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

[6SpeedLX]

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

 

[poneypower89]

wow, the AFR is very lean.. but steady at the same time..

Just know that C&L mafs lean out the car by nature... they arent supposed to do it much, but they do do it.

Check your fuel pressure, it may be a little low.

As far as the CEL and pulling codes. If you aren't seeing the light AT ALL even with the jumper hooked up then your light is either burnt out or taken out.

Instead, use the jumper and a volt meter to test it like you would if it where an 87-88 non-cel car. You know what im talking about here right?

 

[Psydwaze]

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)

 

[poneypower89]

if the C&L came with the 19# sample tube.. it will not be marked.. .C&L tends NOT to mark the tubes that come with the mafs they sell... only the ones they sell seperately.

 

[r.barn5.0]

You can run the codes without the light. do a search there is a good
sticky on here somewhere on how to do it.

you have to jumper into a plug on the drivers side firewall
and read the codes with an AMPmeter.
It can run a check on all cylinders and injectors make sure
everyone is firing off right and show you any codes.


bump timing up to more like 12-14* with spout out.

it should be reading in the mid-high 20's with spout in.


btw: Your torque looks low too, mine put down more like 275torque
and same hp when I had your same set-up basically.

 

[JimBowy]

i'd try another AFR recorder before totally putting my faith into that one... try another dyno or does a friend have a wideband you could borrow?

 

[stang8urimport]

200 rwhp on that combo is low for a Dynojet. Those are numbers you should see on a stock 5.0 manual with pulleys. The a/f on the chart I think is correct, and where all the power is going. Running THAT lean, I would think you would have to be even leaner at part throttle/cruising... Which would lead to some type of detonation or pinging. Like said, check the fuel pressure... make sure the plugs look good, and make sure your fuel pressure regulator is doing it's job correctly. If it's not upping f/p with no vac (line off or at WOT), that could be causing your problem. Or advancing the fuel not enough to keep it running, but not falling on it's face. Sounds more like a fuel delivery problem to me. Also look into the fuel pump, or even the fuel pump sock being collapsed or clogged... Fuel filter also... SO many variables here. Check them all.

 

[6SpeedLX]

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?

 

[6SpeedLX]

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)

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.

 

[6SpeedLX]

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

 

[JIffy94]

Power and performance huh? Which UTI campus are you at?