Is ICV required MSPNP?

[Saascat1]

Hi All,

Sorry if this is a dumb question........I tried to find info by searching this forum and had no luck.

Do I need to still run a stock ICV? Can someone explain "closed loop" idle for me?

I will be running wideband O2, IAT with AFM delete and inbuilt MAP sensor, I will also be using both a crank trigger, and a cam position sensor for sequential ignition with DIYAutotune 6 pack coils.

And while I'm asking dumb questions............ Wasted spark?

I appreciate any help on this.

Cheers

[Me+SPEED=]

Read

http://www.megasquirt.info/

Read it again
Then read some more

[whodwho]

You do not need to run one but no real reason not

Closed loop is basically you set a target idle rpm and the ECU varies the ICV to keep at the target rpm.

You don't need a cam sensor as you wont be running sequential spark with that system or that coil on a 6 cyl

you will be running wasted spark with that coil and will need to run 3 ignition drivers, that coilpack has three coils that each fire two plugs at a time, one on compression stroke and a 'wasted spark' on the exhaust stroke of the 2nd cyl.

[nando]

You don't need it but you definitely want it.

[Cyrix2k]

You don't need it but you definitely want it.

why? I don't run one in my '85. It's useful for two things - cold starts and load compensation for a/c. I don't run A/C and unless it's freezing cold outside, the car will idle almost immediately after starting. When it's cold, I have to give it a little gas until it warms up. I left it out of this build for several reasons. 1) I didn't want to deal with the gooseneck on my m50 under boost 2) I run three coil drivers for wasted spark and without the ICV transistor, all the coil drivers mount to the internal MS heatsink 3) it's one less thing wire and tune. I'll be adding it back in on my new build since the objective is to move towards a factory-like DD.

[Saascat1]

why? I don't run one in my '85. It's useful for two things - cold starts and load compensation for a/c. I don't run A/C and unless it's freezing cold outside, the car will idle almost immediately after starting. When it's cold, I have to give it a little gas until it warms up. I left it out of this build for several reasons. 1) I didn't want to deal with the gooseneck on my m50 under boost 2) I run three coil drivers for wasted spark and without the ICV transistor, all the coil drivers mount to the internal MS heatsink 3) it's one less thing wire and tune. I'll be adding it back in on my new build since the objective is to move towards a factory-like DD.

Thanks Cyrix2k,

That answers my question quite well as the throttle body I'll be using does not have any facility to mount an ICV.
I have bought a "Quadspark" ignition driver from DIYAutotune, it is an external driver with a built in heatsink, to run their IGN-6 coils, essentially a triple pair. With all due respect to Whodwho, do you run sequential ignition with your setup?

Thanks to all contributors

[nando]

why? I don't run one in my '85. It's useful for two things - cold starts and load compensation for a/c. I don't run A/C and unless it's freezing cold outside, the car will idle almost immediately after starting. When it's cold, I have to give it a little gas until it warms up. I left it out of this build for several reasons. 1) I didn't want to deal with the gooseneck on my m50 under boost 2) I run three coil drivers for wasted spark and without the ICV transistor, all the coil drivers mount to the internal MS heatsink 3) it's one less thing wire and tune. I'll be adding it back in on my new build since the objective is to move towards a factory-like DD.

LIke I said.. you don't need it, but you want it. ;)

if you don't daily drive the car, you can probably do without. But if you DO dd the car, then it's going to be a gigantic pain in the ass every morning on your way to work. Also, your idle will change with the weather, you can fiddle with the throttle stop all you like but it will never settle at one RPM.

it's not that hard to tune, either. The latest idle codes are pretty well sorted out, it doesn't take more than a few cold starts and maybe 15 minutes to get them dialed in to 95% these days. Not tuning isn't really a reason to not use one. You could just use warmup mode if you don't want to spend time on it right away, or set it to a fixed DC.

When I had MS2 I had an external board with the coil drivers and ICV drivers (glensgarage board), I didn't mount them on the main heatsink. You need two drivers for the 3 wire ICV anyway, I'm not sure there's room.

One more reason to use MS3 - no extra mods, it's all built in. :p

as far as sequential ignition - not really any point on MS2. There are benefits to sequential fuel, but diminishing returns going from wasted spark to sequential ignition. I can switch mine on the fly and you can't tell any difference at all. MS2 is more I/O limited than MS3, I'd want to save all the I/O I could for better purposes (boost control is one). Semi sequential fuel would be worth doing though, and you don't need a cam sensor either.

[whodwho]

Not thinking >4 cyl sequential fuel or spark is an option on any of the MSPNP units??

[nando]

you can do sequential spark, I think up to 8 channels but only semi-sequential injection above a 4 cyl.

[Jaxx_]

You don't need it but you definitely want it.

yes. I have no ICV on my setup, but it's nice to have to not have an overly hunting idle. Once you get the 4 main idle cells dialed in, it's not too bad. It is always better with it, though.

