Hey Guys,

Having a few problems with a 280zx l28 EFI.

On cold start the revs fluctuate a lot until it gets warm and it will drop to a steady idle. Will also stall if keep your foot of the accelerator.

The vehicle also seems to be running very rich, fuel smell is strong and black smoke every now and again as well.

So far we have replaced injectors, water temp and coolant temp senders. replaced all vacuum lines and also have changed injector plugs as they where dodgy and fuel pressure regulator and multiple sets of plugs (bp5/6/7es) The colder seem to run better!

Have tried to find a mechanic around Brisbane to help but no ones seems too interested in the old EFI setups!

Sort of stuck as to what to try next.

Any help would be great!

You hit the nail on the head, "no ones seems too interested in the old EFI setups!".
What you have already changed is good analysis of the problem.
There are a couple of things left which may be the cause of rich running.
1. The Air Flow Meter.
This is a moving vane type device which after all these years may be well overdue for a good clean and test.
2. Cold start valve.
This is as the name implies only use during cold starts but may be leaking fuel past the valve ruining the mixture.
You could clean this fellow up as well and even disconnect it electrically and see if the engine behaves any differently.

I gather you have a Manual of some sort?
I have a Haynes Manual which seems to be very comprehensive for the 280ZX EFI engine, let me know if you need a scan

P.S.
It may be time to upgrade to an aftermarket ECU which would do away with 50% of all that old outdated troublesome technology

_________________
Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net

Cold start Valve(injector) and or Aux Air Valve.

Next step would be TPS and airflow meter, even just cleaning spade contacts

Do a search for 280zx L28 bible and print it off

this makes life easier



http://www.atlanticz.ca/zclub/techtips/EFI&fuel.htm