I have an issue on my Evo V (with an Evo VIII ECU) where after a cold start it idles low (below 750) and bucks/sputters/hesitates if you try to drive it before it warms up for a few minutes. Once it warms up it runs great. I had this same map (it's a tephra v7) on my last Evo VIII and it would do the same thing, so I think it has something to do with the tune. Is there anything I can adjust to fix this?

Stock engine, turbo, etc. 91 octane.

 

is your IACV working properly?

 

What are your AFR's when its doing this? Is the car in closed or open loop when it does this?

 

also, if tuned, you could check your cold start enrichment tables.

 

I just started driving the car this week so I haven't done much diagnostics yet. Because my old VIII did the same thing, with the same map, my first thought was map. I will check the mechanical things as well.

I will start it up later in the evening or in the morning and report back with both.

It is a tuned ROM, actually it was tuned by Boosted Tuning, that I had on my VIII. When I turn the key it fires up instantly when the engine is cold. It does take a few cranks after the engine is warmed up. I have messed with the cold start enrichment tables on the E85 side of the map (it's a dual map) back when it was on my VIII because it used to take a lot of cranking to start. Should that affect it once it running or just while cranking?

 

wait, so it starts fine when cold, but harder when warm?

 

That is correct. Cold start it's running on the first crank, but isn't even drivable. Warm start it cranks for a few seconds and then fires up and runs great. This is 91 octane.

 

oooh. disregard my previous statements LOL. i had this issue and Jay was able to fix it. but it was a while back and i can't remember what the issue was...

 

Bump, looking for a table fix.

This seems to happen when running SD also. The car is in Open Loops at cold temps. Do we look at adjusting the high octane map for open loop?

 

post primer enrich decay - try raise it

i went from this

1.5 1.43 1.37 1.30 1.08 1.05 1.03 1.00 1.00

to this

1.5 1.43 1.38 1.33 1.28 1.14 1.12 1.08 1.05

 

Thanks are you referring to the Load Accel IPW Enrichment - Decay Rate? This is a 10.

 

which rom are you using ??

 

So today after I started it I had to use the gas pedal to keep it running so it was hard to tell you the exact AFR's. However after a minute or two I was able to let of the gas without it shutting off and at idle it was very lean, 17:1 to off the gauge. Again, once it warms up it runs and idles great. Any ideas Todd or anyone else? It's Tephra V7.

 

You can also check for a vacuum leak

 

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