N/A acceleration intermittant problem

hey, was wondering if anyone could point me in the right direction on where to look on sorting out my n/a jspec '94 supra. When acelerating hard sometimes it hits about 5000 rpm then the cam kicks in and accelerates hard, other times it doesn't and seems flat or hesitates then kicks in

i've only just bought this car , had a mk3 n/a auto previously ( which blew the head gasket ) so i'm a newbie to this engine....

Thanks

'94 wouldn't be VVTI would it?

Surely not.

its the e-jza80 model if thats any help

It's just I thought the VVTI came in around 97-98. The NA does give most of its "power" around the 5000rpm range, but it's not a change in cams kicking in, in the non VVTi engine.

When was the last service, air filter change etc etc?

Possibly the valve that controls the two-sage intake manifold isn't working properly. If you look down between intake runners 3 and 4 you should see a vacuum actuator operating a lever. Maybe the vacuum hose is leaking.

full service just under 3k ago , cam belt was changed about 18k ago. Does feel like cams tho , its a definate "kick" when it hits 5k when its running properly

Possibly the valve that controls the two-sage intake manifold isn't working properly. If you look down between intake runners 3 and 4 you should see a vacuum actuator operating a lever. Maybe the vacuum hose is leaking.

Yep good call, normally operates between 4500-5000 and gives the extra kick, could be a bit sticky give it all a good clean and check the vac pipe to it

thanks for the info guys , shall give it a look when this weather improves a little

Did you have new leads . plugs, in the service

Usually the Rotor Arm and dizzy cap gets over looked too in most cars, maybe worth taking the cap of and having a look what condition its in,

The NA as you say kicks in around 5 -5500rpm,

However with my new intake pipe the car has totally changed, and it pulls hard from 3500 in mine, Appears the NA responds very well to induction changes, but if you look inside the standard pipe that maybe why, you tend to find this on many Jap cars, the intake and exhausts are very restrictive(especially so in the Skyline) but hey they are restricted to 180kmh (112mph) out there so they don't need to be great i suppose hence the huge tuning market.

I had a similar problem with my old NA it was the vac pipe to the butterfly valve that opens at 4500rpm.

There is a pic on here somewhere that shows the valve its in the y section of the intake manifold.

It is supposed to close at low revs to give you more torque and open at higher revs,my vac pipe had fallen off.

Did you have new leads . plugs, in the service

 

Usually the Rotor Arm and dizzy cap gets over looked too in most cars, maybe worth taking the cap of and having a look what condition its in,

..but hey they are restricted to 180kmh (112mph) out there .

checked + in good order . heh i made sure it wasn't restricted driving it back the day i bought it

There is a pic on here somewhere that shows the valve its in the y section of the intake manifold

i've searched but cannot find the pic , altho i found the valve and i can't see anything wrong with it so far, no tubes missing etc , maybe have to take it off and look closely....

Always keep your pipe clean for good performance.

That's what my nan used to tell me, and she was one of SE Londons most experienced prostitutes.

Always keep your pipe clean for good performance.

 

That's what my nan used to tell me, and she was one of SE Londons most experienced prostitutes.

LOL!