# Don't want to baby my throttle on start up anymore. MS 16vT



## fakename (Apr 5, 2012)

I've got to rock my throttle to get my car started, it's tuned so that it fires on the first crank but with feathering the throttle. Then I need to hold it around 3500 rpms for 5-10 secs to keep it from stalling. I'm fine with this just being the way that it is, but I'm hoping there's something I'm missing that could make it start a little more like stock. 16vT, MS, no IAC, stock distributor. Any other information that may be needed, please ask. Any input will be helpful. Thanks!


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## ps2375 (Aug 13, 2003)

Add an IAC valve. On a cold start the motor needs the extra air until it warms up a bit.


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## youlostme21 (Aug 12, 2008)

Sounds like you ASE or warm up enrichment isn't right.


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## fakename (Apr 5, 2012)

I've tried different wue settings, leaner, richer, doesn't seem to make a difference in those first 10 seconds after if fires up, still needs throttle. I think I would just need an IAC.

But to those of you who aren't running IAC's, do you have the same experience?


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## youlostme21 (Aug 12, 2008)

I have no iac, and if its below 50 or so I do new to baby the throttle alil to keep it running. But if its warmer then that it starts right up and idle fine. I'm still working on the tune, and would like to add an iac eventually, but it's not crucial at this point


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## fakename (Apr 5, 2012)

youlostme21 said:


> I have no iac, and if its below 50 or so I do new to baby the throttle alil to keep it running. But if its warmer then that it starts right up and idle fine. I'm still working on the tune, and would like to add an iac eventually, but it's not crucial at this point


Oh yeah? That's the vr in your signature? Is it on MS? Single coil/distributor? My buddy mentioned that crank sensed ignition and indiv. coils do a better job. I'm just trying to narrow it down.


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## youlostme21 (Aug 12, 2008)

Yea vr, MS2 on a V3 board. Running off the toothed wheel, using a ford coil pack.


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## fakename (Apr 5, 2012)

Ok, maybe it is my ignition set up. I think I'll ask in the 16v forums. Thanks


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## ps2375 (Aug 13, 2003)

It's not the ignition setup, it's what you think it is, needs a ISV to help it when cold. With mine I can turn the key and most times never even touch the gas pedal to start and idle when cold. And after checking mirrors and fastening seat belt, car can just drive away with little to no fuss.

What coil are you using, I found that a mkIII/IV coil gives a noticeably better spark, just by the difference in drive-ability over the stock canister style coil.


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## fakename (Apr 5, 2012)

Oh ok. Does yours have an IAC valve? My coil is an MSD blaster 2 8222


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## ps2375 (Aug 13, 2003)

Yes, I do have a valve. I'm running a v2.2 board and I added the TIP120 transistors to run the 2 wire bosch valve, same one as on the VR's and digi cars, not sure what it was on originally, as it was in a bunch of spare parts my brother got from somebody.


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## fakename (Apr 5, 2012)

So how do you suppose youlostme21 (above) has an easy start and idle without the valve? Is it just differences in engines, vr/16v? Turbo/supercharged?


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## ps2375 (Aug 13, 2003)

fakename said:


> So how do you suppose youlostme21 (above) has an easy start and idle without the valve? Is it just differences in engines, vr/16v? Turbo/supercharged?


That could depend on a number of things, like where the TB stop is set to, what rpm he has it idling at. And the things that he mentioned.

You could use the bypass screw to add air at idle and then retune to bring warm idle back down near where it is now. There is also the ability to advance the timing with colder coolant temps, aiding cold start idling.


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## fakename (Apr 5, 2012)

Yeah, I've done those things, adjusted idle screw, advanced low rpm timing and retarded my warm idle timing, they're about 150-200 rpms away from one another. Once I've got it after those first 5 secs, it's gold. It's just having to keep my foot in it until then... cadillac problems, I know 

youlostme21, do you have an electronic throttle or is it cable driven?


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## youlostme21 (Aug 12, 2008)

Cable throttle with a set screw. I idle around 900 rpm. When cold I do have an issue where it wil stall on rev down. Real pain in the ass. I need more time with the car. Kids,wife and house are slowing progress


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## still_a_G (Jun 23, 2008)

3,500 RPMs sounds like a lot for After Start. Air is one thing and an open ISV will help. I've found that ramping my timing up during the transition from 300 RPM to 1,500 RPM helps liven it up after the engine engages Run mode.

Also, our ISV's are useless without PID control. The PID routine has its quirks though.


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## fakename (Apr 5, 2012)

still_a_G said:


> 3,500 RPMs sounds like a lot for After Start. Air is one thing and an open ISV will help. I've found that ramping my timing up during the transition from 300 RPM to 1,500 RPM helps liven it up after the engine engages Run mode.
> 
> Also, our ISV's are useless without PID control. The PID routine has its quirks though.


