BRTNCUSTOM

I just finished upgrading my secondary fuel rail, But now when the car is idleing it surges between 500 to 1000 rpm. The car never did this before so im guessing it has to do with when i removed the UIM but im not sure. The injectors were installed yesturday. When i first started the car it idle fine untill it warmed up then it started to surge and it did it this morning. If anyone has any info i would appreciate it.

Thanks,

cewrx7r1

iTrader: (2)

AIR LEAK caused by the work done.
Easy to verify by manually reducing idle speed(air intake) and if this works you know for sure.

BRTNCUSTOM

Last time i took my UIM Off it surged for awhile but the next day it went away. Would that also been an air leak?

Carl Byck

Usually that is caused by an over lean idle. Did you do anything in that regard? Are you running a stand alone? Do you have a WBO2?

BRTNCUSTOM

I hive a WBO2 and im running a PFC

Carl Byck

What are your AFRs at idle? Did you change injector sizes?

93FD3S

Airtemp sensor umplugged maybe?

BlaCkPlaGUE

Sounds exactly like you didn't change the injector grommets, unmetered air is now entering the system through them. Either they are old and shrunk, or cracked, or your injectors were of a slightly different size (smaller) than your stock ones. If you had your injectors cleaned and the pintle caps replaced, they could be of the wrong size for the stock grommets, as in slightly smaller. Finally, and the last thing if the other reasons do not check out, your fuel rail is not seating the injectors properly. They should be nice and snug in there and difficult to twist whatsoever.

good luck.

Carl Byck

Unmetered air will show as a lean condition, thus my original post. But then you have a solution.