4G63 engine noise in eclipse 94', help needed

Hello sorry for my english at start I've got Mitsubishi Eclipse GS from 1994, it has 150tys km done and the engine sound is strange. It's ticking when cold on low revs but that's not a problem. The problem is that is sounds bad over 4800 revs , and it accelerates good from 2500 to 5000 revs and not so good over 5000. I know that maximum torque is in 5500 revs and maximum power on about

6600revs. I don't know why it sunds like french 1,4 litre 8 valve engine revd over 6000. And why it goes poor over 5000? Mayby you can help??
Reply to
kubamtx
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It sounds like a stuck lifter or a bad valve. You can remove the valve cover and watch/listen to see. I had a similar issue with the 2G. It was actually a rocker arm that fell off after an over-rev.

Reply to
Nobody U. Know

So today I'll remove valve cover and check everything. Mayby it's good idea to check the compression??

Reply to
kubamtx

Compression wont be down if you have a stuck valve, rocker arm off, or a collaped lifter. It wasn't in my case and two others with the same problem.

The valve cover has around a dozen 10 mm bolts with 7 ft-pounds of torque on them. It takes about 5 minutes to remove. In my case the rocker arm was quite obvious and took about 5 seconds to put back into place. 15 minutes of work to get power and gas mileage back was well worth it in my opinion.

Reply to
Nobody U. Know

I've checked rocker arms and everything is ok with them. I've also chenged spark plugs and now power and culture is better on revs lower than 5500. Over 5500 acceleration is poor and engine is loud. Mayby something with fuel/air?? I've cheched error codes using LED and 2 wires and there is no error. Mayby something is wrong with settings ??

Reply to
kubamtx

Well it appears you are OK in the valve area. I doubt it is a fuel mix problem on a non-turbo. It maybe, but that would be a first in my experience. The next thing I would recommend is to check timing related issues. The 1G timing can be set with a light. It should be 5 degrees BTC when the timing connector is grounded (brown connector behing battery). There are two possibilities here: you are off time or the timing belt has jumped a tooth (and you are really freaking off time). If your belt is old or you went cheap on the last timing belt change (didn't replace tensioner), you really could have slipped a tooth.

I would check the timing first. It is somewhat easier. All you need is an alligator clip to ground the brown/tan connector behind the battery. Do this with a hot engine. If you ground the right connector (there is a pump tester back there too...I think) the check engine light should come on. Then connect a timing gun up to number one (drivers side plug wire). Fire it down on the drivers side and look for 5 degrees. If you read 15, you may not have grounded the wrong connect, but you are probably OK regardless. This whole proceedure is on

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If timing is off you will need to loosen the cam angle sensor on the passenger side of the head (12mm nut) and rotate it to adjust. The sensor is a round bell that is probably green (copper). If it WAY off, you need to check the belt. This part requires more work as you will have to remove the timing belt cover (upper and lower) and all the accessory belts. Then you will need to line up both cam marks and the crank mark to make sure you are properly timed. If not, you will have to get dirty and do a timing belt. If not, you are driving a grenade.

Reply to
Nobody U. Know

Tomorrow I'll check ignition timming . If it will be ok then I'll check belt and marks . It's strange. It goes good to 5500 and poor and loudly over 5500. Tell me if you can what I have to check tomorrow if ignition and belt will be allright?

Reply to
kubamtx

Reply to
Simpleton

That 5500 RPM limit is exactly why I said valve in the first place. It did the same thing on mine (rocker arm off) and two others (seized valves). Timing is the next logical guess...although I've seen one car with a broken air filter that did a similar thing when the filter would get sucked into the maf.

Reply to
Nobody U. Know

Is it possible that my engine works with one shaft rotated 180 degres?? The marks are aligned with a straightedge but both of them are set toward driver.

Reply to
kubamtx

Ohh sorry I;ve checked wrong marks, now is ok. I have to check if the 1 piston is in tdc when marks are aligned. Then I'll check timing and air filter. And valves.

Reply to
kubamtx

I've checked belt,ignition timing and air filter , everything is ok. Mayby I've made a mistake when checkin rocker arms. How does it look when rocker arm is off? Is it simple to see that rocker arm is off or it's not so evident ? If timing , rocker arms and air fllter are ok so what's next in my checking procedure?

Reply to
kubamtx

I forgot about another thing , there is a loud hum that seems to peak at 3K RPM when I'm slowing down it's really loud. Mayby balance shaft is guilty??

Reply to
kubamtx

I don't know about that noise, but I'd pull the ECU and look for capacitor damage next...then move to a clog cat-con.

Reply to
Nobody U. Know

I've changed T-belt and B-belt checking all marks and now my car works great. Thanks for help

Reply to
kubamtx

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