Any tips for tuning open loop?
Thread Starter
Drifting
Joined: Aug 2009
Posts: 1,972
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Any tips for tuning open loop?
Any tips on how to tune fuel for open loop part of tune? After the 30lb injectors (and associated constant updates) I had to add a lot of fuel to get it to run smoothly in open loop. I can still literally feel the transition to closed loop, then it’s dialed in. I don’t know how to tune the fuel without INT/BLM data from the o2 feedback. How do you do this? I’m playing a blind guessing game on what makes it feel like it’s running smoother when cold.
94 but currently running speed density.
94 but currently running speed density.
Melting Slicks
Joined: Jul 2005
Posts: 2,218
Likes: 302
Any tips on how to tune fuel for open loop part of tune? After the 30lb injectors (and associated constant updates) I had to add a lot of fuel to get it to run smoothly in open loop. I can still literally feel the transition to closed loop, then it’s dialed in. I don’t know how to tune the fuel without INT/BLM data from the o2 feedback. How do you do this? I’m playing a blind guessing game on what makes it feel like it’s running smoother when cold.
94 but currently running speed density.
94 but currently running speed density.
Which injectors did you get? Brand and P/N... I"m assuming Bosch-III style, in which case you can often find the p/n molded into the body of the injector.
There are two tables you need to update to make sure the ECM drives the injectors correctly:
Injector offset vs battery voltage => Hopefully there's an injector datasheet associated with your injectors
Low Pulse Width Injector Offset Adder vs BPW => Typically with Bosch-III's, you zero out this table. The older factory injectors needed this "helper" table due to inefficiencies at low PW's. The newer injectors typically don't need it.
Thread Starter
Drifting
Joined: Aug 2009
Posts: 1,972
Likes: 243
They are 30lb Bosch3 that I had Southbay mod with adapter. You actually helped me out. Year or so ago with the voltage offsets (I did find a data sheet) and I did zero out the low pw adder.
good news, I do have a wide band pinned to my pcm, that’s how I tuned WOT. I didn’t really consider this for open loop. It is heated but it’s also located AFTER the cat, which for WOT and a rich condition is ok (I know not perfectly ideal, but WOT is already too little oxygen to burn the fuel then it’s not burning in the cat either). Any way, for open loop (obviously not wot) is the wideband post cat doable? I could always swap it where one of the upstream sensors is if I have to and tune the open loop that way since I won’t be using the narrowband anyway for that
good news, I do have a wide band pinned to my pcm, that’s how I tuned WOT. I didn’t really consider this for open loop. It is heated but it’s also located AFTER the cat, which for WOT and a rich condition is ok (I know not perfectly ideal, but WOT is already too little oxygen to burn the fuel then it’s not burning in the cat either). Any way, for open loop (obviously not wot) is the wideband post cat doable? I could always swap it where one of the upstream sensors is if I have to and tune the open loop that way since I won’t be using the narrowband anyway for that
Thread Starter
Drifting
Joined: Aug 2009
Posts: 1,972
Likes: 243
I’m planning on changing the oil after I get some more easy miles on it since there was assembly lube in the motor. I’ll have to swap the sensors then. My wb is an Innovate LC2, just checked documentation and only needs a max 60 seconds to warm up so definitely will still be in open loop. Even post cat it should be able to at least indicate if I’m running stinking rich.
What afr do you aim for in open loop?
What afr do you aim for in open loop?
Melting Slicks
Joined: Jul 2005
Posts: 2,218
Likes: 302
I’m planning on changing the oil after I get some more easy miles on it since there was assembly lube in the motor. I’ll have to swap the sensors then. My wb is an Innovate LC2, just checked documentation and only needs a max 60 seconds to warm up so definitely will still be in open loop. Even post cat it should be able to at least indicate if I’m running stinking rich.
What afr do you aim for in open loop?
What afr do you aim for in open loop?
I'd probably aim for about 13.5-14.0 in open loop when cold.
