Ok guys I just finished a 5.3 swap in a 89 c1500 has a base tune I made to run it cracked run perfect had some small things had to change to get it to idle correct but that’s it. My first time using hp tuner also but I’ve had it running for about a week last night was going to crank it do a little tuning truck cranks goes dead I crank back is running really bad idle about 600 if u touch the gas it dies this is the same tune I’ve been running on take some plugs out have 3 that are black go get a set of plugs and change Those three injectors crank
back up runs the same take plugs out now all 8 are like this so I’m thinking maybe high fuel pressure i didn’t have a way to check bc I have an fuel line don’t have a adapter for the rail so I went got a new regulator and filter I’m jsomg
the corvette one come back change same thing im
almost down to the ecu have some issue what do y’all think

 

You need to run a scan on it and watch what the sensors are doing.

 

I have both sensors unplugged with a wide band on it to see what it’s doing

 

also on speed density

 

Check your pressure regulator...possibly a hole in the diaphragm.

 

Have changed it already

 

Going to have to figure out a way to put a pressure gauge on it for starters. What fuel rails do you have?

 

Holley

 

Yeah, it sucks they don't have a port on them somewhere. Here's what I did. Maybe you could do something similar. https://ls1tech.com/forums/conversio...-wagon-13.html Post 244

 

Good idea I’m stumped I’ve changed ecu that’s not a issue now going to get a fuel pressure reading tomorrow and make sure some injectors are not hung open

 

when you load scanner it allows manual over-ride of air fuel adjusting. Simply open the fuel panel and set the a/f ratio to something appropriate, something lean enough to start with. Then watch the wideband and work your way rich until you have 15's to 14's on the wideband. Engine will run good there, gota watch that wideband behavior.

Then see how far off it is. For example if your scanner shows 12:1 but wideband says 14.5:1, you know there is some adjustments need to be made in the tune. Getting the numbers to match is important for beginners because the air mass calculations are used for lots of other things like trans-shifting pressure and idle routine behaviors.

 

Had it running 14’s afr this issue happen out of the blue running fuel pressure test tomorrow hope to find something