Jb4 cold start

[Bdavid1122]

Installed the jb4 and have been experiencing a rough idle/miss on cold start. Once the car idles down its gone. I'm assuming this is from the colder HKS plugs needing time to warm up, but I'm not sure. I'm using 93 octane gas. Is there a way to log the cold start? Or is this a common thing?

 

[monusa]

Installed the jb4 and have been experiencing a rough idle/miss on cold start.

Set the jb4 to map 0 (disabled) and drive the car as normal including cold starts. This could be just the HKS colder plugs as you suspect. My Stinger did the same thing on cold starts which is sort of common for that type of plug. If you get missing while driving with the jb4 disabled, then could be bad gas or may want to confirm plug gap.

Extreme case would be to replaced plugs with a new set W/proper gap and see if those symptoms ease up.

 

[Bdavid1122]

Set the jb4 to map 0 (disabled) and drive the car as normal including cold starts. This could be just the HKS colder plugs as you suspect. My Stinger did the same thing on cold starts which is sort of common for that type of plug. If you get missing while driving with the jb4 disabled, then could be bad gas or may want to confirm plug gap.

Extreme case would be to replaced plugs with a new set W/proper gap and see if those symptoms ease up.

Started the car on map 0 today and the issue was gone. Guess I'm going to have to remember to put the car in map 0 before I turn it off.

 

[monusa]

Started the car on map 0 today and the issue was gone. Guess I'm going to have to remember to put the car in map 0 before I turn it off.

When I first used the jb4, I didn't do that either. At some point, it just made sense to me to set the map to 0 but nothing in the documentation/forums say it is necessary. Test it a couple more days and if the hesitation does not come back, then by all means, set it to map 0 when done for the day. I would still check plug gap at some point but that would just be for "ease of mind".

 

[Intelliburn]

Jb4 does not engage until WOT. So map 0, map 2, map 3, etc are the same until this occurs. Also, unless the safety feature is turned off (I forget what bit), JB4 doesn’t engage until the car is warmed up (usually around 200). More than likely the plugs need properly gapped. If you have misfires after cold start (such as on WOT) then it is probably a bad plug. A more extreme case would be a bad coil pack (most likely not the case but possible)

 

[Spaceme17]

Installed the jb4 and have been experiencing a rough idle/miss on cold start. Once the car idles down its gone. I'm assuming this is from the colder HKS plugs needing time to warm up, but I'm not sure. I'm using 93 octane gas. Is there a way to log the cold start? Or is this a common thing?

Colder heat range spark plugs do not need to “warm up”. The “colder“ plugs just mean there is more area of the porcelain of the plug in contact with the body of the plug. It helps draw more heat away from the cylinders to help prevent knocking.

Likely is that the plug gap needs to be adjusted. If you are at say 0.024 gap, I would go to 0.022 and see if it is better.

 

[ChaneRZ]

Your car should not have a rought idle at start up. Might be a bad plug. Don’t tell me you bought your plugs at Amazon.
I have HKS @ .022 and E30 mix and have no problems at start up even on cold weather. Engine purrs good.