2006 Honda Fit loses power after starting, but runs normally when warmed up

Question

I have a question similar to this one: "What would cause a car to lose power a few seconds after starting, then run normally?". The answers from that question didn't help me for my car and I am having the exact same problems.

I have a 2006 Honda Fit GD3 which loses power after starting, then runs normally when the engine temperature is right.

• The "check engine light" is off
• The battery is brand new, and the alternator is still good
• I've checked the spark plugs and they are still sparking
• The ignition coils appears to be OK (doesn't have any cracks)
• I also inspected the throttle body and IACV, and they appear to be OK
• I double checked the O2 sensor, with computer (launchpro x431), it said nothing is wrong with the electricals.

This is the first problem I had after 10 years with this car. Does anybody know what could cause this problem on this model?

Answer 1

Sounds like the cold start portion of the ignition/fuel system is not functioning correctly. The IACV controls air flow at cold start to give enough air because the engine is not warm enough for optimal combustion, so, you need more fuel and consequently more air to get enough fire to warm up the cold engine components. That is why it will idle higher on cold starts, somewhere around 1800-2200 RPM. When things are warmed up enough according to the ECU, it will idle back down. The IACV may not throw a code, but, the results of it will, like misfires and whatnot.

Next time, on startup, hold the throttle open just a hair, like rest your foot on the gas pedal with a slight weight. If it runs better, it might be the IACV itself or the wiring to/from it. The colder the air is outside, you may need more air/throttle. Another troubleshooting bit, is to open up everything to get to a point where you can see the IACV, then, have someone turn on and off the ignition from ACC to ON and watch the IACV to see if it moves in and out by a little bit. DO NOT GO BY FEEL as you can DAMAGE the component if it is not already damaged. You may however be able to feel the little motor from the outside of it move.

p.s. The throttle isn't controlling how much fuel you get, it controls the air going in to the engine. The ECU uses mass air flow, pressure, and temperature to determine the right amount of fuel to use. If equipped, it will also use a spark knock detector of some sort to adjust ignition timing.