Okay, to begin with my application is a little different. I have a 2005 F22C installed in a 1964 Triumph TR4. I have Urge ITBs and Headwork, Crower Stroker kit and Crower Stage 2 cams. None of that should be related to the issue I'm having.

The have an in-tank aeromotive fuel pump, actuated by an Emerald K3 ECU, 43-45 psi at idle. When driving the car, it will run great for a while, then blah, step on the gas and it starts surging, stopping, backfiring. It does not die, if i I let off the gas it still idles fine and I can nurse the car back home as long as I stay off the throttle. Oh and the A/F ratio climbs to 16+. Sometimes I can go 4 miles, sometimes 20. I can accelerate hard wind to Redline before it starts happening, after it begins it leans out with almost any amount of throttle. I thought initially it was surging due to cornering and added a surge tank with it's own pump. That didn't fix it.
I'm thinking electrical, intermittent contact from fuel pump relay, but, I have ruled out mechanical.

Any thoughts would be helpful.

Rod

 

Poss map sensor related,search Map wack,it just involves wacking it,or a bad connection there,pull plug of and on,there is also a tie strap mod<just sucure it better>
Thats if you have a map sensor with your set up

 

Thanks, I'll give it a try.

Rod

 

Does the ecu try and compensate with more fuel when it leans out?
If so then it sounds like injectors or pump issues. Have you checked the fuel pump wiring, including the relay?
Log fuel pressure to make sure it doesn't drop on higher load.

 

My gut is telling me its engine temp sensor related. Like ecu is confused about what to do at what temps. Like maybe temp sensor was not working when it was tuned or something, so now what it does at what temp isn't correct for what engine needs.

What is making me think this is:

1. Issue starts right around when ecu would see engine fully up to temp, coolant and oil, and adjust fueling ratios accordingly

2. Ecu is supposed to make things richer when cold, as a sort of modern version of engine choke, then lean things out as engine comes up to temp

Its acting as if 'cold' is fueling like warm should be, then leaning further from there (leaning way too much) as things warm.