Why Wont It Go?????

M

MAD MATT

Forum User
HI IM NEW TO 300ZXs GREAT CAR BUT WHY WONT IT GO FROM COLD??
STARTS AND RUNS FINE WHEN YOU FINALLY GET IT RUNNING BUT THE NEXT DAY 1/2 A TIN OF EASY START AND TWO STARTER MOTORS TO GET IT GOING.CAN ANYONE GIVE ME A CLUE? IVE CHANGED THE COOLANT TEMP SWITCH BUT STILL NO GOOD AND NO CODES ARE STORED IN THE ECU.:confused: :confused:
 
i hope this helps but you can go on listing possibles for ever.

replace plugs first and check air filter first as this is cheap( ish)...mjp will have in stock.

question. if you put your foot on the gas when you start from cold then dont. oh also dont use easy start, great for a one off to get you out of the poo but it ruins engines ( burnt valves) over a long period of time.

get fuel pressure checked, if low or high this will change the mixture.even the lambda sensor will struggle to rectifi this .

if no help there remove all injectors, switch on ignition( dont crank the engine) and look for any injectors leaking fuel as when you turn off the car you still have some pressure in the fuel lines and the injectors may be leaking into the combustion chamber causing flooding when you start from cold.

im sure the gods of z's can also help!
 
Hi,
I had starting/running problems on a previous Z...turned out to be the battery!...these engines take a lot of juice to turn over in the mornings!
Make sure the battery is OK first and then work from there.If in doubt...change the battery for a new, correct spec one.
Beware of too much 'jump starting' as the ECU may not like it!
Cheerz,
JEZ
 
Seemed To Take Forever To Get It Sorted But It Was The Air Flow Meter Thanks For Your Help Just Got To Get It Sprayed And Im Away.
 
LOOKS LIKE I SPOKE TOO SOON.PAID £375 TO FIND OUT THIS MORNING IT WOULDNT START.SO BACK IT WENT (GETTING ANNOYED NOW ):mad: :mad: :mad: :mad:
 
You'll get there and it'll be all worth it in the long run.

Anyone else any ideas?
 
what about the temperature switch in the cooling system,common problem on the z31s,
this if working incorrectly send lots of mixed incorrect info to the ecu
ask mike feeney
 
I Have Already Changed The Temp Sensor.but If Youve Got Any More Ideas I Would Be Grateful.i Have Driven It Once So I Know Spending All This Money Is The Right Thing To Do.(just Dont Tell The Missus)
 
If you've just replaced the airflow meter, try disconnecting the battery for a couple of hours to reset the ECU.
 
This Guy Says That He Has Already Done That But Now He Says It Has Got Low Fuel Pressure So He Has Got To Change The Fuel Pump.does This Sound Right Or Am I Being Taken For A Expensive Ride.(but Not In My Own Ill Zx).
 
low pressure would be a possible but you may find the fuel pressure regulatormaybe at fault, speak to mr f and ask the price of both, i would suspect the regulator is cheaper....has your garage checked the pressure or is it a guess?
 
THE PRESSURE WAS CHECKED AND HE SAID IT WAS 2.5 BAR WHICH I THOUGHT WAS ALRIGHT.HE SAYS HE HAS CHANGED THE FUEL PRESSURE REGULATOR.BUT IT IS GETTING TO THE POINT WHERE I DONT KNOW WHAT TO BELIEVE.DOES ANYONE KNOW IF THE TT FUEL PUMP AND THE NA PUMP ARE THE SAME OR DIFFERENT:unsure:
 
enter mr F for those different fuel pumps and the pressure sounds right to me, most multipoint injection systems run at about 2.5. although there are some that run at 5 bar... again mr F will know!

i assume the cold start sensor was a nissan one not a pattern one, if pattern launch it in to the nearest bin.

other things to consider,
not sure if your engine has hydrolic lifters but if it has are you using the right oil, do a compression test, when it does start are you getting alot of blue smoke from the exaust?
 
Fuel pressure at idle is 2.55 bar / 37psi rising to 3.04 bar / 44psi the moment the throttle is opened.

As you might expect, fuel pump is different between NA and TT...

Further ideas for poor cold starting:

Faulty air regulator and AAC valve - does holding throttle to the floor when starting help?? If the regulator is closed for cold start, then the engine will over-fuel.
Poor injector contacts - are all the injector firing? Remove crank angle sensor and rotate with ignition on - you should hear each injector click in turn.
Are all the connectors to the coil packs in good condition - do you definitely have a spark at each plug? What plugs are in the engine? I've had reports of some users on Champion the Wonder Plugs - ensure they are the correct NGKs or maybe the Denso Iridiums.

When the engine starts, does it run well? Are there any misfires or suggestions that a cylinder might be down on compression? Can your man do a power balance test to see if any cylinder is misbehaving? Alternatively try a direct compression test to see if there are sticky valves when cold.
 
HOLDING THE THROTTLE OPEN DOESNT MAKE ANY DIFFERENCE.BUT IF YOU REMOVE THE FUEL PUMP FUSE IT TRIES TO FIRE THEN GOES BACK TO NOT FIRING.ALL INJECTORS ARE WORKING FINE.IT DOESNT MISFIRE WHEN RUNNING.ALL PLUGS WERE REPLACED WITH NGK.AND THE COMPRESSIONS CHECK OUT GOOD.I DONT KNOW ABOUT YOU BUT IM GETTING CONFUSED ????:confused:
 
if when you remove the fuel pump fuse it tries to start then it is over fueling simple as that.


back to the possibles again.

leaking injectors, temp sensor, fuel pressure too high, faulty air flow meter, sticking airbypass valve.( you didn't say you put a genuine nissan temp sensor in! did you?)

you may have to do resistance checks on the ecu cables to make sure you have no breaks in the wires, also check ecu earth points and body earths. remember that ecu controlled circuits use 5 volts not 12 before ya start sticking jumper wires anywhere!

might sound a tad silly but have you checked to make sure the airways to the filter are clear? ie; a mouse hasn't tried to build a little detached home there!
 
Dodgy 300

Hi mad matt r u saying that the car doesnot start or it goes for a little while then cuts out ??? & wont start i had a similar problem with my car recently & changed the ptu for the modern one i might be barking up the wrong tree here but i know having spoke to different owners recently the fault of the old type ptu pre 93 i think is cutting out & not starting ??
 
Im Pretty Sure That Another Ptu Has Been Fitted Ive Just Tried The Fuel Pressure Reg And The Fuel Damper But Guess What ??? Thats Right It Didnt Start.ive Had It For 8 Weeks And Not Drove It.please Can Anyone Solve This Problem.:( :( :( :( :( :( :(
 
Grolls Mentioned The Air Bypass Valve . Where Is It Fitted Is It At The Back Of The Right Hand Side Of The Engine With A 2 Wire Plug And 2 Pipes About 1/2 Inch In Dia.if So I Found The Small Black Wire Broken And The Plug Was Green Inside.but Once Cleaned Still No Go.
 
sorry
i've never heard of a z32 giving this much trouble just to get it running. You seem to have tried everything. As i can vouch that i'm the least mechanical minded person on here, would you consider selling/breaking it?
don't know if you paid a lot for it, but it's an option. I can imagine your frustration.:(
 
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