engine running issue

[double exposure]

Hi guys! Hope i can get some help here, lateley i have been expriencing engine struggles/roughness after 3000 rpm. It is a 1999 jdm spec R, it boosts fine (1 bar) but is undrivable after the 3000 pm rev range. It feels like its not sparking or something but just a huge loss in power and real jerky and rough with smoke coughing out the exhaust. Below 3000 rpm it is quite fine and drives smoothly with the occasional rough idle. Just wanted to get othere peoples thoughts before investing money to this issue.

Thanks.

 

[Matiu]

Air flow meters (AFM) are infamous for falling over. Best way to check that is plug in a mates afm into your car nd take it for a drive. Most afms off nissans of similair age should work ie r32 r33 r34 skyline, s13 s14 s15 silvia, cefiro laurel etc etc etc.

 

[andeep]

Check properly for a boost leak.

 

[DeanS15]

sounds like it's blowing out spark when boosting.....
if you slowly and gently accelerate off boost, can you drive through the 3k 'barrier' and on to higher revs?

 

[sliding-r]

what they said, sound advice...

 

[S15 SILVIA]

Could this be the coilpack? Wrong temp plugs?

 

[DeanS15]

normally coilpacks break down one at a time....
if a coilpack went it would normally bog the car down, but it wouldn't give these fuel/spark cut symptoms you are getting. i'd clean the plugs and see if it goes away, if not stick a new set in. apart from checking for boost leaks that is the next cheapest thing and very likely cause

 

[double exposure]

Thanks for all replies guys. Yeah will check for boost leaks when I get a chance. Even under gentle acceleration it will do this. The issue is really inconsistent too, there are days where it drives perfectly normally but over the last fortnight i'd say about 75% of the time after hitting over 3000 rpm it hits a brick wall.

 

[sliding-r]

brickwall feel normally is fuel cut from what i have heard.. boost leaks feels like a stutter hesistation which is similar to spark, coil issues.

 

[double exposure]

Yeah sorry it is more a hesitation and huge loss of power, kinda like running on 3 cylinder feeling.

 

[sliding-r]

Mine was stuttering bucking due to a boost leak recently.. All cured now.. I originally suspected fuel related

Do a proper pressure test I would on the pipes while ur at it. Instructions on how to do it is on sxoc.. U can make the block offs outta cans and bottles etc. Then just pressure the system and listen for leaks.

Check plug gaps aswell or just swap the plugs over of there old..

Plug gap should be about .9 mm at that boost. Some one may correct, but I'm at more boost running a smaller gap of .7