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Idle/driving rpm dip questions

Old 03-11-2015, 10:42 AM
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Default Idle/driving rpm dip questions

Hi All,

I've got a couple of questions concerning my MS3. I think I have the answer but just need to be confirmed before I go ahead and tune it out.

Background: the car is a stock MS3 (with a CAI and an exhaust), stock injectors etc.

I've got my idle to sit around ~800-850 when warmed up, so that's a check mark. But here are my questions..

1) In regards to timing, if I jump the switch at the front of the engine, will it make the car idle at a constant 850 for timing tuning? I've been reading through a few threads and they all suggest that this switch is done to keep RPM constants. I'm thinking if I have a new ECU, this switch will do nothing for me. How would I go about keeping the idle sensitive enough to adjust base timing?

2)When I'm driving and I take my foot off the gas, the RPMs dip into the 650 and the car rumbles. I've played around with the VE table around that area and its made it a tad better, but the dip is still prominent. I'm going to guess this has to do with my timing as I've also read that you generally advance your timing at the low end to prevent from this. However, when I use my accessories, turning on heat, turning on radio, lights etc, the dip occurs too. Not sure if that means timing needs tuning or not.

3) My car likes to crank, catch, then die. I'm guessing this is ASE. How many point increments do people usually tune ASE up? (I'm guessing I need to increase as I can save my car by throttle inputs).

4) My WUE autotune keeps lowering my WUE across the range to 100. When I start the car from a cold start, it struggles to stay alive at 500-600 RPM, why is WUE lowering my % when it should be increasing it? I thought it would try to ramp my car up to around 1200-1500RPM to warm it up then drop it back down to idle. Should I be adding WUE while sitting in the car during warmup to hit the 1k+ warmup mark? Or is this not how it works?

5) I've got a reading of knock in Cyl#4: 3.6-4.0 (oscillates between those two). Not sure if this is just a random reading or if I'm actually experiencing knock- I can't hear anything. If this is a problem, what can I do to fix it? (this question I have no clue how I can go about it).

I've done my searches and couldn't find an answer that I deemed fit. Hopefully someone can confirm/deny my logic so I can continue tuning.

Thanks

Also, once the car hits normal operating temperatures, I'm at 14.7 AFR. So everything on that side is good.

I've attached my log incase you'd like to see whats going on with WUE and ASE. My coolant temps are usually around 0C in the winter months up here in Canada.
Attached Files
File Type: msq
MiataFinal.msq (224.8 KB, 67 views)

Last edited by Chowcow; 03-11-2015 at 11:12 AM.
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Old 03-11-2015, 11:32 AM
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lots of issues to tackle in one post.

what are your AFR targets for your warmup AE?

idle dip has to do with a lot of factors, probably the biggest for you when blipping is the accel enrichments. you need to tune your accel-pump.

otehrwise is sounds like your msq needs refinements in general based on your setup. are you more or less stock?
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Old 03-11-2015, 12:31 PM
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Originally Posted by Braineack
lots of issues to tackle in one post.

what are your AFR targets for your warmup AE?

idle dip has to do with a lot of factors, probably the biggest for you when blipping is the accel enrichments. you need to tune your accel-pump.

otehrwise is sounds like your msq needs refinements in general based on your setup. are you more or less stock?
1) I haven't a clue what my AFR targets is for warmup as the idle VE is set to off. But I generally get around 10 then it slowly moves to 14.7 as it warms up.

2) I tune accel pump in the lower regions?

3) I'm stock aside from CAI and exhaust.
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