More Questions About Codes
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5th Wheeling
Joined: May 2021
Posts: 48
Likes: 6
From: Mountains of Tennessee
More Questions About Codes
'87 F150 EFI 5.0 2WD AOL 19(3.55)
Idle RPM 721
Vacuum 17
Fuel Pressure at 2000 RPM 48
Timing 10 degrees
KOEO 31, 82
KOER 41, 34, 25
-EGP (new) tests good with Multimeter, getting 5.04V from EEC
-EGR (new) tests good with vacuum applied (looses RPM, threatens to stall, returns when vacuum is removed)
-Solenoid (new) does not seem to pass vacuum with increased throttle, but this was all very unscientific
-TAB/TAD visibly damaged, removed from system
-New O2 sensor (Delphi, three wires)
-Did not repeat WOT to confirm Knock Sensor, but not experiencing pinging
Please inform me about the Air Diverter Solenoid. I cannot locate this part. Is this the Air Bypass Valve? I just need to know to start the shop manual diagnostics.
Do I have the right O2 sensor for my truck?
What in the hell is with the EGR? I've been fighting this since the truck was a new to me no start a year ago. Frustrating.
My sincere thanks to anyone who made it this far and might give me pointers outside of what I've found going back in the forums thus far.
Idle RPM 721
Vacuum 17
Fuel Pressure at 2000 RPM 48
Timing 10 degrees
KOEO 31, 82
KOER 41, 34, 25
-EGP (new) tests good with Multimeter, getting 5.04V from EEC
-EGR (new) tests good with vacuum applied (looses RPM, threatens to stall, returns when vacuum is removed)
-Solenoid (new) does not seem to pass vacuum with increased throttle, but this was all very unscientific
-TAB/TAD visibly damaged, removed from system
-New O2 sensor (Delphi, three wires)
-Did not repeat WOT to confirm Knock Sensor, but not experiencing pinging
Please inform me about the Air Diverter Solenoid. I cannot locate this part. Is this the Air Bypass Valve? I just need to know to start the shop manual diagnostics.
Do I have the right O2 sensor for my truck?
What in the hell is with the EGR? I've been fighting this since the truck was a new to me no start a year ago. Frustrating.
My sincere thanks to anyone who made it this far and might give me pointers outside of what I've found going back in the forums thus far.
Last edited by AHHeck; Jun 1, 2022 at 11:25 AM. Reason: Unclear Title
Hotshot
Joined: Jun 2015
Posts: 12,878
Likes: 2,446
Disregard the KOER codes. You don’t perform that test until you get a system pass code from the KOEO test. Is the code 31 an active code or is it stored in the memory? Does the truck still have the air injection system?
More Turbo
Joined: May 2014
Posts: 587
Likes: 73
@AHHeck ,Without knowing your symptoms, (i don't have access right now to 2 digit codes, my truck does 3 digit codes), I am curious what you mean by:
"TAB/TAD visibly damaged, removed from system"
There are 4 vacuum lines on mine, and electrical connections. These will affect the egr valve, and other components. How did you remove them, and what did you do for the vacuum and electrical connections? From my understanding, the air diverter solenoid is part of the Tab/Tads solenoids. If the computer is not reading a signal from these, it will throw codes.
I completely removed the air injection system on my 94, 7.5. Kept the Tab/Tads solenoids hooked up. I had to remove, and cap off at the solenoids, the line that ran to my non existent thermactor valve. I would replace these solenoids, ensure they are plugged in, and insure vacuum lines going out from them are either in good shape, or replaced. Our trucks are different years, and motors, but, when I started researching my build, I realized I needed these to run smoothly, and the computer needs these signals.
good luck
"TAB/TAD visibly damaged, removed from system"
There are 4 vacuum lines on mine, and electrical connections. These will affect the egr valve, and other components. How did you remove them, and what did you do for the vacuum and electrical connections? From my understanding, the air diverter solenoid is part of the Tab/Tads solenoids. If the computer is not reading a signal from these, it will throw codes.
