I think I'm starting to understand this. Without the AIR pump running, the TAB and TAD solenoids don't do anything anymore? Can I just run a single vac line to the EVP so the EGR with function properly?

 

Minor correction...run a vacuum line to the EVR (EGR Valve Regulator) then you will have proper EGR operation, assuming the components are in good working order.

For reference:

Fuel Injection Technical Library » EGR Vacuum Regulator (EVR)

Fuel Injection Technical Library » EGR Valve Position sensor (EVP)

 

Perfect. I'm off work in 8.5 hours. Ill try it then. Thank you.

 

Is it necessary to clear the codes in order for it to take affect. Assuming the components are functioning?

 

Will it be an issue to leave the secondary AIR system mostly intact? Or should I cap everything off?

 

If there are codes in Continuous Memory, then yes you need to clear them.

 

If you leave the AIR tubes and hoses intact you open yourself up to an increased chance of falling prey to a leak somewhere down the road. it is not mandatory but be aware of the pitfalls.

 

Ok, Ill let you know how it runs after I route a new vac line.

 

Ran two new lines. One to the EVR from the intake and one from the EVR to the EGR. No change. I'm going to test the electrical side tomorrow.

 

With the Thermactor system inoperative you will never "fool" the computer into making the engine run right. The Thermactor system is the fresh air injection that is comprised of the air pump, the diverter valve (behind the passenger cylinder head), the TAB and TAD solenoids, all of the plumbing from the pump to the check valves, the check valves (one atop the crossover tube between the back of cylinder heads and one at the upper end of the air injection tube into the upstream end of the catalytic converter) and last but not least, the HEGO (O2) sensor which is the single device that will ALWAYS tell the ECM (computer) that the fuel/air ratio is wrong if the Thermactor system is not operating. The ECM will compensate ad infinitum for the missing air injection. There is no way around it. End of story. Can you get the engine to run "pretty well" without it? Yes. Will it have adverse affect on the engine over time? You better believe it will.

Without the air injection, the system "believes" that the fuel-air mixture is "rich" consequently, the computer compensates by "leaning out" the mixture. In some cases it becomes so lean that hard starts are commonplace and get worse in cold weather. Spark plugs foul with greater frequency and cylinder walls super heat at EVERY engine operation. Fuel pressure regulators fail prematurely and if this has been the condition for a long time, the "rich" condition that you are chasing was probably PO induced to correct idle problems when the Thermactor was disabled.

 

Sounds like Ill be hooking my air system up. Luckily my dad is parting out his 95 bronco. Thanks greystreak.

 

I will kindly have to disagree with the doom and gloom picture of removing the Thermactor system. Many on the 1987-1996 F150 and Larger Truck forum have removed it, including myself, with no ill effects.