LS1 keeps throwing P0171 & P0174

[Immortality]

Testing with a vacuum gauge should of shown something like that.

 

[ari666]

actually, that vid has reminded me: you havnt actually done the intake condoms yet, have you reap?

 

[ari666]

this cnuts funny-as!

ahahaha

 

[Immortality]

Also, he's getting both banks so it's unlikely to be something like an injector or valve which should only effect one bank

 

[ari666]

i wonder if you have a damaged exhaust valve?

he has done a leak down and pressure tests and comps are all fine.

 

[Immortality]

LOL, that is gold (above vid).

 

[VBhero]

Mate this really smacks of a vacuum leak. Only throwing on 0 throttle (decel and idle), and both banks...

 

[ari666]

interesting log.

couldn't log fuel pressure sadly, not sure why, but whatever. what we did see is MASSIVE swings in O2 voltages, ranging from 80mV to 800mV on both banks.

we were able to replicate the SVS light by taking off the RHS rover cover breather (to the intake before the TB) and blocking it off. crankcase would build pressure, release the pressure and bam, SVS light. now whether that's the same code as what its doing normally, or just triggering and SVS due to high vacuum in the crankcase, im not sure, the code seemed to self clear. we did managed to trigger the lean codes once though.

I noticed the LTFT went up to 18.8% just sitting at idle.


im still saying a vacuum leak but thought id post up to get some ideas. a visual inspection of the engine is fine. there is a random stray vacuum hose just hanging not doing anything, but it looks like its a breather to the front transfer case, don't think its related, but still wondering what it does.

View attachment reapers2.rar

 

[ari666]

also I did a power balance test and all 8 cylinders came back with healthy numbers, so a damaged cylinder/valve etc is completely ruled out.

 

[SS-REX]

also I did a power balance test and all 8 cylinders came back with healthy numbers, so a damaged cylinder/valve etc is completely ruled out.

So the maf is ruled out too? and vacuum leak somewhere is causing this...