ZCar Forum banner
Status
Not open for further replies.
1 - 13 of 13 Posts

·
Registered
Joined
·
316 Posts
Discussion Starter · #1 ·
My Z will run 5-10 min. at idle less if driving.
As soon as it cools off it will crank and samething
I have replaced the,
AIRFLOW METER,
COIL,
PLUGS,
DIS. CAP,
ROTOR BUTTON,
FUEL PUMP,
ALL NEW PARTS.

PLEZ. HELP.
 

·
Registered
Joined
·
1,610 Posts
OK - Planned Attack

Alex,
First Start your engine like you have so many other times but be prepared to do the following as soon as it stops.
1) Crank the engine and see if there is spark to the plugs.
2) Install a fuel pressure gauge and check for fuel pressure when you crank, or pull the hose just after the filter and see if it will pump into a jar.
At that point, post the following information on the forum.
1) You did or did not have spark.
2) You did or did not have fuel pressure.
3) What color are your spark plug electrodes - white, tan or black?
Phantom
 

·
Registered
Joined
·
107,695 Posts
Three things will keep a 280z from running. First, can you access your fuel pump relay? If it's burning hot when your car shuts down, then it's bad and has to be replaced. Second, do you store your car outside and/or do you drive in the rain? If yes, check your ignition box for water damage. Third, again in response to that question of water, check your main ECU for water damage. I have three backups for each of those pieces, and my windshield used to leak also until I siliconed it around the perimeter, which had caused me many problems on my '75 Federal model. My best guess is that the fuel pump relay went bad and can't handle the heat of operating the pump and ignition at the same time.
 

·
Registered
Joined
·
158 Posts
Can you help my '73? similar problem.

On my Z, it only dies during stop and go driving. First it starts to choke a little and won't pass 3500 rpm. Then chokes completely and dies. Then it takes at least 2 hours to start again, then runs fine like nothing happened. Even if I pump the gas over 50 times fuel can't even reach the fuel filter. Anyone have any idea what it is? Thanks.

Wes
 

·
Registered
Joined
·
316 Posts
Discussion Starter · #5 ·
> Three things will keep a 280z from running.
> First, can you access your fuel pump relay?
> If it's burning hot when your car shuts
> down, then it's bad and has to be replaced.
> Second, do you store your car outside and/or
> do you drive in the rain? If yes, check your
> ignition box for water damage. Third, again
> in response to that question of water, check
> your main ECU for water damage. I have three
> backups for each of those pieces, and my
> windshield used to leak also until I
> siliconed it around the perimeter, which had
> caused me many problems on my '75 Federal
> model. My best guess is that the fuel pump
> relay went bad and can't handle the heat of
> operating the pump and ignition at the same
> time.
 

·
Registered
Joined
·
107,695 Posts
Re: Can you help my '73? similar problem.

> On my Z, it only dies during stop and go
> driving. First it starts to choke a little
> and won't pass 3500 rpm. Then chokes
> completely and dies. Then it takes at least
> 2 hours to start again, then runs fine like
> nothing happened. Even if I pump the gas
> over 50 times fuel can't even reach the fuel
> filter. Anyone have any idea what it is?
> Thanks.

> Wes
sounds like a weak fuel pump / plugged fuel filter (tank mounted?) or line...suggest you follow phantom's planned attack when this occures...have the tools with you and see what you get.
 

·
Registered
Joined
·
316 Posts
Discussion Starter · #7 ·
Re: OK - Planned Attack

> Alex,
> First Start your engine like you have so
> many other times but be prepared to do the
> following as soon as it stops.
> 1) Crank the engine and see if there is
> spark to the plugs.
> 2) Install a fuel pressure gauge and check
> for fuel pressure when you crank, or pull
> the hose just after the filter and see if it
> will pump into a jar.
> At that point, post the following
> information on the forum.
> 1) You did or did not have spark.
> 2) You did or did not have fuel pressure.
> 3) What color are your spark plug electrodes
> - white, tan or black?
> Phantom
I do have fire and gas. My plug electrodes are black. It acts like it is choking or not getting proper air. None of the relays are hot.
 

