Trans Am LQ9 Swap Now Runs Super Rich At 8:1 AFR???

[WS6_LOU]

Whats up yall, just the other day I finished my LQ9 swap that ive been working on for about 18 or so months. Rebuilt from the ground up with new bearings, rings, oil pump, etc and a bunch of other non-performance stuff (gaskets, bolts, etc.). I installed 821 heads with LS3 intake manifold and Deatschwerks 65lb LS3 injectors. My car was tuned before hand and ran great until it burnt a couple valves. After I uploaded the new tune, I was expecting to be running leaner than normal since it was tuned for a 5.7 and now its a 6.0 without changing the fuel. After the first fire, I noticed my wideband was reading everything from 2:1 (!!!!) to 22:1. I was not aware these sensors could even read that low. After doing some research I found that the lowest they can read is 8:1 since I have the 4.9 sensor. First fire it stumbled and acted like it wanted to die with AFRs staying around 7:1-8:1 and overall didnt want to idle very well. After lowering the min pulse width to .350 ms and changed the min fuel miligrams to .010 and uploaded the tune. It fired over quickly and sounded much better with the rpms fluctuating +/-50 rpm from target but my wideband was still reading 7:-8:1. After a few more seconds it started to go all over the place, all the way down to 2:1 and all the way up to 22+:1. Am I missing something? Could the sensor itself be bad just from sitting out gently tucked in the trans tunnel for 18 months?? I live in Florida so its typically quite humid for most of the year, though my car spent the entire time in a closed garage. I spoke with Deatschwerks and they confirmed my tune has the correct injector information. What do you guys think could be the issue?? Ive included my tune below as well as a short log of starting the car up and idling. I didnt want to do it for too long incase I am actually running that rich. I apologize for being kind of all over the place and I appreciate any help in advance!

[kevin87turbot]

Whats up yall, just the other day I finished my LQ9 swap that ive been working on for about 18 or so months. Rebuilt from the ground up with new bearings, rings, oil pump, etc and a bunch of other non-performance stuff (gaskets, bolts, etc.). I installed 821 heads with LS3 intake manifold and Deatschwerks 65lb LS3 injectors. My car was tuned before hand and ran great until it burnt a couple valves. After I uploaded the new tune, I was expecting to be running leaner than normal since it was tuned for a 5.7 and now its a 6.0 without changing the fuel. After the first fire, I noticed my wideband was reading everything from 2:1 (!!!!) to 22:1. I was not aware these sensors could even read that low. After doing some research I found that the lowest they can read is 8:1 since I have the 4.9 sensor. First fire it stumbled and acted like it wanted to die with AFRs staying around 7:1-8:1 and overall didnt want to idle very well. After lowering the min pulse width to .350 ms and changed the min fuel miligrams to .010 and uploaded the tune. It fired over quickly and sounded much better with the rpms fluctuating +/-50 rpm from target but my wideband was still reading 7:-8:1. After a few more seconds it started to go all over the place, all the way down to 2:1 and all the way up to 22+:1. Am I missing something? Could the sensor itself be bad just from sitting out gently tucked in the trans tunnel for 18 months?? I live in Florida so its typically quite humid for most of the year, though my car spent the entire time in a closed garage. I spoke with Deatschwerks and they confirmed my tune has the correct injector information. What do you guys think could be the issue?? Ive included my tune below as well as a short log of starting the car up and idling. I didnt want to do it for too long incase I am actually running that rich. I apologize for being kind of all over the place and I appreciate any help in advance!

The wideband is reading incorrectly. It should show a reading from 10:1-18.5:1 on your AEM 4110.

[tana99ss]

im curious to know how you figured that out, i was going to suggest removing 50% from ve table during start up.

[kevin87turbot]

im curious to know how you figured that out, i was going to suggest removing 50% from ve table during start up.

There were a couple of clues. I looked at his tune. The fuel injector characterization data appears to be spot on. The VE table looks to be reasonable numbers as well.

But the main giveaway was the instruction sheet for that wideband. It can read from 10:1-18.5:1 on a gas scale. Looking at his datalog, it's reading around 2:1...which isn't a valid number.

[tana99ss]

There were a couple of clues. I looked at his tune. The fuel injector characterization data appears to be spot on. The VE table looks to be reasonable numbers as well.

But the main giveaway was the instruction sheet for that wideband. It can read from 10:1-18.5:1 on a gas scale. Looking at his datalog, it's reading around 2:1...which isn't a valid number.

awesome thank you for the information

[WS6_LOU]

That?s what I was thinking. Because all sensors have their range. They cannot read above or below their limits. Another thing that made me suspect that it wasn?t reading correctly was that my injector pulsewidth was pretty steady at about 2-3 ms. If my AFR truly was 8:1 (or much less 2:1 for that matter) I?d sure as hell see a lot higher pulsewidth than 2-3 Ms. The size injector needed to reach 8:1 AFR with a 2-3 Ms pulsewidth must be impossibly large. I proactively ordered a new bosche 4.9 sensor and it should be coming in some time tomorrow. I will update the post with my conclusion.

