# Running rich **URL:** \ **Category:** SON240sx Automotive\ **Created:** [February 2, 2006, 6:24am UTC](https://forums.speedlife.net/t/running-rich/92471 "2006-02-02T06:24:22Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![absolum](https://avatars.discourse-cdn.com/v4/letter/a/e47c2d/32.png) [@absolum](https://forums.speedlife.net/u/absolum)\ **Post date:** [February 2, 2006, 6:24am UTC](https://forums.speedlife.net/t/running-rich/92471/1 "2006-02-02T06:24:22Z")
I recently swapped a 96 motor in my car, a 1990 240sx, car is running rich like hell , it also have a lumpy idle. I checked for code and get a long beep and 2 short so I assumed that would be code 12 for the maf, I replaced the maf from a 92 to a 91 unit, still having the same problem, I also change the ecm from a 92 to a 91 unit, same issue. The idle only change when I unplug the maf, I can even move the maf out of the intake path and the car still idle the same, I unplugged 3 out of 4 plug wires and the car still idle rich. The distributor has been replaced with a 91 unit and crank set to tdc before install. I went as far as replacing the entire wiring harness, still having the same issue. The motor is from 96, I replaced the lower intake with a 91 unit, and I soldered the underdash harness as per the faqs and matching all colors. Car is still running pig right, I purchased new park plug yesterday and they are all black. What could be causing this problem? A could of more thing that I may try before running out of ideas, replace the entire fuel rail system to eliminate the fact that I may have bad injectors of a faulty fuel regulator, Trying to use a 96 240sx maf sensor on the car. The car drives but carries out black smoke and backfires a lots. Any suggestion is welcome at this point. ---
**Author:** ![Ed1](https://avatars.discourse-cdn.com/v4/letter/e/958977/32.png) [@Ed1](https://forums.speedlife.net/u/Ed1)\ **Post date:** [February 2, 2006, 7:36am UTC](https://forums.speedlife.net/t/running-rich/92471/2 "2006-02-02T07:36:00Z")
bad o2 sensor? ---
**Author:** ![absolum](https://avatars.discourse-cdn.com/v4/letter/a/e47c2d/32.png) [@absolum](https://forums.speedlife.net/u/absolum)\ **Post date:** [February 2, 2006, 9:35am UTC](https://forums.speedlife.net/t/running-rich/92471/3 "2006-02-02T09:35:52Z")
I drove my ka sohc with no o2 sensor for 2 month and it never ran that rich , I am not sure if that will cause the maf to not have any reading . I will replace it anyway and see what happen . ---
**Author:** ![Hector](https://avatars.discourse-cdn.com/v4/letter/h/43a26b/32.png) [@Hector](https://forums.speedlife.net/u/Hector)\ **Post date:** [February 2, 2006, 10:29pm UTC](https://forums.speedlife.net/t/running-rich/92471/4 "2006-02-02T22:29:58Z")
#1. vaccum leak and a question for ya , did u take off the egr shit ? ---
**Author:** ![S13GG](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/s13gg/32/5506_2.png) [@S13GG](https://forums.speedlife.net/u/S13GG)\ **Post date:** [February 3, 2006, 7:56am UTC](https://forums.speedlife.net/t/running-rich/92471/5 "2006-02-03T07:56:56Z")
> [@Hector](#): > > and a question for ya , did u take off the egr shit ? and seal the outlet in the manifold? very important… ---
**Author:** ![absolum](https://avatars.discourse-cdn.com/v4/letter/a/e47c2d/32.png) [@absolum](https://forums.speedlife.net/u/absolum)\ **Post date:** [February 3, 2006, 10:21am UTC](https://forums.speedlife.net/t/running-rich/92471/6 "2006-02-03T10:21:58Z")
I blocked it with a home made block of plate . I am pretty sure this does not leak , I will however run a pressure test on the intake manifold just in case . Few are the things I have not tried yet , Can a bad TPS cause the problem , assuming that it’s not senting the signal to the ECM ??? ---
**Author:** ![s13Junkyard](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/s13junkyard/32/5502_2.png) [@s13Junkyard](https://forums.speedlife.net/u/s13Junkyard)\ **Post date:** [February 3, 2006, 8:51pm UTC](https://forums.speedlife.net/t/running-rich/92471/7 "2006-02-03T20:51:15Z")
make sure the dizzy is in correct change that water temp sensor to the s13 one i gave you then let us know whats happening ---
**Author:** ![absolum](https://avatars.discourse-cdn.com/v4/letter/a/e47c2d/32.png) [@absolum](https://forums.speedlife.net/u/absolum)\ **Post date:** [February 4, 2006, 7:06am UTC](https://forums.speedlife.net/t/running-rich/92471/8 "2006-02-04T07:06:46Z")
I pulled out the valve cover yesterday and set the dizzy to piston 1 . I even opened and close the intake valves before setting to tdc just to make sure I was in the right compression stroke . It lines up perfect with piston 1 . Today I am regrounding the entire engine , I am off the create my own kit , if it fails that I will replace the fuel system , that include fuel rail and injectors . I am guessing that some injector may be suck open or maybe some debrit got in the fuel rail plugging the regulator . Wish me luck. ---
**Author:** ![absolum](https://avatars.discourse-cdn.com/v4/letter/a/e47c2d/32.png) [@absolum](https://forums.speedlife.net/u/absolum)\ **Post date:** [February 6, 2006, 11:10am UTC](https://forums.speedlife.net/t/running-rich/92471/9 "2006-02-06T11:10:15Z")
I replaced the fuel rail assembly and have new injectors in , the car has a good trottle response , buggs a bit between 1000 and 2500 but pulls great to redline . Still getting occasional black smoke from the tail pipe but no as much as I used 2 , also not getting as much backfire when I drive . I am gonna try to reground my MAF to the car itself and see what happens . any mopre sujection ? ---
**Author:** ![absolum](https://avatars.discourse-cdn.com/v4/letter/a/e47c2d/32.png) [@absolum](https://forums.speedlife.net/u/absolum)\ **Post date:** [February 11, 2006, 7:40am UTC](https://forums.speedlife.net/t/running-rich/92471/10 "2006-02-11T07:40:35Z")
Update Got it running after replacing pretty much every sensor in the motor , Now motor has a loud ticking noise when reving passing 2000 rpm , car dies after 30 sec , ticking get louder and louder when trying to rev , all that occur during the 1st test drive after fixig the richness problem . :roll: Could be the timing chain , tensioner , guide or valves kissing each other. All that before even reacing 120 km from purchase . I guess the motor is now crap.