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zclocks last won the day on April 5 2018

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About zclocks

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    Seal Beach, CA
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My Cars

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    75 280Z

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  1. S30 Grit Yep, I tested my new switch and it was a solid connection through the complete range of the "Start" portion of the switch. No sweet spot just continunity. Ron
  2. S30 Grit, I'm with Dave WM. I had the same problem your having and it turned out to be the ign switch. Perform the testing , out of the car, as Dave's video mentioned earlier and pay close attention to the resistance in the start position. Mine was OK on several tries in the start position, but not consistent.
  3. Len, very cool! So is this a program you developing? I wish I had something is see whats going on with my beast. BTW my voltage is being sucked down by the ignition resistor or what ever is hooked to the IGN wire on the ign switch. when I disconnect both of these the voltage jumps back to battery voltage. Now I just have to discover why! Ron
  4. Len, Just to be clear I disabled the starter per the manual to make the measurement at pin 4 . I measured the voltage at W47 and the voltage is 9.8 vdc. However, the motor starts right up and runs very nice. I did notice that the fuel pressure was at about 5 psi before I started the car. Not sure where the leak down is, but at least it starts. Ron
  5. Superlen, There shouldn't be a relay(switch) in the path from the Ign start to pin 4. It's a straight in and out connection to the control unit(pin 4).I have a couple FI relays and will measure this path. The connections are 86 to 86a of the FI relay or am I missing something. Maybe the cold start valve and thermotime swithes are pulling down the voltage? They are connected to connection 86 on the FI relay. I'm almost tempted to relocate the FI relay . It's a PIA to access. Ron
  6. Just an update as what I found with my start problem. Actually all of you were correct. I went back and reviewed my data I took on the ECU connector and found pin 4 voltage was low, 9.6vdc. My battery was low, 11.8 volts so I recharged and took readings at pin 4 again and it was still low, 9.6 vdc. So I started at the ign sw and worked my way down to the connector on the FI relay. The ign switch was open or a momentary resistance reading on bench testing. Luckily I had a new switch and I verified the old switch was bad. I reinstalled the new switch and again checked for battery voltage at pin4 and it was still 9.6 volts? If I held the key in the start position for 60 seconds the voltage would rise to about 11.4 volts. I connected everything up and started the motor. It started right up 6 times in succession. I let the motor get to full operating temp and it 's running great and very smooth. In addition the vacuum increased from 18 hg to 21 hg? BTW I did replace all my injector connectors several months ago and verified each is firing consistently. I installed new plugs, fuel pump, wires, cap/ rotor, checked timing, and adjusted valves several times. I'm not complaining , but I still don't understand why I have 9.6 volts at pin 4 going to the ECU at start. Appears to me that something something is pulling the voltage down. Maybe this is normal , yet the FI manual says it should be "battery voltage". I did check the relay pins 86a to 86 and there is no resistance and yet I have 9.6 volts output. Before I declare victory I will try and start the car from a dead cold start and see if that makes any difference. Thanks again for all the great comments and help....Ron
  7. Len you are correct on what is happening. I wasn't sure what happened during the crank sequence or where the input was to tell the ECU to supply fuel. The engine will turn over during the start sequence, there is spark, but no fuel. I used the cold start injector to to just get the motor started. Once started the motor runs without a problem. I still might have a small leak in my injectors , but generally the fuel pressure stays at 32 PSI overnight and several days after the motor is turned off. Actually, the pressure is at 40 psi when the motor won't start. As soon as the motor starts the pressure drops back to 32 psi and maintain that pressure. I will check pin 4 of ECU and see what I have . Dave thanks for your input and I will check my ignition switch. Zed the fuse link I was talking about is the Green one. The 75 has 2, one Black and One Green. I did notice that one terminal of the Green was hotter than the other so I need to investigate that. Thanks all for your inputs and will let you know what I find. Ron
  8. Ok, My basic problem is my 75 280z will not start. A couple of months ago I had a similar problem, but fixed the issue by replacing the fuel pump. Through out the summer is was hot and not a problem starting the car. First crank and the engine started right up. The first cooler day, below 95 F and the car will not start. The fuel pressure is 40 psi when cranking and 34 psi when running, when car is running the vacuum is 18 mHg, I can get the car started by actuating the cold start injector.This pumps in a small amount of fuel and the car starts right up. I did go through all the measurements in the FI manual and discovered that there was a bad connection at the TPS. This was corrected and the car started right up. So I shut down and tried to restart with no luck. I did go through all the rest of the measurements on the connector of the control unit and everything seems OK. If I had to guess I would say the control unit is not activating the injectors or is not receiving the correct input. Why then does everything work when a small amount of fuel is added at the AFM ? The only other observation is that the green fuse link is getting hot to touch which I believe supplys power for the AFM? Any inputs would be appreciate. Thanks ...Ron
  9. Hey Motorman, Does the Fry's in SD look like it's going out of business? I went to Fry's in Fountain Valley a couple of days ago and the store is really empty. I guess Amazon and the other on line stores have really put the hurt on Fry's
  10. Thanks for posting my article. I've attached a photo of a random 240 clock , which is the one that Jeff has, and this is what causes most the 240 clocks to stop. I have worked on many 240 clocks over the years and it's always the same thing. If you add oil this is what you will end up with. If you try to clean things in place you can't do a very good job and you will damage parts. There are plastic parts in the clock (some plastic motors in later 240 clocks) which can be attached by several cleaners. I use only IPA (alcohol) which does a good job, but you need to scrub the parts to get the gunk off . The 280 clocks have a completely different design which uses plastic gears against metal. If you oil on these parts you can degrade the plastic over time. There is nothing in this clock that needs be oiled. The 2 main rotating components are metal against nylon. Nylon is self lubricating and it shouldn't be oiled . Again this clock mechanism needs to be disassembled and cleaned, not oiled. The main failure of the 280 mechanical clock is the circuit board. I do repair these and sell them on my web site. Anyone can usually repair either of these 2 clocks, it just takes time and patience or you can send it to me. Just my 2c.....Ron PS: The first photo is the 240 clock and the second is the 280 clock

