89 240 surging problem
89 240 surging problem
Over the last year or so I have been upgrading my 240. I recently installed an Injen cold air intake and an OBX stainless header on my 89 240sx. The problem I am experiencing is that in 5th gear between 2800 - 3500 rpm while holding a steady speed the engine seems to intermittently loose power slightly like it is leaning out. I have noticed that it seems to do this when I am driving in high cross wind conditions (enough to move the car around a bit) it's almost as if the wind is changing the air pressure inside the engine compartment or something. Also on startup, when stone cold it sometimes is very hard to start and seems very rich until I rev the engine. The car was running perfectly before I upgraded the intake & exhaust. When I installed the header I was not impressed with the location of the O2 sensor as it hits the fire wall and I wonder if this has something to do with the problem. I'm going to have to remove the header and make a dent in the fire wall to give the O2 sensor some room. I am also going to build an aluminum air dam to separate the filter from the engine compartment and fit a cold air duct into the new filter compartment (maybe this will help). I am very happy with the power increase I got with the intake and header but the surging is frustrating. Anyone have any ideas what is causing this?
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matt240det
- Posts: 126
- Joined: Fri Aug 30, 2002 4:35 pm
Re: 89 240 surging problem (240GT-R)
sounds like possibly a bad O2 SENSOR, IF NOT CHECK POSSIBLY THE COOLANT TEMP SENSOR FOR THE COLD START PROBLEM
Re: (fatboy)
What do you mean CHECK the EGR?
When I installed the header I had to modify the inlet at the header because it didn't match what was on the original manifold as the EGR outlet pipe was welded on and the header had a threaded nipple. I welded a pipe to the header that would allow the cut off EGR outlet pipe to tightly slide over it and then I hose clamped it in place. It is passable that there is a slight air leak there.Would that be a problem?
When I installed the header I had to modify the inlet at the header because it didn't match what was on the original manifold as the EGR outlet pipe was welded on and the header had a threaded nipple. I welded a pipe to the header that would allow the cut off EGR outlet pipe to tightly slide over it and then I hose clamped it in place. It is passable that there is a slight air leak there.Would that be a problem?