[Cyrix2k]

LIke I said.. you don't need it, but you want it. ;)

if you don't daily drive the car, you can probably do without. But if you DO dd the car, then it's going to be a gigantic pain in the ass every morning on your way to work. Also, your idle will change with the weather, you can fiddle with the throttle stop all you like but it will never settle at one RPM.

it's not that hard to tune, either. The latest idle codes are pretty well sorted out, it doesn't take more than a few cold starts and maybe 15 minutes to get them dialed in to 95% these days. Not tuning isn't really a reason to not use one. You could just use warmup mode if you don't want to spend time on it right away, or set it to a fixed DC.

Did you ever try DDing the car without an ICV? I drove mine during the summer (put 3k miles on it in a month) and it's not a problem as long as the weather is reasonably warm. Yes, the rpm will drift depending on the temperature but it's more consistent than you would think. With the gslender firmware, it's actually possible to use the timing & fuel mixture to adjust the idle speed by minor amounts. A fast idle valve would certainly be nice for the winter.

So yes, for a DD, an ICV is nice. For a fair weather car I'd consider it optional. Just my two cents.

When I had MS2 I had an external board with the coil drivers and ICV drivers (glensgarage board), I didn't mount them on the main heatsink. You need two drivers for the 3 wire ICV anyway, I'm not sure there's room.

One more reason to use MS3 - no extra mods, it's all built in. :p

as far as sequential ignition - not really any point on MS2. There are benefits to sequential fuel, but diminishing returns going from wasted spark to sequential ignition. I can switch mine on the fly and you can't tell any difference at all. MS2 is more I/O limited than MS3, I'd want to save all the I/O I could for better purposes (boost control is one). Semi sequential fuel would be worth doing though, and you don't need a cam sensor either.

agreed.

yes. I have no ICV on my setup, but it's nice to have to not have an overly hunting idle. Once you get the 4 main idle cells dialed in, it's not too bad. It is always better with it, though.

The idle shouldn't hunt. That's a result of tuning and an ICV shouldn't be utilized to correct it.

[nando]

Did you ever try DDing the car without an ICV? I drove mine during the summer (put 3k miles on it in a month) and it's not a problem as long as the weather is reasonably warm. Yes, the rpm will drift depending on the temperature but it's more consistent than you would think. With the gslender firmware, it's actually possible to use the timing & fuel mixture to adjust the idle speed by minor amounts. A fast idle valve would certainly be nice for the winter.

So yes, for a DD, an ICV is nice. For a fair weather car I'd consider it optional. Just my two cents.

Yes, actually, and it was during the summer. It sucked.

i spent 4 hours or something in a border lineup on a hot day with no ICV. It was awful.

it's like, you can do without one of your thumbs.. but life is a lot nicer when you have both. :)

The idle shouldn't hunt. That's a result of tuning and an ICV shouldn't be utilized to correct it.

it hunts because air density is variable and there's no way to compensate because the TB is stuck in one place. I could set it for a perfect idle one day and it would change 100rpm the next day.

[Cyrix2k]

Yes, actually, and it was during the summer. It sucked.

i spent 4 hours or something in a border lineup on a hot day with no ICV. It was awful.

it's like, you can do without one of your thumbs.. but life is a lot nicer when you have both. :)

And what did being stuck in a backup do? I worked in DC... unless something is wrong with your setup, it should be fine. Remember that's how all older vehicles are.

it hunts because air density is variable and there's no way to compensate because the TB is stuck in one place. I could set it for a perfect idle one day and it would change 100rpm the next day.

the rpm the engine idles at will change, but it shouldn't hunt for idle. The hunting is a result of timing or fuel mixture changes. So yes, if you have a problem with the engine not sitting at a specific RPM, then you will have issues. If all you care about is the engine idling around a given speed, then no ICV is needed.

[FLG]

Turbo m20, No icv and besides having to wait for warmup (which you should do regardless) she's pretty solid once warm. Had to bump the idle up to 900 or so but not an issue freezing winter or hot summer days.

Yes cold winter days it tends to idle more at 1k but took temps to get below freezing before that happened. Normally just sits happily at 900

Driven in summer and winter and have never touched he idle screw after It was set.

Sent from my Galaxy Nexus using Tapatalk 2

[nando]

exactly.

As the engine warmed up, or heat soaked, the idle changed, and if I didn't have a laptop I had no means to change it. It didn't oscillate, it was just different everytime I drove the car. sometimes it would be 800rpm, sometimes it would be 1200rpm.

If you drive your car 5 days a week that will drive you insane. it might be a perfect 900rpm on your way to work and then a shitty 500rpm at lunchtime.

older cars usually had a choke, either manual or electric (mopars had a thermal choke that worked OK). actually, I didn't mind manual chokes. once you got used to it you could get cold idles down pat. But, that's like 1950s bullshit right there. electronic idle control is like 1985 technology, it's really a no brainer IMO. :)