TAB and TAD Solenoid Delete but Keep EGR

[AeroCoupe]

I know this has been asked before and I was literally just looking at one of those threads. Walked out and looked at my car and I think mine is done right but it would not surprise me if I did it wrong as I did the conversion 24 years ago this week and lets just say I didn't know what I know now. I just want to make sure I did this right so I can put it to bed in my head.

I left the TAB and TAD solenoids intact and wired up but removed the vacuum lines. The TAB and TAD vacuum supply lines were removed at the source and capped off. Left the EGR solenoid intact and wired up but moved the source vacuum to a manifold vacuum source. The EGR valve is still installed as I did not want to deal with the CEL.

From what I read today I could clean this up a little more and just remove the TAB and TAD solenoids and tape up the connectors. Does it sound like I have the rest of it correct?

 

[Noobz347]

It sounds like it.

EGR opens at idle
You should have codes for TAB and TAD and that's it.

I need to do what you're doing and clean up that whole side of my engine bay.

I still have [everything].

 

[Mcmahst]

But Question: What changes in strategy occur in the ECU when it detects both of the air valves have failed?

 

[General karthief]

Yeah, what he asked and will that trip the CEL?

 

[Mustang5L5]

TAD/TAB delete doesn’t trip the CEL. It’s a soft code but nothing changes.

You get a code 81/82 if I recall.

When I deleted mine, I made resistor plugs. Just measure the resistance of the solenoid and wire in a resistor that matches that. I got some junkyard TAD/TAB off some other ford and hacked them up to make resistor plugs.

When I get back to work next year I’ll dig through the GUFB strategy and see what the ladder logic is for these solenoids. That doc is huge though so let see how quick I lost interest

 

[Mcmahst]

I remember, but my memory is not the best, that there is some calibration that occurs with the O2 sensors after start up that uses one of those solenoids to set. So, on my 73 with the 87 drive train, I kept them. Only one does anything, with the other just venting the air pump out of the engine compartment. I’ll be interested in the finding on the strategy outcome.

 

[Mustang5L5]

Upon startup, the TAD switched states so the air pump flows air into the heads with the specific purpose of feeding the upstream cats. The oxygen helps the catalyst react quicker while the cat is still cold. The o2 sensors are actually not reading anything until the vehicle warms up.

Once the vehicle warms, the TAD switches state again to flow air to the main cats. It will remain this way until the car cools down. The upstream cats are not toasty enough that they do not need supplimental oxygen so it’s diverted to the main cats.

The TAB is the bypass when you go WOT. It just dumps the air from the pump to atmosphere for the sale of freeing up a HP or two.

Once you go a two cat setup, you don’t really need the TAD diverting flow to the heads. The air pump can be directly routed to the main cats only; with a bypass TAB in place.

With no cats you don’t need any.

Now, while o2 function is used to verify they are working, they have no impact on the ECU itself in terms of air and fuel trims and such. But like I said when I get a chance I’ll dig into the ladder logic and see what it says.

 

[AeroCoupe]

So if you do not have cats i.e. a race only vehicle as not having cats on a street car is illegal (nothing to see here EPA) then you can punt the TAB, TAD, and all associated vacuum lines and only set soft codes (no CEL). A person can keep the EGR solenoid wired up and the vacuum output connected to the EGR valve while rerouting input side of the solenoid to a manifold source of vacuum. Do I have this correct?

If you want to keep from getting the soft codes then resistors as Mustang5L5 mentioned would be necessary. Overall it sounds like the removal of the TAB and TAD solenoids will not affect performance.

 

[Mustang5L5]

Yes


I only did the resistors to avoid getting tv r codes when I pull them. I like seeing all 11s

 

[Noobz347]

So if you do not have cats i.e. a race only vehicle as not having cats on a street car is illegal

I have 3-way cats. No additional plumbing required.

Are they good in Cali? Nope... Are they good the majority of other states? Yup.

Like you, I want to keep my EGR active and the charcoal cannister doing cannister things.

All that plumbing tho... I think it's gotta go.

