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78 Z will not start


AndysPlit

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Hehe....You're right. I am still a beginner when it comes to working on the car. This started as a simple radiator / water pump job, now a "starting" issue. I did state that the engine does crank once in a while, but dies after a second. Thank you for your tips. I'm really in this alone, so I am having to learn by trial and error. I'll get her started for sure. Diagnosing the problem over the internet can be tricky, I agree :)

Edited by AndysPlit
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Here are my two cents and a few questions....Assuming that you can turn the engine over (good battery)

  • When you put the key in the ignition and turn it to the on position, does the fuel pump hum? It should hum for a 10 or so seconds and then shut off.
  • Have you removed the fuel line going from the Fuel Filter to the Fuel Rail and observed fuel flowing in a strong steady stream? No Fuel? Check Fuel Pump.

Assuming you have fuel.....

  • Do you have a Spark?
  • Do you know how to check the Timing? Check the Timing. (10 Deg. BTDC)
  • Check the Air Flow Meter to make sure the flap is free and moving and the wiring harness is in good shape and plugged in.
  • Check the Throttle Position Switch to see if the wiring harness is in good shape and plugged in.
  • Did you wash off the engine? Check for moisture in the Throttle Position Switch plug.
  • Make sure the Large White Wire going from the battery is intact and tight (this is for the EFI).
  • Check the condition of the Fusible Links to make sure they are tight (especially the red one in the housing closest to the battery)
  • Check ALL electrical connections to make sure they are secure.

Check those out and report back. Your answers will help members to isolate your issue and get your Z running.

There are no stupid questions!

Edited by ZCurves
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Here are my two cents and a few questions....Assuming that you can turn the engine over (good battery)

  • When you put the key in the ignition and turn it to the on position, does the fuel pump hum? It should hum for a 10 or so seconds and then shut off.
  • Have you removed the fuel line going from the Fuel Filter to the Fuel Rail and observed fuel flowing in a strong steady stream? No Fuel? Check Fuel Pump.

Assuming you have fuel.....

  • Do you have a Spark?
  • Do you know how to check the Timing? Check the Timing. (10 Deg. BTDC)
  • Check the Air Flow Meter to make sure the flap is free and moving and the wiring harness is in good shape and plugged in.
  • Check the Throttle Position Switch to see if the wiring harness is in good shape and plugged in.
  • Did you wash off the engine? Check for moisture in the Throttle Position Switch plug.
  • Make sure the Large White Wire going from the battery is intact and tight (this is for the EFI).
  • Check the condition of the Fusible Links to make sure they are tight (especially the red one in the housing closest to the battery)
  • Check ALL electrical connections to make sure they are secure.

Check those out and report back. Your answers will help members to isolate your issue and get your Z running.

There are no stupid questions!

Thank you :) I'm no mechanic, but I try to do my own work as much as possible. I appreciate the support.

One fusible link wire did burn out, but I fixed that. I found some spare copper wire and crimped it tightly to the connectors. That gave the car life for a second after starting, but before when I blew the wire the car wouldn't start at all. I will order a new one soon as my "McGayver" job is for the short term. I hate those links by the way. The battery is brand new. I believe I am hearing a humming after turning the key. The pump was replaced a couple years ago, with very little mileage since then. So, I do think that might be the pump making the hum.

I will check the line from the filter. Been thinking about that as well. If I am getting fuel, I suppose it's time to check those other things you mentioned. I will report back this evening!

Edited by AndysPlit
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Got her running :) It was not a fuel issue after all. There was gas in the hose connected to the fuel filter. So.....I started looking elsewhere. It was a faulty wire on the positive battery terminal. Yeah, kinda embarrassing to admit, but glad it was an easy fix. She put out white smoke from the exhaust, but I didn't hear any backfiring, etc. I'm going to assume (for now) that it's really old fuel that needs to be blown out. I had the head gasket changed, so I doubt it's that. Anyway, thanks everyone for the tips! Much appreciated.

Edited by AndysPlit
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Congrats on getting her running! Now you need to order a complete set of Fusible Links (Go to Bonzai Motorsports, Courtesy or MSA), You need to keep an eye out to find out why the link popped. If it keeps popping, then you risk frying some of your wiring harness and that would suck:mad:. Quick note about the Fusible Links and Replacing/Testing Batteries in the car. The load testers at the local parts house have almost always popped my fusible links - I encourage you to remove the Positive battery cable prior to doing such a load test on a suspect battery. You might consider placing a fresh set of fuses in your Z. Many Z's have 30+ year old fuses in them -lot's of "Weirdness" was removed when I replaced all of the fuses and cleaned the connections at the fuse block. If you have not located a Factory Serivce Manual (FSM), EFI Bible or the Propero's Color Wiring Diagram - I strongly suggest you do so, it will save you many headaches. I have a great PDF version of the '78 FSM. PM me and I'll send you a copy. Good Luck

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Congrats on getting her running! Now you need to order a complete set of Fusible Links (Go to Bonzai Motorsports, Courtesy or MSA), You need to keep an eye out to find out why the link popped. If it keeps popping, then you risk frying some of your wiring harness and that would suck:mad:. Quick note about the Fusible Links and Replacing/Testing Batteries in the car. The load testers at the local parts house have almost always popped my fusible links - I encourage you to remove the Positive battery cable prior to doing such a load test on a suspect battery. You might consider placing a fresh set of fuses in your Z. Many Z's have 30+ year old fuses in them -lot's of "Weirdness" was removed when I replaced all of the fuses and cleaned the connections at the fuse block. If you have not located a Factory Serivce Manual (FSM), EFI Bible or the Propero's Color Wiring Diagram - I strongly suggest you do so, it will save you many headaches. I have a great PDF version of the '78 FSM. PM me and I'll send you a copy. Good Luck

Thank you so much! Yes, I ordered a new fusible link today and another cover. Over the years I have replaced all of the fuses down there. Yup, best to keep on top of them I agree. Thanks again, and I look forward to that FSM.

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