A few Link ECU tuning questions
#1
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Hi guys,
I've spent a lot of time trying to tune my link ECU and I think maybe I started out with the wrong base map. Relevant info:
LINK ECU 1.8 02-SEP-2004
1995 miata
99 Head
GT-X bottom end
550cc FC injectors
On the keypad I loaded up Turbo1 default as my basemap. Master Fuel is set at 87.
I set the injector offset to 80 from what I read on this forum since they are 550cc high impedance injectors
I calculated the proper AFR targets based on my wideband's voltage curve
When I was tuning I had to remove a TON of fuel (like 20 points) from a lot of zones to get it to even be close to the targets.
Most annoying problems:
1. Lurching when getting off and on the throttle. I try to get on the throttle smoothly but it still lurches for a second before smoothing out. I haven't figured out a way to get rid of this. This one really annoys me because it's a track car and I can't be lurching back and forth when I'm getting on the throttle at the apex of a corner.
2. No matter what I set the prime (z715) to i can't get it to start up consistently. Sometimes it will fire right up, sometimes I crank it for like 5+ seconds to get it to fire up. Sometimes I need to give it throttle to get it to fire up. Is this a normal Link ECU problem or is it possible to get this thing to start like a stock car?
Also when I compare my values to the "1.8L Turbo" Benchmark in DLL, it's nowhere close to my map. Both the fuel and ignition settings are all over the place, even though I've never touched the ignition map.
Then when I compare it to the "MK1 Turbo1" Benchmark in DLL, the fuel map is all over the place (anywhere from 16 to 50 points different) but the ignition map is the same.
I'm super confused. Any help would be appreciated.
Someone did mention that it could be due to the 550cc rx7 injectors not being able to control small amounts of fuel very well. He said that might cause lurching and starting problems?
I've spent a lot of time trying to tune my link ECU and I think maybe I started out with the wrong base map. Relevant info:
LINK ECU 1.8 02-SEP-2004
1995 miata
99 Head
GT-X bottom end
550cc FC injectors
On the keypad I loaded up Turbo1 default as my basemap. Master Fuel is set at 87.
I set the injector offset to 80 from what I read on this forum since they are 550cc high impedance injectors
I calculated the proper AFR targets based on my wideband's voltage curve
When I was tuning I had to remove a TON of fuel (like 20 points) from a lot of zones to get it to even be close to the targets.
Most annoying problems:
1. Lurching when getting off and on the throttle. I try to get on the throttle smoothly but it still lurches for a second before smoothing out. I haven't figured out a way to get rid of this. This one really annoys me because it's a track car and I can't be lurching back and forth when I'm getting on the throttle at the apex of a corner.
2. No matter what I set the prime (z715) to i can't get it to start up consistently. Sometimes it will fire right up, sometimes I crank it for like 5+ seconds to get it to fire up. Sometimes I need to give it throttle to get it to fire up. Is this a normal Link ECU problem or is it possible to get this thing to start like a stock car?
Also when I compare my values to the "1.8L Turbo" Benchmark in DLL, it's nowhere close to my map. Both the fuel and ignition settings are all over the place, even though I've never touched the ignition map.
Then when I compare it to the "MK1 Turbo1" Benchmark in DLL, the fuel map is all over the place (anywhere from 16 to 50 points different) but the ignition map is the same.
I'm super confused. Any help would be appreciated.
Someone did mention that it could be due to the 550cc rx7 injectors not being able to control small amounts of fuel very well. He said that might cause lurching and starting problems?
#6
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Okay so taking advice I've gathered from the net. I think my lurching problems are likely related to tps adjustment so I'll be tackling that shortly. But I also wanted to post some logs on here to see if you guys could help me make sense of them.
Here's the 2-3-4 onramp pull I logged today with L3 and L4 turned on.
![](https://www.miataturbo.net/attachments/ecus-tuning-54/34876-few-link-ecu-tuning-questions-234pull.th.jpg?dateline=1329881501)
Here's just a zooming in on the 3rd gear portion
![](https://www.miataturbo.net/attachments/ecus-tuning-54/34877-few-link-ecu-tuning-questions-3gear.th.jpg?dateline=1329881501)
as you can see I run lean almost all the way up to 6k rpm. Not happy, so I increased the fuel across the board for the 500 row and also a portion of the 400 row. I also increased the fuel on the 600 row for safety. Here's a comparison of before and after my changes:
![](https://www.miataturbo.net/attachments/ecus-tuning-54/34878-few-link-ecu-tuning-questions-mapchanges.th.jpg?dateline=1329881501)
There's this lean spike every time when I get on the throttle. How do I fix that spike? Is that where accel fuel comes into play?
I've also attached the datalog in the text file if someone has time to poke around and see what else I'm doing wrong.
Here's the 2-3-4 onramp pull I logged today with L3 and L4 turned on.
![](https://www.miataturbo.net/attachments/ecus-tuning-54/34876-few-link-ecu-tuning-questions-234pull.th.jpg?dateline=1329881501)
Here's just a zooming in on the 3rd gear portion
![](https://www.miataturbo.net/attachments/ecus-tuning-54/34877-few-link-ecu-tuning-questions-3gear.th.jpg?dateline=1329881501)
as you can see I run lean almost all the way up to 6k rpm. Not happy, so I increased the fuel across the board for the 500 row and also a portion of the 400 row. I also increased the fuel on the 600 row for safety. Here's a comparison of before and after my changes:
![](https://www.miataturbo.net/attachments/ecus-tuning-54/34878-few-link-ecu-tuning-questions-mapchanges.th.jpg?dateline=1329881501)
There's this lean spike every time when I get on the throttle. How do I fix that spike? Is that where accel fuel comes into play?
I've also attached the datalog in the text file if someone has time to poke around and see what else I'm doing wrong.
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