Engine hard to start when cold or wet

[camry98cool]

I am hoping to find some really good experts or someone had same problem as me here. Thanks in advance. The car is 98 camry. 2.2 L engine, 138k miles.

Usually in the chilly or wet morning, when I turn the key to start engine, it wouldn't start, but if I keep pressing gas for 10-30 seconds, the engine could be started and the card runs well. In last Oct., I replaced the fuel filter, ignition wires, spark plugs in a garage, the symptom disappeared and engine's noise became much lower. But happy time never last long, now the problem comes back again. Two garages gave two different diagnose, one said the ignition coil was bad, one said the idle air control valve worn out (they said 80% possibility for the problem), now I am really confusing and I don't want to replace the good part which waste my money. So, any suggestions and informations would be highly appreciated.

[Kep]

I'm not real happy with either suggestion.

A cold coil "works" better than a warm coil. If a coil is cracked (not unusual) it will perform OK while dry and not perform well (or at all) when wet. It would explain the problem in wet conditions but it would be opposite of what to expect in dry cold conditions.

I can't see how dampness would affect the IAC valve at all and I would suspect other idle problems while you were driving if it were "worn out".

Of the two, I tend to lean towards the coil myself. There are static tests that can be run with a multi-meter if you wanted to do that. However, a cracked coil doesn't appear bad until it is wet enough to short out. Might you have a third mechanic available?

Kep

[Mike Gerber]

Check the engine coolant temperature sensor (Toyota calls it an ECT sensor) when the car is cold. You or your mechanic will need a digital volt ohmeter and the specs from any manual to do this. It will only take a few minutes. The sensor may be out of range and not telling the ECU (computer) the engine is actually cold. It may be telling it it is warm. The ECU needs to richen up the fuel mixture to facilitate starting a cold engine. It gets this information on engine temperature from the engine coolant temperature sensor.

Mike

[camry98cool]

Originally Posted by Kep

I'm not real happy with either suggestion.

A cold coil "works" better than a warm coil. If a coil is cracked (not unusual) it will perform OK while dry and not perform well (or at all) when wet. It would explain the problem in wet conditions but it would be opposite of what to expect in dry cold conditions.

I can't see how dampness would affect the IAC valve at all and I would suspect other idle problems while you were driving if it were "worn out".

Of the two, I tend to lean towards the coil myself. There are static tests that can be run with a multi-meter if you wanted to do that. However, a cracked coil doesn't appear bad until it is wet enough to short out. Might you have a third mechanic available?

Kep

Thank you for reply! Now it's pretty confirmed that the problem comes from wet. Because when in a warm raining afternoon, the symptom showed up. But when in dry cold morning, it is ok.

[Hajoca]

Check your connections on a dry day, cold engine and a water mist. I am wondering if you have any loose (unsealed) connectors to your coil pack right now.

Clean the Throttle body and the IAC with intake cleaner? then that will rule out the IAC being the culprit.

[camry98cool]

Originally Posted by Hajoca

Check your connections on a dry day, cold engine and a water mist. I am wondering if you have any loose (unsealed) connectors to your coil pack right now.

Clean the Throttle body and the IAC with intake cleaner? then that will rule out the IAC being the culprit.

I have ordered new No.2 ignition coil to replace because I can see some wet oil around the No. 2 (front) ignition coil but the No.1 ignition coil is dried well around. Should I hold on the new part before checking connectors?