HELP! Legnum being strange!

[Guest]

Hey guys,

I have a 98 Legnum VR4 and have had since February this year. i have had no issues until now. Was driving yesterday and noticed the revs jumping slightly. Not sure why. But as i was going a up a windy bit of road up a hill i noticed the revs would falter andf then like a popping/clunking noise but only about the third falter.

A few things:
It doesnt happen off boost or if im not pushing the car, for example can rev to 4500 and change without issues as long as im not full throttle

It happens mainly when im in lower revs and loading the car up trying to make it come on boost.

No lights on the dash

No leaks on the driveway.

My initial thoughts were the turbo as it mainly happened on boost but have been told that the fuel might be shit thats in it. I use 98 fuel from Woolworths Petrol, which i believe is caltex vortex? Could be wrong. I would like to know whatyou guys think it is? It doesnt affect the idel or anything either. Its really not a big issue i guess. Any help would be appreciated.

Thanks!

 

[VR-4-PLAY]

boost leak?

 

[Hotwire]

Is your car auto? Is it just the Revs flaring, or actual popping sound out the exhaust? if it;s just before a gear change of the auto, i.e. get a flaring then change gear, could be your trans fluid is old and in need of changing.

 

[Guest]

No its a manual and the gearbox feels fine. I thought about a boost leak but wouldnt think it would do that, just make the car slow.

 

[Skurfer]

Maybe need a change of plugs. Sounds like they are getting old and are getting blown out at full revs. Might be worth a shot maybe

 

[Guest]

Maybe need a change of plugs. Sounds like they are getting old and are getting blown out at full revs. Might be worth a shot maybe

Yeh it isnt at high revs though, its mid as its spooling?

 

[SiliconAngel]

Maybe need a change of plugs.

John have you got new plugs, then?? Or still running what came with the car?

 

[pu-11-me]

Sounds like over or under fuelling to me.... Yet last time i thought it sounded like that it was a boost leak

Disconnect your battery to do an ECU reset then have another go, it should then remap your air-fuel ratios

Another good point of diagnosis is to get an ECU scan, may bring back something

Good luck, hope its fixed soon

 

[trounced]

turbo leak will cause mix to be wrong as it is expecting more oxygen and adds fuel but the air is leaking and not entering engine. make sure everything is tight and no leaks sounds like it to me

 

[Guest]

Fouled plugs or cracked leads would be my first guess but it may be ecu or coil packs. Coil packs can develop a misfire at a specific rev range under certain tempreture, boost or throttle setting.

 

[Guest]

I had the jerking problem at high revs and I changed leads but also eveen though I had installed new irridium plugs and then had them re gapped and the jerking faded it was still around in 3rd and 4th gears.
I cracked the shits and did what I did in my 1991 vr4.
I went and bought bosch super 4 plugs with a colder rating. BX56 or PX56 cant remember.
Anyway car goes like a rocket now. I always found my tripple tip ngk plugs to work better then platinum and irridium. The high reving turbo motors seem to be more liking to the 3 and 4 tip plugs. I recomend it especially as they cost 4 times less and I dont care if I change them even every 10,000kms as long as I get a really strong 10kms out of the plugs and I thought that the new vr4's would like the irridiums or platinums better but here again I keep on hearing heaps of ignition problems so I think you guys should look at the 4 electrode plugs more seriously and they are more cost effective as far as I am concerned.

 

[Hotwire]

^Problem with that is, if you aren't handy with a spanner or are concerned about removing the intake manifold yourself, do you really want to be paying someone 2-3 hours labour (around $200 @ most workshops) to change your plugs evey 9-12 months?

I dont mind changing mine myself, but there are a few members on here not so mechanically minded, or just innexperienced and don't have the confidence.

 

[Guest]

Took the car for a drive yesterday with a mate who believes that it may be the clutch! The falter in the revs is the clutch slipping and the clunking is the clutch also. What are your thoughts? It only happens when i load the car up on a hill or make it spool down low and make it work. It makes senese to me but still would appreciate your input. and i guess the next question is... how much is a new clutch!?

 

[pu-11-me]

Sounds plausible.... A mate of mine is going through the same thing at the moment with his S13 and has almost the same symptoms

His comes on boost and feels like a Hyundai being powered by a air compressor. Very sad for a SR20 with 12PSI boost lol

 

[Guest]

Well i cant find a replacement clutch anywhere as i dont want to spend the quoted $850 for the exedy model. Has anyone got a standard clutch for sale? does anyone know where i can get one? I tried to get the DIY clutch replacement off clubvr4 but i cant get it. I need big help guys as i have to borrow money to fix the car and still have to sell it to get a house. Any input? are the standard clutches even available?? Repco is unhelpful and super cheap not much better lol. Does the 3rd gen stock magna clutch bolt straight up??

 

[Hotwire]

To confirm its the clutch, try a sprited take off.
If the clutch is stuffed, you'll get slip on takeoff, not just under load like you've described.

 

[Guest]

So rev it to how much do you think?

 

[Hotwire]

No idea, I dont have a manual... best ask someone like Bradc, Gly, or Leebuts, as they should know from personal experience

 

[bradc]

It shouldn't be clunking unless there is something seriously wrong with the clutch, ie it is falling apart!

Clutches normally first start to slip if you try and do quick launches or quick gear changes with them. The clutch in my ST-R has done 127,000km and when I change from 1st to 2nd quickly the revs don't drop straight down, if I change at 7000rpm it shoud drop down to 4000rpm quickly, but it doesn't. By the time I have changed the revs are at say 6000rpm when I lift off the clutch and floor it, the revs slowly drop down to 5000rpm or so over about 1 second, and by that stage the road speed has increased to the engine revs should actually be 5000rpm and the car starts to accelerate again.

 

[LEG_IT]

A test for your clutch is.
1. Put your car in 3rd gear with your engine running. (Flat Surface)
2. Handbrake on.
3. Ease the clutch out slowly with no accelerator and handbrake still on.

If the car stalls where the clutch usually disengages fully you have a perfectly good clutch, if it rides for a while or short period of time. Your clutch is about to give way.

Do not do this all the time as it is stressful on your gearbox and clutch systems.

Bottom of the line your car should stall and there should minimal delay in stalling.