Let me first say that I already asked this question in my "Failed Emissions test" post down below. But it is buried at the bottom of the thread. I'm trying to correct a code 44 problem and have a question for our resident experts. This is with regards to the TAB/TAD solenoids mounted on top of the engine. There are two vacuum ports on the combined air bypass control valve that is directly behind the upper intake manifold. Which solenoid is connected to top vacuum port? With that question answered, I would assume that the other solenoid is connected to the side port. I'm installing temporary vacuum lines in place of the factory-installed ones to see if the tubes are causing the trouble code.

BTW, the truck failed for high HC and CO. Here is the link to my previous thread https://www.ford-trucks.com/forums/9...test-help.html.

Thanks in advance,
Ed

 

Does the under the hood sticker specify which one is which? Either way, if you just do a quick run of the vac lines between the diverter valve and the solenoids, it shouldn't be too difficult to figure out which is which just by the shape and length of the lines.

 

Thanks for pointing that out. I looked at it before but it seemed at the time that it wasn't specifically showing which line goes where. The sticker shows the TAD (front solenoid) hooks up to the side of the valve and the TAB to the top of the valve. But there are two drawings of this valve in my Ford Emissions Diagnosis manual, one has the Air Bypass (port D) on the side and the other shows it on the top. I guess I'll have to figure out which is correct by looking to see where on the valve the air pump hose is connected to.

With regards to the lines, both lines from the solenoids are yellow and are routed to the back of the intake manifold. They are held in place by a tubing separator/holder (along with the other vac lines). With the upper intake in the way, its a bit difficult to see which lines goes where.

Also, I'm smelling a hint of fuel in the engine compartment too. not sure if it's coming from the vapor canister. The truck hasn't been driven since I failed the test, so maybe it just needs to be ran for a while. I guess I'll replace the line from the TB to the canister too.

Sorry for the winded post.

Ed