RPM fluctuates Knocking sound

[aleemy]

Greeting all sifus,

Do you guys ever face any problems when you can't accelerate anymore on the 5th gear when the rpm reaches 3k. Make it worse it produces an awful knocking sound .

My car is currently at nearby workshop and Im just out of ideas about it.

 

[weiye]

knocking sound? or misfire? if knocking means tuning is out? need to double check all vacuum hoses and do a boost leak test. If not leaking, then check spark plugs whether all firing ok? if not then have to check engine compression whether any loss already. If all ok maybe check tuning. Should not have such an issue I think.

 

[vr2turbo]

Do you mean other gears can still accelerate, only in 5th cannot?

 

[4gbanger]

might be the AFS.. thats common issue

 

[stutzedward]

Yup... MAF is the most common... need to get it replaced every 5 years... but ignition too. Is the Engine Light on?

 

[aleemy]

thank you guys, I'll update it with my foreman.

Highly appreciated

 

[Tom]

Do elaborate, your problem starts only at 5th gear onwards?

 

[aleemy]

Do elaborate, your problem starts only at 5th gear onwards?

Its worsen at the 5th gear, more like loss power.

 

[weiye]

So other gears have also? or only at 5th gear? if it is MAF, I think the problem will be random, not only at gear 5 or beyond some rpm. If the problem always comes only at gear 5 or above a certain rpm, I don't think it is MAF. And yeah there should be a check engine light or error code if MAF start to have problem.

 

[aleemy]

So other gears have also? or only at 5th gear? if it is MAF, I think the problem will be random, not only at gear 5 or beyond some rpm. If the problem always comes only at gear 5 or above a certain rpm, I don't think it is MAF. And yeah there should be a check engine light or error code if MAF start to have problem.

Yes problem comes above certain rpm usually after 4k, and no, engine light didn't appear .

 

[weiye]

oh ok. if only after 4k rpm, first thing I will check is spark plugs - see whether gap is same for all spark plugs and whether any spark plug got problem. Not likely to be boost leak or MAF if the problem is always only after 4k rpm.

If spark plugs all nice and same gap, then have to check whether any nuts, bolts or intercooler pipes loose. The knocking sound could be something loose then cause sound also. I had that problem before with the gearbox housing screw.

If all ok then try to check tuning and check engine compression.

 

[pijoy]

I have similar problem like this before. Drive on highway and exceed 3k rpm, start to hear
knocking sound. I realise that my engine oil exceeded max mark on the dipstick. So, I adjust oil
level (suck it out) back below max level marking. And now no knocking sound at all after that. Base on my experience.

 

[pert]

Encounter this before, 5th gear slow drive, when pedal about to reached 3+++ rpm knocking start. my foreman re-set the cams setting and fuel pressure, kawtim.

 

[aleemy]

Encounter this before, 5th gear slow drive, when pedal about to reached 3+++ rpm knocking start. my foreman re-set the cams setting and fuel pressure, kawtim.

So basically whats the problem,maybe we encounter the same problem

 

[pert]

So basically whats the problem,maybe we encounter the same problem

Mine last time caused by cams setting was too advance and fuel pressure low. My formen re-tune back the cams degree and fuel press, kawtim. No more knocking even hit the red line. ;)