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With my Maft-Pro on cold startup produces a VF=0. During this time it runs lean and tends to surge unless under load or under no load. Once the engine warms up the VF=0 problem will go away after a Warm restart. Problem is present whether cold like 10* outside or 50* outside. When engine is warm VF signal is normally very near 2.0 or 1.99 etc.

Any suggestions? Also recently it has been taking about 3 5 second cranks to get the Supra started unlike the old start on first try.

Thinking I might be a defective temp sensor, however the ECU does know once the engine is warm. I'm confused.
 

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OK-This is wierd. Bear with me Rusty, You know I dont have a Maf-T pro. However, I had a very similar problem for about a year. Ive seen a Half dozen 7MGTE owners with same problem, mostly in MK3s. Mine would stay in cold start Lean mode(lets call it Mode 1 for purpose of this discussion), until I rekeyed car. I could drive car the 60 miles to shawns in Mode 1, stop at his house, rekey car immediately, and car is in Full Rich(Mode 2). I could modify overall AFRs up or down by changing fuel pressure, IE, Mode 1 at 17, Mode 2 at 14. During boost in Mode 2, I had open loop. My VFs read like yours, I even changed datalogger to record VF, It was flatlined at either 0 or 2.0, just like yours. Was told over and over it couldnt be happening, didnt know what I was monitoring, yadda, yadda. Problem started on a day I was lengthening AFM harness, cause old one was under tension. One other thing happened that day. I accidentally spilled some antifreeze onto/into wire harness by firewall. OK-I redid AFM extension-no change. I took wire harness out, dried out, checked all voltages and resistance per TSRM. Reinstalled-No change. I installed new sensors, Adjusted TPS, Changed out ECUs, did a few things, to no avail. Bit the bullet, and bought another harness. TADA. VF works again. The cars with this problem have all shared one thing, and one thing only-7mgte Electronics with Piggybacks. I dont have an explanation, I usually start with myself when looking for someone to blame. I think its possible something got shorted/grounded/quantum hole tunnelled during one of my many mods to already bastardized wiring harness. Its possible Antifreeze had something to do with it, the problem started the next time car started, however, I did several things all at once that weekend. Heres a relevant thread from supramania. I may be only person who has "fixed" issue. http://www.supramania.com/forums/showthread.php?t=65663
 

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I had a simmiler problem when i was running the pro on my 7M till i played with the cold start enrichment settings.

Thing is when cold the car reads 0 witch is closed loop but your lower VE table is set up to run in open loop so when the motor is cold the ve you have is just plane wrong.

Only way to fix this is to play with the cold start richness. IE changing the ve scale down low when in worm up but then back to normal ve when worm


Hope that made sense

I only had problems with this in the dead of winter since in CA for me thats only like 30F out side
 

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It did not matter what temp it was outside for myself or any others that had same problem. And, second keystroke(warm restart) always engaged Mode 2, also no matter what temperature. Could be 30 seconds between keystrokes, could be an hour. Could be 10 degrees out, could be 80. Toward end of year I fought this, my car also would buck, and occasionally stall, while in Mode 1. I got good at re-keying car at any time.:zzzzz: Sure sounds like your issue, Rusty. The VF signal is key-A flatline 2.0 on a warm restart, after every warm restart, No matter what settings you change, and youve got same issue as we all did.
 

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wth i have this same problem with my 7m na
it takes a few cranks, and i have to rekey her to get her to stop acting dumb!
 
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