What do I need for vortec?

[bill28734]

Hey all,
Just getting into hho and am installing a system on a 99 chevy 5.3 Vortec. I have a manipulator for the maf and am waiting on the o2 extender. Without the extender no mileage gain. Anyone work with a vortec before. Thanks, Billy from Franklin NC

[Gary]

I'm getting similar results from my '2000, same engine. Waiting on extenders also. I had a few miles per gain on the first 60 miles (19.2) then dropped off from the computer. Tried "flashing" the battery cables together to no effect. Mechanic friend said that'd do nothing, as it didn't.

[bill28734]

Guess just have to see how the extenders work. I'm thinking about hooking on my map instead of the maf if the extenders do not work like I hope. I will also build an install an extra unit for more production. Hope yours works out too.

[romulus]

I know this thread is old but if your monitoring this I have an 04 tahoe. those extenders made my mileage worse by about 3mpg. Went to a Duel EFIE started seeing some gains (2mgp) added a MAP enhancer and finally got 25mpg on a short run today. Still early.

[Gary]

Hmmm...I was really hoping not to need the EFIE's, but time will tell - once I start using the truck again. 25 looks promising.

[bill28734]

Thanks for the info. Have not had time lately but planning on working on it next week. The extenders hurt my mpg too. Next I am planning on ordering the efie. You have a double but my 99 has only 1 o2 sensor. I think I only need a single. Thanks for any info.

[glbart]

1999 silverado 5.3l has 4 ho2s. u will need a double efie. Hooked into the front 2 o2sensors.

[bill28734]

Thanks for the info. I had looked on the drivers side but did not see the sensor before. After reading your post I checked better and what did I find? The sensor was hid real good. Will change it next week and then retry. Thanks again.