Need some invice on my 78 280z..

[draztik280]

I've checked the tps for proper operation. seems good. The fuel pressure reads about 33 psi. and the gauge is not fluctuating.

Any ideas?

Thanks

[Nazgul280]

Draztik, you should start your own thread with questions, as technically you are hijacking Shade123's thread here. You will also get more responses as probably most people have stopped watching this thread. <: You might want to refer to the links above for help, it is really a great and complete trouble shooting guide for your 280Z.

Shade123, how have you come along with the testing you have done per Blue's Tech Tips that was provided?

[FastWoman]

draztik, your starting problem might be from fuel dribbling out of your fuel rail. I finally replaced the check valve on my fuel pump (screwed into the fuel pump body, not the check valve I referred to above), and it made a big difference for morning starts, but it wasn't the entire problem. I suspect the remainder of my problem is that I have old, dribbly injectors that leak fuel out the other direction, thus flooding the intake with raw fuel and simultaneously removing it from the fuel rail. When I start the engine, it fires up immediately and then dies. Then it takes a few restarts before it will barely run, and then after 10 sec or so of sputtering, it will smooth out and run normally.

Here's why I know it's an absence of fuel in the fuel rail that's to blame: When I manually engage the fuel pump for 5 or 10 sec to charge the fuel rail, before turning my key to start the car, the engine will start right up without a complaint.

I have no idea about your stalling problem at cruising speed.

[ZCurves]

When I start the engine, it fires up immediately and then dies. Then it takes a few restarts before it will barely run, and then after 10 sec or so of sputtering, it will smooth out and run normally.

I've got the same problem..... Hmmmm

When I manually engage the fuel pump for 5 or 10 sec to charge the fuel rail, before turning my key to start the car, the engine will start right up without a complaint.

OK, If my Z sits for longer that a day or two, I experience the exact same problem AND my Z is running rich too. (I am reading your other thread...). So we both have '78s with the same problems. I know that you will post your solution, I will do the same.....

[FastWoman]

I know that you will post your solution, I will do the same.....

Absolutely! Deal!

[TewFodyZee]

draztik, your starting problem might be from fuel dribbling out of your fuel rail. I finally replaced the check valve on my fuel pump (screwed into the fuel pump body, not the check valve I referred to above), and it made a big difference for morning starts, but it wasn't the entire problem. I suspect the remainder of my problem is that I have old, dribbly injectors that leak fuel out the other direction, thus flooding the intake with raw fuel and simultaneously removing it from the fuel rail. When I start the engine, it fires up immediately and then dies. Then it takes a few restarts before it will barely run, and then after 10 sec or so of sputtering, it will smooth out and run normally.

Here's why I know it's an absence of fuel in the fuel rail that's to blame: When I manually engage the fuel pump for 5 or 10 sec to charge the fuel rail, before turning my key to start the car, the engine will start right up without a complaint.

 

 

I've got the same problem..... Hmmmm

OK, If my Z sits for longer that a day or two, I experience the exact same problem AND my Z is running rich too. (I am reading your other thread...). So we both have '78s with the same problems. I know that you will post your solution, I will do the same.....

 

Did either one of you guys figure out this cold starting/sitting for a few days issue?

[FastWoman]

Wow, that was a LONG time ago.  I've gone pretty far down the road since then, and I can't really remember where in the road that was.  But yes, I've resolved that problem.  My engine runs pretty well now, but it does miss a bit on hard acceleration.  The ECU is probably at fault for that.  Old age is not kind to linear circuitry.  I'm hoping "Superlen" will soon come charging over the hill with a drop-in replacement digital ECU for our cars.

 

I did confuse my engine's very LEAN running for a rich condition.  Either results in black soot.  A lean condition also results in backfiring out the intake, the exhaust blowing hard and spitting droplets of water, and the exhaust manifold geting quite hot.  My engine ran lean because of massive vacuum leaks and drift of the ECU.  I remedied the latter problem by adding resistance to the coolant temp sensor circuit.

 

Restart problems after sitting were due to leaky injectors and a bad fuel pump check valve.  Now with new injectors and check valve, my system holds pressure virtually indefinitely.

 

All the details are in past threads.  One in particular is "purs like a kitten."  You'll find most of my major finds and remedies detailed in that thread.

[TewFodyZee]

Wow, that was a LONG time ago.  I've gone pretty far down the road since then, and I can't really remember where in the road that was.  But yes, I've resolved that problem.  My engine runs pretty well now, but it does miss a bit on hard acceleration.  The ECU is probably at fault for that.  Old age is not kind to linear circuitry.  I'm hoping "Superlen" will soon come charging over the hill with a drop-in replacement digital ECU for our cars.

 

I did confuse my engine's very LEAN running for a rich condition.  Either results in black soot.  A lean condition also results in backfiring out the intake, the exhaust blowing hard and spitting droplets of water, and the exhaust manifold geting quite hot.  My engine ran lean because of massive vacuum leaks and drift of the ECU.  I remedied the latter problem by adding resistance to the coolant temp sensor circuit.

 

Restart problems after sitting were due to leaky injectors and a bad fuel pump check valve.  Now with new injectors and check valve, my system holds pressure virtually indefinitely.

 

All the details are in past threads.  One in particular is "purs like a kitten."  You'll find most of my major finds and remedies detailed in that thread.

 

 

Thanks for the update, I'll have a look in your other thread.

[ZCurves]

Still have the starting problem - probably the Fuel Check Valve.  I have fixed the rich running condition by changing out the injectors and installed a custom fuel rail.  Isolating the injectors with bake-lite insulators and getting rid of all of the wonky fuel piping has definitely helped eliminate vapor lock.  I believe that I posted all of the parts and work done.

 

Final analysis is that the engine runs well and pulls hard - just have to get the fuel check valve replaced.