    • WANTED
    • USED

    Looking for the coil wire bracket in photo. Please pm or e-mail if you have one for sale. Thanks....Ron


  12. View Advert 280z coil bracket Looking for the coil bracket in photo. Please pm or e-mail if you have one for sale. Thanks....Ron Advertiser zclocks Date 07/20/2019 Price Category Parts Wanted Year 0 Model 280z  
  13. FOUND SMOKING GUN!!!! I finally found the source of my miss and sometimes backfire thru AFM. With all the things I had done I didn't look at the spark at the plugs. So...... I removed the spark wire at each plug, plugged in a spare spark plug and started the motor. Each plug was firing, but VERY weak. To cut to the chase the ignition coil was the problem. Let me rephrase that....I was the problem. I remove and replaced the coil many years ago for whatever reason. The Primary side coil resistance is supposed to be 0.40---0.55 ohms, per service manual for the 75. The Fire ball I put in there many years ago was 1.6 ohms. This might not seem to be a big change , but when I replace the coil with a "Flame-thrower -2" what a difference. The new coil has a primary resistance of 0.6 ohms , but try and find a coil today which is 0.4 ohms is not possible. I know I have my OEM coil , but at the moment I can't locate it .BTW this new coil is used with the OEM ballast resistor. This is a good day!!! PS : I should give credit to a u-tube guy with a site called "Restoration for beginners". He seems to have good understanding of basic mechanics and after watching his segment on ignition systems, which covered coil replacement, he ran into the same problem with selecting coils. Oh yea his car is a 78 280z.

    • FOR SALE
    • USED

    For sale is a very nice 280z clock that keeps excellent time. The circuit board was rebuilt , mechanical internals cleaned , lens polished , set knob re-blacked and lamp replaced. Thanks for looking......Ron


    Seal Beach, California - US

  15. View Advert 75-76 280Z Clock For sale is a very nice 280z clock that keeps excellent time. The circuit board was rebuilt , mechanical internals cleaned , lens polished , set knob re-blacked and lamp replaced. Thanks for looking......Ron Advertiser zclocks Date 07/19/2019 Price $155.00 Category Parts for Sale