·
Registered
Joined
·
316 Posts
Discussion Starter · #8 ·
> Three things will keep a 280z from running.
> First, can you access your fuel pump relay?
> If it's burning hot when your car shuts
> down, then it's bad and has to be replaced.
> Second, do you store your car outside and/or
> do you drive in the rain? If yes, check your
> ignition box for water damage. Third, again
> in response to that question of water, check
> your main ECU for water damage. I have three
> backups for each of those pieces, and my
> windshield used to leak also until I
> siliconed it around the perimeter, which had
> caused me many problems on my '75 Federal
> model. My best guess is that the fuel pump
> relay went bad and can't handle the heat of
> operating the pump and ignition at the same
> time.

None of the relays are hot. I am getting fuel and fire. It acts like it is choking or not getting proper air. HELP!!!!
 

·
Registered
Joined
·
107,695 Posts
> None of the relays are hot. I am getting
> fuel and fire. It acts like it is choking or
> not getting proper air. HELP!!!!
Alex
Is your cold start valve stuck open and flooding
the engine
Dave S
 

·
Registered
Joined
·
316 Posts
Discussion Starter · #10 ·
Still won't stay Runnning......HELP!!!!

> Alex
> Is your cold start valve stuck open and
> flooding
> the engine
> Dave S

Dave,
I am not sure I checked it correctly...I pulled the cold start valve out and disconnected from power source...no fuel at all...then i connected to power source still no fuel...I even got the car to crank by putting finger over hole in manifold still no fuel...
NOW WHAT??????
 

·
Registered
Joined
·
1,610 Posts
Re: OK - Planned Attack - next step

> I do have fire and gas. My plug electrodes
> are black. It acts like it is choking or not
> getting proper air. None of the relays are
> hot.
OK Alex - next step. The black electrodes are indicative of an overly rich engine. Here's what I want you to do.
1) Look at the three sensors that are on your thermostat housing. The single wire sensor is for your engine temperature gauge inside the car. That's all it does so ignore it for now.
The larger two-wire sensor is for your thermotine switch which fires your cold start injector.
The smaller two-wire sensor is the engine temperature sensor that sends a signal to your ECU telling it how long of a duration to fire your fuel injectors. If it has a bad electrical connection anywhere it will read high resistance and think your engine is cold thus super enriching your fuel. Did your plugs seem a little wet? That is another symptom of an overly rich condition.
2) Remove the elctrical connectors at the senosrs and physically scrape them very clean, pinch down the female contacts and then put them back together.
3) Follow those same leads back up the wiring harness about 16 and you'll see a lump in the wiring. Under the shrink tubing at that point are two bullet connectors that are notorious for corroding. Remove the insulation and take the connectors apart. At this point jumper the connectors across cutting the engine temperature sensor out of the circuit. this will make the ECU think the engine is hot and will lean the injectors out. Pull all six plugs and clean them thoroughly and then try to start the car. If it starts and runs you've found the problem. Shut it down, clean the connectors up really well, hook them back together and test it out again.
Let me know how it comes out.
Phantom
 

·
Registered
Joined
·
107,695 Posts
Re: Can you help my '73? similar problem.

> On my Z, it only dies during stop and go
> driving. First it starts to choke a little
> and won't pass 3500 rpm. Then chokes
> completely and dies. Then it takes at least
> 2 hours to start again, then runs fine like
> nothing happened. Even if I pump the gas
> over 50 times fuel can't even reach the fuel
> filter. Anyone have any idea what it is?
> Thanks.

> Wes
I had a 73 which acted up on warm/hot days after the engine was warmed up. It acted like there was a vapor lock between the gas tank and engine. In 1980? I read in Road & Track (a few months after I sold it) there was a recall that 1/2 year on the carbs. If you ever thought about different (high performance carbs) now would be the time to consider it.
 

·
Registered
Joined
·
432 Posts
Re: Hey, Alex, is it better??

> My Z will run 5-10 min. at idle less if
> driving.
> As soon as it cools off it will crank and
> samething
> I have replaced the,
> AIRFLOW METER,
> COIL,
> PLUGS,
> DIS. CAP,
> ROTOR BUTTON,
> FUEL PUMP,
> ALL NEW PARTS.

> PLEZ. HELP.

Hey Alex, is your car running better now?? Did you replace the airflow meter with a new or used one? Verify the part #'s to be sure, trust no one. just because it fits doesn't make it right for your year model. those pieces are very YEAR specific. Let me know.

Tim
 
1 - 13 of 13 Posts
Status
Not open for further replies.
Top