• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

240 Starting Issue - 1992 240

IansPlatinum

IansPlatinum

Active member
Joined
Jul 23, 2018
Location
Texas
Ok TB gurus,
Here's a fun one.

Problem: intermittent non-start. No cranking, no clicking, nothing.

Background info:
New ignition switch 1 year ago (Volvo brand)
Jumped neutral safety switch blue/yellow wires with a crimp
1 year old Optima yellow top
Issue started back in may 2019, happening maybe a total of 5 times since then

Diagnostic findings at time of non-start:

  • Connected voltmeter to battery terminals. 12.98V, freshly shut off engine (just filled up on gas)
  • Connected voltmeter to positive terminal on starter, negative battery terminal. 12.98V, exactly same as Battery.
  • Connected voltmeter to blue/yellow spade terminal (while disconnected from starter) and negative battery post. 10V, decreasing slowly to 9.7V over the next 30 seconds or so, even when the key was released from position 3 and put to position 2. The 10V only went away when the key was moved to position 0 (or maybe 1?).
  • Disconnected battery negative, placed ohmmeter between pink test spade terminal (behind dipstick tube) and positive battery terminal. 20k ohm when key out, door closed. 0.1 ohm when key out driver's door open (is that normal???). Verified behavior by manually switching the driver's door position switch, and observed 20k ohm to 0.1 ohm just as before. Again, not sure if that's supposed to be that way...
  • With battery negative still disconnected, I placed ohmmeter from blue/yellow spade connector (off of the starter solenoid) to positive battery terminal, and turned key to position 3.
    Measured between 0.0 and 0.2 ohms (it oscillated, average about 0.1 ohm)
    Measured 2kohm when key in pos 2 or lower.
    ***This test seems to indicate that there is not significant resistance in the circuit.
    *****This further puzzled me as to why I was only seeing 10V at the blue/yellow spade connector when trying to start. So I did the test below:
  • With negative cable disconnected from battery, I placed the ohmmeter on the blue/yellow starter spade connector and negative battery terminal connector (NOT the battery terminal- battery is disconnected).
    Measured 2k ohm at key position 2.
    Measured 10 ohm at key position 3 [?!]

My diagnostics indicate that voltage is 'leaking' from the starter solenoid circuit to ground, which is why I'm not seeing the full voltage at the blue/yellow terminal.

The big question is, however, is that how it is supposed to be??
Should the starter be able to start with just 10V at the spade terminal? I thought the blue/yellow solenoid wire is just supposed to get the armature moving, and then the positive terminal at the back of the starter takes over to power the actual cranking of the engine.
Should there really be only 10 ohms between negative terminal and blue.yellow spade when key is at pos 3? I feel like it should be more... Maybe I'm just measuring the resistance of the computer or whatever else is active when the key is in pos 3?
Maybe the starter solenoid is just weak?
Before anyone comments the inevitable 'put in a new starter and send it', keep in mind, this is an intermittent issue that would be really crappy to pop up on a trail (I'm lucky it was at the gas station and not in the middle of ouachita national forest). I need to be certain that the starter is at fault, and that my wiring harness circuitry is functioning as intended and as designed.


Thanks, sorry for lengthy post.
 
Last edited:
Some things I'd examine:

1. Grey Bulkhead connector at firewall
2. Does it start with a jumper wire between the female spade test port hanging from firewall to the starter lug?
3. Does it start with a hotwire to battery?

I'd get the starter rebuilt by a quality rebuilder and send it ;)
 
Go over what you did with the ignition switch and defeating the neutral safety switch. Problem likely to be there.

Measuring voltage without the load connected (what you did at the starter terminal 50 disconnected) is bound to be misleading, especially given the ECU's cranking sensing (214 in the drawing).

In any case, you should see solid continuity between battery + and that terminal 50 with key in KP-III, but you already know that. Yes, solid continuity isn't "ten ohms" but reads like your shorted probes when using a DMM for an ohmmeter.

91wdm20.jpg
 
kyote said:
Some things I'd examine:

1. Grey Bulkhead connector at firewall
Click to expand...
just went an disconnected it. no obvious corrosion, but the bullet jackets are crumbly as would be expected. Ya know, now I wonder if that blue/yellow bullet wasn't fully plugged in, and maybe heat/vibrations caused a temporary disconnect :thinking:
kyote said:
2. Does it start with a jumper wire between the female spade test port hanging from firewall to the starter lug?
Click to expand...
it starts 99% of the time with the key so yeah, it would. I didn't get to that point sunday when it wouldn't start. I was going to change the starter to my spare that I keep in the trunk, but decided to jump the battery with my battery pack thing and see if I could get more juice to the blue/yellow spade. That got it started. Every time its done this though, I just fiddle with it and it will randomly start up eventually. sometimes after 5 min, sometimes after 30.
kyote said:
3. Does it start with a hotwire to battery?
Click to expand...
should
kyote said:
I'd get the starter rebuilt by a quality rebuilder and send it ;)
Click to expand...
lol i knew it. probably gonna buy a fatty bosch starter from kjets
 
cleanflametrap said:
Go over what you did with the ignition switch and defeating the neutral safety switch. Problem likely to be there.

Measuring voltage without the load connected (what you did at the starter terminal 50 disconnected) is bound to be misleading, especially given the ECU's cranking sensing (214 in the drawing).

