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Discussion Starter · #1 ·
I have a 92 bronco with a 351 104,000 original miles and it has absolutely no power. I took it to get inspected but I knew it was not going to pass. The mechanic said it could not even generate enough power on the dyno. Since then I checked the timing, it's right on 10 btdc. I than pulled the codes. 172, 334, 536, 538, and 632 came up. I than replaced the oxygen sensor and the egr sensor, the egr valve was replaced last year. Well it still ran the same so I pulled the codes again and 172 was now gone but every other one remained and one new one, 311. My smog pump seized up two years ago so I put a shorter belt on it to bypass the pump and plugged up all the lines going to and from it. before this it was still running the same. I have only put a couple hundred miles on this truck within the last 5 years and oh yea completely tuned up. I would appreciate any help you can give me. And hi all I am a new member. Thank you.
 

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I have a 92 bronco with a 351 104,000 original miles and it has absolutely no power. I took it to get inspected but I knew it was not going to pass. The mechanic said it could not even generate enough power on the dyno. Since then I checked the timing, it's right on 10 btdc. I than pulled the codes. 172, 334, 536, 538, and 632 came up. I than replaced the oxygen sensor and the egr sensor, the egr valve was replaced last year. Well it still ran the same so I pulled the codes again and 172 was now gone but every other one remained and one new one, 311. My smog pump seized up two years ago so I put a shorter belt on it to bypass the pump and plugged up all the lines going to and from it. before this it was still running the same. I have only put a couple hundred miles on this truck within the last 5 years and oh yea completely tuned up. I would appreciate any help you can give me. And hi all I am a new member. Thank you.
Probably well covered in previous posts! but anyway:
172-EGO lean or System lean-bank 1
334- -EVP voltage high- EGR valve voltage higher than expected when closed
536- BOO circuit failure- brake circuit on/off switch not activated during KOEO- ( usually just didn't punch brake at start of test)
538- Cylinder ID system failure/ TPS failure
632- O/D cancel switch-(again, usually just not cycled during test)
311- refers to the AIR sytem failure
These are from OTC Pathfinder. I could not quickly locate the Ford OEM manual.
The first ones I'd address is the TPS and EGO codes, although you will probably need to re-instate the AIR system if you are required to pass emissions testing.
Paul
 

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Discussion Starter · #6 ·
Probably well covered in previous posts! but anyway:
172-EGO lean or System lean-bank 1
334- -EVP voltage high- EGR valve voltage higher than expected when closed
536- BOO circuit failure- brake circuit on/off switch not activated during KOEO- ( usually just didn't punch brake at start of test)
538- Cylinder ID system failure/ TPS failure
632- O/D cancel switch-(again, usually just not cycled during test)
311- refers to the AIR sytem failure
These are from OTC Pathfinder. I could not quickly locate the Ford OEM manual.
The first ones I'd address is the TPS and EGO codes, although you will probably need to re-instate the AIR system if you are required to pass emissions testing.
Paul
Will it run properly without the smog pump? Thats all I am trying to do is get it running good again.
 

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Discussion Starter · #7 ·
Probably well covered in previous posts! but anyway:
172-EGO lean or System lean-bank 1
334- -EVP voltage high- EGR valve voltage higher than expected when closed
536- BOO circuit failure- brake circuit on/off switch not activated during KOEO- ( usually just didn't punch brake at start of test)
538- Cylinder ID system failure/ TPS failure
632- O/D cancel switch-(again, usually just not cycled during test)
311- refers to the AIR sytem failure
These are from OTC Pathfinder. I could not quickly locate the Ford OEM manual.
The first ones I'd address is the TPS and EGO codes, although you will probably need to re-instate the AIR system if you are required to pass emissions testing.
Paul
Will it run properly without the smog pump? Thats all I am trying to do is get it running good again.
 

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It will run fairly well. The only things that might relate to the AIR system would be the incorrect signal due to the lack of extra O2 at the sensor. A leak in the plugged ports would also affect the O2 readings.
Does it run better when first started? Do you know if it actually goes into closed loop? The fixed tables used in open loop may have an effect.
I'd suggest starting with the basics such as spark, compression and vacuum. Check fuel pressure and delivery. The fact that it will run at all helps with the basics. Certainly check the TFI module. The indicated lack of a correct TPS signal also needs to be explored. Also recheck firing order and spark advance. I am assuming the 10 degrees was with the Spout disconnected. With the spout re-connected , you should see a significant timing advance as the rpms are increased.
Good luck, it is often the really simple things that contribute to, or are, the problem.
Paul
 

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If there is a tps failure code it can also cause that lean code. Had that problem on my old chevy, Changed the tps sensor, cleaned the iac sensor, cleaned throttle body and changed plugs and got rid of the 2 codes.
 

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I forgot to mention I just put on bassani shortys, y pipe, high flow cat, and tail pipe.
Gotcha, I'd start with your TPS then. Read Xris's thread on it.
 
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