Hi, my 1994 Accord EX 2.2L VTEC 4cyl is at 250k and is making a knocking sound. The car runs hot and almost failed CA Smog Test with Very High NO Readings. I have made several clips of the sound

http://www.youtube.com/watch?v=D6DDLJRnO40
http://www.youtube.com/watch?v=bCw6JFFGRiw

I changed the oil, and tried higher OCTANE Fuel but the sound is still there.
I was told it could be piston slap, Valve Lifters, Timing belt, Spun Roller Bearings, and some other stuff but I dont know where to start.

Thanks

 

High NO readings can come from clogged EGR ports in the intake manifold.

Google T2T013.pdf. The last two pages show how to clean the ports on the 94-97 accord.

 

Thanks for the info. I will have to spend some time this weekend cleaning that. How about the knocking sound? I had a mechanic listen to a recording and from that, he said that it is probably a blown head gasket leaking gas to another chamber.

 

I listened to your sounds and could not hear anything terrible. Honda's typically make some valve train noise and timing belt noise (a whirring sound). It could be the sound you hear is not on the audio tape, but you should know that. A non-functioning EGR system (totally blocked) can cause high combustion temps and pre-ignition, a sort of rattling under load. I did not hear this in the tape.

I would adjust valve train and if it's due, replace timing belt and tensioner bearings. It they are dry, you will get a rattling and finally some squealing. Stop car if you hear squealing as you may have a timing belt jump some cogs and damage the valve train.

My 94EX has 230K miles and runs pretty smooth. A little cold engine valve rattle that disappears when warm and some timing belt noise when engine is overrunning downhill (soft whirring).

good luck

 

Thanks Texas, The sound is in both videos but very faint in the driving one. The sound is very bad. It knocks so loud that I can feel it in the gas pedal. It could just be nothing, or it could be something very bad. Imagine the sound in the stationary video but through out most of the RPM ranges. Thanks

 

Well the fan problem came back again. Car started to overheat at a red light after a 10 minute run on the freeway and BOTH fans come on when the AC is on. When the car gets a little hot and I turn it off. Only one fan continues to work, the one closes to the radiator reservoir. I have no idea if they are turning on while the car is running but Im going to clean the EGR Ports and replace the PCV Valve. Hopefully I can find the knock while rolling around the engine. I cant find a F22B1 right now but a full engine swap is still on the table.

I was told there is a way to have the Fan on 100% of the time. Does anyone know how I can do this? Thanks

 

You should try to figure out why the car is overheating. Check that the radiator is full of coolant by removing the radiator cap when the engine is cold.

Your hoses should both be hot when the engine is running. If one is significantly cooler than the other, the thermostat is stuck and should be replaced with one from the dealership.

There is a fan switch on top of the thermostat housing (ECT A) that turns on the fans when the coolant reaches 200 F. The two wire colors are green and black going to the connector.

You can unplug that and short the connector with a piece of wire or a paperclip. That should trick the fans into turning on all of the time. That ECT A switch should be open across the terminals when the car is cool and closed when the coolant is hot.

 

Thanks PA, I opened the radiator cap, filled the reservoir and radiator to max, ran the car to operating temp and bled the system. Whats odd was the coolant didn't seem to go anywhere, The top radiator hose was hot but the bottom one was only warm. I squeezed the hose and some air bubbles came out. I will buy a new thermostat and re bleed the system w/ new coolant.

I didn't notice any overheating but then again, I didn't make a run on the freeway and get stuck at a red light.

I will clean the EGR tonight
Also I will have to give it a compression test, but I only understand the process a little.
Unplug fuse to ignition coil
Remove spark plug in cylinder being tested and install the compression tester. Cycle the engine 5-10 times for each cylinder.

I don't have the original manual that came with the car.

Is there a good aftermarket manual for hondas?

Something with torque specs and how-to's

once again, thanks

Torn

 

just finished switching out the old thermostat and gasket for a new one. Havent had a chance to thoroughly test it out.

just a question that I got into a discussion with a friend with. Will a car with 50/50 coolant be any benefit over 100% water?

 

100% water is better heat transfer but has absolutely no corrosion protection. (You really should have the corrosion protection if you want the car to last more than a few months.) Unless you've modified your engine for 400 hp, you don't need the extra cooling.