Gtt Problems

[SKY 34]

hi guys,

about a week ago my car start jerking between 2-3k rpm. My sister first spotted the problem, but when I drive it, nothing happens. a week later I start feeling the jerk and this time it is more consistent. The idle has become rough as well...soft idling and suddenly few poping sound like missfiring with large enough force to be felt by the driver.

My initial reaction is it's an afm problem. Whip out contact cleaner clean the afm (mesh intact, perfect condition). The jerking got better, but still there...a day later the jerking got relatively bad again.....

Also when on boost usually at 0.4-0.5bar there's be a jerk and continues going up until 0.7-0.8 bar. The boost controler I used is profac B spec II. I had a power Fc once fitted tuned to run 0.9bar. However since then the pfc is removed and the profac hasn't been set, it's been boost creeping randomly from 0.6 - 0.8 bar...

Also I need to mention that there is a loss in coolant level since I last check about 3 months ago. The level is 3/4 that of the maximum level.

so my next diagnostic is a leak in the head gasket. I don't know much about symptoms for leak gasket. All I know coolant level will drop and white smoke will puff out. So far no white smokes, just the drop in coolant level, however I think that can also be attributed to evaporation?

anyone have this problem please share

cheers

[Race_Bred]

hi guys,

about a week ago my car start jerking between 2-3k rpm. My sister first spotted the problem, but when I drive it, nothing happens. a week later I start feeling the jerk and this time it is more consistent. The idle has become rough as well...soft idling and suddenly few poping sound like missfiring with large enough force to be felt by the driver.

My initial reaction is it's an afm problem. Whip out contact cleaner clean the afm (mesh intact, perfect condition). The jerking got better, but still there...a day later the jerking got relatively bad again.....

Also when on boost usually at 0.4-0.5bar there's be a jerk and continues going up until 0.7-0.8 bar. The boost controler I used is profac B spec II. I had a power Fc once fitted tuned to run 0.9bar. However since then the pfc is removed and the profac hasn't been set, it's been boost creeping randomly from 0.6 - 0.8 bar...

Also I need to mention that there is a loss in coolant level since I last check about 3 months ago. The level is 3/4 that of the maximum level.

so my next diagnostic is a leak in the head gasket. I don't know much about symptoms for leak gasket. All I know coolant level will drop and white smoke will puff out. So far no white smokes, just the drop in coolant level, however I think that can also be attributed to evaporation?

I'd be changing the afm

If you had a blown head gasket it would run real rough when starting it in the morning until the water pumps out of the cylinders

[-_-StRyDeR-_-]

if its a gone head gasket, take the radiator cap off while its running and see if your getting alot of bubbles come through. other then that try a general service first, fuel filter, plugs etc. (better to do all the small things to try and fix the problem cheaply/quickly before looking at head gasket, hope its not the gasket tho! )

CJ

Edited March 9, 2007 by -_-StRyDeR-_-

[AARR34]

highly doubt its the head gasket....another way of makin sure is checkin ur oil, if its changed colour to a white/beige creamy liquid then yes, ur head gasket is gone but i doubt ull be havin head gasket probs on a Neo unless uve just thrashed the tits of it or never took care of it which im sure its not the case for u

think maybe it is ur profac as u did mention it hasnt been tuned after removing pfc. As already advised, get some new iridium plugs, oil & filter change, then take it to a dyno and get the profac tuned accordingly.

on a dyno they should be able to tell exactly what causes this...misfires n such are usually caused due to a bad tune. Also check all ur turbo piping (intake, intercooler etc) and also make sure theres no leakage from radiator pipes. When I had the same problem with another car it turned out to be a loose intercooler pipe that was letting air out....so check everything to do with air flowing through ur car

[666DAN]

coil packs.....and any drop in coolant level should be investigated. My coolant level doesn't move at all, even in the QLD summer so you can discount evaporation. I saw an R34 the other day that was dumping coolant on my driveway, the head-gasket was gone for sure even when the car wasn't displaying the traditional white smoke etc etc there should be no reason to have those sorts of pressures in the coolant system.

[SKY 34]

highly doubt its the head gasket....another way of makin sure is checkin ur oil, if its changed colour to a white/beige creamy liquid then yes, ur head gasket is gone but i doubt ull be havin head gasket probs on a Neo unless uve just thrashed the tits of it or never took care of it which im sure its not the case for u

I mantained the car well service every 5k, but previous owned has not been that good, there was scales collected in radiator and I had to replace whole radiator. Mechanics said may be an indication of corroded head gasket....

however run the test you guys mentioned, oil's looking normal and no bubbles coming out of radiator...although I find the radiator test a bit stupid, the moment the engine is on longer than a few minutes, the coolant start spewing out....but for the few seconds it was on, no bubbles

I've got a major service in a weeks time, I'll probably find out then....given me a bit of hope here~~

cheers

[-_-StRyDeR-_-]

i dont think you should have coolant spewing out...:S not unless u have driving the car till its hot then opend the radiator cap haha. if you just turn the car on then open the cap there shouldnt be alot of pressure to be spewing the coolant out... :S

CJ