# 90 300zx crank but will not fire ( HELP Z FRIENDS!)



## thexskywalker9 (Aug 24, 2008)

Ok i have a 90 300zx 5 speed n/a. Everything is hooked up, and when I start the car it will crank but will not fire, fuel pump works, because, I checked the fuels lines, and pressure , and gas is coming up. I checked for spark on the plugs and grounded while doing it with my pops cranking the motor, and there is no power, so I have fuel and no power. And the other thing is to that, for every car you guys no how when the key is in the on position and all the dash lights come on with the check engine light? Then when you start the car the check engine light will go away if there is nothing wrong.? Well my car to begin with, when in the on position, all lights will show EXCEPT the check engine light. Does this mean my ecu is messed up? or my check engine light fuse is blown? and if if the check engine fuse is blown that will now allow my car to start correct?...Please help me out guys, my dad bought this for my birthday 2 3 weeks ago and now we're having problems. Those are the only problems.


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## Spongerider (Nov 18, 2002)

Did you do a ecu diagnostics? If not it's located on top on the Z32 forum. Tell us what codes come up?


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## thexskywalker9 (Aug 24, 2008)

I tryed to get the codes, and no codes come up at all, I put the key in, and turned it into the on position not the acc, the on one, then I turned the ecu knob thingy clockwise waited for about 3-4 seconds then turned it counterclockwise, the ecu you light that suppose to be flashing to give me codes doesn't flash, it just stays lit from the beginning of the procedures, the thing is lit and stays lit from the point when the key is in the on position, no codes are coming to me, and no check engine light is on when the key is at the on position,what you think it could be? ecu is jacked up or something else?


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## Spongerider (Nov 18, 2002)

Strange, I would redo the test because if all is well then the code should come back 55.


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## thexskywalker9 (Aug 24, 2008)

nothing man, ecu light just stays lit.


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## Spongerider (Nov 18, 2002)

Try disconnecting the battery then disconnect the ecu. Check and make sure the harness and ecu pins are clean and reinstall.


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## thexskywalker9 (Aug 24, 2008)

the problem to begin with the car doesn't start, i cant let it idle or anythng it doesn start, no fire. i tryed the disconnect battery and ecu, then plug back in then test still stays lit, any other ideas?


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## Spongerider (Nov 18, 2002)

thexskywalker9 said:


> the problem to begin with the car doesn't start, i cant let it idle or anythng it doesn start, no fire. i tryed the disconnect battery and ecu, then plug back in then test still stays lit, any other ideas?


My bad, since you have a 90 call a nissan dealership and ask if the PTU (Power Transistor Unit) was replaced because there was a recall on the 1990 unit. You'll need to give them your VIN# to check.

I believe the recall is over but this would cause the problem you are describing.


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## thexskywalker9 (Aug 24, 2008)

alright man, that sounds like a shot, because I do have the ptu and mines is the aluminum fins one, so replacing that might solve the problem? and is there anything else you can think of besides the ptu?


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## Spongerider (Nov 18, 2002)

Call 1-800-NISSAN1 to find out if your Z has the new PTU. Make sure you have your Vin#. You can test the PTU with a OHM/volt checker as well.


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## thexskywalker9 (Aug 24, 2008)

mines is the old ptu, it is not the black box with sub harness, it is the silver aluminum looking one with fins, and also do you have any idea why would the ecu have no power?, dude checked it for me, and when the key is in the on position, ithe circiut signals doesnt reach all the way to the ecu,....so i have no damn clue whats going on but for sure I have the old ptu's.


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## Spongerider (Nov 18, 2002)

Replace PTU first.


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## thexskywalker9 (Aug 24, 2008)

alright, I just orderd the newer ptu from concept z performance, just waiting on that for a couple of days maybe next monday I'll get them, do you have a screen name on aim? if so it would be easier to chat with you or anyone who can help.


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## thexskywalker9 (Aug 24, 2008)

alright, new ptu didnt help, and I got a ecu same make and model year and 5 speed, both didnt help, still same problem....please help, dude did a diagnostic, not with a conzult but he said there is no power feeding to the ecu, its a wiring problem, or a shortage somewhere, u know when u put the key in the on position the check engine light is lit? mine DO NOT, please anybody know anything? any ideas?....and my battery is new, and a new starter...all fuses are good...dont know the problem..Im sure Nissan can fix it no problem, but it would be an arm and a leg....please help me!


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## Spongerider (Nov 18, 2002)

I was wondering if you changed anything on the car before your problems?

Also have you checked your fuel pressure?


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## thexskywalker9 (Aug 24, 2008)

didnt change anything...fuel pressure i have...


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## Spongerider (Nov 18, 2002)

What is your psi? You need to get a gauge if you don't have one.


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## thexskywalker9 (Aug 24, 2008)

the problem is no power to the ecu, and i need help on what it could be..fuel pressure i have..its always been the same...nvm guys...i do appreciate your help though...its just i asked for help but i guess i have to bring it to nissan, almost 120 view and only one dude helps...real z32 know it all huh...? waste of time... but thanks sponge man, I appreciate your help.


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## Spongerider (Nov 18, 2002)

The thing is it's hard to diagnose the problem when we don't have access to your car and can only give _suggestions_ on how to solve problem. I'm a Z enthusiast and never once claimed I knew it all and I hope I did not come off like that to you or anyone else. Most of us are just people who like the Z so please don't bag on the z32 guys. 

Ok, enough with that. I do have one last suggestion for you and that is the remove your key ignition switch and test it? If you have a Ohm reader it's easy to use with the down load of the service manual located at the top of the z32 forum.

If this does not work and the ignition is good it's time to bring to the shop.


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## CESAR95 (Aug 3, 2016)

I'm having the same problem does any one know what it was? The check engine came on just a few days ago it didn't come on anymore. any idea what it could be? 95 300zx


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## rode2nowhere (Jan 16, 2017)

ckeck fuses, then a voltage check at ecu


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## Kav300zx (Dec 1, 2019)

thexskywalker9 said:


> Ok i have a 90 300zx 5 speed n/a. Everything is hooked up, and when I start the car it will crank but will not fire, fuel pump works, because, I checked the fuels lines, and pressure , and gas is coming up. I checked for spark on the plugs and grounded while doing it with my pops cranking the motor, and there is no power, so I have fuel and no power. And the other thing is to that, for every car you guys no how when the key is in the on position and all the dash lights come on with the check engine light? Then when you start the car the check engine light will go away if there is nothing wrong.? Well my car to begin with, when in the on position, all lights will show EXCEPT the check engine light. Does this mean my ecu is messed up? or my check engine light fuse is blown? and if if the check engine fuse is blown that will now allow my car to start correct?...Please help me out guys, my dad bought this for my birthday 2 3 weeks ago and now we're having problems. Those are the only problems.


Hi thexskywalker9. I am having the exact same problem as U, have fuel, replaced ECU , still no spark . Did u get your car to start? If u can pls help me i would appreciate it..


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