Hey guys! I have an VIII that has rough idle when cold. This is on SD with Built 2.0L FP Red, HKS 272, PTE 880, and 91 octane.

Here's the symptoms and diagnostics so far:

Symptoms:

• rough cold start
• engine turns off after first 3 start ups
• drives rough when cold
• AFR stoich cold or warm

Diagnostics:

• swapped CAS with working one
• swapped map sensor
• checked CAS trigger
• boost leak tested
• fixed timing on Fidanza cam gears to 0 (was at 7* advanced)
• logged and found that timing is 8* advanced over timing map (All (all that I know of) warm up maps are disabled and zeroed out). Follows timing map at around 150*F.

The strange thing about this is before the build it had the same symptoms, but I didn't catch the high timing before, so it may be unrelated. After the build I tuned it and never had a chance to do a true cold start. Finally got the car for a couple of days and see the issue, but I don't see how to fix it.

To me it seems like either an ignition warm up table that I'm not familiar with or a heat sensitive sensor that's defective.

With that said I've never needed to change the "Ignition Unknown Control (warm-up?)" table. I'll try it out, but it seems odd I've never had to do this before.

Thanks Evo community!

 

Im having this same issue too :/

I will hit you up on fb

 

Are you running open loop or closed loop during idle/warmup?

If it transitions to closed loop, you could change the "Minimum Temp For Closed Loop Operation" to a desired temerature to try and cure the issue... It is a band aid fix, but it is only for warm up anyway...

 

id look at ign trim v eng temp table zero them out / and post primer enrich decay table, i added 0.03 to them leaving the last 2 untouched cured my cold start probs

also 560 for start ipw latency msec , im using pte 880cc also similar spec on sd

 

Thanks Freddie!!!

I'm running CL for idle/warmup. It's set stock at 45*F. It hasn't been that cold until today.

Thanks Todd!!

Fuel is spot on. I tried a richer start up and it keeps the timing the same at 8* higher than the timing map. All it did was made it run richer until o2 kicked in.

I've since band aid fixed it. I wanted to run 11-13* at idle. To do that during warm up I had to put the timing to stock at idle at 5*. On cold starts it idles and drives fine now at 13* (5* set in map plus the odd additional 8*). When warm it's at 5* which works good on these cams.

I'd still like to know why this is happening. Must be a scaling thing in my ignition warm up tables.

Thanks again everyone. I'll see if I can find this and report back if I do.

 

It's running 8* additional timing compared to the timing map? Interesting.

 

hmm interesting try evoscan actuators " Ig 5deg btdc " ign on /eng stopped

 

That is strange Is this only happening in open loop or closed loop or regardless? Perhaps bump the minimum temp for closed loop up to around 90* F and see how that helps... I will have to check that on my car when I get back home this weekend...

 

Yes, both open and closed loop. It appears to go away, like it interpolates as the temp starts hitting 150*F. Finally it hits the target timing in the map.

 

if you have bigger injectors all those tables should have been changed
- IPW while cranking starter (main maps)
- post cranking IPW adder #1
- post cranking IPW adder #2
edit : new value = old value * (stock inj. cc / aftermarket inj. cc)

0/5 "pro tuners" where I live did that and people had their engine drowned in fuel especially in winter because of that
I discovered this in one of threads on evolutionm, my car also didn't have that change

can't tell you much about timing because with the MIVEC on my IX it seemed to never do what was in the maps