stanglx2002

I have a C&L MAF with the 24 lb tube in it, but that wouldnt explain why the 302 run with no richness and the 331 did with the same MAF and size injectors

saleenpride1986

Have you adjusted your fuel pressure at all? Also tuning your car would highly benefit you. If you did a lot of changes when you made it a 331, such as h/c/i and anything else, you should tune it so it all flows in sync. Mine ran rich and I got an adjustable fuel pressure regulator and ended up dropping the pressure by around 15 psi, and when i had it tuned they ended up adjusting it an addition 3 psi...

saleenpride1986

Remember, the 02 sensors readings and the MAF help tell the computer what is going in to the car and what's going out. When it see's more air going into the engine through the MAF it is saying it needs more fuel, but if you're not needing that much fuel then it's running it too rich..

stanglx2002

What was the ending fuel pressure that you had to go down too?

Joel5.0

Fuel smell in the exhaust could be HC's due to valve train setup or cam timing....... which could cause A/F to be on check, since O2 sensors do not check for HC's. A simple DIY KOER self test will provide you with more details regarding any A/F control problems. LUK

dudeboy

Running a C&L on an X3Z can be a challenge because the sensor required is NOT the same as was used on the 5.0...

You should have an F1SF or F4SF part number on your sensor.
What size is the sample tube? Color will help, but if you can measure it with calipers that would be best.



Another issue you may be having...

The ecu calculates fuel metering and ignition timing based on LOAD. The LOAD is calculated based on the airflow, in relation to CID. You changed the CID of your engine, and didn't change the tune. That means there is a certain amount of error in the calculations for fuel metering and ignition timing.
The ecu has an adaptable range of +/-12.5% (I've confirmed this on an X3Z) for the fuel. This is the adjustment made based on feedback from the O2's.

Most healthy engines will fall within this 12.5%, and the driver will never know that the ecu is making adjustments.
If there is anything else throwing off the calibration, then you could run into issues.


Let us know what you have for a MAF sensor, and what sample tube...

jason

stanglx2002

What I did is have a 302 with 24 lb injectors in the car with the same MAF and Sample tube and it ran fine. Then I took the 302 out and put in the 331 with 24 lb and it runs rich but it doesn't have any idle problems or again thing like that.

So if everything is exactly the same as the 302 then shouldn't it be a sensor or fuel pressure problem then?

dudeboy

Read through my post again... especially the part about the difference in CID and how that affects LOAD.

Let me know what parts you have in that C&L.

Pull your codes as Joel suggested...

dudeboy

The reason I am so concerned about the combo?

I ran an X3Z with a C&L for a while myself. With 351w CID it seemed ok. I rebuilt to 408w, and the car ran rich at cold start.

It wasn't until I started using a tweecer that I found out that I had a mismatched sensor/ecu combo.

It's worth double checking...

94StinkinLincoln

does the headers glow at night after you make a wot run?

my 331 ran lean on the stock tune w/ stock FP, to the tune of about 15:1 wot lol