View Full Version : Running Rich 10.5:1 or richer

06-10-2004, 06:21 PM
Hit the dyno with the T-Bird today.

243 HP
324 TQ

10.5:1 AF ratio
about 10-11 psi of boost.

We have some work to do. The AF ratio goes to 1:1 when you crack it wide open. Seems that was the problem when going to WOT in the corners, not the fuel issue (might still be, but this seems more likely).

So we need some help! Why is it going so incredibly rich when we crack the throttle wide open, and any thoughts on how to lean it out. Here is what we are running:

Stock bottom end, cam and all.
42 lb injectors
77 mm MAF
5% pulley
Ported, Heads (exhausts), intake, blower housing.
Powerstroke Intercooler
3 inch intercooler tubing
MAC 3.8 Mustang headers
Stock colectors and 2 inch exhaust (we were in a pinch. Open to ideas. The pipes end at the end of the transmission currently).
255 fuel pump
I believe everything else is stock.

Thoughts? We have access to an EEC Tuner. We could use a bunch more HP, but the TQ number is perfect (per the rules).


Mike Puckett
06-10-2004, 07:04 PM
You could try changing the sample tube in the MAF. Is the one you have good for 42# injectors?

06-10-2004, 07:13 PM
It is supposed to be. With my mods, what do you think about changing back to the stock MAF and stock injectors? I have a feeling that it will run too lean. Thoughts?


06-10-2004, 10:30 PM
42's are to big in my opinion...How di dyou get 2inch stock collectors hooke dup to full lenghts?..And why?

06-10-2004, 10:33 PM
They are the MAC mustang shorties, and we had to get to the track quick, so we just hooked up the stock collectors. The MAC's certainly have a larger opening than that.

Do you think the 42's alone are the issue?

Randy N Connie
06-10-2004, 11:28 PM
No 42# injectors are not to big.I run them with a stock block,cam, & heads.
With most of the boltons.

If your running a C&L 76mm MAF.Your sample tube color is purple.
I think you just need to get back on the dyno with A/F.And tune the fuel
curve to what you need.


Rich Thomson
06-11-2004, 06:31 AM
Your Air/Fuel table is commanding 10.98.

Unless you change the tables you get the following Fuel tables with the air/fuel ratio commanded. The stock fuel tables do run rich on the top end above 90 degrees ECT.


06-11-2004, 10:22 AM
I agree with Rich. Hey Rich do you mind if i give you a call in the near future about runing my SC via EEC tuner?

06-11-2004, 10:29 AM
To make sure I understand: The computer always runs this rich at WOT?

How would you suggest we solve the fuel dumping the engine is getting when going to WOT from part throttle?

What should we change the fuel mapping to?

Thanks for the insight!


Mike Puckett
06-11-2004, 04:52 PM
You'll probably need to put it on the dyno to change it. A good tune is worth the cost. I wonder if there is an incorrectly sized sample tube that just by coincidence would make it run leaner. Thanks for the fuel mapping data, Rich. I always wondered. What do the vertical and horizontal axis represent each?