In any case, you should see solid continuity between battery + and that terminal 50 with key in KP-III, but you already know that. Yes, solid continuity isn't "ten ohms" but reads like your shorted probes when using a DMM for an ohmmeter.
Click to expand...

ignition switch was a simple remove & replace, neutral safety was a simple cut-off-the-connector-and-crimp. The issue also existed before the NSS bypass. I bypassed the NSS thinking it may have been the issue.

continuity between battery + and terminal 50 at pos3 was 0.0-0.2 ohms, not 10. The 10 ohms was between battery negative connector and terminal 50 (when battery was disconnected). Likely I'm just measuring the computer's resistance in that case. For a moment I thought maybe the ignition switch only had 10 ohms between the internal switch connecting the terminal 50 wire to battery +, which is no bueno. But after some more digging it is obvious now that other things are also switched on when in key pos3, so I'm probably just getting that measurement.
 
IansPlatinum said:
ignition switch was a simple remove & replace, neutral safety was a simple cut-off-the-connector-and-crimp. The issue also existed before the NSS bypass. I bypassed the NSS thinking it may have been the issue.

continuity between battery + and terminal 50 at pos3 was 0.0-0.2 ohms, not 10. The 10 ohms was between battery negative connector and terminal 50 (when battery was disconnected). Likely I'm just measuring the computer's resistance
Click to expand...

Now you have to get it to act up again. Probably will work just fine, especially now that you've touched that bulkhead connector. If it fails again, measure the voltage at terminal 50 with the terminal in place on the starter solenoid. Work your way back from there.

There's no such thing as a simple remove and replace, or a reliable crimp, when viewing through the internet.
 
cleanflametrap said:
Now you have to get it to act up again. Probably will work just fine, especially now that you've touched that bulkhead connector. If it fails again, measure the voltage at terminal 50 with the terminal in place on the starter solenoid. Work your way back from there.
Click to expand...

I should be seeing full battery voltage, I assume?
 
IansPlatinum said:
I should be seeing full battery voltage, I assume?
Click to expand...

Actually, no. There's quite a bit of drop through that wiring while the solenoid is in full current mode (not yet pulled in). But I'd be happy to see 10 volts. If you see much less, work backward toward the switch with your voltmeter until you identify the reason for the drop.
 
cleanflametrap said:
Actually, no. There's quite a bit of drop through that wiring while the solenoid is in full current mode (not yet pulled in). But I'd be happy to see 10 volts.
Click to expand...

So then the starter should be able to start with only 10V at the solenoid, provided it has the full 12.7+ volts at the positive post?
 
IansPlatinum said:
Also, why is the starter service terminal (pink wire) changing from closed to open with respect to the positive terminal when I open/close the door switch :???:
Click to expand...

Yeah, that's a confusing one, which depends on a lot of your observations and definitions which don't explain easily except by "because TB."

Maybe get back to the car and come back later to the forum with more info?
 
cleanflametrap said:
Yeah, that's a confusing one, which depends on a lot of your observations and definitions which don't explain easily except by "because TB."

Maybe get back to the car and come back later to the forum with more info?
Click to expand...

Repeated the test; I had misremembered. Switching the door switch makes the ohm meter jump from 2k to 20k ohms, so no worries there. Human error
 
IansPlatinum said:
  • Connected voltmeter to blue/yellow spade terminal (while disconnected from starter) and negative battery post. 10V, decreasing slowly to 9.7V over the next 30 seconds or so, even when the key was released from position 3 and put to position 2. The 10V only went away when the key was moved to position 0 (or maybe 1?).
Click to expand...

With the wire disconnected from the solenoid, it's not going to try to start and there won't be a high load from the starter. This means that you should measure almost the full 13.0V battery voltage on that wire when the ignition switch is in the Start position. Measuring 10ish volts means that the bulkhead connector, or your PN splice, or the ignition switch is bad.

There's a weak pullup resistor to +12v within the ECU (connection 214 in the diagram). This might explain why you were still seeing voltage when the ignition switch was on, but not in the Start position.

Next time it happens (?), try a jumper wire from the pink Starter Service Socket to the + post on the battery. This will bypass the ignition switch, but still includes your PN splice and the bulkhead connector.

On your meter, does it have a 20K ohm setting, and were you using it? If so, a reading of 0.2 is 0.2 Kohms (200 ohms), not 0.2 ohms.
 
bobxyz said:
With the wire disconnected from the solenoid, it's not going to try to start and there won't be a high load from the starter. This means that you should measure almost the full 13.0V battery voltage on that wire when the ignition switch is in the Start position. Measuring 10ish volts means that the bulkhead connector, or your PN splice, or the ignition switch is bad.

There's a weak pullup resistor to +12v within the ECU (connection 214 in the diagram). This might explain why you were still seeing voltage when the ignition switch was on, but not in the Start position.

Next time it happens (?), try a jumper wire from the pink Starter Service Socket to the + post on the battery. This will bypass the ignition switch, but still includes your PN splice and the bulkhead connector.

On your meter, does it have a 20K ohm setting, and were you using it? If so, a reading of 0.2 is 0.2 Kohms (200 ohms), not 0.2 ohms.
Click to expand...

i've learned a lot since investigating this issue (didn't know there was a service terminal at all on sunday lol). Will be trying that next time.

I'm starting to suspect bulkhead connector since I've never played with it. I'm pretty confident in my NSS crimp, especially because issue has happened before and after crimp.

My meter just has one ohm range setting, and automatically adjusts the displayed units (ohm, kohm, mohm).
 
A meter is the wrong tool for testing a power circuit. A test lamp is the correct tool. I have been taught this in training and in the field.
 
Last edited:
You must log in or register to reply here.
Back
Top