280z 280z 78 Wont idle, Running Rich, out of ideas.

[Cyrillink]

Hey Team

I have spent a lot of time on this  forum and i want to say thank you all so much this is an incredible community.

I have hit a brick wall and looking for a little help.

Background story; I'm helping a friend of mine fix his 280z with 30,000 miles on it all original. Car has been garage kept all its life. Really really well taken care of. Apparently some one A-hole mechanic tried before me and failed miserably and i don't know what he/she messed up or touched. After them the car didn't even start. Fixed that issue. (FACE PALM) ?‍♂️  

When you try to start the car it tries to start but never does on its own. If you give it gas than the car starts but it is runs rough(motor shaking). Have to keep the gas paddle pressed in just a little to keep it running. Car smokes white/bluish smoke from the tail pipes. (running rich) ( Gas smell). Changed the oil after the previous Mech worked on it smelled like gas was in it.  Did a double flush much better now.  

Things i did and tested on the entire car:

Spark Plugs - New

Spark Plugs Wires - New

Battery -  New

Battery Terminals - Cleaned  

Distributor cap - Cleaned and polished

Dizzy - Cleaned and polished

Pick Up - Adjusted to correct distance from roller according to 0.08in or 0.2mm

Distributor Vacuum - Good

Ignition Coil - NEW (built in resisters original ceremic resistor was missing) (https://www.holley.com/products/ignition/ignition_coils/street/super_stock/parts/8140C)

Fuel Pressure - 22-25psi in when engine is off,  while the car is running at low rpm 30psi+ ( 700 to 1k)

Smoke test - No leaks

AFM - Refurbished still sealed was installed last month

AFT Idel screw - Did not mess with

Throttle Body Screw - NO EFFECT when turning clock or counter clock

Electrical - 12V all over from Body, Engine, - All good

Ground Connectors - Clean

Coolant Temp Sensor - Ordered Arriving tomorrow (CANT IMAGINE ITS THE REASON)

Timing - Seems good 10 degrees of from original zero marking

Cylinders Compression Test - 125 + on all Cylinders  

Injectors connections - look good

Injectors - listen to them with stethoscope sound health strong tick

HELP!!!?

Thank you again for reading. I will be testing tomorrow. 

 

 

 

 

 

 

 

 

[Zed Head]

43 minutes ago, Cyrillink said:

When you try to start the car it tries to start but never does on its own. If you give it gas than the car starts but it is runs rough(motor shaking). Have to keep the gas paddle pressed in just a little to keep it running. Car smokes white/bluish smoke from the tail pipes. (running rich) ( Gas smell).

Coolant Temp Sensor - Ordered Arriving tomorrow (CANT IMAGINE ITS THE REASON)

The coolant temperature sensor is the most likely cause, based on your symptoms.  You need to measure the resistance at Pin 13 of the ECU connector to ground to know for sure.  Installing a new one won't help if the wires aren't connected to the ECU.

I just now realized, after many years of browsing through FSM's and Fuel Injection Guides, that this drawing has the pins numbered, right in the drawing.  I never looked closely enough before.

[Cyrillink]

  Installing a new one won't help if the wires aren't connected to the ECU. - Zed Head

_________________________________________________________________________

Thank you for confirming my suspitions. What do you mean if the wires are not connected to the ECU.?

Do you believe that cables broke, just dirty inside or disconnected? Should I  not even take out the coolant temperature sensor and clean it or even bother replacing it even  i have it?  Sorry for the weird question.

Edited December 16, 2019 by Cyrillink
didnot add the quote

[Cyrillink]

5 minutes ago, Cyrillink said:

 

2 hours ago, Zed Head said:

The coolant temperature sensor is the most likely cause, based on your symptoms.  You need to measure the resistance at Pin 13 of the ECU connector to ground to know for sure.  Installing a new one won't help if the wires aren't connected to the ECU.

I just now realized, after many years of browsing through FSM's and Fuel Injection Guides, that this drawing has the pins numbered, right in the drawing.  I never looked closely enough before.

 

 

Installing a new one won't help if the wires aren't connected to the ECU.  - reply

thank you for confirming my suspitions.

What do you mean if the wires are not connected to the ECU.?

Do you believe that cables broke, just dirty inside or disconnected? Should I  not even take out the coolant temperature sensor and clean it or even bother replacing it even  i have it?  Sorry for the weird question.

And thank you for attaching the exact connections with pins

 

Edited December 16, 2019 by Cyrillink

[Zed Head]

The only way to be sure that that the wires are intact from the coolant temperature sensor to the ECU is to measure resistance at the ECU plug.  If you do that you are testing the wires, the sensor, and every connection along the way.  I would not do anything to the coolant sensor, not even remove the plug at the sensor, until I measured resistance at the ECU plug.  Start at the the end, not the middle. 

[Dave WM]

have you pulled the plugs to confirm the rich running?

[Cyrillink]

9 hours ago, Zed Head said:

The only way to be sure that that the wires are intact from the coolant temperature sensor to the ECU is to measure resistance at the ECU plug.  If you do that you are testing the wires, the sensor, and every connection along the way.  I would not do anything to the coolant sensor, not even remove the plug at the sensor, until I measured resistance at the ECU plug.  Start at the the end, not the middle. 

Hey Zed,

Tested the resistance and i was able to get a reading back, the reading was similar to when the sensor was pulled out of the car for cleaning.  Took out the plugs cleaned them to make sure everything is well.

Car did the same thing. Blue smoke, rough idle while only holding the paddle down. 

Going to do another smoke test just to triple check.

 

[Cyrillink]

3 hours ago, Dave WM said:

have you pulled the plugs to confirm the rich running?

Yes, plugs had moisture on them.

[Zed Head]

2 minutes ago, Cyrillink said:

Hey Zed,

Tested the resistance and i was able to get a reading back, the reading was similar to when the sensor was pulled out of the car for cleaning. 

Without the actual number and knowing where it was taken, can't really tell what you're saying here.  It might the the most important measurement you can make on the EFI systems.  "a reading back" doesn't read well.

[Cyrillink]

5 minutes ago, Zed Head said:

Without the actual number and knowing where it was taken, can't really tell what you're saying here.  It might the the most important measurement you can make on the EFI systems.  "a reading back" doesn't read well.

I am getting a better snapon Multi meter right now going to test it again and get back to you.

Thanks again

Edited December 16, 2019 by Cyrillink

[Reptoid Overlords]

Not to throw you off the troubleshooting track that's been laid out, but is there a chance that the guy who worked on it before you removed the injector connectors and cross connected them, or in other words, put the wrong connector(s) on the injectors?

Sent from my Coolpad 3310A using Tapatalk

[Cyrillink]

23 minutes ago, Zed Head said:

Without the actual number and knowing where it was taken, can't really tell what you're saying here.  It might the the most important measurement you can make on the EFI systems.  "a reading back" doesn't read well.

car is indoors with the heat on to 60f 

sensor reading from the ECU Harness 2.07k Ohm.