MaTTSuN Posted August 6, 2005 Share Posted August 6, 2005 Now igot you here please read on, you will win something if you know this, just not sure what yet Ok here it goes, did my turbo swap into my 78z its a 81 turbo engine. Now i hooked everything up the only thingis that the AFM is upside down. Im not sure if this matters but i got to put it out there. The problem is it will not run rite everything "seems" to work some of the time but most of the time it runs really rich and shoots black smoke out the tail pipe. when i check the NEW sparkplugs today they had gas on them and lots of carbon build up. I thought it was the AFM conections but now im thinking it might be how the coil is hooked up and it doesnt have enuf spark if anyone has had the same problem id love to know how to fix it since its the last thing i have to do befor i can drive this badboy Thanks: Matt Quote Link to comment Share on other sites More sharing options...
Thumper Posted August 6, 2005 Share Posted August 6, 2005 Its either the head temperature switch or the coolant temp switch. Coolant temp switch is located on the front of the engine near the thermostat. The head temp switch is the passenger side of the engine near the rear of the head. It is a two prong connector. I would check both of there resistances. Even if one is off just barely it can cause a big problem. Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted August 6, 2005 Share Posted August 6, 2005 Hi there Vancouverite. By "AFM upside down" you mean the air entry is still pointing forward, only rotated 180 around the axis right? I have a AFM off of a 76 L28E I am assuming the AFM is similiar to the one used in L28ET. I just went downstairs to fondle with my AFM in the garage. Here's what I think : The AFM uses a large L shaped metal flap gate and spring to "know" the amount of air flow. When the AFM is in its original position, the weight of the L-shape metal flap gate RESISTS the gate opening(more pre-load to the spring) o--- the --- arm weighs it down. valve opens counterclockwise | When you flip the AFM upside down, the weight of the L-shaped metal flap gate HELPS the gate opening.(less pre-load to the spring) | o--- the --- arm "promotes" opening. valve opens clockwise o is the pivot point Funny thing is when the flap gate opens more, weight of both arms come into play. i.e. instead of one arm adding/removing pre-load, BOTH arms adds/removes pre-load. SO the upside down deal will make your engine run rich no matter what the valve gate position is. I used my finger to poke at the metal valve and it does make a little difference when it is upside down compared to when it's mounted normally. With the AFM upside down, the AFM gate will open more easily. So the ECU thinks your engine is admitting more air in than it really is. The extra squirt of fuel makes things rich in all conditions. Try to mount the AFM in it's normal position and then test run the engine. I live in Richmond BC....if I win something let me know....HECK I would love to meet a fellow Z member expecially when they have done a L28ET swap. Quote Link to comment Share on other sites More sharing options...
MaTTSuN Posted August 6, 2005 Author Share Posted August 6, 2005 Thumper: ive checked and cleaned the sensors and grounds to make sure its not that, but you never know with these old birds. TheNeedForZ: thanks for all that ill let you know if that works, the afm seemed to fit better with what i had upside down. It was a temp install till i make my 3"madrel cold air intake with my AFM infront of the rad. Ill flip it and try it again god i hope thats it. Hey TheNeedForZ are you going to the datsun/nissan autoX in sept its the most fun i have ever had in my Z. As for what u might win i got a few parts kickin around, ill let ya know. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted August 8, 2005 Share Posted August 8, 2005 when i did my zxt install i ended up with afm mounted to top of radiator core support using holes from old air filter assembly.i had the afm mounted in the motor compartment but it was on an angle and the gate inside hung up making a rich condition.the gate in the afm has to swing freely.i had the hinge point on the bottem. Quote Link to comment Share on other sites More sharing options...
datsunlover Posted August 8, 2005 Share Posted August 8, 2005 I'll second the AFM thought. I'd say run it EXACTLY as it was stock before looking elsewhere for the problem. When I was messing with my 280z's afm (when I was still trying to figure out the FI.. I eventualy went to carbs cause it was simpler) I noticed some weird things with the afm fliped over, or moved around. At one point I had it on it's side (rotated about 45* from original location) and the engine ran smoth as a babys but; Only problems was it idled from 700-1500 up and down, up and down... as if I was slowly bliping the throttle. Quote Link to comment Share on other sites More sharing options...
MaTTSuN Posted August 9, 2005 Author Share Posted August 9, 2005 ok i got the AFM mounted the right way. It solved the rich problem. But it still runs bad. It no long blows black. it will run ok when itsfirst started up but once its warmed up it runs like crap again. I know its prob one of the sensorshead temp or front water temp. i cleaned the conections and put dieletric grease on them. So its prob a sensor itself, but if anyone has any other tricks id love to hear them. Thanks guys: Matt Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted August 9, 2005 Share Posted August 9, 2005 Did you clean the connectors at the ECU? When it runs like crap open up the kick panel and play with the connectors and see any changes. Do you still have the VCM module hook up to the EGR? if so disconnect it from the EGR valve or better yet just remove the EGR valve and cap it. I experienced this problem before . My car ran rough after warmed up and it turn out to be a bad EGR valve. Good luck Quote Link to comment Share on other sites More sharing options...
MaTTSuN Posted August 10, 2005 Author Share Posted August 10, 2005 ive capped the EGR and it still does it. did your Z run fine on warm up then start acting up. It still runs but it stumbles instead of reving smoothly. I just changed the Head Temp sensor and conector but still the same... I know once i get it ill belike dam thats so stupid but intill that time grrrr haha thanks again guys Quote Link to comment Share on other sites More sharing options...
MaTTSuN Posted August 10, 2005 Author Share Posted August 10, 2005 oh yeah, does it matter if you mix up the 2 front water temp sensor plugs? Ive switched them and i dont think its changed anything.... anythoughts on that? Quote Link to comment Share on other sites More sharing options...
MaTTSuN Posted August 19, 2005 Author Share Posted August 19, 2005 still no winner ha... anyways i took the vacume off the FPR and the thing started running great till it ran out of gas i guess... is it the FPR? Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted August 19, 2005 Share Posted August 19, 2005 I'd think head temp sensor, thermotime sensor, It's obviously a sensor that is used once warmed. unplug your cold start valve and see if it acts the same way. Also try tuning your AFM, you can pop off the black box and adjust it, but if your no longer running rich don't bother yet. Wait till it runs -Ed Quote Link to comment Share on other sites More sharing options...
MaTTSuN Posted August 23, 2005 Author Share Posted August 23, 2005 is the thermo time sensor the one with 2 wires? i dont have that on my turbo. im thinking of putting it on cause i have some extra engines with it on it. could i use that for my ecu temp sensor?i guess i should just buy all new sensors and stop posting haha, thanks tho Quote Link to comment Share on other sites More sharing options...
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