Without question, the CSS pulls more current than the 10A circuit can handle, plus that joker wire they used. Seems like an oversight to me. Pretty certain we can just drive it with another power source and be fine. It's on a 20A fuse now and doing just fine.
-
Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!
Isuzu NPR 4HE1. Very odd behavior from Zexel Cold Start Solenoid (CSS)
- Thread starter fastline
- Start date
Toddgarage
Well-Known Member
- Joined
- Jun 13, 2022
- Messages
- 80
- Location
- S.E. Michigan
- Occupation
- Construction, welding/fabrication, operator
I got 3.6 ohms between solenoid power and ground.
heymccall
Senior Member
I put the circled values in the calculator.
Only a 4 amp draw. Meaning wire integrity is suspect.
Only a 4 amp draw. Meaning wire integrity is suspect.
Appreciate it! I did find the same on the visor. Mentally trying to understand why the full pedal for starting but we will give it go!
As for CSS, ours tests under 2 ohms. I know it is out of spec but still works. Obviously the CSS should just be replaced.....if it wasn't such a big deal.
I should mention we tested the CSS unplugged right off the solenoid. No need to suspect wiring further when that is out of spec. This is why I have to ensure it is fused because it might either open or go dead short down the road. Hopefully get through this winter and deal with it later. We don't need to run that truck all that much.
As for CSS, ours tests under 2 ohms. I know it is out of spec but still works. Obviously the CSS should just be replaced.....if it wasn't such a big deal.
I should mention we tested the CSS unplugged right off the solenoid. No need to suspect wiring further when that is out of spec. This is why I have to ensure it is fused because it might either open or go dead short down the road. Hopefully get through this winter and deal with it later. We don't need to run that truck all that much.
heymccall
Senior Member
Even at 1.5 ohm, it's still only 8 amp draw.
At 14 volt, it's 9 amp draw.
At 14 volt, it's 9 amp draw.
V=IR....lol I do a lot of electrical work so this is down my lane. The resistance values on the CSS coil moved around enough for me to suspect the lacquer coating is probably failing and leading to a partial short somewhere. We dumped the 10A fuse and went to a controlled current device with breaker and could see current would start at 7A and climb to about 10A-ish.
All I know is the circuit was built around 10A so we should be no where close to that and my guess of 3A was close to book spec. We know this is well outside normal and that coil will likely fail because it is eating an extra 100W of power (heat) it wasn't made more. Maybe we can keep it alive due to the cold for the winter.
But will prob have to figure out how we replace that CSS. Pretty frustrating to realize all the drama to swap it.
All I know is the circuit was built around 10A so we should be no where close to that and my guess of 3A was close to book spec. We know this is well outside normal and that coil will likely fail because it is eating an extra 100W of power (heat) it wasn't made more. Maybe we can keep it alive due to the cold for the winter.
But will prob have to figure out how we replace that CSS. Pretty frustrating to realize all the drama to swap it.