Need some guidance!!
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Need some guidance!!
Hey guys, I have a 1985 L98 with the 870 ECM.
I had a tuner set me up with a base tune and I've been trying to fine tune it myself. The BLMs were okay, probably within 10 numbers of 128.
Anyway, here's what was happening. The car was running lean in open loop, at closed loop it was good. At some temperatures, the car would idle at 17:1 AFR in open loop, at other temperatures, it would idle at 20:1 AFR in open loop. In closed loop it would idle at 14.7:1, and as I revved it up, the AFR would stay 14.7:1 at all RPMs. Also, it would get lean spikes to 22.4:1 and bog down and then rev up when I tried to rev it.
So I changed the table "%Change to Fuel/Air Ratio Vs. Coolant Temp", and I was able to work it down to around 14.1:1 throughout all temperature ranges. Which is where I want it because I am running 10% ethanol in my gas. I fixed the lean spikes a little bit. Some times it will lean spike to like 17:1 instead of 22.4:1. But, on hotter temperatures, like around 100* F, it will go to 22.4:1 for a split second, a lot better than it was before though. This only happens under 1300 RPM and at 25% or more throttle. I would like some help fixing that.
The tables I modified are these, and these are what they are set to:
- AE Enable Min. Delta LV8 Threshold: 20 Counts
- Accel. Enrich Enable Pos Delta Thresh: 3.9% TPS
- A.E. Disable Negative Delta Thresh: 3.9% TPS
- Accel Enrich Delta TPS PW Scale Factor: 0.000 Mult.
The other problem I am having now is that when I raise the RPMs in open loop, it gets rich like between 12:1 and 13:1. How can I lean that out to 14.1:1?
In closed loop, I had noticed at one point while raising the RPMs it went to 18:1 at 3k-4k RPMs. Then I tried it again later and it was back to 14.7:1.
I would like to change closed loop to idle and rev at 14.7:1, can anyone show me what table to modify to change that?
That's pretty much it, I'm installing AFR 195 heads soon, so I will probably start over from a stock tune with my tuner, this is just to tie me over until the heads are done being built.
Thanks a lot!!
I had a tuner set me up with a base tune and I've been trying to fine tune it myself. The BLMs were okay, probably within 10 numbers of 128.
Anyway, here's what was happening. The car was running lean in open loop, at closed loop it was good. At some temperatures, the car would idle at 17:1 AFR in open loop, at other temperatures, it would idle at 20:1 AFR in open loop. In closed loop it would idle at 14.7:1, and as I revved it up, the AFR would stay 14.7:1 at all RPMs. Also, it would get lean spikes to 22.4:1 and bog down and then rev up when I tried to rev it.
So I changed the table "%Change to Fuel/Air Ratio Vs. Coolant Temp", and I was able to work it down to around 14.1:1 throughout all temperature ranges. Which is where I want it because I am running 10% ethanol in my gas. I fixed the lean spikes a little bit. Some times it will lean spike to like 17:1 instead of 22.4:1. But, on hotter temperatures, like around 100* F, it will go to 22.4:1 for a split second, a lot better than it was before though. This only happens under 1300 RPM and at 25% or more throttle. I would like some help fixing that.
The tables I modified are these, and these are what they are set to:
- AE Enable Min. Delta LV8 Threshold: 20 Counts
- Accel. Enrich Enable Pos Delta Thresh: 3.9% TPS
- A.E. Disable Negative Delta Thresh: 3.9% TPS
- Accel Enrich Delta TPS PW Scale Factor: 0.000 Mult.
The other problem I am having now is that when I raise the RPMs in open loop, it gets rich like between 12:1 and 13:1. How can I lean that out to 14.1:1?
In closed loop, I had noticed at one point while raising the RPMs it went to 18:1 at 3k-4k RPMs. Then I tried it again later and it was back to 14.7:1.
I would like to change closed loop to idle and rev at 14.7:1, can anyone show me what table to modify to change that?
That's pretty much it, I'm installing AFR 195 heads soon, so I will probably start over from a stock tune with my tuner, this is just to tie me over until the heads are done being built.
Thanks a lot!!
Joined: Apr 2004
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From: Browns Town
Car: 86 Monte SS (730,$8D,G3,AP,4K,S_V4)
Engine: 406 Hyd Roller 236/242
Transmission: 700R4 HomeBrew, 2.4K stall
Axle/Gears: 3:73 Posi, 7.5 Soon to break
Re: Need some guidance!!
Hey guys, I have a 1985 L98 with the 870 ECM.
...
- Accel. Enrich Enable Pos Delta Thresh: 3.9% TPS Make 2-2.5 % will start AE sooner
- A.E. Disable Negative Delta Thresh: 3.9% TPS
- Accel Enrich Delta TPS PW Scale Factor: 0.000 Mult. being zero disables the AE if I'm not mistaken. Check what the original value was and try that
...
- Accel. Enrich Enable Pos Delta Thresh: 3.9% TPS Make 2-2.5 % will start AE sooner
- A.E. Disable Negative Delta Thresh: 3.9% TPS
- Accel Enrich Delta TPS PW Scale Factor: 0.000 Mult. being zero disables the AE if I'm not mistaken. Check what the original value was and try that
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