What do you mean by PID control? And I'm certainly ambivalent to adding any more quirks to this car :facepalm:

How does your timing ramp up from 300-1500? I have my timing higher around 800 than I do at 1000 to keep my cold and warm idles within a hundred rpms. Works great.


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## fakename (Apr 5, 2012)

I'm a dummy, forgot that I had adjusted my VE idle boxes richer and didn't compensate my WUE so I was running too rich on start up . I'm a dummy. Thanks guys. At least this is giving me another opportunity to adjust my neglected cold start tuning.


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## ps2375 (Aug 13, 2003)

progress?


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## fakename (Apr 5, 2012)

Thanks for asking. I'm getting as far as I did last time I tried tuning. I realized that I wasn't even using ASE and just relying on my warmup enrichments. So bringing those down and bringing the ase back up has helped a lot with keeping it from stalling (still have to hold the throttle but it's not as bad). But right now it fires up after the second crank. Here are current settings:









Previously I had everything the same except my extra cranking fuel enrichment was 60% and it would fire up after the first crank. I don't know why my settings need to be so much richer than others that I've seen.


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## still_a_G (Jun 23, 2008)

fakename said:


> What do you mean by PID control? And I'm certainly ambivalent to adding any more quirks to this car :facepalm:
> 
> How does your timing ramp up from 300-1500? I have my timing higher around 800 than I do at 1000 to keep my cold and warm idles within a hundred rpms. Works great.


I have a 12 lb flywheel so idling is a little harder to achieve. If I try leaving my ISV in one position, it will die due to variations in air density. PID or "closed loop" control of the ISV will adjust the position accordingly. It's hardly perfect but it's better than stalling at traffic lights.


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## ps2375 (Aug 13, 2003)

I notice on the "Spark Settings" table, that you have a value of "2" in the hold ignition, put that at "0" to get spark sooner. Right now you are "holding" spark for two revolutions of the motor before you get spark.


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## fakename (Apr 5, 2012)

ps2375 said:


> I notice on the "Spark Settings" table, that you have a value of "2" in the hold ignition, put that at "0" to get spark sooner. Right now you are "holding" spark for two revolutions of the motor before you get spark.


Yeah, that's intentional. When I put it at 0 or 1, it turns over but doesn't catch until the second crank. With these setting (and extra cranking set to 60%) it fires on the first crank with the hold set at 2. I think it just needs to cycle fuel a couple of times before it can start or something like that-needs a lot of fuel. I'm trying to get that elusive first crank start up and with a hold of 0 would be totally ideal but I keep pushing up against what I feel is way too much fuel on cranking. Maybe I'll try the 60% with a hold of 0, haven't tried that in awhile. Admittedly though, I do a pretty bad job of noting changes every morning that I go out to tune it so I'm sure I've tuned my cold start in circles more than a few times. I'm just going for leaner/richer and seeing what makes a difference.


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## -RalleyTuned- (Nov 17, 2008)

You will never get the car to start and idle perfectly cold without using an idle valve or setting the idle of your car really high. 1500 rpm warm idle makes a near perfect 900 rpm cold idle :laugh:

I will note that having a crank trigger/coil pack setup works 100% better for cold starts and tuning. My 1.8t without an idle valve will idle in 20 deg weather at 400rpm. The stock distributor just has too poor of a signal to work well under 800 rpm or so


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## fakename (Apr 5, 2012)

Thanks, it's Brendan right? (we know a few of the same ppl)
Jake was also mentioning that about crank triggering and coils. I was surprised when I fired up that porsche 1.8t at his place and it turned right over without any throttle at all. No IAC either. So jealous of that car, but that wasn't the only reason...

The power steering on my block doesn't accommodate something like the 034 crank trigger wheel which I was thinking about using. But I'd also be a little nervous about debris or whatever messing it up. I think I'll just stick it out until I ultimately swap blocks but it's not big enough of an issue to do that right now. I'm just looking for shortcuts/easy ways out. :thumbup:


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## -RalleyTuned- (Nov 17, 2008)

yup :beer:

install a rabbit IAC, its two wires and you can hook it up on a switch if you dont have the ecu setup for the on/off style idle valves. Would take a relay and about 10 min to install :thumbup:


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## fakename (Apr 5, 2012)

-RalleyTuned- said:


> yup :beer:
> 
> install a rabbit IAC, its two wires and you can hook it up on a switch if you dont have the ecu setup for the on/off style idle valves. Would take a relay and about 10 min to install :thumbup:


Oh man, never thought of hooking it up to a switch like a choke. Why does that seem so brilliant?!? Thanks man, I'll look into that. Rabbit IAC have a particular part number, or for a specific year/engine?

I've done some quick searching and found a few isv's. Do you guys know if any has an idle adjustment on the isv itself? Looks like the ecu would control it by regulating the voltage. It would be nice to have one with a manual adjustment that would do that.


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