mooser83 Posted July 2, 2010 Report Share Posted July 2, 2010 In the FAQ post lo-buck FCD for MAP equip cars (1986's) The post mentions to install a 4.3v zener diode to prevent the ECU from cutting fuel above 13psi. The issue with my 83 is that it cuts at 10psi, so if I get a 4.3v zener will this work for me? I would assume that the MAS would be similar to that of the 86 and 4.3v would be 13psi also, which means my ECU will still cut at 10psi. I would assume I would need a slightly lower volt zener to prevent the ECU from "seeing" over 10psi. I am trying to tune for 11psi, but I have to keep it tuned for a constant 9 and if I get the slightest boost surge it cuts the fuel. Any insight would be greatly appreciated. Link to comment Share on other sites More sharing options...
MikeMeyerhoff Posted July 3, 2010 Report Share Posted July 3, 2010 Yes it should work (its a common trick). I did it to an 84 and was able to run well past 10psi until the car went off the fuel map. Thing about going off the fuel map is that its not a certian PSI. If its cooler air temp it might cut at a lower PSI than higher air temp. Same for gears, lower gears might have a little less psi than higher ones. Link to comment Share on other sites More sharing options...
mooser83 Posted July 3, 2010 Author Report Share Posted July 3, 2010 Ahh ok. I wasn't sure about what point the ECU cut fuel at since I know some of the later years came with 10 or more PSI stock and mine cant even hit 10 without fuel cut (sometimes a bit less). I'll give it a try and see if it works. I can get the diode for 15 cents anyway, worst case I just take it off. Thanks again Link to comment Share on other sites More sharing options...
Komeuppance Posted July 3, 2010 Report Share Posted July 3, 2010 You could also unhook your map sensor. -Robert Link to comment Share on other sites More sharing options...
Tim_C. Posted July 17, 2010 Report Share Posted July 17, 2010 I have one '83 that has no fuel cut. I have another at stock boost that I wouldn't know if it cuts or not. Link to comment Share on other sites More sharing options...
83_project_toy Posted July 18, 2010 Report Share Posted July 18, 2010 fuel cut like most things on a 83 is a mystery mine would cut fuel anywhere from 9psi to 13psi just depended on it's mood for the day. i've heard others say there 83 dont have it and i've heard others say it kicks in at stock boost levels. Link to comment Share on other sites More sharing options...
FlattopMike Posted July 19, 2010 Report Share Posted July 19, 2010 I think fuel cut gets the blame for a lot of things it shouldn't.Mine was acting as though it was hitting it so I bought and installed a defender. It didn't change.Turned out to be a vacuum leak causing my distributor to not retard. Link to comment Share on other sites More sharing options...
83_project_toy Posted July 20, 2010 Report Share Posted July 20, 2010 i got a defender installed to and it helped alot but you do have a good point about vacuum leaks Link to comment Share on other sites More sharing options...
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