18:1 AFR....and it didnt grenade itself..HELP!!

well today was the day i dynoed my car at school....it put down more than i expected but i found out i was running incredibly dangerously lean, when all along i thought i was running rich. I hooked up the 5 gas sniffer a few weeks back when i had the chance and i dont remember all the numbers but my HC's were at around 3200 at idle. which to me indicated a misfire or just so pig rich....the pulls i made were from 2500rpm. the car has good compression and the plugs are fairly white which i beleive indicates lean. it has a cobra intake, unknown aftermarket cam ( its definately not stock and pretty lumpy, i know a lot of mustang guys and they also think its really big)...GT40 iron heads,K&N filter, C&L 76mm MAF with stock 19lbers. EGR is there but not hooked up to the exhaust anymore. BBK Long tubes w/ off road H pipe and Hooker Aerochamber mufflers.MSD 6a box with a blaster 2 coil..FMS wires, new cap and rotor. i beleive the timing is 10* w/ spout out and 12* connected, i had the light hooked up a few months ago. also a wide ratio T56 with 3.55 rear gears. i bought the car with the engine the way it is and havent taken it apart yet so i dont really know all the mods to it. what ive told you is basically what ive seen and im assuming thats probably all. It runs fairly well and doesnt backfire or ping, although sometimes under load below 2000 rpms it will buck. when i had it on the dyno today it ran fine but showed 18:1 AFR....i know the probe wasnt reading wrong because the cars before and after me, they were on target. Im suprised the motor didnt blow up. heres the dyno sheet incase it helps




i tried dumping the codes using the check engine light but it never flashed the light...the car is an 89 so it should have it...maybe the guy who had the car before me took out the light? i hear it running through a few tests when i hook up the jumper to the self connector...but i dont see a the light flash. im so confused in this whole situation and i definately dont wanna take it to a shop of any kind, i wanna fix this on my own..i have access to enough tools to get it done, i just need to be pointed in the right direction....if any other information is needed, just ask and ill tell you all i know about it..sorry the post was so long

thanks for all your ideas, im gonna check the fuel pressure and get an AFPR just to keep things under control....maybe i can get a pump for a decent priced off someone 2nd hand but new in box from around me. maybe if i can get that AFR down how much power do you think thats good for realistically?

Psydwaze said:

An exhaust leak may make the sniffer read a lean condition. The AFR is very steady which leads me to believe that the computer is still making corrections. Is your 76mm MAF calibrated for 19lb injectors? Based on C&L's website you should have a gold sampling tube. If the voltages sent from the MAF are calibrated for larger injectors, the injector pulsewidth from the computer will be too short.


COPIED FROM http://www.cnlperformance.com/calibration.html

76mm Unit on 1986-1993 5.0 Mustangs
19lb Injectors Gold Tube (096)
24lb Injectors Blue Tube (102)
30lb Injectors Purple Tube (099)
38lb Injectors Red Tube (103)
42lb Injectors Green Tube (104)
1993 Cobra (24lb) Clear Tube (101)

Click to expand...

i checked the tube and to me it seems like its clear.....i checked the site and the C&L's 73mm for 19 lb injectors is a clear tube. However i called C&L directly and told them my story and they said the color could have possibly faded off if its old. could this mean my MAF sensor is for a 93 cobra or is that probably not the case? would this cause an extreme lean situation?




on a side note: is there anything special about an aluminum spare tire? i found one in the back of my stang when i got it. I asked someone and they said they came on the 93 cobras but im not sure of that.

i pulled out the distributor after struggling too (which i found odd in the first place because you shouldnt have too).....thing was soo tight to turn, you had to use a good amount of force to turn it...so its just, new distrbutor on the way, along with all new gaskets and vaccum lines to try to fix my problem....hopefully all goes well