L337TurboZ

iTrader: (1)

Hey everyone, looking to get some help smoothing my idle in my 1990 with MS3. The idle has been an issue before and after going turbo. Not as bad pre turbo but definitley after swapping to larger injectors and turbo. The main issue is that once fully warmed up, idle will hunt back and forth, sometimes stalling the car out when fans, AC, or headlamp load are initiated or when coming to a stop. I have verified that my battery/alternator are good and my voltage drop on positive/negative cables are less than 0.02 volts (I add this fact as I see a lot of GM vehicles with weird electrical issues due to voltage drop across the battery cables). I have tried to adjust my PWM Idle correction, Closed Loop idle PID settings, and I just cant get this thing to be ok once warm. I also face issues with heat soak restarts especially since it has gotten summer time. There are times when I have to do Clear Flood in order to restart the car. Most of the time the car idles around 11-11.5 even though my AFR chart is supposed to be 13, if I lean out the idle region it begins to sweep and my idle goes to crap. I have watched the Youtube videos about setting idle and have done numerous searches on here but am stumped. There has to be something I am missing so I turn to all of you to help.

Here are the specs on my setup

LNC 1.6
FF 650cc injectors
AEM 320 lph pump
Fuel pressure is at 48-50 psi (aeromotive regulator)
Kelford 256 cams
MS3PNP
AEM 30-4110 wideband

Links to my datalogs and tune file
https://drive.google.com/open?id=16L...UweGoY5dYVSEi8
https://drive.google.com/open?id=1BP...cZlccbwHKXbpFU
https://drive.google.com/open?id=1VN...D1axuDka5mraPw
https://drive.google.com/open?id=1uT...Y_GFRvbO0fLcby

andym

I run my 92 with a ms3pnppro with the same injectors and here is my critique that I see with your tune.

1. You don't have idle VE enabled. I would make a dashboard gauge and set it up for ego correction and sit in your car with your laptop and create your idle VE table. Use different engine loads to get to different map sections. Turn on the ac, turn on the fan, lights, turn signals, hold the brakes... Then when you worked on a column up and down for map enable the idle air control valve checker and add more duty cycle to get you to different rpm points on the graph and repeat the same test. I target about 98% ego personally.
2. You don't have idle rpm timing correction enabled. That helped me have a more stable idle. I used values of around. -200 RPM from target 10 Degrees added, -100 and 8, -50 and 5 degrees added, 0 and 0, 50 rpm higher drop 5 degrees timing, 100 rpm high drop 8 degrees and 300 high drop 10 degrees of timing . Do this after you setup idle ve.
3. You also seem to be targeting a very rich afr for your idle cells. Much richer than you should need to.
4. Are you running sequential injection? It looks like the megasquirt thinks you are but did you wire it for that function?
5. Did you properly set your min and max values for the idle air control valve or did you use some presets you found online? To set it, turn off idle rpm timing correction and go over to the test modes and find your true min and max. Min is when the rpm's stop dropping and max is when they stop increasing. Put that into your closed loop idle settings. I use the use MAT temp for my initial values since that works better if it is a hot day out or a cold day out. Coolant temp when up to temp should be consistent.
6. Work on your idle ve table. From memory of my 1.6 engine your numbers seem to be about 20 more than mine ever were.
7. Which version of tuner studio are you running? Free, Paid, Top level with more tabs?
8. Hot restart issue I was able to deal with my adding a longer taper curve to my ASE and adding a bit more ASE to the hot restart areas. I think my taper curve is based off of seconds and set for 30 seconds on hot restart.

I am going to pull out my tuning laptop and see if I can help you with some of these things with what worked well ish from my car.

Also, you have the wrong injector size selected under general settings which throws off the required fuel setting.

andym

I urge you to run compare tune and check out the few tweaks I made on your file and see what they are for your benefit and go from there. YMMV. I hope it steers you into the right direction.

L337TurboZ

iTrader: (1)

I ran the compare tune and saw most of the changes you suggest. I had been running semi sequential when I was using a Haltech ECU (Injector 3 and 4 connectors flipped) so I had selected that setting in MS when I set it up. However I swapped it back to Batch fire and the idle is much more stable now. Had a problem with hot restart this morning but I was mainly trying to see if there was any big change in AFR before going further. Baby steps I guess. I would have played around with more stuff but having to drive to work I didn't want to change too much and be stranded guessing.

I appreciate your help. I am going to try and get this hot restart issue squared away first before enabling idle VE etc unless you think that enabling that will help with my heat soaked restarts. The IAT sensor btw is on the cold side of the engine by the throttle body. Do you think I would have better results by moving into the intercooler? I am waiting on my radiator cooling bar to be finished before I change out my IC to a better unit (I have a spare Evo X IC I plan to run as the core is larger than what I have now)

andym

I don’t know what to suggest regarding intake temp placement. I would think that intercooler would be a better location.

I like idle ve. It gives a lot more resolution at the idle cells that your ve table otherwise would not give. So you can get more precise in those cells. I would use it and tune it well.

Hot restart is mainly an after start enrichment thing. My best luck fighting it was an extended taper at hotter temp and a larger shot of fuel at that time too.

another thing to mention. You had your ego turned off for rpm below 1500 rpm. I use mine a lot and I have it for 500 rpm so at idle it gets me close to my desired afr. And since the ego would be working it would also affect the ego correction % indication so you can adjust your idle ve cells.

Try loading up my tune and see if it gets you closer and work from there.

curly

iTrader: (25)

Hot restart issues are tuned by ASE settings, which are a percentage of your poorly running VE table, so why would you tune that first? Start with your VE table, make that run well, then enable idle VE, make that run well, then look into hot restarts.

You also shouldn't be idling in the 70s IMO, are you sure you have all your fuel settings correct? Currently it looks like you're using a 1.6 with 720cc injectors?

You also have boost control active but no overboost enabled, are you sure about that?

I also hate when you don't actually have an idle column in your VE table. You have 700 and 1200, do you really idle at either of those? I like one column ~2-400 below target warm idle.

L337TurboZ

iTrader: (1)

The car itself does run well off idle. Since the post last night I have corrected numerous settings and got my idle VE table going. Took it to lunch today and had stable idle all the way up to 195-200 temps and no surging or stalling. I also turned the idle cells down from 70 and my AFR's are steady around 13 with a max sweep of 0.1 AFR. Thanks for your feedback and will look into the over boost settings.