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Originally, about 7 months ago, I was trying to get my 280Z to pass emissions testing in AZ. The CO reading was too high. I started on a mission to find a problem with the fuel injection system. I discovered that the fuel pressure regulator was wide open and dumping gas. The BCDD valve was out of adjustment. I replaced the fuel pressure regulator and adjusted the BCDD valve and leaned it out and it passed emissions.

What I discovered was that it doesn't run at all unless the distributor is fully advanced. And even with it fully advanced it's still 5 degrees retarded from required specifications.

Running characteristics for the car are bad. It appears to miss at <2000 rpm and has a rough idle when the engine is warmed up. Upon going above 2000 rpm the engine runs more smoothly but still will periodically backfire and fire through the intake.

What I've done thus far:

Replaced the air regulator
Replaced the air flow to throttle body boot
Replaced the thermotime switch
Replaced the connectors for all of the fuel injection system.
Replaced the distributor cap and rotor
Replaced the spark plug wires
Replaced the spark plugs with split fire plugs
Verified the operation of the master fuel injection relay.
Verified the operation of the air flow meter
Verified the operation of the throttle body
Replaced PCV hose and all other fuel injection hoses.
Verified coil wiring was correct and that coil was generating a spark.
Corrected the gap between the reluctor and the magnetic pickup switch.

I'm currently waiting for a Crane solid state ignition but the car is still undriveable. It acts like it might blow major components off of the engine. I NEED HELP!!!!

My major avenues of approach were:

Leak on the intake manifold or intake proper

-none found except the PCV hose

BCDD valve adjustment

-adjusted per the Haynes' manual but it basically idles at 14 in Hg

Intake and exhaust valve adjustment

- greatest out of adjustment was .003 and after adjustment the car still ran the same. The car eats gas like a 1969 Hemicuda.

Does anyone have any other ideas other than replacing the ignition system with the Crane system. My greatest fear is I will replace the system and the car will still have the same problem. I am megabucks into this thing, please help.
 

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> What I discovered was that it doesn't run at
> all unless the distributor is fully
> advanced. And even with it fully advanced
> it's still 5 degrees retarded from required
> specifications.

What this says to me is that the distributor/oil pump drive shaft is stabbed wrong. Check that the shaft is in the correct location at TDC. Instructions for this can be found in the Haynes manual. You problems could pe related to the retarted timing. Good luck!!!

Ian
 

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> Originally, about 7 months ago, I was trying
> to get my 280Z to pass emissions testing in
> AZ. The CO reading was too high. I started
> on a mission to find a problem with the fuel
> injection system. I discovered that the fuel
> pressure regulator was wide open and dumping
> gas. The BCDD valve was out of adjustment. I
> replaced the fuel pressure regulator and
> adjusted the BCDD valve and leaned it out
> and it passed emissions.

> What I discovered was that it doesn't run at
> all unless the distributor is fully
> advanced. And even with it fully advanced
> it's still 5 degrees retarded from required
> specifications.

> Running characteristics for the car are bad.
> It appears to miss at What I've done thus
> far:

> Replaced the air regulator
> Replaced the air flow to throttle body boot
> Replaced the thermotime switch
> Replaced the connectors for all of the fuel
> injection system.
> Replaced the distributor cap and rotor
> Replaced the spark plug wires
> Replaced the spark plugs with split fire
> plugs
> Verified the operation of the master fuel
> injection relay.
> Verified the operation of the air flow meter
> Verified the operation of the throttle body
> Replaced PCV hose and all other fuel
> injection hoses.
> Verified coil wiring was correct and that
> coil was generating a spark.
> Corrected the gap between the reluctor and
> the magnetic pickup switch.

> I'm currently waiting for a Crane solid
> state ignition but the car is still
> undriveable. It acts like it might blow
> major components off of the engine. I NEED
> HELP!!!!

> My major avenues of approach were:

> Leak on the intake manifold or intake proper

> -none found except the PCV hose

> BCDD valve adjustment

> -adjusted per the Haynes' manual but it
> basically idles at 14 in Hg

> Intake and exhaust valve adjustment

> - greatest out of adjustment was .003
> and after adjustment the car still ran the
> same. The car eats gas like a 1969 Hemicuda.

> Does anyone have any other ideas other than
> replacing the ignition system with the Crane
> system. My greatest fear is I will replace
> the system and the car will still have the
> same problem. I am megabucks into this
> thing, please help.

Having the timing too far advanced will cause high COs, caused mine to fail. But your problem seems to be timing. My car had almost zero pull to it, and I traced it down to the distributer. I was having problems with the shaft in the dist. wearing out the bushing. This was causing the pole peice and the pick-up coil to bash into each other. Check and see if this may be an issue. May not be *the* problem but could be *a* problem.

Ken
 

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> Having the timing too far advanced will
> cause high COs, caused mine to fail. But
> your problem seems to be timing. My car had
> almost zero pull to it, and I traced it down
> to the distributer. I was having problems
> with the shaft in the dist. wearing out the
> bushing. This was causing the pole peice and
> the pick-up coil to bash into each other.
> Check and see if this may be an issue. May
> not be *the* problem but could be *a*
> problem.

> Ken
Don't know if this will help you but I too have had a similar problem with my '77 280Z in a low vacuum reading and a somewhat rough idle. If you haven't already, pull the EGR Valve off and check to see if the wall has not been eaten away on the intake manifold that seperates the exhaust side from the intake side. Mine was and I replaced it with an intake from Joe at All Z EAST. I have yet to put it on but I belive this will cure my issue as I too have replaced everything you listed. Good luck.
 

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Fuel Injection Tune UP on 77 280Z

Aaron,
In went through 8 months of H--- doing much of what you've done trying to get my '77 to run right. I finally found an independent Nissan certified master mechanic that did what he call a fuel injection system tune-up.
He checked the resistance on the thermotine switch and engine temperature sendor.
He bead blasted clean, retightened and coated with dielectric grease all the connectors in the system except the injector plugs.
He adjusted the AFM and the throttle switch. You need an exhaust gas analyzer to do these right and he has one. Car runs like a bandit even though the cam is scored, burns oil, and has a sloppy distributor shaft. I'm now planning the new engine.
In other words, Find a properly equipped and experienced Z mechanic and be prepared to spen the best investd $300 of your life to make the problems go away.
Phantom
 
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