STOCK FPR OR ADJUSTABLE ??!Hey guys

[shifo]

Hey guys

I finally built my 94 yj stroker. Except I have a little problem. The fuel to air ratio is not good at idle and slow speed.
I was wondering which is better to fix this problem. To use adjustable fpr or map sensor ?? And which FPR to use??

Here is my stroker details.

4.2 crank
4.2 rods
.040 pistons
Comp cams cam 235-4
Rollmaster chain
Mopar performance springs
24lb 6 holes injectors
Stock head
2000 models intake
Throttle body spacer

I appreciate your help.

[Cummins90]

What is your AFR?

[SkylinesSuck]

And what part number are your injectors?

[shifo]

I don't know what is the AFR. How do I know it ?

And the injectors are the ford 24lb (M-9593-LU24A)

[Cheromaniac]

Your injectors are appropriate for your application but when you say "The fuel to air ratio is not good at idle and slow speed", is it too rich or too lean? What about when accelerating and when cruising? How are you measuring the air:fuel ratio?

[shifo]

I said that because when i speed the engine seems to be fine but in low speeds or idle its very weak and stumble. Some times there is black smoke when am warming the car in the morning.

So for my application do I need adjustable FPR at all. Or my problem is unrelated ?

[Cheromaniac]

You could have a bad upstream O2 sensor.

[shifo]

I just installed a new one (bosch) and there is no error codes on the computer at all.

[SkylinesSuck]

Get a wide band O2 sensor. All of this is pointless without actually knowing what your AFR's are.

[shifo]

And how do I actually know the AFRafter I get that o2 sensor ?

[Cummins90]

https://www.summitracing.com/parts/avm- ... gKcrvD_BwE

It is a kit you install and is self calibrating. You will need to weld in the provided bung.