popping at idle

mraloha · Post by **mraloha** » Mon Jan 29, 2007 1:38 am

On idle after a 15 to 20 min drive in closed loop the car sounds like it has a slight popping noise at idle. at start up or when the car is cold idles fine at 14.7 but after a few minutes of driving its goes up to 15.3 to 15.5 and has a slight popping noise I am thinking its the iat but when I run in open loop It idles fine what to do is it the iat or do I need to do a fuel correction ignition correction what to do cant figure it out and plus there is only one hondata tuner here on Maui and charges 350 to tune and 100 bucks to tell me whats wrong thanks

QUICKSILVER RACING · Post by **QUICKSILVER RACING** » Mon Jan 29, 2007 4:33 am

Buy a wideband about $300.

Or enroll at EFI101. I mean this in a good way. Please don't take it negatively.

A/F should be around 12:1 when engine is cold. and 14 when warm.

Ask more tuning questions. We can help you.

mraloha · Post by **mraloha** » Mon Jan 29, 2007 10:12 am

QUICKSILVER RACING wrote:Buy a wideband about $300.

Or enroll at EFI101. I mean this in a good way. Please don't take it negatively.

A/F should be around 12:1 when engine is cold. and 14 when warm.

Ask more tuning questions. We can help you.

it does do that when its cold goes to 12.0 then slowly climbs to 14.7 I do have a wideband my only problem is that when its hot I have popping sounds coming out of my exhaust sounds like missing or something but a/f is 15.3 when I put it in open loop idles fine. just in closed loop. trying to find out what to adjust the iat correction ect correction ignition I also have 750 injectors could that be the problem

mraloha · Post by **mraloha** » Mon Jan 29, 2007 3:46 pm

searched everywhere cant find anything I guess no one can help on here?

Post by **Spunkster** » Mon Jan 29, 2007 4:53 pm

What wideband are you using? What is your short and long term fuel trim reading?

mraloha · Post by **mraloha** » Mon Jan 29, 2007 5:44 pm

Spunkster wrote:What wideband are you using? What is your short and long term fuel trim reading?

I am using aem uego short term -10 ,20 which one is the long term fuel trim

Post by **Spunkster** » Tue Jan 30, 2007 10:32 am

Post a datalog and calibration

mraloha · Post by **mraloha** » Tue Jan 30, 2007 6:10 pm

Spunkster wrote:Post a datalog and calibration

here it is

mraloha · Post by **mraloha** » Tue Jan 30, 2007 6:12 pm

mraloha wrote:
Spunkster wrote:Post a datalog and calibration
here it is

oh yeah if I didnt say yet I have 750 injectors b18c turbo boosting 10 pounds

Shmaa · Post by **Shmaa** » Tue Jan 30, 2007 9:44 pm

What fuel pump do you have and what is your fuel pressure?

mraloha · Post by **mraloha** » Wed Jan 31, 2007 12:56 am

Shmaa wrote:What fuel pump do you have and what is your fuel pressure?

I have a 255 walrbro fuel pump dont have a guage for fuel pressure though

Asc4130SD · Post by **Asc4130SD** » Wed Jan 31, 2007 9:50 am

It almost sounds like a lean misfire condition at idle. If the HC and NOX are high in the exhaust this would verifiy that there is enough unburned fuel to indicate a lean condition. Try adding more fuel at idle, get the A/F to 14.0-14.5 @ idle. This is more important in areas you are closer to sea level vs. high alttuide conditions where air has less density = less fuel. Ambient weather can also increase the problem as heat warm tropical climates tend to require more fuel to control CC temp. :)

When you go open loop, it takes out the O2 and add a predetermined amount of fuel, which you indicated stops the poping sound. This so also reflect a different reading on the Wideband, most likely going rich 12.5-14.0. but thats way to rich to idle at and mileage would be greatly impacted.

just add fuel at idle speed, up 1200 rpm. As long as you dont run lean under any boost condition you will be alright. hopefully this help. 8)

Post by **Spunkster** » Wed Jan 31, 2007 10:30 am

and where is the requested datalog showing the problem you are describing?

oscarmayer · Post by **oscarmayer** » Fri Feb 02, 2007 5:48 pm

^ the dog ate his homework. ;)

Shmaa · Post by **Shmaa** » Fri Feb 02, 2007 11:20 pm

I have seen several cars do the same thing and each time it was because the fuel pressure was too high. With the walbro and the stock FPR the fuel pressure will go up somewhere around 60psi and with injectors as large as the 750's the pulse speed at idle is so low that it causes these pops.