# 85 300z fuel issues



## jamestiff2008 (Mar 21, 2010)

Okay I'm new to this and new to the 300zs. I have an 85 300z that has some fuel issues or at least that is what I think. If I disconect the cylinder head temp sensor it runs fine, a little rich but I can drive it. With it plugged in it idles and runs great in neutral. When you put a load on it around 3000rpms it totally kicks out, has no power at all, and as soon as you give it full throttle it goes past the 3k rpms. I have replaced the mass air flow sensor, the oxygen sensor, the fuel pressure regulator, the cylinder head temp sensor, and the fuel pump. If anyone has any ideas please let me know. thank you


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## Shakojdub1425 (Dec 9, 2009)

The nissans have always had bad fuel injectors. They have specs in Ohms for them, YOu should ohm all of them make sure they are in spec. Sounds like when you hit 3000 they are not flowing proporly. Try that, If they are not inspec i would just replace all of them. Also you might want to hook a fuel pressure gauge to the fuel line and see if the fuel pump is pumping out the correct psi at 3000 rpms or at all rpms for that matter. Let me know if this helps.


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## NissanPartsDept (Mar 31, 2010)

Have you checked it for codes?


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## jamestiff2008 (Mar 21, 2010)

I have checked for codes and the only code it gives me is the cylinder head temp sensor, because it is unplugged to make it run good enough to drive. I have checked the resistance of the injectors all of them are in spec. Fuel pressure is good. I am afraid it is the computer or I think there is a fuel injector pulse controller under the battery tray. I have been fighting with this for over two months now any words of wisdom?


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## jamestiff2008 (Mar 21, 2010)

i checked all of what you suggested, everything seems to be in spec. Fuel pressure is great the whole way through, I replaced the fuel pump right when i bought the car because that was my first guess.


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## NissanPartsDept (Mar 31, 2010)

When you replaced the head temp sensor, did you replace the sub-harness going to it also? It is common for the connectors to build up corrosion and have too high of resistance. This problem is also common on the connectors at the fuel injectors.


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## jamestiff2008 (Mar 21, 2010)

i checked it checked the resistance and cleaned the connectors, there was a little bit of corrosion on them but not too too bad. nothing on there now


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## jamestiff2008 (Mar 21, 2010)

I also have called nissan of north america about the recall on the injectors and they say there is no recall on the injectors for my car. I thought that all of the 85 300z were recalled?


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## NissanPartsDept (Mar 31, 2010)

It most likely already had the recal done. Any chance you have bad fuel in the vehicle?


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## jamestiff2008 (Mar 21, 2010)

it is possible maybe... the person i bought the car from said the problem started to happen after he got gas... I have filled it up several times since then. The injectors look stock, but then again there is no telling how long ago they were done.


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## NissanPartsDept (Mar 31, 2010)

I don't want you to post your vin on here, but if you e-mail it to me at [email protected] I will run it and find out if the recall was done.


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## Xyclonik (Feb 9, 2009)

*Fuel Problems...*

Any chance you may have fouled the plugs with bad gas? It happened to my car when I filled up at the new Chevron in town. Either water in the gas or too high a concentration of Ethanol. Either way, as soon as I filled up and got 5 miles down the road, my car was running like crap. I just did a tune up on it. Plugs, Wires, Distributor Cap and Rotor button. Also, check your distributor cap for cracks that water may have gotten in after an engine wash. Your symptoms sound similar to the ones I had, so...


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## gdombroski (Mar 15, 2010)

Don't know if this helps, but saw this "If your engine idles fine but won't go over about 2000 RPM, then your MassAirFlowMeter is probably bad", it's listed on pg 27 on this site 300zx Parts For You webpage


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