Ok heres the symptoms...Started my car up today and heard a slight knock didn't think anything of it, well later today went to head to the store and the same knock was back but loud, and it was idling really rough going from 1.5rpms to .5rpms roughly i let it warm up some and it was still doing that, but had to go to the store so as soon as i through it to gear it idle so low it about stalled and then it shot up again just b4 it died and then did it again so i just kept my foot slightly on the gas so it stay fairly even when i was sitting still at a light. It sounds like it coming the engine block itself and when I put my hand on the top i can feel it just knocking. Basically if anyone has to any ideas of what it maybe please let me know. Also I noticed my oil pressure at idle was where it should be according to owners manual, but when i actually get going it only gets upto about 20, when it used to get up to about 40 b4 i had the oil changed in it. Again any help or ideas on what it maybe would be greatly appreciated.
Loud Knock
- Thread starter mkIIIforeverdrifting
- Start date
i'm gonna go with rod knock or piston slap. it gets worse with higher reves? doesnt go away when motor is warm? doenst go away at all? started out quiet then got louder and louder, like someone hitting you engine with a hammer?
my diagnosis: rod knock
prognosis: you are SOL, sorry. need a motor.
you can take a sample of your oil to a shop, they can test it for bearing matirial to be shure. also, start the engine and let it idle, then go around and one by one unplug the injectors. if the noise goes away when one is unplugged then that is the rod that is having the problem.
i'm not shure this does come up on a daily basis, and i only see 2 threads on that page that might apply.
my diagnosis: rod knock
prognosis: you are SOL, sorry. need a motor.
you can take a sample of your oil to a shop, they can test it for bearing matirial to be shure. also, start the engine and let it idle, then go around and one by one unplug the injectors. if the noise goes away when one is unplugged then that is the rod that is having the problem.
i'm not shure this does come up on a daily basis, and i only see 2 threads on that page that might apply.
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souprat said:
No it doesn't get louder or worse w/ higher revs it acutally seems to stop and its only when its idling that it knocks really bad you give it a lil gas in the lower end it knocks a little but as you give it more gas it seems to calm down, go figure so as I said it sounds like its from the engine but really hard to pin point, I'm going to look at it some more here in a lil bit and if I can't find the source I'm going to take it to my buddy's shop just didn't want to have to do that if it wasn't that big of a deal. Though if your right and I need a new engine, works for me I'm just trying to keep the 7mge running ok, have half the money for the 2jz already guess I'll have to get my dad to float me the rest so we can get the car running right again if its serious, mans got to work, man can't work w/ no ride. Thanks for the help and the fast reply's this place is great. Must say i was a lil skittish about buying the mkIII but its definately grown on me, I can see me loving this car as much as my 240's i have.
There isn't enough info here to determine if it is rod knock. I'm not saying that it is NOT rod knock, but there is no way to say with any level of certainty that it is.
Try and isolate the sound, pull injector plugs, see if your throwing any codes. Lets start with a problem and work it back logically.
You have a knocking sound coming from the engine.
Many things could cause this. Loose bolts, out of spec shims, worn roller berings on pulleys. Isolate the sound to a specific part of the engine. Top, bottom, front, back. Use a machinists stethoscope, or various creative alternatives. Also clear and check for CEL codes. Once you have checked for codes and isolate the sound, report back here.
Try and isolate the sound, pull injector plugs, see if your throwing any codes. Lets start with a problem and work it back logically.
You have a knocking sound coming from the engine.
Many things could cause this. Loose bolts, out of spec shims, worn roller berings on pulleys. Isolate the sound to a specific part of the engine. Top, bottom, front, back. Use a machinists stethoscope, or various creative alternatives. Also clear and check for CEL codes. Once you have checked for codes and isolate the sound, report back here.
adjuster has a post on rod knock, grounding out plug leads will help you determine where it is, if in fact that's what it is.
The piston is about to go through the block dont rev it if you want to rebuild your 7M.
My brother pushed #4 through hid block under the intake. I pushed #6 in front of the starter through the block.
The weak link in the 7M
#1 head gasket
#2 Connection rods break off when reving 7Ms hard or over stressing them.
sometimes even changing oil religously and keeping good oil levels have nothing to do with this.
#3 is AFM & the brittle VSV valve on the water housing with the two vacume lines going to it look at it wrong and it breaks!
The reason this happins with 7ms is because there is a lot of leverage of stress on the end of the rods because of the long stroke and the huge torque monsters these 7ms are so reving them like a shorter stroked engine then bore like a 1JZ will blow these oem rods out like nothing.
My brother pushed #4 through hid block under the intake. I pushed #6 in front of the starter through the block.
The weak link in the 7M
#1 head gasket
#2 Connection rods break off when reving 7Ms hard or over stressing them.
sometimes even changing oil religously and keeping good oil levels have nothing to do with this.
#3 is AFM & the brittle VSV valve on the water housing with the two vacume lines going to it look at it wrong and it breaks!
The reason this happins with 7ms is because there is a lot of leverage of stress on the end of the rods because of the long stroke and the huge torque monsters these 7ms are so reving them like a shorter stroked engine then bore like a 1JZ will blow these oem rods out like nothing.