What is this? And do I need it?

[1-8-4-3-6-5-7-2]

Yes that is definitely required on anything after 1996. It pulls the fuel vapors and reburns it In the combustion chamber.

Do you have a check engine light on?

Probably throwing code for vent solenoid.

No, no check engine light. I asked in another thread about the check engine light but nobody answered, so I'll ask here again... the check engine light never comes on. When I turn the key on I though the light should come on to show it's working then go off once the engine starts, but the light never comes on. I pulled the cluster thinking maybe someone pulled the bulb, but it was there. I swapped it with another bulb to confirm it was a good bulb, and both bulbs are good. I scanned it and the only code I get is an occasional O2 sensor heater circuit code.

 

[Donald Mitchell]

Somebody got tired of seeing it and took the bulb out.

 

[1-8-4-3-6-5-7-2]

Somebody got tired of seeing it and took the bulb out.

But I took out the instrument cluster and the bulb was still there. I swapped it with another bulb from the instrument cluster and both bulbs work, so I know it has a good bulb in it.

I'm guessing the light comes on via an output from the PCM, so my plan is to feind out which pin is the output and trace it back to the cluster.

I've had the truck for about 3 months and I've cleared the O2 heater circuit fault only twice, and I only got that when it was really cold outside. It hasn't had any other codes.

 

[Donald Mitchell]

Sorry that was the first thing I thought of and actually thought I deleted it after re reading. I have almost took one out after it became a nuisance.

 

[454cid]

When I was changing bulbs in my instrument cluster, I had issues with getting them all to work.

 

[letitsnow]

You had posted in another thread that your truck surges, and that you had a gas smell in your oil. Could the evap system not working as designed cause this?

 

[1-8-4-3-6-5-7-2]

Sorry that was the first thing I thought of and actually thought I deleted it after re reading. I have almost took one out after it became a nuisance.

I'm guilty of that! I pulled one out years ago while waiting for a tune to turn off the rear O2 sensors.

 

[1-8-4-3-6-5-7-2]

When I was changing bulbs in my instrument cluster, I had issues with getting them all to work.

I wondered also if the bulb was making contact to the pcb, but I wasn't brilliant enough at the moment to check for continuity where the cluster plugs into the wiring harness. I'll add that to the things to check for list.

 

[1-8-4-3-6-5-7-2]

You had posted in another thread that your truck surges, and that you had a gas smell in your oil. Could the evap system not working as designed cause this?

I'm thinking that had to do with aged ignition components and the previous owner not changing the oil for 2 years. I guess he drove only a few miles a day because the oil change had only about 1500 miles on it even though it was 2 years old.

The tube with the green cap goes to a valve that is mounted into the intake manifold that does have a wiring connector hooked up. I'm not sure otherwise how the system is supposed to work or if that valve opens intermittently or should be open all the time or if its defective and stuck open. Further investigation is needed...

The engine rarely warms up much past 165*, so I need to check for a stuck or missing t-stat also.

 

[454cid]

The engine rarely warms up much past 165*, so I need to check for a stuck or missing t-stat also.

There are some gauges that tend to read low. If you haven't already done it, verify the temp with something besides the dash gauge. If there was no thermostat, the temperature would likely be even lower.