AFRs with supercharger and Split Second FTC

bluescapegoat

Purveyor of Polished Turds
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Jul 7, 2019
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MN
I have a 2005 4.0 with a 6 speed and Boosted tech kit.

What do you see for AFRs in regards to low boost mid throttle situations? When I'm casually driving out of boost I'm reading around 15.2 which seems lean for the factory tune. When I get into normal sort of acceleration situations, fairly low load, say 50% throttle , 2000-3000 rpm, it'll build up to 3psi and still run at 14.6ish. If I put my foot down AFRs drop immediately to the 12s then taper down to 11s at about 7 psi.

I'm wondering if this is too lean for the mid range, I feel like anything +0 should be seeing enrichment. There's no audible pinging however, power feels good.

Just curious what other people have experienced since everybody says the out-of-the-box tune from Split Second is safe and conservative, and it feels good. Just watching those AFRs makes me a bit nervous.
 
It does sound lean at cruise and rich at wot. Can you make changes? Any friends that are good with HP Tuners? HPT opens up a lot off possibilities.
 
3" pulley, 1,000'. I'm in Minnesota so it's been a bit chilly lately, 40s and lower 50s. Today on my way home I was driving into a headwind and running a continuous 1.9 psi at 60 mph, this is the first time I've done it for any sustained amount of time. After about 15-20 seconds the AFRs dumped from 14.7 to 12.5 and hung there until I lifted out of boost.

I need to monitor the OBDII during driving and see if it's delaying going into open loop. I've read on other forum posts that the 03-06 TJ has a long closed to open loop delay in reaction to +0 MAP readings but supposedly the tuning that Boostedtech did on my PCM via HPTuners should have fixed that. It's my understanding that any positive pressure should be putting me into open loop, correct?

I'm also seeing an engine code for p0038 and p0058, upstream o2 sensor heater control circuit. I know the kit taps into the PCM wiring, it's my understanding it is intercepting the o2 signal to enrich it? But why would it be throwing a code?

Worth noting my downstream o2 sensors are removed and disabled, no codes or issues there.
 
Also found this interesting post over at the HPTuners forum, wondering if it could be relevant:

"could be the issue I mentioned then, fuel trims are just not clearing from the memory. Pull the ASD fuse or try to the fuel trim reset in the scanner special functions (if its there)."

"In order to reset my LTFT's on my 2005 wrangler, I remove the 3 plugs from the PCM for 5 to 10 minutes. It definitely resets the trims. Only way I've found to do so."

https://forum.hptuners.com/showthre...Can-t-force-open-loop-cant-force-PE-until-WOT
 
I have an 04 LJ with the boosted tech kit on for about a year and a half. I am running the medium pulley, and I can push about 8.5 lbs boost with it. I am using the Split Second piggyback tuner that it came with. I am still running all 3 cats in the exhaust, and a turn down right after the dynomax super turbo muffler. I have modified the canned tune quite a bit over what came with it. I generally target about 12.8 - 13.0 in lower boost, lower rpm conditions. In the upper boost and rpm conditions, I target about 11.8 - 12.0. The farther down into the 11s or high 10s the more sluggish it gets. It is more snappy when leaner, but there is a real risk for detonation. Listen carefully for ping at all times, and if you hear it, back off your timing and/or add fuel to combat that. Mine goes into open loop without delay any time it goes into boost. The exception to that is that below 1800 rpm it seems to stay in closed loop nearly all the time no matter what. If you are running at 3psi and over 2000 rpm and your afr is 14.6, it sounds like it is not coming out of closed loop operation. Hook up a scan tool that a friend can watch in the passenger seat and make sure it is immediately going open loop in any boost situation above 2000 rpm. If not, it sounds like your ECU modification was not adequate, and you would talk to Mark at Boosted Tech about that. Good luck!
 
Drove around, monitored the OBD2 readout.
Jumps right into open loop with adequate engine load. But still at 3psi it hangs in closed loop for nearly 12 seconds at 15.0 before it jumps into open. If I just cruise at 60mph at between 0 and 1 psi it just jumps back and forth between open and closed loop every second or two. Then If I bury my foot I'm seeing AFRs as extreme as 9.0 and bogging above 3k rpm. Obviously needs a lot of tuning but I'm starting to think I should just rip it all off and have the PCM tuned for bigger injectors, or even a full standalone with some dyno time. The engine has 80,000 miles on it and I don't really want to blow it up. The transition from open to closed is sometimes jerky, the AFRs have spiked as high as 19 when getting on the gas after shifting gears, it just doesn't look healthy.

I still haven't heard any pinging, and no loss of power. It's hard to tell from my bluetooth obd2 reader but it looks like the split second is doing it's job, retarding timing and adding fuel, but the pcm is cutting the injectors to lean it out until it decides to go open. I have felt loss of power but only at high rpm and it looks like it's from over fueling.

I've gone into HPTuner myself and looked over all the settings, compared the pre-adjust to the post-adjustment that Boosted Tech did and it looks like they hit all the points having to do with the open/closed loop cycle.

Also worth nothing that I was wrong about the o2 sensor codes. In HPTuner the codes are associated with the downstream 02 heat circuits. It didn't throw a code when they were initially disabled but it threw a different code when I unplugged them. I'll disable those codes entirely and do a PCM reset to start from scratch and drive the Jeep for a few days and see what I get.

In the meantime I'm discussing my options with a tuner. I would prefer something that operates smoothly and off one set of data.

To be entirely fair to Boosted Tech, I have not called them back since their initial tuning. I'm turned off enough by the way the piggyback is functioning to begin with that I'm exploring other options before continuing forward.
 
I would at least call Boosted Tech and see if they can help you before you go to all the extra work and money. Mine has never done what you are describing. You are running the standard pulley, so their tune should have been reasonably close but on the conservative side for safety. Mine was pretty rich for the hot Texas summer, and their tune pulls a lot of timing out. I have leaned my tune and reduced the boost timing retard to get more power and response. Mine is an 04, and the stock ECU had the enrichment delay that you speak of. Their modification of my ECU eliminated the delay completely. If yours still has a delay, something is not right. Good luck with your problem resolution.