Guest |306| Posted June 11, 2009 Report Share Posted June 11, 2009 I have a single turbo, 6 spd, 97 Supra TT with Vipec V88 and PnP harness. I have been running it for a couple of months now, and it has been great. My tune was a little rich, so my friend (a good tuner) and I leaned it out a little, so I wouldn't get 13 mpg. We tuned the car on the highway- logs show no knock,timing at 16.5 degrees-17 @ 17-17.5 psi boost, a/f <11.3, pump oct 93 fuel for WOT pulls. Car wasn't breaking up. We were also tuning drivability. This is where the issues are.. I think. We tuned the car to get nice 12-14 a/f for cruising, light throttle, low boost applications last night. She was driving VERY WELL last night. No hiccups, awesome throttle response, etc. This morning, I wake up from work, she started up like usual, but she was acting very weird~ almost like stumbling. During light throttle, low rpm <2700 (I think), oil temp @ 165-195F, boost in vacuum, the a/f jumped crazy from 10 (or lower, this is my aem a/f lower display threshold) to 13 and the car would jerk around a lot. I thought I was going to stall. At ONE (only one) light, the car almost died~ rpms dropped below 800, so I had to blip the throttle to stay alive. I got to work fine, but I was wondering why this was happening this morning. Possible other things are: 1. Plugs? They are basically new @ 5K miles or so. They did take a beating with several wot pulls on the highway last night. 2. Weather? It rained last night. However, I've never had a problem with rain or cold with the Vipec before, why should it start now? 3. Hardware/software? We did tune the car last night with the newest software, but I don't think we updated the hardware. I read somewhere that we need to update the hardware as a separate step? mods that may affect the car's driving: stock fuel system, stock long block, stock cams, T67 single turbo, fmic, aem a/f, aem map sensor, vipec iat, v88 pnp THANKS! Quote Link to comment Share on other sites More sharing options...
Guest Dave-Kriedeman Posted June 11, 2009 Report Share Posted June 11, 2009 Always start with the basics and check your sparkplugs first. You state a cruising mixture of 12 - 14 : 1, 12 : 1 is a bit fat for cruising and 11.3 : 1 for WOT pulls, if you are not using a CDI you may have fouled the plugs. When you say you are using the latest software, what version are you using. A "FIRMWARE UPGRADE" is ALWAYS advisable when upgrading to newer software. Do you have any ERROR CODES and did you log the engine when the problem occured to have a look at possible issues. Quote Link to comment Share on other sites More sharing options...
rayhall Posted June 11, 2009 Report Share Posted June 11, 2009 This is the sort of air fuel ratios you should be tuning too, for a save tune and reasonable fuel economy. This is for a turbocharged engine. Load 30 = 14.7 50 = 14.7 80 = 14.7 100 = 13.5 150 = 12.2 200 = 11.8 240 = 11.6 Some engines will need to be around 13.5 - 14.0 at idle to get a good idle. Quote Link to comment Share on other sites More sharing options...
Guest |306| Posted June 12, 2009 Report Share Posted June 12, 2009 It looks like I may have a bad Engine Coolant Temp Sensor. We were able to replicate it, and it was fluctuating all over the place. Then, it stabilized. Ray, do you know which sensor this is on the Supra TT? I think I do, but I am not sure. I have one of your old pnp harnesses Quote Link to comment Share on other sites More sharing options...
rayhall Posted June 13, 2009 Report Share Posted June 13, 2009 The sensor is a NTC type. Ray. Quote Link to comment Share on other sites More sharing options...
Guest |306| Posted July 14, 2009 Report Share Posted July 14, 2009 This is the sort of air fuel ratios you should be tuning too, for a save tune and reasonable fuel economy. This is for a turbocharged engine. Load 30 = 14.7 50 = 14.7 80 = 14.7 100 = 13.5 150 = 12.2 200 = 11.8 240 = 11.6 Some engines will need to be around 13.5 - 14.0 at idle to get a good idle. I fixed the issue. I thought I had some exposed wiring on engine coolant temp sensor. When I went to put some electrical tape around it, the plug just fell out! It wasn't even clipped in! My guess was that there was poor connection and causing it to go all over the place. The problem has not surfaced again. Anyways, for the above post, that is in kpa right? Is there going to be an update so that we could use english units (like psi)? It makes tuning easier for us folks who are used to this. ninja edit: those number are the map (absolute pressure) right? Thanks, Jeremy Quote Link to comment Share on other sites More sharing options...
rayhall Posted July 14, 2009 Report Share Posted July 14, 2009 Jeremy, That is good you found the problem. There are no plans to make option to use imperial values. Yes the values are absolute. When I went to school there was no metric, so I had to learn it later when Australia switched over. I must admit I still think in Imperial and do quick rough conversions in my head when tuning. My method is to read 100kpa gauge as 15 psi and 50 kpa as 7 psi (or roughly half of 15 psi). Example. 50 kpa = -7 psi 100 kpa = 0 psi 150 kpa = 7 psi 200 kpa = 15 psi 250 kpa = 22 psi 300 kpa = 30 psi Quote Link to comment Share on other sites More sharing options...
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