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weak engine

4K views 15 replies 9 participants last post by  ABUSEDDOG 
#1 ·
on my 85 supra its a little hard to start when cold and the idle is low until it warms up. also it lacks power but the engine runs smooth. any advice would help greatly. and i've already replaced the fuel filter.
 
#4 ·
Yeah I believe the CSI is only used for a few seconds to saturate the mixture at start-up to compensate for fuel condensing on the cylinder walls when cold. Although it MAY play a roll in your "hard start", too often it is replaced when nothing was wrong with it in the first place.

What kind of mileage are you getting?
Have you noticed your mileage drop recently?
Pull codes yet?
Ignition timing?

I would check for and Intake or Exhaust restriction / leak. (Filter, Intake ducting, Catalytic Converter, Crushed exhaust pipe).
 
#5 ·
I would check to make sure that the tube for the ISCV is on there and not cracked/broken, and then make sure that the ISCV is working.
 
#6 ·
car should rev to about 2k right at start up if the csi is working properly. and come down slow and smooth till it warms. if it feels like its bogging down then the iscv might be suspect along with a poor flowing csi,(csi doesnt atomize right). need a little more info for a better diag.
 
#9 ·
The CSI has nothing to do with the engine revving higher during start (that is what the ISCV does), it just makes sure that there is enough fuel with it is revving up like that.



what is the ISCV?
There is a "Search" button on the top right of the forum, you will get very far utilizing that tool. But FYI, it is the Idle Start Control Valve (ISCV).
 
#13 ·
could also be a knock sensor retarding the timing have you noticed any spark knock and what kind of gas are you running?

PS
The ISCV is Idle Speed Control Valve it controls the idle whenever the car is running not just when its cold
 
#15 ·
condition of spark plugs? compression #'s? Air filter?
 
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