Uh Oh. New Engine won't Crank...

[GilligansIsland]

Re: Uh Oh. New Engine won't Crank...

I'm sorry... I'm getting bug eyed. Let me repost findings correctly:

Harness disconnected
Test light connected to Positive:
30 no light
85 no light
86 no light
87 light

Test light hooked to block:
Only 30 lights

There, that's correct now.

I don't know if this helps or not, but with the harness connected, test light on the engine block and the key in START:
86 lights and makes a buzzing noise.

 

[GilligansIsland]

Re: Uh Oh. New Engine won't Crank...

87 does go to the starter and yes, the tester lights when connected to Positive.

 

[Don S]

Re: Uh Oh. New Engine won't Crank...

Harness disconnected
Test light connected to Positive:
30 no light
85 no light
86 no light (Should light, this is ground for the relay)
87 light (Should not light, means the wire is shorted to ground or the starter solenoid itself is shorted to ground.)

DO NOT plug the harness in again until the problem on the engine is fixed.

 

[GilligansIsland]

Re: Uh Oh. New Engine won't Crank...

Would having electric fuel pump matter schematically?

 

[Don S]

Re: Uh Oh. New Engine won't Crank...

It shouldn't have anything to do with it. But I have no clue how your engine is wired. As I recall the engine is from Michigan Motorz correct?

I also finally updated the troubleshooting file. Has a drawing of the circuit breaker and fuse now instead of just a box and wavy line. Didn't have them when I first made that file.

View attachment Troubleshooting a Volvo Starting system.pdf

 

[Don S]

Re: Uh Oh. New Engine won't Crank...

I see you have come back a couple of times but not posting. Have you found the problem with the 87 wire or starter?

 

[GilligansIsland]

Re: Uh Oh. New Engine won't Crank...

no... I'm coming back to reread some stuff.

I think I'm going to peel back all the tape/harness to expose the wiring to see where it goes and check for failure points. I suspect there is damage somewhere in there.

 

[Don S]

Re: Uh Oh. New Engine won't Crank...

Before you do that, take that yellow red wire off the starter and see it the test light from battery positive to the 87 socket still lights. If it does, you know it's that wire that is the problem and you know exactly where to start looking.
If the test light does go out, then you have a starter solenoid problem.

Harness disconnected
Test light connected to Positive:
30 no light
85 no light
86 no light (Should light, this is ground for the relay)
87 light (Should not light, means the wire is shorted to ground or the starter solenoid itself is shorted to ground.)

And fix the ground wire on 86

 

[GilligansIsland]

Re: Uh Oh. New Engine won't Crank...

WOOO HOOOO!

Finally it fired up! So many crazy readings, and trying to learn basic electrical troubleshooting, this proved to be an exercise in patience.

I finally decided to cut the negative wire going into to harness and ground it to the block, figuring I would at least eliminate a bad ground wire... And, vroom! I guess the ground wire is damaged somewhere in the harness.

Thanks for all of your patience and instruction. Admittedly, I am an idiot in this regard and I needed all the help I got.

I have to publicly thank the gang at Michigan Motorz who tried to be as helpful as they could. They Would have been within their rights to not take my calls but they remained VERY accessible and willing to help.


Thanks again... I'll sleep good tonight.

 

[Don S]

Re: Uh Oh. New Engine won't Crank...

Glad you fixed the problem.

 

[GilligansIsland]

Re: Uh Oh. New Engine won't Crank...

Thanks again.

 

[Don S]

Re: Uh Oh. New Engine won't Crank...

Had to think about it for a while because I couldn't understand why the test light was lighting on the 87 terminal with the test light clipped to positive. I was forgetting the coils in the solenoid DO go to ground. That is what makes the solenoid work. Shame on me. :redface: :redface:

Sorry about that.

 

[GilligansIsland]

Re: Uh Oh. New Engine won't Crank...

Ahhh... Glad you mentioned it. I didn't realize that.

Thanks again.