Hi All, Newbie to the site not to Fords...

I did a search and posted on the Thread but no one has answered to it.

I am getting a 172 Code about Five or Six minutes into my drive. The Bronco runs good and has Power. I replaced the 02 sensor and also replaced the MAF sensor with one I had as a Spare.

After all that, I am still getting a code 172. "HEGO reading Lean on bank one"

Its a 302 with Shorty headers and a Bassani Y-pipe with a 3" cat back exhaust. Also, I have an MSD 6A and a MSD coil. I also have a K&N FIPK.

I can here a "Bad" Noise when my son turns the key on at the Fuel pump {Inside the Tank}. Not that "Normal" Sound of it Pumping Fuel and then stopping.

I will have to make a door for the Fuel Pump. I shoulda done it the first time.

If anyone has a Diagram of the Fuel lines {Steve83} I would appreciate it. I am pretty certain I have narrowed it down to the check Valve inside the Fuel Pump ~ Sending unit assy.

Any help would be greatly appreciated.

Thanks to all,
Allcruisen

 

I hope you kept the original parts since there's probably nothing wrong with them. I'd put them back in, or at least bench-test them by Haynes.

If the system says the exhaust is lean, then it probably is. If the engine is running OK, then there's probably an exhaust leak, which is especially likely with any aftermarket exhaust components.

I have 0 faith in aftermarket ignition systems & coils, but I doubt either is contributing to this code. Same for the FIPK.

You can find everything about the fuel system by clicking my black Bronco in my sig & reading the captions in the '90-96 Fuel System album, but I doubt that's it. I think it's a simple exhaust leak. Read these captions:

 

for future reference here is a website you should bookmark if you are going to do self testing... http://www.freeautomechanic.com/diag...blecodes7.html