Hey everyone. I replaced my original MAF sensor, which had been ported w/no screens, about a month ago. I replaced it with the WElls 145 unit. After that the car won't idle when cold and was running really rich at WOT. I burn my own proms and based on the Winaldl data the car was rich. The car is an '87 GTA 350 TPI and I am running the 165 ECM and am using the 29c256chip and the $32b bin, cold start injector used. I am using Winaldl, Winbin and the PP2. Also running 40-43 psi of fuel w/ 30lb. injectors. The car has quite a few mods, but ran fine before the Maf change.
I adjusted the BPW constant and leaned it out somewhat. This fixed the WOT rich issue, however it still wouldn't idle cold. The plugs looked really lean and the data showed roughly 140 at idle. So I adjusted the Open loop afr ratio% change vs.coolant in the 20-56degC range from 3 to 17 and everything in between. I also tried adjusting the IAC Warm Park steps vs. coolant in the 8-56 degC range from 75-100 and then down to 25-30. Right now with the IAC set at 30 and the Open loop aft ratio vs. coolant set to 16 it will start then stall and once restarted will idle halfway decent until warm. I have adjusted the TPS to .54V and also adjusted the throttle. I have adjusted the PW correction vs. battery voltage in the 12.8 cell only from 32 to 36 w/ no difference. I also adjusted the MAF Table 1 values to 5.7,6.7,8.8 in the .37V,.55V and .73V tables to richen it up a little. Between all the changes I'm not sure which one is making the most impact. FWIW, The BL's in park at 1200 rpm are 108 and in gear at nearly 1000rpm are 128. As a side note, when the car is hot and started it races to 1500 rpm and sits there for about a minute then quickly falls to 950???? I generally only change one thing at a time, turn the key and see if it dies before it warms up. I tended to stay away from things that should not have changed when the MAF was changed.
Prom idle is set at 800-1050 depending on coolant temp. I have verified the CTS works properly and the IAC is newer. Also, When warm the IAC counts won't fall less than 70. These problems didn't start until I installed the new WElls MAF. My original was ported with no screens or heat sinks. This one just has the outlet screen removed.
Any other information just ask. Thanks for the help folks. I have spent the last 2 weeks working on this problem.

 

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