[tonyroc14]

Well I have been having a CEL come on and off every 2-3 days, or like today, twice. I don't ever get any kind of problems with driving or anything. But it concerned me, so I bought a code reader for 32 bucks Anyways, let me give you a little background. 1991 with a 351 and an e4od. I am getting 10-11mpg, and I can always smell gas or a very rich smell in the exhaust. Anyways here we go. I have a code from an engine running test, number 41, which indicates that my oxygen sensor is giving a lean signal. Now this doesn't make sense to me, it doesn't smell lean, and my fuel economy doesn't show lean. Would this mean that maybe the system is running rich to try and compensate? Thats basically all I wanted to know, and any other useful information that would help. Thanks

 

[jopes]

code 41 if your saying is lean it means the o2 is sensing too much oxygen in the exhaust. you have cracked manifolds? vacuum leaks?

pm sent

 

[tonyroc14]

nope, no leaks, or cracks. and okay, I'll go check. Thanks

 

[miesk5]

yo, great info by jopes!

btw, 97beast has a DTC 41 last Sep and it was a bear to diagnose.

Since the Hot Links I had in my replies in that post won't copy & paste well, here is the LINK http://fullsizebronco.com/forum/showthread.php?t=155932&page=2

In reply #27, I posted an O2 Sensor test; later in the thread, I posted Fireguy's ...Electrical and Vacuum Troubleshooting Manual (EVTM) Partial, Bronco, F 150 for 86, 89 & 91
diagram showing the color codes DKG/P, P/O (instead of two greys) and BK for ground
Ford wire color code abbreviation chart
BK Black
BL Blue
BR Brown
DB dark Blue
DG Dark Green
GN Green
GY Grey
LB Light Blue
LG Light Green
N Natural
O Orange
P Purple
PK Pink
R Red
T Tan
V Violet
W White
Y Yellow

Where two colors are shown for a wire, the first color is the basic color of the wire. The second color is the stripe marking. For example: BR/O is a brown wire with an orange stripe.

 

[BroncoRN]

Pull vacuum line off fuel pressure regulator and see if it smells like gas. Check fuel pressure. Clear codes and try again.

PCM could be reading lean and dumping more fuel to counteract it.

 

[YatriSA]

Well I have been having a CEL come on and off every 2-3 days, or like today, twice. I don't ever get any kind of problems with driving or anything. But it concerned me, so I bought a code reader for 32 bucks Anyways, let me give you a little background. 1991 with a 351 and an e4od. I am getting 10-11mpg, and I can always smell gas or a very rich smell in the exhaust. Anyways here we go. I have a code from an engine running test, number 41, which indicates that my oxygen sensor is giving a lean signal. Now this doesn't make sense to me, it doesn't smell lean, and my fuel economy doesn't show lean. Would this mean that maybe the system is running rich to try and compensate? Thats basically all I wanted to know, and any other useful information that would help. Thanks

I also have a 1991 bronco and need some help. what code reader did you get an where is the connector? thanks in advance

 

[deadsquiggles]

I believe you can use the Innova 3145.

 

[YatriSA]

I believe you can use the Innova 3145.

Thanks!