So got the Sambar running with the new turbo set up and everything is working great except.... At very light throttle the check engine light comes on and the truck will only idle at that point. Shut off the key for a second or two or let the truck idle for 10-15 seconds and the light goes off and everything is happy again. As you can imagine this is pretty exciting driving along at 60mph. My first thought was TPS adjustment. Found this little write up for subarus in general and it seems set pretty close to this. No change with the adjustment per this. https://main.experiencetherave.com/subaru_manual_scans/FSM_Scans/TPS_testing3.jpg I plugged the two pin green connector under the dash together to check for codes. It is either a code 64 or 73. The transition between the long and short flashes is super quick so not sure. I realize I'm way off in the weeds with my set up so who knows what could be causing it. If anyone else has had something similar on a stock truck or any ideas let me know.
Do you have any idea what sort of manifold pressure you are hitting? It is possible that it may be sensing an overboost or even underboost condition causing the ECU to freak out.
Ok hmm. I was thinking that if it had a MAF it could be a tuning issue. Issue is still probably tuning related, I wonder if it is something as simple as the ECM is expecting to see a certain pressure at a certain RPM since supercharger build linear boost and you are not meeting this requirement with the turbo.
That is my thought too.. Too low of a boost pressure before the turbo spools up, and the ECU thinks there is something very wrong.
I wish I could figure out what the code was saying. For the life of me I can't find a meaning for that trouble code(s) anywhere.
I pulled up the Japanese service manual, and it does not list an error code that high. The highest I see is 63, which is "Heater Blower Signal"
Pretty sure I fixed it. Bad O2 sensor. I just thought about what was in play with the ECU at light load steady state cruising and guessed the O2 sensor. Was able to get a replacement for $15 locally so figured it was worth a shot. I put about 10 miles on it since and not a hiccup. Before it was every 1/2 mile or so.
banz, I'm glad that you found it! I've been following this, and wasn't sure what was going on! This could help others down the road! Good find! Limestone
Ughh! That wasn't it. It drove great last night, went to drive into work this morning and bad as ever.
Sorry to hear that! ECU? Maybe acting up? I'm throwing darts here. You know yourself, even new electronic parts, act up! I can't tell you how many stories I've heard, over the years, where newer parts go bad! Limestone
I'm bringing it to the dyno tomorrow. That will be more of a controlled environment where I can monitor A/F ratios and things to see if we can pinpoint the problem. The upside is I'll get some power numbers too. I've definitely lost power on the low end but I think it will make it up on top. Also the thing just sounds awesome! The exhaust, turbo and blow off valve make it a hoot to rev up and listen to.
Sort of found the problem or at least a solution. We were able to narrow down to it only happened at 20-40% throttle and at 4250rpm on up. The "fix" was fiddling with the TPS. We finally found a setting on it where it wouldnt throw an engine code. Videos are in my dyno thread!
banz, Keep tweaking! You'll get! Were gonna call you the TWEAK MASTER! By the time it's all said and done! I hope that's it! Great thread and Info.! Keep us posted! Limestone
