Wideband reading lean at wot

[nicknorth11]

I had a good 93 octane tune, and when that tank ran out, I switched to E85. I changed my global settings with link and went to the highway to tune a bit. After several pulls, I noticed that no matter how much fuel I added, I wasn't able to get my afr's below 13:1 or so. On top of the global change, I've added an additional 30% of fuel! Wideband still reads lean at wot. I know for a fact it's running pig rich at this point, but I have no idea why my wideband continues to read lean. Btw, it shows around 14.7 at idle, which seems to me an indicator that there is no exhaust leak.

Boost leak test held at 30psi. I didn't test any higher.
I've checked for exhaust leaks and can't see/hear any.
I've swapped out sensors. (The alternate sensor was an old one I had laying around, not new, but was working back in the day.)

 

[nicknorth11]

RESOLVED! (For me, at least). When I last checked to see if my fuel pressure was rising at 1:1 with boost, I used anti-lag at 15psi since my gauge is under the hood. Today, I taped my phone above the gauge and recorded a video of a pull. What I found was pretty telling! Fuel pressure fell off big time!

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. My problem turned out to be the 0-ring that slides over the pump nipple and into the fuel sending unit. I got a new o-ring and put a shim under the o-ring with a worm-clamp to ensure the new o-ring doesn't get pushed down. Base fuel pressure immediately increased. I've decreased my fuel significantly, and afr's are right where they should be during the entire pull. I hope this is able to help you guys!

 

[StrokerMax]

Nicknorth11, Great find!!!! and thanks for the follow-up.

When I installed my Walboro 450, I remember that O-ring giving me trouble. It kept wanting to slide. When I re-wire my fuel pump this next week I'm going to check that O-ring and do the same thing you did.

 

[nicknorth11]

No problem. The new o-ring I used was much thicker than the original. It barely fit on the pump nipple and barely into the sending unit. Make sure yours is also this tight.

 

[StrokerMax]

I just took apart my fuel pump, replaced the o-ring and built a shim like you did. It fixed my problem too!!! Thanks again bro!

 

[nicknorth11]

Very happy to hear it!

 

[enriquez2000]

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