Help with building your Speeduino, installing it, getting it to run etc.
By Svetoslav
#68414
I think I got that. The strange thing is that it seems to me that the valve I use has a very narrow usable range.
What I mean is that with a fully warmed up engine and the valve opened 100% the idle is around 1500rpm. When the valve starts to close just a little, lets say 80% open, the rpm drop significantly and idles at around 800rpm (which is ok).
However if the valve continues to close the engine dies. There is simply no way the engine to run below that, and in the "limp mode" when it's slightly open it can't .
Which makes me wonder if the valve I have is just too small for my application. It is the Bosch 0 280 140 516.

For the time being I installed the original slide valve and adjust the idle manually to tune in the engine. I'm almost ready to get the car on the road and start tuning it.
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By PSIG
#68416
Svetoslav wrote: Tue May 21, 2024 8:12 am I think I got that. The strange thing is that it seems to me that the valve I use has a very narrow usable range.
A narrow range often means incorrect or an inefficient Hertz, but if it's not tuned around idle, then it's almost irrelevant at this point.

Svetoslav wrote: Tue May 21, 2024 8:12 amWhat I mean is that with a fully warmed up engine and the valve opened 100% the idle is around 1500rpm. When the valve starts to close just a little, lets say 80% open, the rpm drop significantly and idles at around 800rpm (which is ok).
However if the valve continues to close the engine dies.
The throttle stop should permit minimum idle rpm, with no IAC flow. Higher rpm if in limp-home or disconnected. I often cap the IAC inlet so initial tuning is not complicated by changes in IAC flow. This of course requires setting reasonable warm idle with the throttle-stop. Many throttle-stop resets may be required during tuning, before the IAC can be used effectively.

Svetoslav wrote: Tue May 21, 2024 8:12 amThere is simply no way the engine to run below that, and in the "limp mode" when it's slightly open it can't .
Which makes me wonder if the valve I have is just too small for my application. It is the Bosch 0 280 140 516.
I have used tiny IAC valves on relatively large engines. I'll bet it isn't set for good idle, which can be difficult without at least initial tuning for idle stability.
Svetoslav wrote: Tue May 21, 2024 8:12 amFor the time being I installed the original slide valve and adjust the idle manually to tune in the engine. I'm almost ready to get the car on the road and start tuning it.
On first start, I warm and tune idle and high idle immediately. This allows both a good setting for IAC, and building the tune foundation from the bottom-up. Many functions (such as active IAC) are not helpful until the tune is ready for it.

I would suggest IAC is mostly for general idle speed range. It does not work well for controlling real-time idle rpm. Idle Advance control or Spark Table timing troughs work much quicker and better for that. In a sense, I only use IAC for general warmup rpm, and warm idle rpm ranges. Other idle stability is with Idle Advance or timing manipulations.

There are several approaches to IAC tuning, but I suggest using the throttle-stop for minimum warm rpm, and IAC only for warmup air during early tuning. Hope that helps.
By Svetoslav
#68427
I think I already tuned the idle at warm engine pretty good by setting it with the bypass valve. It is stable and comes down very nice when I rev the engine.
I could try setting the throttle for the idle, but that's not how it is on the M30 engine and the adjustments are pretty limited. Originally the throttle was always closed and the idle is set by a bypass air valve. There is also a simple auxillary air valve for the warm-up. However this valve is defective, so I decided to change it for an electric valve, like the later M30. They don't seem to have any other way of setting the idle, like the earlier ones with the bypass valve, just the ICV.
But as you said, It wouldn't be а good idea to control the idle only with the ICV. So I think I'll just use the original bypass valve to set the idle and the ICV in open loop to increase the airflow during warm-up.
By Svetoslav
#68464
The issue got worse recently. From the logs I can see that it is caused by the crank sensor. Tried different stuff like readjusting it, routing the cable away from the ignition and connecting it to 12v, instead of 5v. The last thing seems to fix most of the issues. There were still a couple of rpm spikes at idle, but it was a lot better and they dissappeared when the engine warmed and I took it out for a ride.
Maybe the sensor is not very good, it was pretty cheap, I will buy a better one to see.
By Svetoslav
#68586
I got my tach working. I Installed an ULN2003 because I need it for fan control and decided to try once more with the tach and what do you know, it works. Although it only shows correct up to 3000 rpm, after that it shows higher than it actually is in tunerstudio. Not sure how to fix it. Tried both Match dwell and the other option, but the results were similar. I'll have to play with the settings a bit more to see.

I will also get a new wideband controller, because the LC-1 seems unreliable to me. Every time I start the car with the same settings it shows similar but different values at idle. Maybe the sensor is not good, but from what I see on the internet there are many people who complain about it.
So I'm thinking of getting the Spartan 3 Lite V2. Does anyone of you use it and do you think it's a good choice?
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By PSIG
#68592
I have used 14point7 products successfully. Note the important factor is that the unit responds consistently. Accuracy is not as important. If it reads 1 AFR lean or rich of another unit, that's OK and usable, so long as it does so consistently.
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