TurboSpider
Proven Member
- 223
- 16
- Nov 2, 2015
-
York,
Pennsylvania
So just had my engine rebuilt, got about 70 miles on the rebuild. I am trying to get my a/f dialed in. Here is a list of the mods I have so everyone knows. 97 spyder gst. Bottom end is a 6 bolt, stock crank wiseco pistons .20 over, stock 6 bolt rods. Top end is 2g head running green top CAS. 1200cc injectors, walboro fuel pump, rewired fuel pump. Aftermarket FPR. BC heavy springs and retainers and 272 cams. LC2 wideband mounted after flex pipe and before downstream factory o2 and hard wired to factory downstream o2 sensor input on ecu. Front o2 is the stock sensor that came on the car, not sure how old and possibly maybe bad? I am letting ecu get readings off front o2 and am not simulating narrowband as my wideband is further away from turbo where instructions said to mount it. Car is running Speed density with no boost leaks at throttle body, throttle plate ect.
I had to bump idle up to 900 because sometimes car was dying out when I pulled up to lights or stop signs and would definitely stall if I turned the a/c on. I did fix this somewhat by getting ISC position to around 30 It was originally at like 70 at idle. It now hovers around 30 range but does go up when a/c is kicked on. I changed the open loop thresholds to make the car run in closed loop more like ECM link wiki suggested to do and drove car around 30 minutes or so trying to get the throttle over a complete range. Keep in mind this is still a new engine on its break in so I didn't want to take the rpms up too much. Car should of been running on waste gate pressure but seems the boost is getting pretty high for waste gate pressure according to 4 bar map sensor.
The main issue I have is car seems to idle ok when first started and warmed up and seems to idle around 14.7. Once car has been on for a long time or if car has been shut off and restarted hot it idles rich around 12:1. This is in closed loop mode.
When I started the cruise a/f seemed to be around stoich at idle like it should and car seemed to be running overall really good. Possibly the best it has. I went out on lots of hills trying to put engine under different load factors like I should have. Somewhere around the 2,171 seconds into the log, the car started to seem to have more rich a/f at idle and fuel trims where increasing much higher then they did earlier on when first started. Around 2291 seconds in the log, the car seemed to be back to idling better around 14.7. No changes where made at all in ecm link at all during this cruise. I was strictly trying to gather data to do the combined fuel trim adjust for SD.
Closer to the end of my drive, I started increasing my rev range to try and get the higher rpm cells of the VE table to be activated. Around 2857 seconds into the log, I reved the car up to about 5,000 using 1/4 throttle and then gave it about 1/2 throttle for a short time. Boost spiked to 22 psi according to baro and CEL flashed as I recorded 8 degrees of knock. I didn't dare do that anymore and drove the car home pretty conservatively after that. When I got back I right clicked and did the combined ft adjust sd ve and applied the recommendations into the chart. I noticed the car was back to idling around 12:1. I shut the car off and reflashed the stock open loop threshold numbers back in and restarted the car.
It seemed car still wanted to idle in closed loop around 12:1 and was not idling as good as it did in the beginning of the drive. I locked it in open loop and took it for a short cruise and got a log. Locked in open loop I was able to idle closer to 14.7 at idle but my a/f seemed to jump around a little with rpm variation, possibly because my VE table still needs more work? Also when locked in open loop when I come to a light or stop sign the cars idle seems to go lower then it should almost stalling. Actually at the very end of this log I turned on the ac which stalled the car.
So the main issue I seem to be having is the car starts up cold and idles around 14.7 once warmed up. After driving it for awhile it seems to go back and forth between wanting to idle around 12:1 and around 14.7:1. I cannot figure out why the variation in closed loop a/f. In open loop it appears to be closer to stoich like it should so am I looking at a possibly bad o2 sensor that is going from working ok to not working right? What is your thoughts on that?
Another thing I did notice is that during my entire first cruise in which i was gathering data for the combined ft adjustment I had lock manifold different pressure checked. No sure that was supposed to be checked or not but I do have the stock MDP on stock intake.
I had to bump idle up to 900 because sometimes car was dying out when I pulled up to lights or stop signs and would definitely stall if I turned the a/c on. I did fix this somewhat by getting ISC position to around 30 It was originally at like 70 at idle. It now hovers around 30 range but does go up when a/c is kicked on. I changed the open loop thresholds to make the car run in closed loop more like ECM link wiki suggested to do and drove car around 30 minutes or so trying to get the throttle over a complete range. Keep in mind this is still a new engine on its break in so I didn't want to take the rpms up too much. Car should of been running on waste gate pressure but seems the boost is getting pretty high for waste gate pressure according to 4 bar map sensor.
The main issue I have is car seems to idle ok when first started and warmed up and seems to idle around 14.7. Once car has been on for a long time or if car has been shut off and restarted hot it idles rich around 12:1. This is in closed loop mode.
When I started the cruise a/f seemed to be around stoich at idle like it should and car seemed to be running overall really good. Possibly the best it has. I went out on lots of hills trying to put engine under different load factors like I should have. Somewhere around the 2,171 seconds into the log, the car started to seem to have more rich a/f at idle and fuel trims where increasing much higher then they did earlier on when first started. Around 2291 seconds in the log, the car seemed to be back to idling better around 14.7. No changes where made at all in ecm link at all during this cruise. I was strictly trying to gather data to do the combined fuel trim adjust for SD.
Closer to the end of my drive, I started increasing my rev range to try and get the higher rpm cells of the VE table to be activated. Around 2857 seconds into the log, I reved the car up to about 5,000 using 1/4 throttle and then gave it about 1/2 throttle for a short time. Boost spiked to 22 psi according to baro and CEL flashed as I recorded 8 degrees of knock. I didn't dare do that anymore and drove the car home pretty conservatively after that. When I got back I right clicked and did the combined ft adjust sd ve and applied the recommendations into the chart. I noticed the car was back to idling around 12:1. I shut the car off and reflashed the stock open loop threshold numbers back in and restarted the car.
It seemed car still wanted to idle in closed loop around 12:1 and was not idling as good as it did in the beginning of the drive. I locked it in open loop and took it for a short cruise and got a log. Locked in open loop I was able to idle closer to 14.7 at idle but my a/f seemed to jump around a little with rpm variation, possibly because my VE table still needs more work? Also when locked in open loop when I come to a light or stop sign the cars idle seems to go lower then it should almost stalling. Actually at the very end of this log I turned on the ac which stalled the car.
So the main issue I seem to be having is the car starts up cold and idles around 14.7 once warmed up. After driving it for awhile it seems to go back and forth between wanting to idle around 12:1 and around 14.7:1. I cannot figure out why the variation in closed loop a/f. In open loop it appears to be closer to stoich like it should so am I looking at a possibly bad o2 sensor that is going from working ok to not working right? What is your thoughts on that?
Another thing I did notice is that during my entire first cruise in which i was gathering data for the combined ft adjustment I had lock manifold different pressure checked. No sure that was supposed to be checked or not but I do have the stock MDP on stock intake.