Boosting and Vibration

[Fastfast]

Hi guys, following my issue on hoses which I have fixed, now boost works. However I'm experiencing vibrations whilst boosting or revving at higher rpms. It happens on lower gears when speed is low. Whilst boosting at say 20kph or second/first gear, te engine bay vibrates sometimes seems like whole front end. Whilst boosting at say 60 onwards not so prominent or none at all.

Was wondering whether its too much boost for low speed or mounting cannot cope? It any other issues...

Thanks

[Kelv27]

Really depends on what you mean by vibration. Do you mean that the engine is hesitating/jerking/misfiring when on boost? If so, could be a few things. I would start with the MAF, followed by the coilpacks.

[Fastfast]

Yes, its like hesitating rather jerking or misfiring. Its like the transfer of power is not full to the wheels. When i can, i show you.... maybe during a year end Ulu Yam run? Time to do one maybe?

[Kelv27]

You want to run at ulu yam like that?? Kaboooom

You're so nearby, just call me anytime la.

[Fastfast]

Won't kaboom one. Hold back throttle during start of run and get cursed from ppl at the back only.... hahahah....

[raitag]

could be clutch?

[Fastfast]

I guess it's possible but would it happen to only first 2 gears? But it only happens when I push. Normal driving like say revving up to 3.5 rpm before changing don't see this occurring or at least less le depending on the foot.

[bravosx]

could be clutch?

Could be drive shaft too.

[Fastfast]

Wah that one expensive aint it?

[desin]

if rpm hit 6800rpm, it will auto-cut... and car will be jerky during that period.

[Fastfast]

Don't really go to that level so would not know whether cut off or not...

[ognam]

I guess it's possible but would it happen to only first 2 gears? But it only happens when I push. Normal driving like say revving up to 3.5 rpm before changing don't see this occurring or at least less le depending on the foot.

Clutch usually slips (if its slipping) in those gears. Does your rpm shoot up but your car is going nowhere?

Eh. Go visit your neighbor la senang cerita. Haha.

[Fastfast]

hahaha... ok la i think its about time i actually visit my neighbour le... can't seem to define it properly here. I'll contact him.

[Pangmy3]

or maybe ur drive shaft inter head kong,,,better go to shop n check..bro

[Fastfast]

Ok ok thanks... Will get EMech to look at it when possible. Thanks for all the feedback.

[Fastfast]

Following up from this, I think may have found partial answer to this. The turbo hose which I replace is loose or at least dunno why I keep needing to tighten it every once a while. When I tighten, the vibration is less and the pick up smoother. Only when it's loose it gets noticeable. EMech tested clutch and said no problem. However not sure if it could also be caused by manifold which could have cracked. Will check next round.

Is there anyway to make the boost hose tighter and not get loose once a while? Think when boost too much it gets loose. Or maybe the clip I use is not thick enough to withstand the pressure.

Merry Christmas!!

[ognam]

If your hose keeps loosening up, then perhaps it's not up to the job.

Go to your local parts shop and get a new one. Ask for the most expensive and thickest one they have. They're usually around RM6-RM12.

Or go to a kakimotor outlet and grab some t-bolt clamps.

And since you will be in that area of the engine, also check condition of the big ass hose after the throttle body. Those are prone to cracking and I've known some people who never check and live with a boost leak. That particular piece is readily available in silicone. Not a Fiat Coupe specific part unlike the S-shaped hose.

All the best!

[Kelv27]

Which hose is this that keeps getting loose btw? Yeah as Ognam mentioned, a new hose clip would sort it out.

As for the hose that meets the throttle body, there's actually a slight bend to it so that the big plastic intake pipe doesn't get too close to the cam cover.

[Fastfast]

Kelv, its the same hose which i was looking for. The S-curve boost hose.

Ognam, yes its probably the job and material. Job i.e. me doing a lousy job :p material i.e. the clip i used was not thick enough to hold it in place. Now replaced better, but still got little vibration in gear 1 and 2, something which was already there prior... which i think could be attributable to maybe a cracked exhaust nearest to the engine. Cracked once but welded it ;D

[Fastfast]

Oh and where is the hose near the throttle body. Don't even know where is the throttle body. hahaha...

[Kelv27]

See label 'Throttle Position Sensor'. That sensor is attached to the Throttle Body a.k.a butterfly valve.

[Fastfast]

Oh wow. Thanks! so according to ognam, the hose he mentioned is the straight one before the s curve turbo hose? Will see how I can check that out. Thanks

[ognam]

Oh wow. Thanks! so according to ognam, the hose he mentioned is the straight one before the s curve turbo hose? Will see how I can check that out. Thanks

Yeah the big kahuna. The fiat part is ever so slightly curved as Kelv mentioned, but I see a few cars using a generic straight hose with no issues. In fact, I was using a straight silicone hose before I got my Samco kit.

[Fastfast]

Ah ok ok... Will picit picit and see if got cracks. Thanks

[Fastfast]

Yo guys, dunno whether this is normal.... So I've re tighten the hose clip. Think it's a stronger hold. At te start its ok. After couple of days the vibration starts again... Sienzzz... Then the strange thing is, it's less when there's 2 person in the car ie passenger front and driver. Strange strange. I already dumbfounded already or just dumb le.... Asked EMech not clutch, hose change, clip wider. Dunno what else since its an on and off thing.

[bravosx]

Rims got bengkok? Drivevshaft ok?

[Fastfast]

Dunno whether drive shaft ok a not. EMech quite busy now so no time entertain me. But if drive shaft koyak it should be permanent vibration no? Not just some gears... Could it be tayar botak has effect?

[bravosx]

If tyre surface uneven then maybe yes. If tyre surface uneven you could be looking at rim bengkok too I guess.

[Kelv27]

Could be simple things like wheels out of balance..

[Fastfast]

ok. let me go change the front tyres and see whether its the same. Anyway, will be going to SS14 shop to change. Can't remember the name but few doors down to Fawaz... anyway just want to ask, when they do alignment do you let them adjust or insert a camber. They always ask me one....

[bravosx]

Camber nuts are shite.....it doesn't do jack shit. Better to get someone who knows our cars well to do alignment, balancing or even camber adjusting like CD in OKR or the other guy a few blocks away. Being NY Eve, I reckon everyone is rushing to get things done.

[Fastfast]

Hi guys happy new year!!

Got it all done... Fingers crossed no more issue with this. Was due to the joint of the drive shaft to the body (not sure what that is called). The cover tore and probably some sand went in. But mainly the vibration was due to the drive shaft being loose to the joint. And some rubber bearing old already and brittle giving space for rattling and vibration. Now can feel the power from the pedal.

Anyway thanks for all the advice.. Next... Boost meter installation. Haha still not done yet.

[Pangmy3]

drive shaft joint to the body???to gear box or to wheel???

[Fastfast]

To the wheel.

[Kelv27]

It's called the outer Constant Velocity Joint (CV Joint).

[Fastfast]

Haha thanks kelv!