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View Full Version : quick help with 5.3 idle question... Help!



Mr.VENGEANCE
12-17-2013, 09:24 AM
fellas.. at a bit of a hiccup on Stormy..

I have driven it without O2 sensors twice for a short distance twice..

The idle isnt balancing after I rev the engine but the car maintains an idle of 500rpm.. so if I rev the engine the car conks out.. crank it up.. idles until I rev.. everything else is hooked up properly.. the car drives fine but keeping that idle when it stops.. also its kindof cold here.. 35 degrees.. condensation coming out of the tailpipes.

the other problem is that I used a harness from another engine that I dont know what year it is from and the O2 connectors are "female".. So I took the "male" ends off of another harness I had laying around and wired it to the random O2 sensors I had.. put them in the car before and it ran super rich and conked out.. should I have let it cycle?.. would it have balanced out?.. does the O2 sensors HAVE to be year range exact?

thanks for the help fellas!!!!

Mr.VENGEANCE
12-18-2013, 10:11 AM
noone have an idea?

srh3trinity
12-18-2013, 10:31 AM
Check the fuel pressure at the rail. I had a boat that would do the same thing. Fuel pressure regulator was bad and it was running rich. The ecm didn't like it and it would fall on its face after an initial throttle cycle.

Red67Mustang
12-18-2013, 04:46 PM
One though might be that the 'new' harness isn't allowing proper control over the IAC valve, or that the IAC is bad. (Full disclosure, I'm not an LS Engine guy, but I've been around my share of EFI issues.... and I stayed at a Holiday Inn Express last night!).

Anyway... If you have the ability to run a Data Log to observe the idling / rev / conk-out scenario - that'll likely show you the problem pretty quickly.