AFR issues

theHumP · Post by **theHumP** » Fri Jul 28, 2006 7:29 pm

I currently have the dreaded 12:1 obx, accompanied by a 1:1.

I am having problems getting enough fuel in boost. Does anybody have any ideas that will help?

Even some basic info like what order do they (the FPRs) go in, and which is in/out on the obx.

Now for the rest of the fuel system FYI, Im running a 255lph w/ return line, 24# injectors.

I am aware that this is not the best setup and that going to a cartech or begi rrfpr or megasquirt, and larger injectors can probably fix this, however that costs money. Im trying to get it running good/safe with what ive got and upgrade when funds are sufficient.

Kevin_GP · Post by **Kevin_GP** » Fri Jul 28, 2006 11:39 pm

I dunno about your 12:1 and 1:1, like you said best bet is get a rrfpr. The only thing I can think of is make sure your vac signal for both of them is right off the manifold so they act quickly. You are kinda stuff because you have no adjustablity. I would just drive around without boost untill you get a rrfpr. Im not trying to be negative but im sure you spent alot of time installing your turbo, it would be a shame to blow the motor over a regulator.

60trim · Post by **60trim** » Sat Jul 29, 2006 1:02 pm

Take out the 1:1 and leave the OBX in place. Run a check valve off your manifold to the FMU so it doesn't see vacum. My car runs fine, actually pretty rich. Mine doesn't stumble underboost, it did when I was having fuel cut due to a loose line in the tank on the fuel pump, but I fixed that with some new fittings.You sound like you on ther right track, but give us some signs and symptoms of your problem to better diagnosis the situation. Thanks

lethalp1mp · Post by **lethalp1mp** » Sat Jul 29, 2006 7:36 pm

You need to keep the 1:1, otherwise you have no way to set your base fuel pressure. If you had a rrfpr like a Begi, Vortech SFMU, or Chill factory, then you don't need a 1:1.

tooslow · Post by **tooslow** » Sat Jul 29, 2006 8:31 pm

what did you do too disable the stock regulater

theHumP · Post by **theHumP** » Sun Jul 30, 2006 12:19 pm

Kevin_GP wrote:The only thing I can think of is make sure your vac signal for both of them is right off the manifold so they act quickly. You are kinda stuff because you have no adjustablity. I would just drive around without boost untill you get a rrfpr. Im not trying to be negative but im sure you spent alot of time installing your turbo, it would be a shame to blow the motor over a regulator.

I only have vac signal going to the 12:1, directly off the manifold, and Im not driving it at all, because of these issues.

5280 wrote:Take out the 1:1 and leave the OBX in place. Run a check valve off your manifold to the FMU so it doesn't see vacum. My car runs fine, actually pretty rich. Mine doesn't stumble underboost, it did when I was having fuel cut due to a loose line in the tank on the fuel pump, but I fixed that with some new fittings.You sound like you on ther right track, but give us some signs and symptoms of your problem to better diagnosis the situation. Thanks

I actually tried that and it was super lean at idle, I did however read up some more and saw that I should hook the 1:1 up before the 12:1 so I did that and now I keep blowing fuel lines. Just need to go over the entire system again and lock everything down so I can get a good test run to check the AFRs again.

tooslow wrote:what did you do too disable the stock regulater

spoolboy

thanks for all the input, Ill keep you all posted on the issues and you keep the info coming.

tooslow · Post by **tooslow** » Sun Jul 30, 2006 12:23 pm

is the 12:1 actaully seeing vac or is there check valve. neither the 1:1 or the 12:1 is seeing vac right

how is the cars idle? like normal?

theHumP · Post by **theHumP** » Sun Jul 30, 2006 12:33 pm

No, there is check valve on between the 12:1 and the vac/boost signal, Idle is good, around 13.8-14.2, If I hold the break and hit the gas in gear the AFRs drop down around 9.8 (super rich but easy to work with) but it doesnt do that while driving, It drops down to about 11ish and then shoots up to 15ish

60trim · Post by **60trim** » Sun Jul 30, 2006 1:57 pm

What are you using to monitor your A/F? do you have a wideband? Do you have a simple L.E.D one that bounces back and forth? My car is running fine without an A/F gauge so far. I still need to get tuned, but I have been running really rich, ev between shifts.

theHumP · Post by **theHumP** » Sun Jul 30, 2006 4:59 pm

wideband

tooslow · Post by **tooslow** » Mon Jul 31, 2006 1:14 pm

get a check valve for the 1:1 too it will solve the super rich problem but for the lean problem the 12:1 is not doing its job

theHumP · Post by **theHumP** » Thu Aug 03, 2006 6:42 am

the 1:1 doesnt need a check valve because its not getting a vac signal, its only there to act as the stock one once did, and rich is not a problem as its easier to pull fuel than to add it at this time,

I did hook up a check valve to the 12:1 and at idle my AFRs went to 16.00, (thats not good BTW)

so anyways I realized that the leaning out in boost was actually the "stumbling into boost" that everyone talks about, so I wired the mapclamp back up, adjusted it, and now its good going into boost.

So what ended up working for me is runing the 1:1 with no vac signal directly after the fuel rail, and the 12:1 after the 1:1. and a MAP clamp.

as for pulling/adding fuel, I will increase/decrease injector duty cycle as needed with the SAFC and pull fuel in boost by using an MBC to hide a little bit of signal from the fmu as needed.

60trim · Post by **60trim** » Sat Aug 05, 2006 1:39 pm

Glad to see you got her running the way it should.

unsuper man · Post by **unsuper man** » Sun Aug 06, 2006 2:58 pm

i didnt read this thread. but ive hd a 14.5:1 a/f for 40+k miles and ive been fine. if it dosnt blow up leave it,

leaner in meaner.