Prelude 2.2 VTEC 5SP Manual JDM 1992 100,000 miles

When the engine is warming up it goes fine throughout the whole rev range.

As soon as the engine is fully warmed up and cruising then a slight touch of the accelerator will cause a loud judder to appear about 4 times a second.The problem gets louder going uphill.

If I press the clutch and rev the engine then it won't vibrate.
Once I let the clutch out again and press the accelerator again then the noise will re-appear.

If I change gear from 5-4 and 4-3 it will vibrate in those gears as well so it's RPM independant.

I've turned the ignition on and off whilst driving but it re-appears immediately.

If I slow the car down to 10-20 MPH and then speed up the engine will be ok up to and including the VTEC part. But the problem will re-appear once I start cruising again a few minutes later.

I have changed the spark plugs, air filter and cleaned the EGR valve. I have also added injector cleaner. All vacuum hoses seem ok. I've also disconnected the battery to reset the ECM. Checked there is no misfire at idle etc. Now thinking of battering it with a hammer.

I don't think it's a problem with leads or injectors because it does seem to go to VTEC at all other times.
I'm not sure whether this is related but when I rev the engine and go back to idle the engine has a slight vibration noise for a second or two and then it dissappears. This is not the same noise as the main vibration though.

There are no fault codes present so it's a pain trying to diagnose the problem. It's also hard to diagnose a problem which only appears whilst driving.

If I drive 40-50 miles the vibration will come and go i.e. it's not here for the entire journey

Please help. I'm British, so sorry if my language is slightly different.
I'm taking it to a garage next week but I would like to point them in the right direction to limit damage to my cobweb covered wallet.

Many thanks in advance

Dave

 

Start by pulling a compression test. It sounds ever so slightly like rod knock, but you need to run some tests to make sure, we'll start with compression.

What grade oil are you using?

 

Mobil 1 0W 40 Changed about a month ago. Was 5w-40 before and still did the noise.

If it is rod knock shouldn't it be there at VTEC? It shouldn't really come and go like it does.

I'll do compression test and get back to you.

Thanks

Dave

 

If it's only doing it under heavy load, it sounds like either fuel pinging, or rod knock.

 

"If it's only doing it under heavy load, it sounds like either fuel pinging, or rod knock."

I don't think it's rod knock because it would be worse when VTec comes on.

Sometimes its there sometimes it isn't but over a journey of 30-40 miles it'll do it about 4 times.

I'm was just wondering whether a sensor could produce this symptom e.g. oxygen or knock sensor?

 

No, if either the O2 or knock sensor were doing something wrong, you'd get a CEL.

Try some fuel dry in your gas tank and top off the tank with high-test.

 

I did a compression test.

No 1 (Near Cambelt) - 17 Bar!
No 2 14.5 Bar
No 3 14.8 Bar
No 4 14.5 Bar

Options are

Fluid in the system (oil, petrol,water)
or excessive valve clearance.

I don't think it's water because the exhaust is pretty clean with no white smoke coming from the back. No excess water on my hand etc.

I don't think it's oil because of the exhaust but you never know.

Could it be fuel injector out of spec?

How does excessive valve clearance create higher compression? Does the extra clearance bring more air into the cylinder? Is it only on the inlet valves because I can't see how it would do it on the exhaust manifold. What are the valve clearances?

This could explain the erratic behaviour because the high compression detonates the fuel.

Let me know your thoughts on the subject and whether I'm moving in the right direction

Thanks again and sorry about the 20 questions :-)

Dave

 

This sounds very similar to my problem, but mine isn't as loud as you describe, and more than 4 times per second... I'd be interested in any replies as well!

 

I would suspect a dirty injector over one out of spec.Valve clearances that are too loose will eliminate some overlap, but that would mean more trapped exhaust gasses more than an increase in effective CR.

Clearances differ for different engines, but I believe most Hondas stay happy with about .007" IN, .009" EX.If it's been a while since your last valve adjustment, go ahead and try that first.

Quote:

Thanks again and sorry about the 20 questions

That's what we're here for.

 

Anything new on your situation?

I came across this on another forum:

"Hmmm, sounds similar to what my car did when I had an axle problem.
I had this problem with my h22a in my EG. The passenger-side axle popped out of the transmission and caused MTF to leak. It also caused vibrations at different speeds and when under strong acceleration.

"