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Discussion Starter · #1 ·
I request your assistance in helping me trouble shoot a couple of problem. First, I have replaced the, fuel injectors, AFM, TPS, Air reg., Fuel Pres. Regul., etc. etc. My car continues to loose power or cut out especially when warmed up. But it continues to idle ok. I notice when I rev the engine to 5K rpm and let of the gas, there is a slight backfire.

Second, I notice that the voltage meter pegs when I rev the engine at sometimes. When I switch the headlights on the voltage meter fluxes. Also, the headlights brighten & dim when I rev. and release throttle. Sometimes my voltage light turns on and the needle pegs and when this happens my car seems to have difficulty idling, but manages to surge and continue to idle. I notice that the condenser broke off of the alternator, but this should not cause the voltage probelm, it just suppresses the radio noise (so i'm told). I notice that when the voltage light turns on, my idle is affected and I'm not sure if this is what is causing my power loss. I recently replaced the voltage regulator with a salvage yard one. Could it be the advance control relay?

Any help you can provide would be greatly appreciated. I've been working to resolve the power loss problem for about a year now including cleaning and filing some of my connectors. I replaced the injectors with used ones, but they all seem to be making noise. I'm at the end of my rope.

Thank you.
 

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<b>RE: 280Z76 Coupe Help w/ Tough Problem</b>

Does your car ever cut out and won't start for awhile?
What is the battery voltage at idle?
tom2Z²
 

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<b>RE: 280Z76 Coupe Help w/ Tough Problem</b>

I have been asking about this sameproblem for awhile now and it seems that the light dimming is just a part of the Z. I dont know why. Out of all my searching the only concrete fixes for this are
1 a smaller alt pulley; causing the alt to sppin faster at idle
2 A higher output alt. I have found a company that builds high output alts for powerful stero systems. This will also solve the lighting problem

The surging problem under load is new to me, it started about two months ago. I took it to a mechanic after I tried everything I could. He found that some of my injector clips were bad. Also get a voltmeter and make sure that you are getting enough power to the injectors. One last thought, get another throttle position sensor from a yard and see if that makes a difference. Good luck and please post your results

Craig76Z
 

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<b>RE: 280Z76 Coupe Help w/ Tough Problem</b>

As I read about the voltage problem, "regulator" kept screaming in my ear. But you replaced that - did anything change after replacement?

Also, I haven't been able to see a correlation between the voltage and the power problem - unless perhaps you fried something at high voltage.

I'm also wondering about the ignition advance. Have you checked the proper operation of the centrifugal and vacuum advance? A stuck centrifugal advance will allow okay operation at idle, but will kill you at higher RPMs. Just a thought.

Good luck. Would be very curious to hear what you find!
 

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A Z needs good ground wires

Check the condition of your ground wires. Clean connections are essential. On my Z I had the dimming headlight problem and fluxuating voltage gage. Not only did I clean the grounding surfaces and make sure the factory wiring harness is well grounded, I added 2gauge battery cable from the tranny to the frame rail, another from the block to the frame and another in the back by the muffler I added a ground to the chassis. After my voltage is very stable and my 75watt headlights do not dim. Overall your car will run smoother due to less resistance in the whole electrical system including the fuel injection computer and ignition. This can be done for $10-15 so even if it doesn't solve all the problems it couldn't hurt, I'm sure you will notice a difference though. Otherwise check your voltage regulator again with a meter.

Good Luck
Matt
 

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RE: A Z needs good ground wires

definitly check grounds, between Matt and Rob's reply (headlight ground wires) above, pretty much sums it
 

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CHECK THE EFI GROUND WIRE ON THE INTAKE

SPECIFICLY CHECK the ground wires that run out of the EFI harness onto the Intake Manifold, if they do not have a near perfect connection it causes the car to do ALL KINDS OF STRANGE THINGS! some of which you desrcribed to me. I changed my intake manifold gasket on mine, and when I reconnected the 2 ground wires ( there is 2 on my ZX ), I ended up with one bolt that was just a hair to long for the hole, in effect when the car would warm up at all, the ground wire would loose connection, and my car acted totaly bizzare from cutting out, to power surges to you name it. Other than that the voltage sure can really only come from the Alternator or more specificly the (REGULATOR), not regualting the alternators charge. I had to change mine reciently because when I would rev the car, I would charge 19 volts, changed my Alternator which has a regulator BUILT IN, and the problem went away. But again check those ground wire(s) comming out of the EFI harness that ground the EFI system to the Intake manifold.

Scott Milella
 

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Another thing about that ground for the EFI on the Aluminum intake. Aluminum is not the best metal for conductivity. I recommend to keep the ground going to the intake, but make an extra ground wire from good wire I used 8 gauge but I like overkill, and attach it to the same bolt on the intake right with the factory ground wire and connect the other end to the fender well or frame rail. This changed the way my car ran, and only took 10 minutes.

Later
Matt
 

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I was going to try that also, but did not know if the EFI had to be specificly grounded JUST to the intake maifold or not, I am assuming you ran into no problems by the sound of your post.

Scott Milella
 

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Discussion Starter · #11 ·
RE: A Z needs good ground wires

Thanks for all the ideas. I will take another look at the voltage regulator replacement as now that I recall, this is when the voltage problem began. The voltage regulator was significantly larger than the stock version that was taken out. I even have a third voltage regulator with two fuses connected to the wiring. For some reason all three voltage regulators look different even though they were supposed to be from a 280Z76? Regarding the loss of power, I will check the contacts and clean them. In addition I will look into the other suggestions. I'll keep you posted. Thanks for tremendous response efforts and help. I appreciate it.
 
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