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1976 280z 2+2 spark plugs


bhermes

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A little new to the sight but have posted previously. I have recently purchased a 1976 280Z 2+2 and use it as a daily driver. It runs and starts fine but about once per month it stops running while I am driving. It starts to sputter (if that a word) and acts like it wants to keep going and then dies. Occassionally if I keep pumping the gas pedal it will pull through and run again for several days but others it just dies. If I try and start the car immediately it will try and turn over but not start. If I wait an hour or so it will almost always start. I drive the car 3 miles to work and 3 miles back daily and not much more driving.

My original thought was rust in the gas tank or hole in pickup line in tank but not sure why this triggers only occassionally. I beleive it was suggested that it may be an ignition module (not sure where this is located). Before fixing both of these items I thought I would get one last round of posting. Gas tank thing is somewhat expensive and not really sure I want to do this unless it is necessary (ok probably a good idea regardless). There was an earlier comment about looking when the car dies to see if the rpms drop to zero which would seperate from fuel issue to electrical issue. Unfortunately the car died early morning and my dash lights do not work. I did notice a small red light coming on and the brake light came on as well when it died or stopped running.

Little additioanl history; car has 80k miles and sat for about 12 years. I have replaced the alternator, battery, and voltage regulator. I have not replaced the spark plugs but will do so sone. What plugs should I use.

Enough for now. Any help would be greatly appreciated.

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black gold man

Can you give me a little history on the ignition module? Just want to make sure it is good. I realize it is used.

Is it just the module or the distributor etc?

Is it difficult just to replace the module?

Is it for a 76 or does it matter?

Thanks.

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Does anyone know if the igintion module is bad would the car be difficult to start? This has not been my problem. In addition to the car stalling out on me I also notice a high rev when I come to a stop. The rpm rev last about 2 to 3 seconds and then lowers.

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If it is a stock ignition module, it is in the passenger footwell by the fusebox. If the car has been converted to a ZX ignition, the module is attached to the distributor.

A bad ignition module could make the car difficult to start if it is not triggering the spark properly. However, sometimes the coil or module can start the car and get overheated and not function until cooled down. There are many threads on that issue.

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If you can, check for spark when it is difficult to start. If you have no spark, that's a sign that you have an ignition problem, but it may not be the module. If you have spark but it still won't start, then fuel supply or injector signal might be something to look at. Try starting fluid also, if it starts then dies, you have a fuel problem.

You should verify fuel pressure first thoguh. You could have a dying fuel pump. You really need to take some measurements with fuel injection, there's no way around it. You could have 15 psi fuel pressure, which will look like a lot of flow, but won't be enough pressure to run the engine right.

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Zed head, thanks for the reply.

I have a masters degree in mechanical engineering and a masters degree in education but I know very little about being a mechanic. One of the reasons I bought the car not to mentioned I owned a 280Z back in 1981 so bare with me.

Injector signal??? You mentioned starting fluid, apply where??

Replaced the fuel pump already but no real help. What is the easiest way to check fuel pressure?

I am currently replacing the spark plugs to see if that helps at all.

Again, I learn quickly but know very little.

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The injectors are grounded by the ECU, which is triggered by a wire from the negative side of the coil. That's what I meant by injector signal. It's kind of uncommon but needs to be verified. It's easy to do, but sometimes hard to understand.

For starter fluid, I would pull one of the vacuum hoses from the intake manifold and squirt some fluid in. That way you don't have to mess with the AFM hoses. The easiest would be the very small hose that runs to the firewall and around to the air conditioning vacuum tank. It's small enough that you can leave it off without affecting intake vacuum much.

Fuel pressure should be measured between the fuel filter and the fuel rail, with a temporary gauge (some install a permanent gauge,which is nice since you can check it when the problem happens. These cars did not come with a Schrader valve so you'll need to remove the hose and attach T-fitting. The hose is typically very difficult to remove, so I would buy an extra foot of high pressure fuel injection hose since you'll probably have to cut it off.

IF you haven't downloaded the FSM yet, and read the Engine Fuel section, you should. It's very informative and good to have the knowledge in the back of your brain while you're pondering what your engine's doing.

I will bear with you, but, to be honest, will probably never bare with you.

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