Flex fuel injectors
 

I am at the point where I am getting ready to start working my harness and wanted your input. I have a complete 5.3/4l60 that I pulled from a 99 Silverado. I am putting it into my 73 step side for a nice daily driver that is decent on gas. I also have a 2004 5.3 flex fuel engine that I bought for parts.

So here lies my problem, I was looking up flow rates and noticed that the injectors on the 99 are only 21.8 lbs. The flow rate for the flex fuel injectors is 33 lbs but the connections are different. So now I have to decide what injectors to use prior to building my harness. I know that the flex fuel injectors will help if I do power adders, but will it hurt my fuel economy until I decide to go that route. The guy flashing my pcm said that he needs to know what injectors I am using as well.

I guess the question I am trying to ask is will the 33 lb injectors vastly effect my fuel economy on a stock tune?

Re: Flex fuel injectors
 

Make sure your flex fuel injectors are good before you start changing things. It may just be my luck, but the flex fuel injectors seem to be more prone to sticking than the others. I have a full set of '03 injectors that are all completley stuck and no amount of cleaning them has been able to make them work.

Re: Flex fuel injectors
 

If the guy flashing the pcm knows which injectors your running, then you won't suffer like you would with larger injectors on a stock tune.

If your really going to change injectors, looking for the "taller" injectors that run the ev1/ev6 plugs is a better bet. You can swap to the injector clips, then have the freedom to run most of the aftermarket injector companies, aftermarket flowed injectors, or even "regular" car injectors from junkyard f*rds etc (like the svo green or blue top injectors at about 39lb/hr...cheap). the multec II truck injectors and clips limit you to only a few injector choices.

Re: Flex fuel injectors
 

Ok thanks for your help guys. So if the tuner knows what injectors I use, than the impact on fuel economy should not be so bad. I believe that the 33lb injectors should be enough for anything I am going to do. The good thing is the performance mods will be set in the tow/haul program so I can have fun with the push of a button.

Ls1nova71 - thanks for the tip. I remember seeing someone do a home made tester on here, I will try this before rewiring my entire harness.

Re: Flex fuel injectors
 

Ok guys I can't find the thread on the home made tester at all. I have been looking for 2 hours. I remember that there was a bucket of gas, a washer pump, and a battery in the system but I just can not find the thread.

Re: Flex fuel injectors
 

The flex fuel injectors have EV6 connections.

Re: Flex fuel injectors
 

I think that ls1nova71 built a homemade tester on one of his builds on ls1tech.

Re: Flex fuel injectors
 

They don't use the fat MultecII clips injtectors? Didn't know that, useful info if your doing your own harness. I thought all the trucks (At least from my experience with return-style trucks) used the multec's.

I suppose that being said, the F*rd injectors would be plug and play aside from the tuning.

Re: Flex fuel injectors
 

Thank you JJH Jimmy, I thought it was ls1nova but could not find it on thid board. Now I know why, because it was never on this board.

Re: Flex fuel injectors
 

http://ls1tech.com/forums/conversion...-c-10-a-6.html
Here it is, page 6, post 107. It wasn't a washer pump though, it was a fuel pump, you need good pressure to make it work. But if you try this, BE CAREFUL! You are working with gas, and a battery that could cause a spark, and that could lead to bad consequences. Also doesn't hurt to have a fire extinguisher handy, just in case.