'02 Hard Starting/Running Rich

[badgerbacker]

Hello gang, I have a '02 4Runner with a 3.4L, 2 wheel drive and auto tranny. It has 160,000 miles and has been a great truck.
This morning, it wouldn't start. Turned over well, but wouldn't fire. I held the accelerator down and finally was able to start it but it ran very rich and smoky. The tailpipe was dripping bit of water also, but no coolant smell. The truck is not throwing any OBD codes, I have not gotten around to testing the voltage across the O2 sensor(s).


After letting the engine run for a few minutes, it restarted up easily but still ran rich.
After letting it sit with the engine off for about 10 minutes, it restarted easily and seems to being running correct.

Besides the O2 check, any other ideas? Cold start injector possibly?

 

[that$pit]

Mag ?

 

[badgerbacker]

I guess pulling and cleaning the MAF wires would be a good start, it hasn't been done in about 90k.
I looked for my voltage meter, I think my little brother has it so I cannot test the O2 sensor.

 

[Stick Figure]

o2 sensor isn't online and effecting anything on a cold start. Research closed loop vs open loop.

My first guess would be a maf problem by your description. This could be electrical, or could be a mechanical issue like a torn or loose intake hoses. Next thing I would look at would be the temp sensor. Your air fuel ratio and timing curves are manipulated by the coolant and intake air temp sensors. Your IAT is combined with the MAF, the coolant temp will be its own entity. You should be able to either check it with a volt meter, or with a scan tool.

 

[badgerbacker]

I couldn't find any torn intake hoses, would dirty MAF sensor wires create an intermittent problem? I just started it with no problems after it sat for a few hours. ODB scanner does not show any codes.