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Hello All,

New to tuning, this is my first project.

Issues:
Running rich at idle and not getting to 1250 cold rpm setting. Autotuning, the VE table.is between 1 and 5. (I see tables online that are in the 30's at idle.)
Idles low rpm with IAC valve open to the max or min and everywhere in between in open loop.
Warms up and eventually will get close to, target rpm idle but, it's higher.

What's been tried:
Adjusting timing between 0-8* and 22* BTDC. This has an effect but, not enough to hit 1250 cold idle.
Open loop, closed loop and both together.
Idle Advance setting, set to Added and Switched. ( Not sure I understand the explanation of the difference.)
Adjusted Advanced Idle timing, adding and subtracting.
Played with PID in closed loop for idle. (Is there a graph or something that shows what's going on when changing PID settings?)

Thank you in advance for any information you may provide.

Michael Latini

Can’t speak from experience yet but will be tuning my speeduino ecu over this summer.

I’d be surprised if you’d be much below 30% on the VE table. The starting point is typically 50% around the low load/rpm area & then tune from there.

However, if your settings for capacity, injector specs, voltage adjustment, dead zone etc is not accurate you will be compensating by messing with VE outside of a realistic value.

Bruce,

Thank you for your response and the great recommendations. I have checked and rechecked all of those settings so many times and cannot find a solution.
I have the specs for the injectors from bosch website, 440cc and 1.2ms open time. It's a 2ltr turbo by the way, reason for the big injectors. I have changed that setting while the car is running and it helps sayin open loop cold, when it hits closed loop warm, it's hurting. The wideband o2 has been recalibrated 2 twice just in case. Added 24" of additional exhaust pipe so the end was further away from the o2. I have no idea what else to try.
If something you learn can be helpful, please pass it on.\

Thank you,
M

Perhaps it’s worth testing the injectors? I’ll be doing that with mine and at a couple of different voltages to work out the voltage calibration. I’m going to do it on the car rather than making a test rig. I’ll remove one throttle body & set it up outside the engine bay with the wiring & fuel hose attached pointing the injector into a large glass bottle. Run the injector test sequence in tuner studio and measure the amount of fuel it sprays out into the bottle. You can do this by weighing the bottle before / after

Not sure if you can enter the flow rate in grams per min, but it’s easy to convert to CC (water is 1gram per CC, & petrol is less dense at approx 0.76).

You can look up on you tube about testing the dead time, but the easiest way in my opinion is to set the injector test sequence to use a very short pulse, then gradually increase that value until you can get some fuel flow from the injector. That is your dead time. I’d test it with the car battery & also with a charger attached to get a couple of different voltages. Ideally you want to power it from a bench power supply to get a spread of readings but most people don’t have one of those.

How did you set up the cold start settings for warm up enrichment? Could that be causing problems?

& just to clarify the situation. Is the idle rpm too high or too low? Too high could be an air leak at the manifold-head flange or elsewhere.

TS does a great job but it does some unexpected things if given free reign over too wide an area of the ve table.
Ditto on vacuum leaks or exhaust leaks, if you "lie" to tuner studio expect poor results.

The autotune has min/max rpm and load settings, idle and very low load areas best manually tuned, as well as high boost.
(start rich, work your way lean, where lean is ~13:1-ish, conservative timing, etc)

Works great for cruise and getting a drivable tune in 5 minutes given a good hill or local freeway onramps.

Don't have a speeduino setup (yet) but have used Tunerstudio and Megalogviewer for a long time...

In theory, if you give tuner studio all the correct info on the fuel delivery it will calculate the right amount of fuel to inject, based on the amount of air (based on capacity in CC * %air consumed based on VE) and the requested ratio of fuel to air.

If you get the fuel specs correct, you can figure out the true VE by measuring the error between the actual exhaust lambda vs the requested air/fuel mix. Then tweak the VE value until the actual is very close to the request fuel/air ratio.

If you get the VE & fuel specs right, you can change the requested air/fuel ratio and the actual lambda reading will track it closely. In theory

One part I haven’t figured out is how tuner studio accounts for the fuel pressure differential without having a fuel pressure sensor reading. The flow from the injector is a function of the difference between the fuel pressure & the MAP. Given that fuel pressure regulators can have different behaviours (fixed fuel pressure, 1:1 adjustment based on MAP, 1:? Adjustment) which will change the amount of flow from the injector. TS must make some assumptions without that data & the tune will need to compensate in the VE table.

There is a good Haltech video on manual tuning which explains it clearly although it might not translate 100% to Tuner Studio.

Worth a watch, especially the 2nd half.

https://youtu.be/uPjIS9Tg83M

Thank you to everyone, above.
Sorry for the late reply. I am a technological mess. I am not receiving notice by email there were responses. # 741 on the to do list.
All of the advice is awesome and I thank you all for taking the time to respond.
It seems that, the IAC valve is not opening up enough to allow the needed air flow for cold idle. The idle has always been low and too rich. Chris from, Speeduino has my current tune and is going to review it and let me know if there is any settings that need to be changed.

I will keep you posted.

M

I sent my tune for examination. Here is the response from, Chris at Speeduino.

"Ok, a few things are not correct.

You have 200%,100% and 0% punched in for closed loop PID control. These numbers are invalid. (see attached picture).
I suspect it'll work flawlessly when in open-loop mode, with cool time set to 0.

You have idle up input turned on, and the idle up output turned on, and I just went through this exact menu with a customer. Where did you get this base tune?"

Saw a video on PID settings an still don't understand it so, it's off now.
I had, "cool time" set to 1. I will change it and give it a try this week and let you know. Such a small number causing a huge issue.
Idle up was turned on figuring it would be needed for A/C when the time comes. Not sure what to do when the time comes.

Thank you for reading,

M

Some how I changed the maximum duty cycle when adjusting the voltage adjustment for the injectors down to 15 from 85 .
, a small error caused a lot of head scratching . I spent a day looking for a WOT issue .
The issue with speeduino is the lack of resolution on the VE table , no decimals . I bought larger injectors to run E85 if I wanted to .Problem is the VE number at cruise and idle is low . A work around on an na vehicle is to put down a larger size injector in the engine constants to raise the VE numbers . I played with the injector size (565cc fitted to engine) to raise the WOT VE maximum to the 230's (255 is max) .

I'm new to EFI and got the speeduino cheap and it has been a fantastic learning tool . I have read that the processor is not fast enough for the auto tune function in tuner studio to work well . I go for a drive and try and get steady throttle settings at different rpms , then sit down with a coffee and revise the data logs , make some changes , smooth out the table a little and try again .
I am probably going to up grade to a better ECU ,( low end Haltech , Link or Ecumaster ,or even a MS3pro board) and make a patch harness to my loom so I can plug in the speeduino as a breakdown spare ecu.

Sounds like you are making progress.

A correction from what I posted above. Megasquirt & speeduino don’t include corrections for the fuel pressure differential. Effectively you manipulate the VE value to include that adjustment.

The autotune runs on the laptop running TunerStudio, not the ecu.
I guess if the updates/comms are too slow it could be a drag.