I completely removed the air injection system on my 94, 7.5. Kept the Tab/Tads solenoids hooked up. I had to remove, and cap off at the solenoids, the line that ran to my non existent thermactor valve. I would replace these solenoids, ensure they are plugged in, and insure vacuum lines going out from them are either in good shape, or replaced. Our trucks are different years, and motors, but, when I started researching my build, I realized I needed these to run smoothly, and the computer needs these signals.
good luck
Thread Starter
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5th Wheeling
Joined: May 2021
Posts: 48
Likes: 6
From: Mountains of Tennessee
31 is active, all the codes listed are. EGR is functional, the TAB/TAD are hooked up electronically for better or worse, but I have bypassed the vacuum canister and those two solenoids from the circuit for to eliminate as many fail points as possible. If that isn’t what you mean by air injection system, I apologize and would appreciate clarification. Thanks for your help.
Thread Starter
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5th Wheeling
Joined: May 2021
Posts: 48
Likes: 6
From: Mountains of Tennessee
Thanks for the feedback. I thought the two solenoids were damaged because they were missing their caps and had cracking on their housing. Now that you mentioned removing your caps, I might need to put them to the test. Otherwise They are electronically connected but as of recently they do not have vacuum applied. The code however is brand new. I will give them a second try after diagnostics and see where that puts me.
Lead Driver
Joined: Oct 2016
Posts: 6,185
Likes: 633
From: Houston/Sugar Land
Here is a listing for your 2 digit diagnostic codes.
https://www.therangerstation.com/tec...gitcodes.shtml
Here is some info on the EVR that you may find helpful. It says that the vacuum needs to be hooked up for the EGR to work.
https://web.archive.org/web/20110501...tion.com/?p=43
https://www.therangerstation.com/tec...gitcodes.shtml
Here is some info on the EVR that you may find helpful. It says that the vacuum needs to be hooked up for the EGR to work.
https://web.archive.org/web/20110501...tion.com/?p=43
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
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More Turbo
Joined: May 2014
Posts: 587
Likes: 73
Thanks for the feedback. I thought the two solenoids were damaged because they were missing their caps and had cracking on their housing. Now that you mentioned removing your caps, I might need to put them to the test. Otherwise They are electronically connected but as of recently they do not have vacuum applied. The code however is brand new. I will give them a second try after diagnostics and see where that puts me.
This is a picture of my solenoids after I did the air pump and thermactor system delete. Yours may look similar. But, these solenoids need to electrically activated, and have vacuum applied. If not, you are chasing codes forever. I know this from experience, as you can see the upper vacuum line was not plugged into both ports on the solenoid. Once this was discovered, and fixed, motor ran great. Fix this, then run your tests again would be my recommendation.
good luck
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Thread Starter
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5th Wheeling
Joined: May 2021
Posts: 48
Likes: 6
From: Mountains of Tennessee
That’s a very helpful link, thanks. The chart should prove invaluable. I had never seen that.
Thread Starter
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5th Wheeling
Joined: May 2021
Posts: 48
Likes: 6
From: Mountains of Tennessee
I will put vacuum to them as per your advice. When I got the truck a year ago the vacuum system was an unholy mess. Every other component was plugged with screws in hoses or what line was there was brittle and leaking badly. The whole TAB/TAD circuit was offline, but didn’t throw this code. I had just assumed they were damaged and I’ve had a hard time finding replacement solenoids. Thanks for your very helpful feedback.
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
Completely disagree regarding keeping the vacuum supply attached to the TAB or TAD solenoids when eliminating the air injection/pump system. Totally agree you need them connected electrically (or use comparable resistor values) to keep the computer happy.
When you remove or cap off the actual bypass or diverter valves you will fail a few KOER tests since the computer will not be able to sense the extra air (read that as O2) in the exhaust when it turns on the respective solenoids/valves during the KOER tests. There is absolutely no way for the computer to sense vacuum applied to the TAB or TAD solenoids so keep it simple.
When you remove or cap off the actual bypass or diverter valves you will fail a few KOER tests since the computer will not be able to sense the extra air (read that as O2) in the exhaust when it turns on the respective solenoids/valves during the KOER tests. There is absolutely no way for the computer to sense vacuum applied to the TAB or TAD solenoids so keep it simple.
Hotshot
Joined: Jun 2015
Posts: 12,878
Likes: 2,446
That is how mine is set up: plugged into the engine harness with the vacuum lines disconnected. No check engine light or codes.
More Turbo
Joined: May 2014
Posts: 587
Likes: 73