So I’m having an idle surge problem with my 2003 s2000. So far I’ve replaced the iacv, 02 sensors, map sensor, tps sensor, fuel pump, changed all the gaskets on the fuel injectors, installed the ballade air pump delete, cleaned the throttle body. I aligned the tps to the proper voltage multiple times to even adjusting it differant bolts to see if it would fix the problem also replaced the spark plugs and still can’t get rid of the surge. Any ideas would be greatly appreciated I’m almost out of ideas. Oh and the pressure on the fuel rail is at 42psi with the vac line connected.

 

Possibly the actual fuel injectors?

 

I guess I can check the voltage

 

Did you pull any codes?

 

I drove it for a bit last week and a cel came up for a knock sensor replaced the knock sensor and haven’t had any codes come up so the answer is CEL. Would the car needing a valve adjustment cause the problem or maybe a bad TCT cause the problem?

 

When you say idle surge, is it constantly going up and down between idle and 2k rpms or is the idle dipping too low and stumbling?

 

i attached a video maybe that will help explain

 

my 2000 civic SiR had this issue earlier this summer. It drove me bonkers. Honda IACV's are dead nuts reliable- which I discovered after replacing it. Still no help. Think about a vacuum leak of some sort- I checked timing, cleaned the throttle body, I replaced the intake manifold gasket, vacuum lines, throttle body gasket and those fixed the issue. I did the idle relearn as well.

Listen for a hissing sound. You can try to find a vacuum leak by using propane- idle the car and selectively route propane around the gaskets and lines, etc- If there is a vacuum leak, it will suck in the propane and the idle will suddenly rise.

idle issues suck.

Unlikely to be TCT- you'd hear that. I redid my valve adjustment too. Unlikely to be fuel pump especially if you've got 42 PSI. The idle relearn procedure is also important.

darcy

 

Thanks Darcy I’ll give that a try

 

Low coolant/air pockets in coolant system can also cause the same symptoms