Help please! rough idling on 4AGE 20V Silve

[HNthuytx]

Hi!

I'm on process of installing 4AGE 20 Silve top on Corolla AE101 and I encounter rough idling.

At first, after installing the engine run smoothly but I found that No. EX valve clerance is ZERO then I decide to remove the adjusting shim to correct that (means I have to remove timing belt and camshaft), after install back, engine idling became rough.

Then I noticed that if I adjust advance ignition timing to about 20 degree, the idling become better, so I guess something wrong with intake valve timing, maybe too advance.

I tried to return intake valve timing to correct position by holding intake camshaft and turn crankshaft to clockwise dirrection until it can not be turned.

Then matching the timing mark and re-install the timing belt.

After that idling became better but still not smooth as before.

I check all valcum leak and it's normal, activate VVT solenoid the engine run rough or even stall. Compression check all cylinders is same about 12 kg/cm2

Any one has any idea?

Thanks alot.

[1jzdreamer]

Your timing belt may be out one tooth on a gear. That could lead to your issues. I would recheck the timing marks on the cams and on the pulley.
Also make sure you put back all the hoses and electrical connectors, as leaving something unplugged could lead to the same symptom.

[HNthuytx]

Originally Posted by 1jzdreamer

Your timing belt may be out one tooth on a gear. That could lead to your issues. I would recheck the timing marks on the cams and on the pulley.
Also make sure you put back all the hoses and electrical connectors, as leaving something unplugged could lead to the same symptom.

Just get back to 4AGE after long time business trip.

I finanlly found the problem! and guess what? one spark plug was not function well! what's an overlook! Now engine run smoothly.

to 1jzdreamer: my 4AGE ST sounds like diesel when idling at 700 RPM? is that normal?

[Hook]

lol Yeah, they all sound like diesel engines. Noisy hydraulic lifters in combination with very loud injectors.
When I'm not in the mood to hear it, I drive around my N16 Almera instead. lol

I have yet to hear a quiet ST20V. You can quiet it a little, but you have to experiment with what oil and oil filter combination works best, but there are some that this doesn't work with. Those who can't try the oil fix usually change the buckets and shims and that quiets it down considerably, but it's still comparatively noisier by far.
I guess it's just something we have to tolerate.

[topnotch]

are possably ther just made to be a bit noiser than a 4afe lol but thumbs up on having a 20V.

[1jzdreamer]

Yes, both my 20v's when hot would have some louder valvetrain noise. I run 5w40 now and will be running 5w50 this coming year to try to see if it makes a difference.

[HNthuytx]

Thanks a lot you guys!
I never expect such noise from 20V, so I'v been thinking there is something wrong, now I can have a peace of mind!

My 20v running quite smooth, but whenever I park the car, pepole start asking what's problem with your engine? why does it sounds like diesel? that somehow embarrassing!

I'm thinking to adjust valve clearance to lower range of standard (standard of 20v is much higher than 4A-FE) and change the oil to see how it works.

By the way, does anyone know about AC compressor? there is plenty of sensors and pin on connector, but I just use one pin to clutch. And current is not cooling enough.

[Hook]

There's nothing to adjust with the 20V valve clearances. The lobes on the cam simply contact the buckets which push the shims which push the valves. Maybe a new kit will help quiet it down, but IMO it's more trouble than it's worth in terms of cost and labour.

About the a/c issue, ensure the compressor is wired properly, the condensor fan is working properly, that there's the correct level of the correct type of gas in the system and that there are no leaks. If that doesn't work then you may have to examine the expansion valve inside of the evaporator below the dashboard or the condition of the compressor.

[midnightmach]

take out the ISCV and run some carb cleaner through it.