Cold Start and Hot Start problems

[martroy]

Hi guys,



I'm trying to smooth out the idle in every situation (Cold start, hot start and idle) and this fall, will do the rest.



Here's the situation:

When I coldstart the engine yesterday with the "BaseTune.msq" in attachment, the engine starts within 1 secs by what the logs says. After, I got some up and down till it warm out. I figured out letter I was too lean and by richening it, it was fine. For the hot start, I had to touch the pedal to start it without letting him die and after started, it was fine.

When I was looking my tune, I tought that would be a problem to have high VE number in the "idle cell" at 100 kpa, witch I changed and repeated the idle VE number that was working fine (58).

Today, I did try another coldstart with the new tune (BaseTune-Mod-Idle.msq). It was looking slower to start and up and down was still there during the warmup. Hot start was looking better than with the last tune.

Is there something I could change in the tune to make it better for faster start without up and down?



Thanks for looking.



Datalogs and tunes

[martroy]

Any ideas for that particular situation?

[Stinger]

I do plan to look at this I just haven't had time. I've had a sinus infection for 15 days and a fever the last 4 days so I'm struggling to get the bare necessities done.

[Stinger]

Why are you running fixed timing? Trying to tune anything (particularly idle) without the timing you'll be running is not going to be productive as things will change once you switch to "use table". So step 1 is to switch to "use table".

Why are you using table switching for ignition at 100kPa but then having that whole table be 14 degrees? Same for fuel and a value of 175? Even the fuel table 1 values are unrealistic above 2500rpm. Are those theoretical "guesses" or have those been tuned to that value and therefore indicate a fuel supply issue? I'm not sure how far into the tuning process you are but typically dialing in cold start comes after the engine is tuned when warm so I assume that's the case here. I "assume" the base tune you're using was already set up with table switching active so that's why you're doing it. Where did the base tune come from? Typically keeping it simple doesn't involve table switching so base tunes typically shouldn't have table switching unless it's necessary for a particular setup (which is very rare). As long as you understand they are active and how they work it's not the end of the world but the values in them need to be tuned as they currently are not at all.

Read this how-to thread for timing: stinger-performance.proboards.com/thread/1003/megasquirt-tuning-basics-timing and set up your timing table so it has "stall saver" timing, as described in that thread. It will help to stabilize idle (once you start actually running the values in the table rather than fixed timing).

A lot of the "up/down" in your current idle is because it's going through values in the 50's, and the 70's in your fuel table so AFR is swinging wildly. This doesn't need to be touched until you start using table timing though as you won't have this problem if you use timing to stabilize idle speed.

These two threads should also help you:
stinger-performance.proboards.com/thread/1616/megasquirt-tuning-basics-cold-start
stinger-performance.proboards.com/thread/1002/megasquirt-tuning-basics-initial-startup

[Stinger]

Jan 6, 2017 15:59:13 GMT -5 martroy said:

Hi guys,

When I was looking my tune, I tought that would be a problem to have high VE number in the "idle cell" at 100 kpa, witch I changed and repeated the idle VE number that was working fine (58).

There is no such thing as an idle cell at 100kPa. 100kPa = 0 vacuum. You can't have idle and zero vacuum without major mechanical issues. If your engine isn't touching that cell (which it never will) it has nothing to do with anything. You could change the cell to 0, or 255, or anything in between and it will never matter. It's impossible for the engine to ever reach the top cell in the table at the lowest rpm column.

With that said, it appears to me that your engine is not yet tuned. If this is the case, you're wasting your timing trying to tune cold start/warm start idle values because those values are based on the values being "correctly tuned" for a warm engine. If they aren't, you'll tune them now, then when you tune it for proper running when warm, your cold start/hot start values will be way off and you'll have to do that all again. So follow the order outlined in the threads linked in my previous reply.

What's your warm idle speed? That gets set before you can adjust cold/hot start idle speed. With your current settings, warm idle speed is set with the throttle stop screw on your throttle body.

Your AFR table is also basically crap and for a stock engine, not something with a larger cam like yours. I know you haven't touched this and it came this way, I'm just letting you know.

To be honest, this is why I hate to see people try to use a generic MS product that doesn't come with a real base tune for their setup as their first MS tuning experience. Those products are for experienced users, not beginners. It makes them think tuning MS is impossible because there is too much stuff to try to understand all at once. If you instead started with something like our PiMPxs that already had all of these fuel tables, timing tables, afr table, cold/hot start settings, etc. properly set up for you, you could basically ignore all of that and concentrate on actually tuning, not concentrate on trying to get everything set up properly so you can start tuning without having to do it multiple times as you learn and change how things are set up. Just looking at your progress over the last 4 months that you've been posting on here, I just feel bad that you're having to spend so much timing on this process. I mean your 4 months into trying to stabilize the idle. If you had a PiMPxs, not only would your idle be stable, but you should be completely done tuning everything and just be enjoying driving your car after 4 months.a If you have the finances to do so, I'd highly suggest selling the MS ECU you have now and getting a PiMPxs. At your current rate, you'll save 6+ months of "setup time" and be MILES ahead to begin with so you can just get your tune dialed in and enjoy your vehicle rather than spend the next year trying to tune it like I fear you're going to do with your current setup. If this isn't financially viable or you don't want to do so, that's fine. We'll try to help you out but understand and accept that it will be a long road.

[martroy]

Hi,

Sorry for my late response, was out for vacations, sometime, it's needed.

Regarding the MS, I bought that one because the wallet cannot afford the PIMPxs as now and was looking for something new to learn. Maybe in the future, I will get the PIMPxs but not for now.

This falls, I did some test with the MS but very part time because I was looking to run (with the PMS and already tuned) with the car instead of trying to make it run. I'm someone that likes to learn when there is not rush for Something. Right now, where the winter and the car is stored so its time for me to work with this.

For the tune, dual table, I did this at the beggining because I was thinking it will give me more scaling for boost but useless for now because I'm not tuning boost.

Warm idle (2,0ms PW)works fine right now with spark table - 950 ishhh RPM around 56 kpa if my minds are good. I'm in the quest of cold starting the engine fast and fine. When hot, it crank and start fast. The tune was fine for the previous deadtime I used but since I changed it, It will be off for everything outside idle cells. For cold starting, it's one try a day...

I do appreciate all help, tips and patience you gave me and hope will get all thoses little things fixed within the next weeks.

[Stinger]

Good luck!