressure.

[celicakitten]

Just try digging in and doing stuff on your own! That's what I did and I can replace almost anything on my car and I know it inside and out (to the most part).

I would really love to, but I couldn't afford that much down time as I need this car to get me around, and I'm very busy...obviously if the engine blows I'm s.o.l. completely! I got the car to save money and gas, but if I had to rebuild I'm willing to incur the cost if I find the right mechanic whom I can trust...just hate to do that right now IF there's an easier fix.

[Box]

Another option is to just give it the middle finger every morning and drive it until something shoots through the top of the engine. Then once it does that sell it for parts. My personal favourite way of dealing with these kinds of problems, and what happened to my 3KGT. OR you can be like the bitch who sold me the 3KGT and cover up with problems with quick fix ****, and lie through your teeth to sell it.

[Amanda66]

My car does the same exact thing o_O Everyone keeps telling me it's rod knock and I'm like it's been doing it now for almost 2 years. It gets better when I put new oil in it and gets worse when I get close to having to do another oil change. I took the valve cover off mine and didn't see anything in there...good luck. I figured best move for me was to nurse her along until I get my 3sgte ^_^

[Smaay]

^^^ since you have a ST you should upgrade to a V6, not a crappy 3S-GTE that is too expensive.

now back on topic. Erynns car did the exact same thing. when i pulled it apart, this is what i found.



all the bearings looked like this. luckily the crankshaft was fine. it just needed a polish and it cleaned up perfectly.

[celicakitten]

^^^ since you have a ST you should upgrade to a V6, not a crappy 3S-GTE that is too expensive.

now back on topic. Erynns car did the exact same thing. when i pulled it apart, this is what i found.



all the bearings looked like this. luckily the crankshaft was fine. it just needed a polish and it cleaned up perfectly.

Smaay, I read your thread on Erynn's rebuild and it's amazing, I really wish I had the tools and the time to do it myself! From your experience how much should I truly be looking to pay someone to do that for me, and would you advise any work on the transmission while in there? Also since you're in So. Cal you wouldn't happen to know a good mechanic anywhere near(within 300miles) Las Vegas that would do such work?! I wish I had the money for a v6 swap! But I'm trying to keep my costs as low as possible. Actually I am torn between just driving her till it goes and then swapping a rebuilt engine in, or just rebuilding now before it gets worse. I'm having a tough time finding a mechanic here I can trust to do the rebuild and I haven't got a quote from the dealer yet but I'm sure they will be even more $$$ than I should be spending. Any help/ideas would be appreciated!

This post has been edited by celicakitten: Sep 19, 2012 - 12:56 AM

[Box]

Well, if you're ready to swap soon go ahead and keep driving it until it pops.

[celicakitten]

Well, if you're ready to swap soon go ahead and keep driving it until it pops.

Well I wouldn't say I'm "ready" for a swap, but I have found a company that I can buy an engine block that's already rebuilt or I was thinking I could find another used 7a-fe to rebuild or swap in... not really sure which way is most cost effective. I've only had the car for 4 months, but have no idea how long it was knocking before I got it. It runs great, so I'm sorta in the "if it isn't broke don't fix it" mode as of now. Plus if I can put off dropping 1500-2000 dollars into it right now that would be nice...

[Smaay]

im actually only about 220 miles from Vegas. it takes me only 3 hours to drive there.