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Hi folks,

Don't know where to start. Just bought a spectacular 77Z. It has a highly modified 82 engine in it. The owner, who I know to be extremely credible and honest, is out of town due to a family illness. I wanted to get some ideas before he returned so I know what questions to ask.

Here's the problem. Throw in a fresh set of plugs and it starts and runs very strong and I do mean strong. Drive it for a half an hour around the neighborhood and bring it back in the driveway shut it off and it will not restart. Let it cool down and it fires up again and smokes like crazy. Pull out the plugs and they are black shiny and fouled. Clean them up and you're off again.

The motor has a fresh rebuild on it and 185 lbs. of compression across each cylinder. However, due to an illness in the owner's family the car sat for the last few years. I emptied all the gas (man did it stink!) and blew out all the lines and put in fresh gas and some injector cleaner.

Here are my questions:

Any ideas for what sensors to look for?

I noticed there was no O2 sensor. Did they not have them in 77 and should I ask if he used the 77 ECU or if he replaced the ECU with an 82 version when the 82 motor was installed? I know the 82 model has an O2 sensor but I'm not familiar with the older models. I didn't think you could have EFI without an O2 sensor?

I have known this owner for many years and I know this was his daily driver. So I have some expectations for this car being reliable but the electronics and the sensors of the EFI throws me and has never been one of my strong points.

Aside from that, this Z is a cosmetic restoration. Sitting in the sun for the last few years wrecked a candy apple red paint job and destroyed the interior. In addition to the engine being modified the front and rear suspension have just about every high performance piece of equipment you can install. The ride is brutal but it handles like it was on rails. When you're in the car it doesn't even sound like a six cylinder. All you hear are the headers and the mechanical noises coming from under the hood. What a nice sound. The manual steering and the heavy duty clutch make me think of a 60's muscle car when I'm driving it. Except this one can handle.

I look forward to the responses and thank you ahead of time. Also, I thought it was a 78 when I looked at it. Turns out it is a 77. I will have to get my user name changed. Thanks again folks. John.
 

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77 has no O2 sensor. It doesn't help your car anyway because it riches your mixture when you are lean. I had 76 with 81 engine modified and no O2 sensor. You're obiously running rich. lean your mixture by channging AFM air screw or water temp. sensor.
 

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A good place to start troubleshooting is the sensors. The head temperature sensor and the air flow meter temp sensor are easy to check. Check the fuel pressure to make sure it is over 30 psi at idle, and rises to almost 40 with the manifold vacuum hose removed from the top of the regulator. It would be helpful to know what parts are on this beast - you could have a modified air flow meter and an adjustable fuel pressure regulator.

If all the sensors and wiring is OK (hint - get the factory service manual - it has an EXCELLENT EFI troubleshooting list), then and only then, start adjusting things like fuel pressure and air flow meters. You cannot compensate for bad sensors by adjusting others.

Good luck, sounds like you have a fun car.
 

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Re: Factory Service Manual

You can find one on Ebay most of the time - they usually sell for $50-$75. There is a CD-ROM version available, maybe on zdriver.com. I don't own one personally, but my local library has a whole collection of them, I just photocopy the pages I need.
 

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Re: Factory Service Manual

You can get a cd-rom version of the fsm from www.ideal-z.com. Follow the links for the Courtsey Nissan site. Courtsey is the actual place you will order it from. Price is 49 to 69 dollars. (depending on if you get the older version 49 or the text searchable 69).
If you are lucky, you can find the orgional paper book version on EBAY. Also you can get a paper copy of the FSM from Dyment for $73.00 w/ shipping. Dyment prints all the Nissan manuals. Their # is 1-800-247-5321.
I have the dyment manual. I had to get 400+ plastic page protectors and a very large binder to hold everything... but I love it!
Another source I heard of is SCHIFF MANUALS 1-888-789-6882. I called them and they have reprints of the Z manuals for $69.95 plus shipping.
Don't balk at the price of a FSM... it is worth every penny! The EFI tests and wiring diagrams for everything else make it rule over the Haynes/Chiltons/Clymer rags.
Oh, btw check out the Courtsey Nissan video selection. Order a copy of the Ztherapy understanding FI video... it too is a must have and will explain how the FI system works and how to fix and test it.
 

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Don't touch the AFM screw

Air Flow Meter adjustment screw. This is really the last thing that needs to be adjusted. It is for fine tunning ONLY. Since your car was running well when you started out I would say that the AFM is adjusted just fine. If you turn the screw you may find it really difficult to get it running the right way again without a 4-gas analyzer and somebody who knows how to tune one correctly. It will still run, but probably not quite as well as it did before. Trust me on this one. I have a owned 3 FI Z cars 75,77,79ZX and I have a degree in automotive technology. I know the system pretty well.
I am quite sure that your problem is the engine temp sensor plug and or connection. It is mounted on the passenger side of the engine near the back of the motor on a 82 engine. It should be the only thing there just below the spark plugs. You will just need to clean it up I believe. Unless the plug is in some way damaged. If your car doesn't start the next thing to check is the cold start sensor (thermo-Time switch) and the air-bypass valve (used for high idle). Usually, you would check these first. But, it will usually not give enough fuel if it does not work correctly. Please feel free to e-mail me if any of this is not clear to you or you just need more help. Ross
 
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