dry shot - super lean
08-08-2008, 11:19 AM
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dry shot - super lean I have a fairly new dry system. Got the 75 HP shot working pretty good. AFR is 11.8 to 12.2 during a 1/4 mile pass. Tried a 100 jet and ran once last night. Glanced at the AFR gauge early in the run and didn't notice anything wrong. At about the 1000' mark, I looked over and saw 22.4 AFR. I flipped the arm switch to off. The gauge stayed pegged at 22.4 even after I let up on the throttle. I made the turn down the return road and pulled up to the timing shack. Finally the gauge dropped down to what I normally see at idle or low cruising speed.
About crapped my pants. Was too scared to make another pass, even off the spray. I'll pull the plugs (TR-6) out tomorrow and check 'em. I took it easy, but the car seemed to run ok on the way home (40 miles). Is it possible for the AFR to go that lean and not cause damage? Is it possible the wideband (LC-1) gave an erroneous reading or the gauge malfunctioned? That pass was my second fastest ET and fastest trap speed, I can't see how it ran that good if it was that lean.
Any thoughts or ideas?
About crapped my pants. Was too scared to make another pass, even off the spray. I'll pull the plugs (TR-6) out tomorrow and check 'em. I took it easy, but the car seemed to run ok on the way home (40 miles). Is it possible for the AFR to go that lean and not cause damage? Is it possible the wideband (LC-1) gave an erroneous reading or the gauge malfunctioned? That pass was my second fastest ET and fastest trap speed, I can't see how it ran that good if it was that lean.
Any thoughts or ideas?
08-08-2008, 11:40 AM
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My car went lean from bad nozzle placement and started misfiring and popping...
If your car really went to 20+AFR, I think you would have been worse than that...
If your car really went to 20+AFR, I think you would have been worse than that...
08-08-2008, 03:16 PM
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I need to check fuel pressure, since I'm still using the stock fuel pump.
As for injectors, the first time I sprayed the 75 shot, I was running out of injectors. Stock is 28#, so I bought and installed redtop Ford/Bosch 30# injectors (more like 36# with the LS1 fuel pressure). It ran great then, AFR was good and I got a new personal best time. Anything is possible I guess, but I can't imagine just going from a 75 jet to 100 jet maxed out the new injectors that quick.
The car felt like it was pulling strong. In fact, if I hadn't forgot to lower air pressure in the drag radials, I probably would of got a new personal best (I was only 3/100's off). I had no indication anything was wrong which is probably why I didn't check the gauges at mid track like I usually do.
As for injectors, the first time I sprayed the 75 shot, I was running out of injectors. Stock is 28#, so I bought and installed redtop Ford/Bosch 30# injectors (more like 36# with the LS1 fuel pressure). It ran great then, AFR was good and I got a new personal best time. Anything is possible I guess, but I can't imagine just going from a 75 jet to 100 jet maxed out the new injectors that quick.
The car felt like it was pulling strong. In fact, if I hadn't forgot to lower air pressure in the drag radials, I probably would of got a new personal best (I was only 3/100's off). I had no indication anything was wrong which is probably why I didn't check the gauges at mid track like I usually do.
08-09-2008, 11:26 AM
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Is the LED for the LC-1 throwing a code?
I think its something up with the LC-1.
Changing the jet by 25 HP is not going to cause an actual 22+ AFR (unless maybe fuel pressure was lost as well). Maybe a 2-4 point towards lean (so 13.8-15.8 AFR on spray from a safe 11.8). See if you can duplicate the AFR glitch NA. Check the wiring on the LC-1 and hit the Innovate forum and see if it has happened to any others.
Checking the MAF wires is a good idea as well, you are running an aircleaner and debris cannot hit the wires can it? The MAF not seeing airflow would command less fuel.
Jim
I think its something up with the LC-1.
Changing the jet by 25 HP is not going to cause an actual 22+ AFR (unless maybe fuel pressure was lost as well). Maybe a 2-4 point towards lean (so 13.8-15.8 AFR on spray from a safe 11.8). See if you can duplicate the AFR glitch NA. Check the wiring on the LC-1 and hit the Innovate forum and see if it has happened to any others.
Checking the MAF wires is a good idea as well, you are running an aircleaner and debris cannot hit the wires can it? The MAF not seeing airflow would command less fuel.
Jim
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08-09-2008, 12:44 PM
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I'll check the MAF after bit to make sure it looks ok. I have a second MAF that I can try too. I am using a cone filter with a filter halo ring.
ET = 11.915 and mph = 119.4.
I can't remember if I hooked up the LED for the LC-1 or not, I'll check. The wideband seemed to work ok on the drive home.
ET = 11.915 and mph = 119.4.
I can't remember if I hooked up the LED for the LC-1 or not, I'll check. The wideband seemed to work ok on the drive home.
08-09-2008, 05:33 PM
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MAF looks ok, wire looks perfectly clean.
The LC-1 wideband LED blinks when I first start up (think it's going through the warm up test phase). Then the LED stays on steady. So, looks like no fault code. The instructions say an exhaust leak will allow oxygen to enter the ehaust stream and will measure leaner than the engine is actually running. I don't hear an exhaust leak, but the slip joint at the collector on my Kooks headers did loosen up once before. I'll check that.
I thought my AeroForce Interceptor gauge measured fuel pressure, but I guess not. I'll have to invest in a fuel pressure gauge I guess.
The LC-1 wideband LED blinks when I first start up (think it's going through the warm up test phase). Then the LED stays on steady. So, looks like no fault code. The instructions say an exhaust leak will allow oxygen to enter the ehaust stream and will measure leaner than the engine is actually running. I don't hear an exhaust leak, but the slip joint at the collector on my Kooks headers did loosen up once before. I'll check that.
I thought my AeroForce Interceptor gauge measured fuel pressure, but I guess not. I'll have to invest in a fuel pressure gauge I guess.
08-10-2008, 06:33 PM
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I pulled all the spark plugs out. They all looked perfectly normal. Kind of a tan color with no deposits and nothing melted.
I tightened up the header collector slip joint. They were a little loose, but not bad. The wideband sensor is in the midpipe right next to the slip joint.
I'm going to pick up a fuel pressure gauge tomorrow. Not a permanent dash mounted one, but rather one you attach to the fuel rail for troubleshooting. Any brand I should look for that's better than most?
If the fuel pressure tests ok, I'm about out of ideas. Guess I still need to check injector duty cycle too, but I don't have anyway to do that at home.
I'm going to swap the 75 HP jet back in for the time being since that seemed to work fine.
I tightened up the header collector slip joint. They were a little loose, but not bad. The wideband sensor is in the midpipe right next to the slip joint.
I'm going to pick up a fuel pressure gauge tomorrow. Not a permanent dash mounted one, but rather one you attach to the fuel rail for troubleshooting. Any brand I should look for that's better than most?
If the fuel pressure tests ok, I'm about out of ideas. Guess I still need to check injector duty cycle too, but I don't have anyway to do that at home.
I'm going to swap the 75 HP jet back in for the time being since that seemed to work fine.
08-10-2008, 08:19 PM
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Well, when I changed the jet back to 75 shot, I discovered the halo cone filter ring alignment was all messed up. Must of got screwed up when I installed the 100 jet. The part of the ring farthest away from the fitting was looped toward the back of the filter. The pic is how it's supposed to be, not how it was when I found it. Not sure if this was the reason I had problems, but it probably didn't help.
