94 engine knock? - Toyota Nation Forum : Toyota Car and Truck Forums

Gshock3vz · 12-31-2011, 01:25 AM

Hello

I bought a 94 4runner, the vehicle has 128,000 miles. The engine seems good when I bought it, no knock and all the belts including the timing were changed at least 42k ago. However, I noticed a slight knock coming from the plenum area or the top block.It's noticeable around 1,500-2,000 and above that seems to go away and disappear. You have to strain to hear over the normal ticking of the lifters and loud injectors.

My oil was changed today it seemed to go away for a bit and then comes back. I have to ' blip' the throttle to create that sound to notice.

stuck valve bad, cam knock?

Thoughts and opinions are welcomed

Thanks, Will.

jetwhine · 12-31-2011, 03:43 AM

Gshock3vz,

You may have a valve out of adjustment.

Gshock3vz · 01-01-2012, 05:54 PM

Heres a video I made of it

You Tube

All I am doing is gently blipping the throttle. And it makes a sound coming from the top of the plenum like a go-kart or someone running their fingers against a fan blade.

I took it to the dealership yesterday and the mechanic wrote this" Customer states he is hearing a knock type noise at the top of the engine area at 1500-2000 rpm then goes away. Check and advise. Checked and heard normal valve ticking noise. No abnormal noise heard when checking".

However he did state the valve cover was leaking heavily. I checked my oil and and rechecked it and I had a hard time finding a reading.

jetwhine · 01-04-2012, 04:31 AM

The only thing I would suspect would be the EGR valve. If it is malfunctioning it might be cauising the noise in the manifold. It might be slow to react to the increase in throttle. Just a guess though.

Gshock3vz · 01-30-2012, 02:45 PM

Alot has happend since I last posted. I ended up taking the 4runner back to the Toyota dealership, the mechanic stated that he heard a ' knocking type of noise from the rear, sounds like a piston' The dealer quoted me at 4k to just tear down and inspect.

The vehicle I bought has a warranty a from the used car dealership(not Toyota), and the work must be performed at their mechanics per contract. Well, their mechanics claimed it was " Valve shims being at maximum spec and a collapsed valve lifter" So they went ahead and adjusted the valves and the lash adjuster etc. After I went to pick it up I noticed on the invoice they switched to 20W50 weight oil. I asked them why did that opposed to the regular 10W40? the shop managers response was " A Toyota tech recommended this weight"

So for the most part the sound went away for the next couple of days I've had it back. But When I made a long trip on the interstate, I noticed it came back when I pulled off at slow speeds. Around 1,000-1500 it's a dull type of knocking sound, or somebody hitting their fingers against a fan blade.

This is how it sounded before it was fixed. It's making that same sound just not as loud. Wrist pin knock? I think if it was a rod, wouldn't that have gone out along time ago?

http://youtu.be/LdmhoDKFzi8

jetwhine · 01-31-2012, 01:23 AM

Gshock3vz,

Your second sound trac sounds like a cylinder that is not firing during low acceleration. Or even a vacuum leak in the intake manifold area, and only effects things until it gets up in rpm. Just a few ideas.

Gshock3vz · 01-31-2012, 02:36 AM

Quote:

Originally Posted by jetwhine

Gshock3vz,

Your second sound trac sounds like a cylinder that is not firing during low acceleration. Or even a vacuum leak in the intake manifold area, and only effects things until it gets up in rpm. Just a few ideas.

Yeah. I was thinking it could be something as simple as a faulty plug. I told my Dad and told he ' dismissed it as a joke'. Supposedly their mechanics checked for compression, maybe they missed a fouled plug?

chuckoff · 01-31-2012, 09:45 AM

assuming this is a 3.0 V6. The mechanic that said it was a collapsed lifter is dead wrong. There are no lifters in that engine. The cams ride on lash caps on top of the valves. Adjustments are made by changing shims. The 4 cyl. is adjusted at the rocker arms, but also has no lifters. A ticking sound is more likely too much valve clearance, where a knocking sound could be a bearing, or piston issue.

Gshock3vz · 01-31-2012, 10:05 PM

Update*

I took the car to a Independent Toyota mechanic, one of their mechanics used a stethoscope and claims he pinpointed the sound coming from the timing belt area. He says one of the main bearings or smaller bearings is making that sound, or the belt is rubbing. I'm totally blown away by that. He says it doesn't like knock he's heard of before.

Interesting thats for sure.

jetwhine · 01-31-2012, 11:33 PM

Gshock3vz,

I'm not sure that I'm buying that analysis. The engine sounds like a cylinder is the issue. A rubbing belt or bearing is not going to make a hesitation type sound. I still think it could be a vacuume leak or a miss fireing cylinder. You could try one at a time removeing a spark plug wire and see if you can isolate which or if it is a miss fireing cylinder.

Gshock3vz · 02-01-2012, 02:36 PM

Quote:

Originally Posted by jetwhine

Gshock3vz,

I'm not sure that I'm buying that analysis. The engine sounds like a cylinder is the issue. A rubbing belt or bearing is not going to make a hesitation type sound. I still think it could be a vacuume leak or a miss fireing cylinder. You could try one at a time removeing a spark plug wire and see if you can isolate which or if it is a miss fireing cylinder.

I think I found my issue. I didn't test for cylinder misfiring yet, I will do that later on today. But I pulled the wire boot on passenger side rear cylinder. Its has traces of oil/ and in the spark plug hole oil

what the easiest way to remove it? With the reed valve and EGR crap in the way a elbow joint socket?

Gshock3vz · 02-02-2012, 08:03 PM

I found that the TTV hose is disconnected and the nipple for the purge is broken on it. So my EVAP canister isn't even hooked up. It looks pretty hard to remove it as it's a sensor with threads on it.

Would a malfunctioning TTV and EGR system cause this? Or am I just discovering more things now.

jetwhine · 02-03-2012, 02:47 PM

Gshock3vz,

I'm thinking that you have found several things that need to be addressed. As far as the sparkplug is concerned, what ever makes it easier to remove is what it takes. If the egr is malfunctioning it will cause problems. I would fix the things you found wrong and go from there.