heavy cam won't idle when cold
04-24-2018, 06:42 PM
#1
heavy cam won't idle when cold Recently changed the cam to a 228R from a ZO6 factory cam. When the car is cold it won't start without a bit of gas pedal, it also requires you to keep it about 1,500 for the first 30-45 seconds before it will stay running. When warm it's fine. I have run the idle air and adjusted as necessary but I have to be missing something simple... Attached is the current HPT file. Any ideas? Pointers? Something glaringly obvious?
04-24-2018, 06:46 PM
#3
Can't look at tune on my phone but general comments and questions.
did you perform ve or maf table changes based on a wideband tune?
Did you adjust the after start fuel temp enrichment? This is overly rich stock and will make a cammed car drive like crap until it's warm.
Assuming you changed the desired airflow table you also need to tweak the different proportional airflow tables for overshoot or undershoot.
How much idle timing? You need to make sure you have enough timing especially during cold start and tweak the timing idle tables.
did you perform ve or maf table changes based on a wideband tune?
Did you adjust the after start fuel temp enrichment? This is overly rich stock and will make a cammed car drive like crap until it's warm.
Assuming you changed the desired airflow table you also need to tweak the different proportional airflow tables for overshoot or undershoot.
How much idle timing? You need to make sure you have enough timing especially during cold start and tweak the timing idle tables.
04-24-2018, 07:08 PM
#6
There is a really good thread on how to fix this properly in the HP Tuners forum. I will see if I can find the link. It's not a fast process to find the sweet spot though.
04-24-2018, 07:10 PM
#7
Can't look at tune on my phone but general comments and questions.
did you perform ve or maf table changes based on a wideband tune?
Did you adjust the after start fuel temp enrichment? This is overly rich stock and will make a cammed car drive like crap until it's warm.
Assuming you changed the desired airflow table you also need to tweak the different proportional airflow tables for overshoot or undershoot.
How much idle timing? You need to make sure you have enough timing especially during cold start and tweak the timing idle tables.
did you perform ve or maf table changes based on a wideband tune?
Did you adjust the after start fuel temp enrichment? This is overly rich stock and will make a cammed car drive like crap until it's warm.
Assuming you changed the desired airflow table you also need to tweak the different proportional airflow tables for overshoot or undershoot.
How much idle timing? You need to make sure you have enough timing especially during cold start and tweak the timing idle tables.
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04-24-2018, 07:19 PM
#11
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It's been a few years now, so I honestly don't remember. I wanna say it does, and that he said it's to small, which is why I have the cold start idle issue. I'll have to ask him. I've just learned to live with it lol. It fluctuates for maybe 30 seconds on a total cold start then it's all good
04-24-2018, 07:20 PM
#12
04-24-2018, 07:24 PM
#14
It's been a few years now, so I honestly don't remember. I wanna say it does, and that he said it's to small, which is why I have the cold start idle issue. I'll have to ask him. I've just learned to live with it lol. It fluctuates for maybe 30 seconds on a total cold start then it's all good
04-25-2018, 11:11 PM
#15
I just tuned a c5 m6 vette with a 228 cam. After a hour tweaking it it drived great. Owner drives it daily. Sounds like your tune isnt very good.
For a good cam tune u need the correct rpm, timing, base running airflow, tb opening, and a good ve/maf fueling. Tht cam should be pretty easy to tune in tht setup.
For a good cam tune u need the correct rpm, timing, base running airflow, tb opening, and a good ve/maf fueling. Tht cam should be pretty easy to tune in tht setup.
04-26-2018, 01:56 PM
#16
I just tuned a c5 m6 vette with a 228 cam. After a hour tweaking it it drived great. Owner drives it daily. Sounds like your tune isnt very good.
For a good cam tune u need the correct rpm, timing, base running airflow, tb opening, and a good ve/maf fueling. Tht cam should be pretty easy to tune in tht setup.
For a good cam tune u need the correct rpm, timing, base running airflow, tb opening, and a good ve/maf fueling. Tht cam should be pretty easy to tune in tht setup.
04-27-2018, 04:22 PM
#18
That's exactly what I did. It idles at 850 and then gradually comes down as it warmes up. The IN GEAR / AC on is also 50 RPM's higher across the board. I have not messed with the over/under tables yet I'll take a look there next time I am messing with it.