 

[Mcmahst]

When I get to Az on Sunday, I’ll pull my Osborne book and see what it says. I remember it said something slightly different. But, I was wrong once before.

 

[AeroCoupe]

I'm keeping it general so I don't implicate myself and get Diesel Brothered by the Feds.

 

[Willybill32]

I know this has been asked before and I was literally just looking at one of those threads. Walked out and looked at my car and I think mine is done right but it would not surprise me if I did it wrong as I did the conversion 24 years ago this week and lets just say I didn't know what I know now. I just want to make sure I did this right so I can put it to bed in my head.

I left the TAB and TAD solenoids intact and wired up but removed the vacuum lines. The TAB and TAD vacuum supply lines were removed at the source and capped off. Left the EGR solenoid intact and wired up but moved the source vacuum to a manifold vacuum source. The EGR valve is still installed as I did not want to deal with the CEL.

From what I read today I could clean this up a little more and just remove the TAB and TAD solenoids and tape up the connectors. Does it sound like I have the rest of it correct?

On my ‘86, the air pump seized years ago, and I installed a gutted one to keep the pulley and stock belt. A few years ago I made mods to the engine, removed the air pump and hoses, and wound up deleting the TAD/TAB solenoids and plugged the vacuum lines. I also removed the EGR valve and bought a little electronic gizmo that plugged into the EGR connector to fool the ECU. The car runs great, and I’ve never felt the need to check the codes.

Bill

 

[General karthief]

On my ‘86, the air pump seized years ago, and I installed a gutted one to keep the pulley and stock belt. A few years ago I made mods to the engine, removed the air pump and hoses, and wound up deleting the TAD/TAB solenoids and plugged the vacuum lines. I also removed the EGR valve and bought a little electronic gizmo that plugged into the EGR connector to fool the ECU. The car runs great, and I’ve never felt the need to check the codes.

Bill

Well Bill, you're gonna get a visit from Code Enforcement soon

 

[Willybill32]

Well Bill, you're gonna get a visit from Code Enforcement soon

Not where I live, General!

 

[General karthief]

I’ve never felt the need to check the codes.

My sad attempt at humor was pointed at this comment.
Oh, and codes can be present without CEL, it will prolly show a code for the spout.
Here's what you do, disconnect the battery for 20-30 mins then hook it back up, drive around in some different conditions like in traffic/stop and go and some running at constant speed. Pull codes, report back here.
DISCLAIMER: advice not based on any actual mechanical training, use at your own risk, not responsible for damage to property or pets.

 

[Willybill32]

My sad attempt at humor was pointed at this comment.
Oh, and codes can be present without CEL, it will prolly show a code for the spout.
Here's what you do, disconnect the battery for 20-30 mins then hook it back up, drive around in some different conditions like in traffic/stop and go and some running at constant speed. Pull codes, report back here.
DISCLAIMER: advice not based on any actual mechanical training, use at your own risk, not responsible for damage to property or pets.

No issue. I know there are codes, but it runs well, so I’ve chosen not to look. No CEL on an ‘86. Car is current being reassembled after paint, so I won’t be able to do anything for a while. I did send the ECU to ECUExchange and they found and fixed several issues.

Bill

 

[Noobz347]

No issue. I know there are codes, but it runs well, so I’ve chosen not to look. No CEL on an ‘86. Car is current being reassembled after paint, so I won’t be able to do anything for a while. I did send the ECU to ECUExchange and they found and fixed several issues.

Bill

If it ain't broke

 

[General karthief]

If it ain't broke

Keep fix'n it till it is

 

[rednotch]

I have no tab /tad plugged in or vacuum, egr plugged in for electrical connection but no vacuum and no hard codes setting the CEL in my beater, been like that since I picked that car up over a year ago. Cel works fine and pulls codes, pops the cel up once in a while since its an unturned 347 with a decent amount of work with a old prom and 36lb injectors running off an a9l. If your keeping vaccum on the egr make sure your keeping evr valve inline, straight vaccum to the valve is a no no and I've seen more then a few ppl delete the evr when they removed the tab/tad selonids.