1988 Foxbody GT. 5.3 swap TorquerV2 cam. LS6 intake blah blah. Lol

i can’t get it to idle….. might be a vacuum thing though…. Idk… that’s my question…. I did everything skimpy to get it to crank…..
open headers… ALL vacuum ports are capped off EXCEPT the Throttle Body to passenger valve cover….

why won’t she idle?
and revs pretty high before trying to settle….

https://vimeo.com/589633905

 

If it hasn't been tuned that would explain it.

 

it was a mail tune by PCMFORLESS

 

I overlooked this the first time, Open headers is a no no, You need a section of pipe on the header or the the O2 sensor will not read correctly, Basically oxygen is pulled in the end of the header through reversion and will make the ECU think it's a lean condition.

 

It’s gonna be a bit before I have full exhaust on it. I’ve seen all these stand cranked LS engines run fine. I didn’t think that would be an issue…
So you think that’s all it is ?
are my vacuum ports all okay for idling?
And as far as the computer. Idk I’d have to call Keith at PCMFORLESS. And I still think it should idle with open headers.
but…. This is my first LS / fuel injection build.

 

It won't run right if the O2 sensor is getting an errant reading and open headers 100% causes that. I don't know if that is all the problems you have but it is one of them and it's a major one. You don't need a full exhaust on it just a 18" length of pipe or muffler.

I also run my engine on a run stand and they have to have the extension or they run really rich and surge and not want to idle.

 

Thank you!

 

If what you left uncapped on the throttle body is DOWNSTREAM of the throttle blade, cap it too for the test start. The only air entering the intake should be past the throttle blades. How are you managing the maf sensor? What are the specs on the camshaft?

 

I am using the truck MAF. and there is nothing uncapped. I have a hose going from the top of the TB to the passenger side valve cover port.
the cam is 232/234 .600 on a 110LSA

 

Shouldn't it cold idle even with weird stuff from o2 sensors? Have you tried just unplugging them?

 

What throttle body are you using - stock 78mm with ls6?

 

I haven’t tried unplugging them. Im wondering if I should try changing out the IAC. And yeah it’s a truck throttle body. With an LS intake. Here is what I have mocked up to run it….