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Engine & DrivetrainDiscussions about the engine and drivetrain of your vehicle.
This is a discussion thread titled "Spark knock", within the Engine & Drivetrain forum, part of the Technical & Vehicle Assistance Forums category.
Will somebody help me. I was reading over the owners manual and it states that youcan use 87 octane gas. I initially used 87 until I heard it knocking. I bumped it to 89 and then again to 93. The knocking is not bad on 93 but when Ipull something it sounds like a diesel. I used to have a k&n fipk and I have since taken it off and gone back stock with the truck. I have even had some problems with a weird sound when the truck shifts at higher rpm levels. Funny thing is, a mechanic and I drove 2 03's and an 02 and they all did it. He concluded it was a sparkknock when the truck is shifting to a the next gear. My questions are 1, doesnt spark knocking eventually damage the valves? 2 I have tried all kinds of gas from amoco to citgo. All have the same results. 93 works best and still spark knocks. I contacted toyota and was told this is a characteristic of these trucks. I am sorry but thats still not going to help any of us when we have to replace our valves. My final questions are, is anyone else experiencing these difficulties and if so have you been ableto correct them? Thanks
The toyota V8's seem to all make that noise during the shift from one gear to another. it is most noticable at higher rpm. I know the old LS400s made the same noise. It sounds like detonation, but the timing is actually retarded during the shift.
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The toyota V8's seem to all make that noise during the shift from one gear to another. it is most noticable at higher rpm. I know the old LS400s made the same noise. It sounds like detonation, but the timing is actually retarded during the shift.
That makes me feel a little better but what about the spark knocking at acceleration?
bear with me for a sec...this might sound a little odd considering the problem has already been "diagnosed", but if you would, please try this...with a friend standing next to the truck with an ear down near the front wheel wells (do this one side at a time), put the e-brake on full, hold the brake pedal with one foot, shift in to drive, and with the other foot gently give a little gas. have your buddy tell you if the knocking sound gets louder and is a noticeable knock coming from the region of the wheel wells.
...on that note, search for "exhaust manifold leak". lemme guess...it's even more noticeable when it's cold out, right? and it's also worst right at startup?
bear with me for a sec...this might sound a little odd considering the problem has already been "diagnosed", but if you would, please try this...with a friend standing next to the truck with an ear down near the front wheel wells (do this one side at a time), put the e-brake on full, hold the brake pedal with one foot, shift in to drive, and with the other foot gently give a little gas. have your buddy tell you if the knocking sound gets louder and is a noticeable knock coming from the region of the wheel wells.
...on that note, search for "exhaust manifold leak". lemme guess...it's even more noticeable when it's cold out, right? and it's also worst right at startup?
-sean
Actually tried that yesterday. The knocking is coming from the motor. Doesnt really do it unless you are accelerating. It is very noticeable when I put a lower grade of gas in it. But you might be right.
MY DEALER told me that it was not a knock or detination but the air accually being sucked in thru the intake manifold.We did try lightly power braking the truck but could not simulate any knock from being under a load condition.I did recieve a phone call from the dealer to know if i'm satisified with the service.I did tell them i want the service rep to she the truck when he's scheduled to visit the northeast (Connecticut).I'll let you all know how i make out.
a few people have rigged up stethescope-type things to more accurately pinpoint the sound. i'd be really curious to find out if some of these really are something other than exhaust manifolds...that's the most common, but certainly not the only possibility. there's always a chance that a truck really does have piston slap, spark knock or something else, but (thankfully) it's usually just the exhaust manis.
Not that there are any ssolutions to the problem on the post under Tundra Pinging, but at least it helps to know your not the only one with this problem. If you haven't looked through that one take a peek.
I have never heard my V8 Tundra make any sort of pinging noise, I always try to use the least expensive gas available 87 oct. load or no load, high or low RPMS , shifting at full throttle makes no difference. my Tundra is a 2000, I have tried a higher octane to see if there was any performance increase, I did not notice any difference. good luck, you might try resetting the ECU, and I though that the Tundra V8 motor has a knock sensor
I thought it was supposed to have a knock sensor too. Supposed to kick the check engine light on it or something but no light and a lot of spark. No matter. I am tired of messing with this truck, so I guess I am gonna get a titan when it comes out. At least my brother-in-law is a mechanic for nissan and he can give me some help if I have a problem with it.
I thought it was supposed to have a knock sensor too. Supposed to kick the check engine light on it or something but no light and a lot of spark. No matter. I am tired of messing with this truck, so I guess I am gonna get a titan when it comes out. At least my brother-in-law is a mechanic for nissan and he can give me some help if I have a problem with it.
If the knock is that bad that you can hear it inside while driving, I'd say it's a problem.
I have a 2000, and NEVER hear any kind of ping out of it, until I put the TRD blower on it. Now I know what ping is..
You mentioned running a K&N, some people report the MAF getting fowled by the oil in it, but I've had a K&N on mine since purchase. Maybe where you live, with more moisture in the air this is a problem.
If you think it's engine knock, go down to the local speed shop, and put a gallon of Methanol in, and get a fill-up of Mid-grade Chevron or something.
If the kock goes away, the truck is A) running to lean, B) running too hot.
I'd also consider the bottom end being a problem, if you still hear knock. Run Castrol stright 30wt oil in it, I do. 5wt is too light for where I live, and I tow all the time, so the Heavy Duty 30wt does me good.
When I worked for Toyota, I herd a lot of Toyotas that sounded like diesels when they had a rod bering spun, or a main bering shot.
If the truck appears to run too lean, pull the vacuum line off of the return regulator (the regulator thingy in the middle of the passenger side fuel rail), and see if more pressure at the injector seats help.
I might be off base but here it goes anyway.
Loose flex plate bolts (or a cracked flex plate) will make a knocking sound under any acceleration. This noise sounds like it comes from the top of the motor and you would think it was extremely loose valves, broken pistons or a "very" bad gas knock. The noise does sound like an extra loud diesel.
I would use a mechanics stethoscope and pin point the source.
just an update. The spark knock has got worse and I have taken it to another dealership. they told me basically the same thing, if the checkengine light doesnt come on, they dont know what to do. I really like this truck and I am really stumped with it. Every mechanic says the same thing, it is definitely a spark knock but they cant do anything about it. If anyone else has anymore ideas let me know.
I might be off base but here it goes anyway.
Loose flex plate bolts (or a cracked flex plate) will make a knocking sound under any acceleration. This noise sounds like it comes from the top of the motor and you would think it was extremely loose valves, broken pistons or a "very" bad gas knock. The noise does sound like an extra loud diesel.
I would use a mechanics stethoscope and pin point the source.
I know this is a stupid question but where is the flex plate. I am getting a constant tapping noise and can't locate it. Replaced manifold with JBA Headers and still have the same problem. 2000 Limited
Spark knock
