Jump to content

IGNORED

280Z Requires Starting Fluid for Cold Starts


S30Grit

Recommended Posts

image.png

This the first group of tests some of you may recognize from the FSM.  At the beginning of today, I flunked this thing BAD.  Spent a lot of time tracing down grounds/wiring issues and made some improvements. Results of before and after are:

  • 1-1 (throttle valve)
    • Before: Fail, 2-3Mohm.  
    • After: Pass
  • 1-2 (throttle valve open)
    • Before: Fail, open circuit
    • After: Pass
  • 1-3 (AFM)
    • Before: 180 ohm, 180 ohm, 100 ohm
    • After: Same
  • 1-4 (air temp sensor)
    • Before: 1.7 Kohm  (weird temp reading)
    • After: Pass, 2.3 Kohm
  • 1-5 (water temp sensor)
    • Before: Fail, 8 Mohm
    • After: Pass, 2.3 Kohm
  • 1-6 (air regulator)
    • Before: Fail, 27 Mohm
    • After: 61 ohm (?)
  • 1-7: Pass
  • 1-8: Pass
  • 1-9: Pass
  • 2-1: Pass
  • 2-2: Pass
  • 2-3: Pass

Where a "Pass" is a resistance of just a few ohms.  Even after "fixing" these wiring issues, still won't start.  Injectors still not pulsing while cranking.  I didn't have time to focus strictly on EFI wiring, but cleaned as many grounds as I could get my hands on.  Maybe drop resistors aren't supporting enough current, or issue at relay pins like Zed Head mentioned...

  • Like 2
Link to comment
Share on other sites


Well the biggie is the water temp sensor, at 8meg it would run big rich, the 2.3k must have been a cold engine (not run in a while, long enough to cool down). the air regulator must be the heater resistance. the water temp sensor should have made a huge diff.

Link to comment
Share on other sites

25 minutes ago, Zed Head said:

One more possibility - bad or disconnected ground on EFI circuit.  It's been known to happen.  It's the wire at the negative terminal of the battery with the plastic connector.

Confirm power to the injectors.  While starting.

Interesting... The negative side of my battery only had one thick wire to it, nothing else.  It went straight to the big engine/transmission ground bolt (cleaned it up).  Maybe that plastic connector/wire is "grounded" somewhere else, or maybe it's just dangling back there somewhere.  Any ideas where that EFI ground comes from or where I should look?

Next time I'm with it, I'll definitely check power to the injectors during starting.

Link to comment
Share on other sites

It's supposed to be attached to the firewall near the battery.  It looks like the one that goes to the positive terminal.  They sit close to each other and sometimes get switched by accident.

You don't show the ground test in your list.  Testing grounds is probably the most commonly overlooked test for automotive electrical problems.

Link to comment
Share on other sites

5 minutes ago, Zed Head said:

It's supposed to be attached to the firewall near the battery.  It looks like the one that goes to the positive terminal.  They sit close to each other and sometimes get switched by accident.

You don't show the ground test in your list.  Testing grounds is probably the most commonly overlooked test for automotive electrical problems.

Ahh, ok.  There was a random wire that was grounded to the firewall near the battery.  Had no idea what it was for, but cleaned it up anyway.

Can you elaborate on the ground test? Test 1-8 in the FSM passed and seemed to relate to the grounds to the ECU wiring harness.  But I'd love to have a more thorough test of the overall grounding.  Is there a detailed test in the FSM?

Link to comment
Share on other sites

We're in the very common troubleshooting loop of "I already did that".  You're about at the point where you just have to understand how the system works.  The first few pages of the engine fuel chapter tell you what is supposed to happen.  The injectors open when the power is grounded, they stay open for a length of time that is determined by things like temperature and how far open the AFM vane is, etc.

Once you start thinking that way you'll have new ideas.  Seems like you've done a bunch already that you haven't described, and haven't done some of the things that have been suggested, like confirming power to the injectors during starting.  Good luck.

 

Link to comment
Share on other sites

27 minutes ago, S30Grit said:

Thanks siteunseen.  Hard to tell if there are multiple wires going to that firewall ground, I know I only had the one black wire.  

I'm sure it's just one and I've seen many that have melted the insulation off that wire.

Sand the firewall too under there.

Edited by siteunseen
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.