Having A/F problems

[ssms5411]

So I got the new heads and Promags in and my A/F ratio will start at 14.7 then after a minute it starts to climb all the way to lean. Its fine when at WoT , it won't stay at 14.7 I have even adjusted my injector table down to 52.00 out of 60.00, has me confused never had this problem before , even changed out the wideband for a new one. Also my command is 12.4 , any ideas?

[bigbrian442]

Re: Having A/F problems

What are the narrow bands reading?

[ssms5411]

Re: Having A/F problems

I only have the DR. side hook up right now waiting for a 12" ext. for the passenger side , but the dr. side will stay in the 800's and drop right down to 9mv when the wideband reads lean. Also if I hit the gas the 9mv will go into the 800mv again. I can't believe I still need to add fuel. Maybe I'll add it in PE.

[ssms5411]

Re: Having A/F problems

I tried setting the PE where its 0 and 800 to -4.000 and still goes lean and narrow shows 9-14mv but when I step on the gas they go up also the wideband does too. I have no clue.....

[bigbrian442]

Re: Having A/F problems

Have you tried to re tune the MAF table?

[ssms5411]

Re: Having A/F problems

Have you tried to re tune the MAF table?

I don't have the turbo on it right now but I'll give it a shot.

[ssms5411]

Re: Having A/F problems

Maf didn't work , out of ideas , maybe my PLX is taking a dump, I know I have enough fuel for idle WOT is perfect, so I don't know.

[ssms5411]

Re: Having A/F problems

I sent a email to PLX to see what they recomend , but for having it almost 10 years and no problems until now isn't too bad if I need another one. It reads fine at wot so I'm not too worried.

[bigbrian442]

Re: Having A/F problems

When is it doing this? Idle, Cruise?

[ssms5411]

Re: Having A/F problems

It does it at idle and cruise if not on throttle. Wot is perfect. I'm thinking its the wideband its old enough. LOL

[bigbrian442]

Re: Having A/F problems

But the narrow band also shows lean?

[LETZRIDE]

Re: Having A/F problems

cruise and not on the throttle? is decel enleanment messing with it?

[ssms5411]

Re: Having A/F problems

I have never messed with the decell before, it was fine before I added the bigger valves and the Promags. I will have to check the narrow bands again (waiting on a 12" ext. ) The car runs strong, so I don't know what to think. I read on other sites that guys having the same problem with their PLX reading lean. When I get it so both narrows are reading than I'll see from there.

[LETZRIDE]

Re: Having A/F problems

if you're not on the throttle you should be leaner...I am usually at 16-17afr when I come off the throttle and coasting...on the throttle I aim for 14.4 at cruise

I dunno, maybe because you are turbo you don't want to be that lean while not under load, but I would look into your decel tables.

And, if it is your PLX going bad, I would not trust it for readings as far as WOT, if the sensors bad assume you are lean all over regardless of what it says.

I think there is a test you can do for wideband sensors to see if they are accurate...I think the test is on youtube actually.

but if your narrows showing lean, chances are you are lean...2-3 sensors reading the same thing??

[ssms5411]

Re: Having A/F problems

I was staying around 14.7 at idle , cruise letting off it would go lean thats normal, but thiss idle is what is bad , I know WOT is good so I scaled my injectors from there. There 60LB injectors and I have them scaled down to 52.00 , so even N/A the car is needing alot more fuel than before. I'm waiting to see what PLX says.