Help with Vems idle issue and cold start (logs)

[ChrisAudi80]

Another thing I just noticed.

You still do have lambda oscillations at idle. Try to set your idle control PID all to zero. PID is the last thing to touch.

[morris400]

I turned off EGO just for that log as I wanted to see exactly what the ecu was doing with out correcting.

I do know how to upload configs. And I looked over yours you sent me. I did not want to make so many changes at once so I made a few small one and have been making small ones then driving and logging.

I'm not a fan of letting my car idle to warm up. I let it idle for 30 seconds or so enough for the idle to come down a bit then I drive to warm it up.

I'll try and log again tonight if I can before start up.

I do have some small idle issues but not all the time now. Other then that my only big issue it why it takes 3 time to start the car.

[PRY4SNO]

Other then that my only big issue it why it takes 3 time to start the car.

Is that a hot start, or cold start issue?

[morris400]

Other then that my only big issue it why it takes 3 time to start the car.

Is that a hot start, or cold start issue?

Cold start.

[ChrisAudi80]

Other then that my only big issue it why it takes 3 time to start the car.

Is that a hot start, or cold start issue?

Cold start.

I would say that is a cranking enrichment issue. I forgot if you used my cranking VE setting of 75. You had it as 42 before, IIRC.
If at 75, you could increase cranking enrichment by 10% and increase cranking ignition advance 2 degrees.

Regarding your other comments, understood. Like you said, it is better to make small changes at a time, but one you should implement is the injection end angle disable. Please set it to 720 degrees across the rev range. End angle is tuned after your VE table is near complete.

The reason for letting it idle until warm is to be able to set the warm up enrichment curve well. If driving, this is very difficult.

[morris400]

Chris.

I raised the crank VE from 42 to 60 and still had the same issue. I will raise it more before I test again. I will look into the fuel injector angle once again. Any recommendations on the warm up enrichment?

[ChrisAudi80]

Chris.

I raised the crank VE from 42 to 60 and still had the same issue. I will raise it more before I test again. I will look into the fuel injector angle once again. Any recommendations on the warm up enrichment?

Just to give you an idea, I have my cranking VE at 80%. By the way, your injector settings are quite different to mine even though we have the same injectors.
Mine are:
Injector open time@13.2v: 496
Effective ramp up 192
ramp up voltage compensatio is the same for all: 4080
voltage compensation: 304

I am not saying this is 100%, but it worked well enough for the last 2 years.

End angle injection: I really cannot stress enough that you need to set this to 720 everywhere. Read the help section on that table. Press F1 when you are in that table. It is an advanced setting for experienced users.

For warm up enrichment, aim for lambda .85 when cold, say below 50C, tapering to 1.0 when warm. It should be a smooth curve, not linear.
For example, my warm up is done at 70C. It doesn't want more fuel after that really.
Reminder: EGO control enable only AFTER warm up enrichment is done.

These old engines use buckets of fuel during cold start and warm up. My pulse width at cranking is 5.1ms. I idle at 2.0 warm.

That said, in your wideband warm up phase, which should be minimum 30 seconds, you can't see what your lambda is doing but you can extend the warm up curve into that area.

However, keep in mind I run E85 all the time and live in Bangkok.

[morris400]

Chris,

Switched the angle to 720 and changed to simplified setting with deadtimes from Dace and wow. Big change. Also upped the crank Pulse to 8.0ms from 4.0 . Still needs some VE table working but it's much better now.

[ChrisAudi80]

Chris,

Switched the angle to 720 and changed to simplified setting with deadtimes from Dace and wow. Big change. Also upped the crank Pulse to 8.0ms from 4.0 . Still needs some VE table working but it's much better now.

See, told you. The basic settings have to be right first.

Now you can tune your VE table correctly. A tip for driveability, spend lots of time on your low rpm, low kpa cells. Turn off EGO control and try to sit at every cell you can for 5 seconds or more. That way, you have a stable reading.

THEN, you can work on your warm up curve. Another thing you can try is play with the cranking ignition advance. When cold, crank it over at your setting. Get it to start, then increase timing by 2 degrees and see if it start faster or slower. You'll get the idea.

Fuel tuning first though!

[morris400]

i have a pertty solid idea now, i just wanted to do my research before i made any big changes first. yes you were right for sure on the 720 settings. it was night and day once changed. as for the lower kpa driving, that is pretty solid and dialed in now but i will log again soon and see how things are now. i found out that i was spiking at 240kpa boost and i had less fuel after 230kpa on my ve which was causing that split second lean issue. i have corrected that and changed the fuel at 240 and 260 higher. the 3D VE looks very flat and smooth now.

i did change the crank ign adv to 12deg and still took 3 starts to fire up. once it fires up it does not stall and idles really nice now.

shitty part now is that snow has now hit and i dont winter drive the beast lol.

