5000RPM misfire with vortech VR7135

[jymbojym]

i've just installed the complete Vortech kit for jeep srt8 seems like when i hit 5000RPM it skips like hell with some misfires... i was wondering if the Kooks Headers combine with the borla catback could be the problem??? And also have to cancel the rear O2 Sensors but there's no option on the predator to cancel them so ... I keep on having DTC for slow O2 response... Predator has the last of your updates...

[Quick]

Yikes! You are running the Vortech tune right? You should be talking to Vortech.
I don't know, but I doubt that your headers or catback are the problem.

[jymbojym]

Seems like we have a problem i called Vortech they said either i remove the headers and replace it with stock one ... or... get a custom tune by Diablosport for the mods i put on the truck... they said the engine leans out...

[Quick]

You do have an AFR gauge? maybe an EGT? you logged all this?
I don't want to sound like an alarmist because I'm not qualified... but "skips like hell with some misfires" sounds REALLY serious if it was due to running too lean. You should ask someone who knows if maybe you should be checking for damage at this point or not.

[jymbojym]

the truck pull hard up to 5000RPM with no misfire hell my neck hurts... LOL... but after that there's a bit of lack of power and then misfires occurs... yes i see the datastream on my scanner.... ok i will road test it again and post the data

[rfoker]

sounds like spark plug blow-out. I would close the gap up if you've got stock plugs or pull them and go 1 or 2 steps cooler along with a closer gap. i would certainly try this before you go removing/replacing headers or paying extra for tuning

LT headers would actually cause a rich situation, not lean. This would not cause high rpm issue's if it were a bit rich. it would just be sluggish is all.

[Quick]

Rich? It would be leaner right? better flow, better exhaust of burnt charge, more fresh air, more O2 ... but the same amount of fuel. Should be leaner right?

[mikel]

sounds like spark plug blow-out. I would close the gap up if you've got stock plugs or pull them and go 1 or 2 steps cooler along with a closer gap. i would certainly try this before you go removing/replacing headers or paying extra for tuning

I agree here...

[rfoker]

Rich? It would be leaner right? better flow, better exhaust of burnt charge, more fresh air, more O2 ... but the same amount of fuel. Should be leaner right?

When I put LT headers on my Cobra i was expecting the same thing. In just 2 days I was spewing black soot all over my tips.
Go wipe out the inside of your exhaust tips and drive the car as usual for a couple of days and see what you've got back there after. Ideally, you should barely have anything on your fingers, but safe bet is too have a little bit if you've got a s/c'er.
Also, when you pull out your plugs to gap them, see what they look like. if your running way lean, it should still show up on your plug even though the proper way to check them is right after WOT under full load.
Make sure you remove and install your plugs on a COLD engine.

I suppose if you really are running lean, then you can try and decrease the injector slope until you've got enough fuel back in the mix. First things first. get those plugs corrected. You def want 1 step colder MINIMUM. along with a smaller gap than factory. Def nothing more than a .050gap for sure. That's too much on most factory ignitions.

[jymbojym]

Ok Mike i'm changing spark plugs after having a good look at them seems like i'm running a bit lean... Alright, so i'll be road testing the monster this afternoon can you tell me what data you want me to record for the custom tune... guess my customer wants to keep the headers on the engine so... i'll send the data after that.

[jymbojym]

Hey mike... I cannot believe it was just the spark plugs but i went with plugs 2 step cooler... The misfires are gone... The truck pulls f!"#king hard all the way up to 6000RPM with 8.5 PSI at the redline... So thanx for everything, i'll keep you updated for news! This shit rocks man! Now i have a supercharged smile!

[mikel]

good deal!!

[jymbojym]

Hey mike I've installed a wideband o2 sensor today on the truck... I'm getting an average of 11/1 ratio so guess the predator is doing it's job even with the headers! So i'm still smiling )... But still i got this question... does the program have a full throttle fuel adaptive map?

[mikel]

Well, 11:1 is certainly nice, you could even get away with leaning it out to about 11.5:1 at WOT.

You can add/remove furl at WOT, but Im not sure what you mean by fuel adaptive map?

[concoursd]

he means, will the WOT mapping adapt to things like headers.