MaTTSuN Posted March 16, 2007 Share Posted March 16, 2007 ok ive been trying to tune this thing for a long time... way to long heres what i know what works for sure Head temp sensor because when i unplug it it stalls out AFM because when i move it around it makes changes i dont think these work water temp sensor and TPS If i tighten the AFM wheel one full rotation it will idle right and rev smooth BUT the spring is so tight the AFM flap will close and it will not start thats the only way i can get it to run so i can move it around but when its under load it still dies i guess its on "limp" mode since its not reading the TPS and maybe water temp sensor im trying to figure out where my TPS wires go and if the water temp has anything to do with fuel delivery. and my O2 might not be working either but ive read some guys unhook that anyways... and it runs better the set up is an 81 turbo with no EGR or vacume pump. ive tried so many things to try and tune it with just the AFM but its not working ofcourse and im just wasting my time ive put new clips on the injectors, cold start valve' and Cylinder head temp loosing his mind: matt Quote Link to comment Share on other sites More sharing options...
PETEW Posted March 17, 2007 Share Posted March 17, 2007 I wish you luck on this one. I know my Z motor started acting up before I pulled it and started to change everything. With that mess they had in the 80's it is hard to find the problem sometimes. It actually sounds like you have the exact problems I had. TPS and AFM issues. I gave up and went with an SDS system. Good luck. Other guys will be able to help you I'm sure. Quote Link to comment Share on other sites More sharing options...
MaTTSuN Posted March 17, 2007 Author Share Posted March 17, 2007 im prob going to go mega squirt but right now i dont have the funds and i want to stop driving my stupid ranger haha the only good thing is my bike will be on the road at the end of the month but i need a car and ive worked on this thing so much grrr if it ever runs it will be fun with all the mods but intill then its not so fun Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted March 17, 2007 Share Posted March 17, 2007 The TPS is two wires, and it is only plugged in between the 2 pins that make contact on idle, which I think is the middle and one closest to the cabin. You can ohm out the temp sensors, I don't remember if the ohm values are in a Haynes or Chilton but they are definately in the FSM. Check the O2 sensor as well, the computer in the turbo models was smart enough to adjust fuel as needed. Messing with the AFM probably allowed it to idle and rev since the water temp sensor is out of whack and is one of the main compenents in deciding fuel mixture if I remember correctly. Check your wiring harness, there is a step by step procedure in the FSM that tests all mosts bits of the ECCS system without the nifty tester. Good luck, Mario Quote Link to comment Share on other sites More sharing options...
MaTTSuN Posted March 17, 2007 Author Share Posted March 17, 2007 thnks mario. ill start with the O2 and get the water after or figure out the oms on it. there are 2 water temps one for the gauge and one for the com what one is for the car? the one with the wire or the one with the connection comming right ut of it? Quote Link to comment Share on other sites More sharing options...
Clifton Posted March 17, 2007 Share Posted March 17, 2007 You can check the O2 voltage. They read between 0-1v. Stoich is .45v. I don't have first hand with 280ZX efi but a few Toyotas. I know that even without the O2 connected the car will run, just a little rich. If yours stall cold, the O2 is not the problem. The ecu won't recognized the signal until it heats up. If it's a single wire O2 it will take longer than 3 and 4 wire O2's. Quote Link to comment Share on other sites More sharing options...
MaTTSuN Posted March 17, 2007 Author Share Posted March 17, 2007 it warms up and idles fine its just when i try to rev it and put a load on it it will get rich and stall out and die. i was doing some searching on here last night and it seams like the O2 should be my prob since the water temp sensor doesnt do anything for the ZXT fuel system Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted March 17, 2007 Share Posted March 17, 2007 Do you have the FSM? If not, contact a zcar.com member by the name of Scared0o0Rabbit and ask him for the address of his FTP server. I believe he has the FSM there to download. I had this problem on my ZXT when it was running the original ECU. What was the problem with mine is that the harness from the CHTS was broke, so I had to run new cables, and the the water temp connections were filthy, so I cleaned those up. After that the car still ran rich and it was from a dying O2 sensor. After that the car ran 100% better, but soon afterwards I installed MegaSquirt.... Mario Quote Link to comment Share on other sites More sharing options...
MaTTSuN Posted March 17, 2007 Author Share Posted March 17, 2007 did you do the CHTS and water temp sensor fixing at the same time? from what i have been reading the ZXT doesnt use water temp for fuel managment one wire for the gauge and one for the injector cooling fan Quote Link to comment Share on other sites More sharing options...
MaTTSuN Posted March 17, 2007 Author Share Posted March 17, 2007 how far away should the O2 be mounted? i have it about 4 or 5 inches away from the turbo should i put it further down the downpipe? Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted March 18, 2007 Share Posted March 18, 2007 There is a "sender" and a "sensor". The sensor goes to the ECU, and I'm pretty sure it is used in calculating fuel. Just because the sensors work (ohm out correctly) doesn't mean the ECU is recieving their signal. My CHTS was good but the WIRING was bad. Yes I fixed them at the same time, and then replaced the O2 and it ran way better. MPG went up as well. Mario Quote Link to comment Share on other sites More sharing options...
MaTTSuN Posted March 19, 2007 Author Share Posted March 19, 2007 well im going to buy a new sender or sensor i have a autometer water temp gauge so i dont need the stock sensor so do i need to buy a new sender or sensor? or does it matter? do they give out the same ohm reading? im going to get new O2 and water senser this week i hope i can get my Z on the road with my bike im shooting for the 1st thnks again mario Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted March 19, 2007 Share Posted March 19, 2007 Sender = Water Temp GAUGE (without it the gauge needle doesn't move) Sensor = ECU Water Temp (has nothing to do with the gauge) You need the SENSOR. They output different resistances (almost 100% sure on this). Get the FSM or even a Haynes or Chilton and look at the wiring diagrams and make sure you ohm out the pins for the SENSOR and CHTS at the ECU to make sure your harness is intact. I believe the Haynes manual has a testing procedure for the sensors. I KNOW the FSM does. Good luck with it, I think you're close. Mario Quote Link to comment Share on other sites More sharing options...
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