[ChrisAudi80]

i have a pertty solid idea now, i just wanted to do my research before i made any big changes first. yes you were right for sure on the 720 settings. it was night and day once changed. as for the lower kpa driving, that is pretty solid and dialed in now but i will log again soon and see how things are now. i found out that i was spiking at 240kpa boost and i had less fuel after 230kpa on my ve which was causing that split second lean issue. i have corrected that and changed the fuel at 240 and 260 higher. the 3D VE looks very flat and smooth now.

i did change the crank ign adv to 12deg and still took 3 starts to fire up. once it fires up it does not stall and idles really nice now.

shitty part now is that snow has now hit and i dont winter drive the beast lol.

Great to see it drives better now!

Just had a look through the file. You changed to simplified. Interesting. You have a deep valley around idle. That usually mean incorrect settings.
https://vems.hu/vt/help/v3/v3_injector_settings.html

There are a few other settings I would recommend to change, but it's very late here, so it'll be some other day. Will make a few changes to those.

Especially your EGO enable settings and your refDC for boost. I wouldn't put 100% anywhere, especially if you have a large change in DC next to it.
Your EGO comes on at 26C coolant. That is too low. Your warm up is fighting with EGO. Try 70C.

Also, your timing table is extremely steep. I think it would drive better with less sharp changes. 45 degrees is a lot for pump gas. For example, you go from 35* on the 80kpa line to 22* on the 102kpa.

Try cranking VE 80%.

[morris400]

the timing was not anything i really wanted to mess with. this was the timing that was provided to the original owner and was provided by Marc at EFI. i did change the idle area but that was it.

ive tried changing the crank VE to 70 and had 0 improved results. i will look to chnage the EGO setting a bit higher though. small changes at at time lol.

the injector settings i switched based on the 630cc injector settings thread. made a world of difference. the idle dip was that only way to maintain proper lambda. even at 56 its still slightly rich at .97 and im looking to get 1.0.

i hope to get the car out soon and test this file, odds are not good lol. getting super busy right now.

[ChrisAudi80]

the timing was not anything i really wanted to mess with. this was the timing that was provided to the original owner and was provided by Marc at EFI. i did change the idle area but that was it.

ive tried changing the crank VE to 70 and had 0 improved results. i will look to chnage the EGO setting a bit higher though. small changes at at time lol.

the injector settings i switched based on the 630cc injector settings thread. made a world of difference. the idle dip was that only way to maintain proper lambda. even at 56 its still slightly rich at .97 and im looking to get 1.0.

i hope to get the car out soon and test this file, odds are not good lol. getting super busy right now.

I see. I think the timing is just a base map that could do with some work. However, that should be done on a dyno. Tuning ignition timing on the street is only for very experienced tuners. Neither of use are that.

When it comes to injector settings, gotcha. Glad it is improving.

Just leave the cranking VE for now. That means having to play with cranking, afterstart and warm up enrichment. Like I said before, start with warm up enrichment by tunring off EGO and letting sit idling until warm. I know you don't like that, but it's not like you will do it all the time. One or two times should be OK.

[ChrisAudi80]

Can you try this:
Set cranking threshold to 199rpm.

See if that helps with cold start.

[morris400]

Back on the ground. Not going to be doing much with the car now that snow has hit. Looking for suggestions on my cranking enrichment and afterstart enrichment. Still takes 3 starts before it keeps running...and I've also had an issue with the car not starting after tuning it off...I have to hold down the gas as i crank to get it to start.

[ChrisAudi80]

..and I've also had an issue with the car not starting after tuning it off...I have to hold down the gas as i crank to get it to start.

How far do you have to push the pedal to get it to start? This is hot start right?

If you have to press the pedal a little when hot, it usually means not enough cranking fuel. However, you should not really need any.
I seem to remember Marc Swanson saying past 20% TPS is flood clear.

[morris400]

Way past 20%. I'm floored to get it to start. I'm not sure why it floods though

[ChrisAudi80]

Way past 20%. I'm floored to get it to start. I'm not sure why it floods though

In that case you might have too much cranking enrichment. Try reducing it by say 30%.

[ringbearer]

Fresh spark plugs may be a good idea too.

[morris400]

Plugs are brand new. Everything on the top end is brand new.

[morris400]

Way past 20%. I'm floored to get it to start. I'm not sure why it floods though

In that case you might have too much cranking enrichment. Try reducing it by say 30%.

this only happens after i drive the car for a while and then stop and turn it off. when i go to fire it back up it just cranks and cranks and wont fire. if i then hold the gas pedal to the floor it fires up right away.

ive attached my current config file. the enrichment curves are still confusing to me, if you can sort me out or explain to me where they should be that would be much appricheated. also looking to see what may be causing the 3 start thing. im leaning towards the afterstart enrichment ? on cold old start it ALWAYS take 3 starts before i mantain idle. 1st start, it will start and hit 1500 rpm...then stall 2 seconds later. 2nd start is same as 1st and 3rd will start and hit 1500rpm then drop to 1200 and stay running. wondering what settings may be causing this?

thank you again,

Kenny

[ChrisAudi80]

Try this.

[ringbearer]

Too rich can foul plugs fast is why I suggested it

[morris400]

Never even thought of this. I'll pull a plug and see what it looks like. So far I only have 300km on the build.

[morris400]

Try this.

Will give this a shot for sure! You set the crank pulse to 0.0, why was that?