a/f going super fat under load

[perk_1405]

as some of you know i got my truck back about a month ago from blowing it up and getting it rebuilt. ok now ive got the break in oil out of it and i go for a quick ride and peggs out my uego a/f at 10.0 when i romp on it and it cuts out b/c of it. i called and talked to sean he said to by-pass the vec3 (the a/f sensor wires) and re connect them to the factory pcm. so i did that and it still goes fat?

any ideas fellas:dontknow:

 

[TNVIPER]

Did you reload your tune or try a different one?......best thing to do is call Sean back...he will get it right for you..

 

[505'sFastestViper.]

too much fuel pressure would be my guess

 

[tsmith3]

I'm having a similar problem with my A/F... at WOT my A/F goes to 10 from 4200 rpm to 5000 rpm. I've changed 02 sensors, checked all the wiring, and I'm having DC performance look over the fuel maps. Hopefully they can figure it out.

 

[perk_1405]

I'm having a similar problem with my A/F... at WOT my A/F goes to 10 from 4200 rpm to 5000 rpm. I've changed 02 sensors, checked all the wiring, and I'm having DC performance look over the fuel maps. Hopefully they can figure it out.

let me know what they find out.

do you have a vec3?

 

[perk_1405]

Did you reload your tune or try a different one?......best thing to do is call Sean back...he will get it right for you..

i have tried several tunes and they all do it. i have sent him an email with the update, hopefully i hear back from him today.

 

[perk_1405]

too much fuel pressure would be my guess

:dontknow:

 

[eddie102870]

sean will get you straightened out. my first tune from him did that and he sent me some updates and cured it.

 

[505'sFastestViper.]

:dontknow:

i have a fuel pressure regulator and if it is runnin a lil lean or a lil rich i can adj the a/f with fuel pressure

 

[RedSrt007]

i have a fuel pressure regulator and if it is runnin a lil lean or a lil rich i can adj the a/f with fuel pressure

This does work in some cases..but I wouldn't recommend this to another member (just incase he does it and something goes wrong)....you can blow up your motor by adjusting (leaning) out your a/'s by dropping fuel pressure. It need to be tuned via fuel tables and logged.

This isnt said to step on your toes Dom

 

[perk_1405]

im thinking in the direction of o2 sensors or map sensor now. im going to pull the sensors and check'em in a minute.

 

[TNVIPER]

Shouldnt be your O2 sensors as they are not in use during WOT...system uses a preset fuel tables...that is why tuning is necessary....

 

[505'sFastestViper.]

This does work in some cases..but I wouldn't recommend this to another member (just incase he does it and something goes wrong)....you can blow up your motor by adjusting (leaning) out your a/'s by dropping fuel pressure. It need to be tuned via fuel tables and logged.

This isnt said to step on your toes Dom

i take back what i said it was a horrible idea

 

[perk_1405]

Shouldnt be your O2 sensors as they are not in use during WOT...system uses a preset fuel tables...that is why tuning is necessary....

this is from the vec3 software packet from roe...."2003 and newer Viper engines, where control of the oxygen sensor voltage output is needed since the PCM’s hold closed loop for a short period of 1.4 seconds after the application of full throttle. ."
so o2 sensors are still an option.

 

[Chuck B]

i take back what i said it was a horrible idea

Yes it was....:rock:

 

[perk_1405]

is it possible that my belt slipping would cause this? i had a buddy ride in it with me he said his made a simmilar noise once before and it was the belt slipping. how do i check or should i just get a new belt?

 

[pokeytemplar]

I can't think of any reason why belt slip would cause enrichment of the A/F. Most likely it is your tune. Check that first and then move on to the other stuff.

You are using the factory fuel system correct? You could put a pressure gauge on the fuel system to see if it is staying around 55psi. If the numbers are going through the roof (100psi+) it could be the pressure regulator.

 

[tsmith3]

I had this same problem with my Paxton. The belt was slipping from 4k to 5k rpm in WOT making the A/R drop below 10. I don't know about the VEC but Split Second fuel maps dump a preprogrammed amount of fuel across the rpm range in WOT. I'm not sure but I think the VEC does the same.