78 280z flooding when starting

[Chickenman]

A couple of things that OP may want to look at. 40 year old EFI systems are very sensitive to corrosion or electrical resistance in the wiring harness. Particularly the ECU CTS. Buy some Deoxit spray or Weicon Electrical Contact spray.  Weicon is a German company and makes a great line of Industrial products.

Carefully inspect all terminals and connections for corrosion. Spray the terminals with the Electrical Contact cleaner, wait 10 minutes and inspect. Weicon usually leaves the terminals looking like brand new. However, heavy corrosions may need a second application. Go through every single electrical connection for every single EFI component. Injectors, all sensors, AFM connections, TPS ( you can also spray the Contact cleaner directly on the TPS contacts. ) and the main ECU plug. It is amazing the improvement this can make. With really stubborn corrosion you may have to get in and pick away with Jewellers screwdrivers or a Dental pick. 

After a proper cleaning you can take some Dielectric grease and coat the terminals with it to prevent moisture from getting back in.

One other thing . It is really easy to get the terminals for the Thermal Time Switch and the ECU CTS mixed up. They are 4 bullet connectors. One pair is Black and the other pair is Dark Green. But after 40 years the Dark green turns Black!!. Peel back some of the insulation tape to reveal the true colors of these four wires. Missing them up will cause the car to run Pig Rich. 

The following picture should help identify the proper way to connect these :

 

[Dogariffic]

Thanks for the suggestions....and yes I have the factory service manual.....but sometimes it is nice to reach out to the group here to get opinions and thoughts.  If I only used the factory service manual I would miss out on all the good advice and banter, right?

And yes I have purchased new parts for the car.  She is 40 years old and I want her to be as reliable as possible.  I would rather replace something today that many have had issues with and move on with it....instead of something breaking today and then next week something else.  

So far things are going fairly well and if not for this flooding issue... that has recently popped up... she would be running great.

Again appreciate the suggestions and I will touch base as I move through the steps to identify this specific problem.

[siteunseen]

Not sure if I've shown you this?  If so, sorry but it has really helped me over the years with my '77.  Thanks again to @240260280

http://atlanticz.ca/zclub/techtips/     Click on "EFI and FUEL"

Another thought that has probably been said before, are you absolutely sure the vacuum hose to the Fuel Pressure Regulator is good and pulling vacuum?  40 year old rubber cracks. 

Edited June 22, 2017 by siteunseen

[Dogariffic]

Thanks Site.

I had not seen the information in this format..

It is helpful!

 

[Zed Head]

1 hour ago, Dogariffic said:

Thanks for the suggestions....and yes I have the factory service manual.....but sometimes it is nice to reach out to the group here to get opinions and thoughts.  If I only used the factory service manual I would miss out on all the good advice and banter, right?

I think we're just a little miffed to be the last resort instead of the first.  You probably spent a lot of money that you didn't need to.  And sometimes old Nissan parts are better than new aftermarket parts.

As far as measuring things, people do it all the time without realizing it.  If the engine dies you measure the fuel level by looking at the gauge, if it starts running weird you measure coolant temperature by looking at the gauge, voltmeter, oil pressure, etc.  A multimeter is just a way to get a little bit more valuable information.  It's just another gauge.

[Zed Head]

On 6/17/2017 at 1:16 PM, Dogariffic said:

new fuel pressure regulator, Thermo time switch and cold  start valve and temp switch, New plugs and plug wires new injectors  and injector wiring, All new fuel filters, all new vacuum hoses, high flow air intake, new started  and alternator new engine gaskets, new fuses valve adjustment.

I might go directly to the coolant temperature sensor circuit.  The best way to test it is at the ECU connector, since what the ECU sees is what matters.  Compare the resistance measured to the value in the chart.  If it's too high you'll get too much fuel.

This book has tests for all models up to 1980 - 

 

[siteunseen]

Try unplugging the cold start valve. I know it's new but it could be your problem and it's hot enough now that it shouldn't even be active.

[JSM]

12 minutes ago, siteunseen said:

Try unplugging the cold start valve. I know it's new but it could be your problem and it's hot enough now that it shouldn't even be active.

Do this and take a pair of small vise grips and clamp the hose going to it. I've seen them fail without being turned on electrically. 

[rcb280z]

You know, I still have never seen one of these efi systems go so rich that the car wouldn't run. But I guess its possible?  Have you checked spark yet? Is there a good strong spark?

On 6/17/2017 at 1:16 PM, Dogariffic said:

this morning I pulled the plugs and they were wet

Plus you still haven't answered the question asked regarding your above statement.

Are they wet before start up? 

Edited June 22, 2017 by rcb280z

[siteunseen]

Good call JSM! I'm not remembering how they work exactly, maybe some type ball valve or magnetic but they are a lot more prone to fail than a fuel injector.

Wrap some tape or slide two pieces of hose over your clamping tool, vise-grips to keep from cutting into the CSV hose.

[siteunseen]

That's something I haven't thought about!  Do you have good spark as Bob states.

[Dogariffic]

1 hour ago, siteunseen said:

That's something I haven't thought about!  Do you have good spark as Bob states.

Spark appears fine...