[blindsquirrel]

Bosch, not Bosche. Whenever I see 'Bosche' I'm reminded of Sory home theater systems and Ferarri sunglasses.

If you're doing interweb searches using 'Bosche' then very nearly 100% of your results will be cheap fakes.

[Alvin]

Whats up yall, just the other day I finished my LQ9 swap that ive been working on for about 18 or so months. Rebuilt from the ground up with new bearings, rings, oil pump, etc and a bunch of other non-performance stuff (gaskets, bolts, etc.). I installed 821 heads with LS3 intake manifold and Deatschwerks 65lb LS3 injectors. My car was tuned before hand and ran great until it burnt a couple valves. After I uploaded the new tune, I was expecting to be running leaner than normal since it was tuned for a 5.7 and now its a 6.0 without changing the fuel. After the first fire, I noticed my wideband was reading everything from 2:1 (!!!!) to 22:1. I was not aware these sensors could even read that low. After doing some research I found that the lowest they can read is 8:1 since I have the 4.9 sensor. First fire it stumbled and acted like it wanted to die with AFRs staying around 7:1-8:1 and overall didnt want to idle very well. After lowering the min pulse width to .350 ms and changed the min fuel miligrams to .010 and uploaded the tune. It fired over quickly and sounded much better with the rpms fluctuating +/-50 rpm from target but my wideband was still reading 7:-8:1. After a few more seconds it started to go all over the place, all the way down to 2:1 and all the way up to 22+:1. Am I missing something? Could the sensor itself be bad just from sitting out gently tucked in the trans tunnel for 18 months?? I live in Florida so its typically quite humid for most of the year, though my car spent the entire time in a closed garage. I spoke with Deatschwerks and they confirmed my tune has the correct injector information. What do you guys think could be the issue?? Ive included my tune below as well as a short log of starting the car up and idling. I didnt want to do it for too long incase I am actually running that rich. I apologize for being kind of all over the place and I appreciate any help in advance!

Looks like you have a issue with your widebands wiring or connection. A engine will not run much pass 9:1 and just be pouring smoke.

Try this.

BTW.. What the hell is up with the timing table? I didn't go over much but there may be other issues.LQ9 Trans Am Start Up Tune.2.hpt

[WS6_LOU]

Looks like you have a issue with your widebands wiring or connection. A engine will not run much pass 9:1 and just be pouring smoke.

Try this.

BTW.. What the hell is up with the timing table? I didn't go over much but there may be other issues.LQ9 Trans Am Start Up Tune.2.hpt

The timing table I have not got around to touching much yet. All I did was decrease timing quite a bit in WOT areas in case I encounter any lean spots. I should actually put it closer down to 5 degrees advance at WOT. Since I had this issue at start up I wanted to correct it before I did anything else. But I dont believe that sensor is reading right. Because she idles pretty well even though it says my AFR is so low. This tune I shared with you guys is the tune that I had done to my car previously and she ran great with AFRs in the 12.5-12.7 at WOT and 14.7 at idle. I figured there shouldnt be much that I would have needed to do other than a slight retune of the MAF and VE tables. Because the idle is already dialed in. I was just not expecting to see such drastically rich AFRs at first start up. Ill be getting in a new sensor today so I will let you all know how that goes later today or tomorrow.

[Alvin]

Timing that low is going to do far more harm than good.

[WS6_LOU]

For some reason my mind always wants to add an "E" to the end of it because idk lol I didnt get a knock off sensor though I got an actual Bosch sensor. Im not having a lot of luck with these sensors for some reason. I had bought a brand new AC Delco crank sensor from Summit and that was dead on arrival. It wouldnt even fire over more than a couple times and even caused a crank sensor code to come up. I switched it to my known good crank sensor from my old block and everything was good. Now im dealing with the wideband sensor. Im almost 100% sure it is the sensor because when she idled she idled nicely with no stumbling or any other symptom typically associated with such rich AFR mixtures. And my pulswidths were holding stead at 2-3 ms which is impossible to achieve an AFR of 8:1 with. I looked back at one of my old logs and I was seeing injector pulsewidths in the 16-17 ms just to achieve 12.5:1 AFR so for sure 2-3 ms is no where near enough to put out enough fuel for 8:1 AFR.

[WS6_LOU]

Timing that low is going to do far more harm than good.

What part in particular is bad about it? 18 degrees of timing is where it idles best at and 10 degrees at WOT is just a safety precaution. What would you suggest I do?

[WS6_LOU]

UPDATE:

So I got the sensor in a little while ago, swapped it out, and now she reads correctly. She was idling around 16-16.5:1 which is what I was expecting. I added 15% fuel to all cells 1600 rpm and under as a quick correction. After flashing and restarting, she was idling at around 14.5-14.8:1 AFR which is perfect to start tuning from. Im just glad it wasnt anything more complicated. I was pretty sure it was the sensor not reading because it wouldnt be able to actually read that low and my pulsewidths were normal for what youd expect at idle. I like to create threads with small issues like this because you just never know who might have a similar answer later on and your thread could lead them to the answer or at least get them headed in the right direction. I appreciate all the input guys!