Silver86 Posted January 5, 2015 Report Share Posted January 5, 2015 Hello everyone, I am pulling my hair out over this one and need help, almost ready to pass this Starion along but can't do that! No way! Have done a ton of searching and have looked through the FSM and tested everything I can think of. My car is an 86 running stock fuel system with new fuel pump, injectors, CTS, TPS and ISC reset. I keep throwing an 02 code, and while monitoring the 02 voltage while driving, it looks like I go into closed loop fine (.1 volts oscillating to .9) when up to temp, but after driving for 20 min or so, 02 voltage drops to super low (.01 or so) and part throttle driveability goes to crap, like it's running super lean. Of course, if I go WOT, it goes open loop, the 02 immediately goes nice and rich, and the car pulls fine. I have good injectors, new CTS, no boost leaks, have tried multiple brand new 02 sensors, swapped out the ECU, and have swapped out three "working" mass air flow sensors. My question is why am I able to go into a closed loop for a while but then it runs super lean. Unplugging the MAS puts it into open loop, and it runs super rich, and driveability is excellent (so I know it's not a mechanical fuel delivery problem.) My best guess at the moment is trying another MAS? Is it possible all three are bad? What am I overlooking? I don't want to go hacking up another "faulty" sensor connector only to find out it's not the problem. Thanks! Link to comment Share on other sites More sharing options...
scott87star Posted January 5, 2015 Report Share Posted January 5, 2015 Is it throwing an O2 code when its in closed loop? Link to comment Share on other sites More sharing options...
Silver86 Posted January 5, 2015 Author Report Share Posted January 5, 2015 Will confirm again, but it is not when last checked Link to comment Share on other sites More sharing options...
scott87star Posted January 5, 2015 Report Share Posted January 5, 2015 Well, low voltage is lean so that would suggest the O2 is reading correctly and the ECU decided not to remain in closed loop anymore, except that its not using it's internal lookup table like it should be. And our ECU's are notoriously robust, meaning it's not likely bad. That's a pickle. To the FSM Batman! Link to comment Share on other sites More sharing options...
scott87star Posted January 5, 2015 Report Share Posted January 5, 2015 After a quick review of the FSM I would check the injector resistors actual resistance both cold (running well) and hot (running like crap). Link to comment Share on other sites More sharing options...
Silver86 Posted January 7, 2015 Author Report Share Posted January 7, 2015 Thanks, Scotty, injector resistance tests good, however when I tested the injector ballast resistor, it showed less than 1 ohm, should show 6 ohms. I have ordered a new one and will report back as to whether this fixes it. Link to comment Share on other sites More sharing options...
Silver86 Posted January 15, 2015 Author Report Share Posted January 15, 2015 Just to update and close out this thread, I finally tracked the problem down to improperly routed vacuum lines that kept the fuel vapor purge valve open at all times. Always turns out to be the simplest overlooked things for me. Link to comment Share on other sites More sharing options...
BandY Posted January 23, 2015 Report Share Posted January 23, 2015 Not ready to let this die. Sorry. I have an 86 also, and I'm pulling my hair out. Taking cabs to get places. This is BS, What the heck is an iinjector ballast resistor? Never heard of it. My 86 WILL NOT RUN. I need someone to tell what the heck is the problem. I am so fed up. Everything is new and good, but still it won't run right. I thought I was good with these puzzle cars, but now I am making a fool of myself. What am I overlooking? Link to comment Share on other sites More sharing options...
mikec Posted January 25, 2015 Report Share Posted January 25, 2015 Injector ballast resistors are 4 to 6 ohm resistors that limit the maximum electrical current flow through the injectors - otherwise they or the ECU will burn out. The injectors are packaged together into one metal box that is screwed to the bodywork bulkhead between the passenger headlight and the air filter assembly. If you remove the whole air filter assembly you'll see the silver box. 3 wires: one input wire (connects to the battery via the ECI fusible link and the ECI relay, this is the pin "by itself" in the connector) that feeds both resistors, then 1 output wire for each resistor. (the two side-by side pins in the connector). mike c. Link to comment Share on other sites More sharing options...
Silver86 Posted January 30, 2015 Author Report Share Posted January 30, 2015 Bandy, hang in there, if you are local to Southern California let me know and I can help you nail that b**** down, I was pulling my hair out too. Post your specific issues and this board will solve it for you. I assume you have checked for fault codes? It always come to fuel, air, spark...and supernatural forces conspiring to ruin your life! Link to comment Share on other sites More sharing options...
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