erratic idle

b16_sol · Post by **b16_sol** » Tue Oct 07, 2008 3:40 am

I have a 94 del sol si, with a b16b swap, jackson racing supercharger, rc 550cc injectors, msd digital 6 ignition, blaster ss coil, hondata s300 in a p28 ecu.

The problem is that when I start the car cold, the idle goes to 3k for about 2 minutes, then bounced back and forth from 1200 to 2600.

When I start the car when it's warm the rpm bounces back and forth from 1200 to 2600 even after driving on the freeway at 80 mph for 30+ minutes.

I have changed the idle air control to one that worked on another car.

the coolant temps seem to stay low even after hard driving, is it possible that the low coolant temps are causing the erratic idle? If they are, is there a way to adjust the valve through the ecu to make this stop? Or should I be looking at something else?

Post by **Spunkster** » Tue Oct 07, 2008 9:29 am

It sounds like you have a vacuum leak. You will have to check for and fix this.

b16_sol · Post by **b16_sol** » Tue Oct 07, 2008 8:28 pm

I will have to check that out. But would a vacuum leak cause it to bounce up and down like that? Every time I have seen a vacuum leak it's been steady but higher than normal.

Post by **Spunkster** » Wed Oct 08, 2008 9:21 am

a vacuum leak can make it fluctuate.

b16_sol · Post by **b16_sol** » Sat Oct 11, 2008 12:37 am

Turns out it was the FITV. Now I have no vtec. Would the vtec settings for a b16a be different for a b16b?

Post by **Spunkster** » Mon Oct 13, 2008 9:25 am

no they will not be any different

b16_sol · Post by **b16_sol** » Wed Oct 15, 2008 5:51 am

I hooked up the laptop to the ecu and monitored what the ecu was reading when the motor went flat. Vtec works, here's what I think the problem actually is:

The tables in the tune go to 12psi and 8k rpm. When the problem occured the map sensor was reading 12.9 psi. So there was no fuel map for the pressure it was reading.

So, 2 questions. How do I get the fuel/timing maps to go over 12psi? How do I get the rpm portion of the map to go over 8k?

I switched the hondata map sensor out for the stock one and it works fine.

I'm attaching the tune, maybe you can figure it out.

Post by **Spunkster** » Wed Oct 15, 2008 9:52 am

Go to Options and clickon show 3 Bar tables. IT does not look like you have proper fuel values above 12psi.

http://www.hondata.com/media/smanager_t ... diting.mov

b16_sol · Post by **b16_sol** » Wed Oct 15, 2008 7:57 pm

It's not tuned above 12 psi. I figured out the problem with the motor going flat was the boost cut was set for 13 psi, and it's somehow boosting over that. Now I can get the car tuned.