Starter issues

S

sven

Member
Well I did my typical thing of making things worse before better.

I’ve been getting a slow crank ever since I took out my secondary battery. I tested out to see if a second battery would help and i may have killed my solenoid. It now will give me the click in the start position but nothing else. I bypassed the solenoid and all that happens is spinning of the starter, it doesn’t sound like the fly wheel is getting engaged.

Time to take the starter out and rebuild or is there something else I should take a look at?
 
Update: put the yellow and black signal wire directly to 12 v and it cranks!
So now something with the relay is my next step.
I don’t like assuming coincidences. But did it just coincidently go out as I put the battery in series? Or did I blow it somehow? I believe I set it up how it was before with dual battery

Ps. It cranks like it used to but doesn’t start…
 
Last edited:
Another update.
Followed the flow chart. Low volt on the glow plugs. Jumped them and then jumped the signal wire. Started up.

Flow chart says replace or repair gcu. Is that supposed to say ECU? Not sure what a gcu is…
 
sven said:
Another update.
Followed the flow chart. Low volt on the glow plugs. Jumped them and then jumped the signal wire. Started up.

Flow chart says replace or repair gcu. Is that supposed to say ECU? Not sure what a gcu is…
Click to expand...
On the L300 it is probably more accurately called ECU (electrical control unit) as it controls both the glow plugs and the EGR valve. The L400 has both a glow plug control unit (GCU) and an engine control unit (ECU).

Your other option is a manual bypass of the glow plug control.

There's a very good chance that you disturbed the solenoid signal wire connection while replacing the battery and it just wasn't making good contact... it's fairly common.
 
Thanks for clarifying.

So a manual bypass fixes the glow plug issue but I still have the signal wire issue. It only works when applying a direct current still. I’ll have the do a manual bypass on that too or fix the ecu?

Still a bit confused how this coincidentally happened
 
As I understand it, the starter relay clicks when triggered by the key, but it does not trigger the starter solenoid; you have to manually apply power to the solenoid signal wire instead. Check the alternator fusible link... you might have caused that to blow somehow when messing with the battery wiring.
You can also test for 12v on the signal wire coming from the relay... if you don't have voltage the relay has an internal fault of there's a break in the wire.

L300 Fusible Link Failure Modes

I spent some time disconnecting everything one at a time to document the symptoms; this is what I found. Please let me know if I missed anything significant so I can add it. Glow Plug/Starter Relay Link: Power for GP system and Starter solenoid No GP relay click when ignition is placed into the...
delicaforum.com delicaforum.com
 
Yeah you got it right. So the readout on the signal wire when in the “start” position is around 5v. Which is similar to the voltages I was reading from the glow plugs when the relay clicks. So some sort of added resistance is happening with that signal.

Alt link box is reading good.
 
So from what I understand, even a glow plug bypass won’t fix my issue with the glow plugs because it sounds like the relay is kicking on but it’s not supplying the full voltage.
 
sven said:
So from what I understand, even a glow plug bypass won’t fix my issue with the glow plugs because it sounds like the relay is kicking on but it’s not supplying the full voltage.
Click to expand...
Ok, check the large GP/starter fusible link for condition/connections. It supplies the battery voltage that goes through the relays to the GP's and to the starter solenoid. Also check the battery connections including both ends of the ground. You should be getting around 10v I think ( a little less than battery voltage), not 5v.

I think it's highly unlikely that two relays are failing.
 
All the connections are good as far as I can tell. Multimeter and visual.

I only have one relay because I have the 12v system. Here’s a video. Can’t remember if it’s supposed to have two clicks or if the weak click is just the relay trying to engage even though it is already engaged. I guess I’m not to clear how this system works, separating the starter signal from the glow plug signal. That’s done in the ECU?

Just realized I was misreading the multimeter. The signal wire and glow plugs are only getting 5mv. It does seem to be affected when the clicking happens. Changes from 4 mv to 5mv. Not too significant but maybe a clue…

 
Last edited:
The starter relay is in the same area and will also click... so the video is a bit confusing to me. My guess is that the weaker click is the starter relay.

The GP relay should click once when the key is placed into the on position, and it should automatically turn off after maybe ~10 seconds based on the ECU sensors (primarily glow plug resistance at this point). Yes, the ECU separates the power for the GP's.

Test the two large BR wires on the GP solenoid. One should read battery voltage all the time (can be either one), the other should read battery voltage when the relay is activated.
 
Yeah only getting 1 v on one of the ends of the relay.
Shouldn’t have doubted you. Was focused on a different link. I think I found the culpritimage.jpg
 
sk66 said:
The starter relay is in the same area and will also click... so the video is a bit confusing to me. My guess is that the weaker click is the starter relay.

The GP relay should click once when the key is placed into the on position, and it should automatically turn off after maybe ~10 seconds based on the ECU sensors (primarily glow plug resistance at this point). Yes, the ECU separates the power for the GP's.

Test the two large BR wires on the GP solenoid. One should read battery voltage all the time (can be either one), the other should read battery voltage when the relay is activated.
Click to expand...
Thanks for all the help and patience. Knew it would be something dumb I overlooked.
 
sven said:
Yeah only getting 1 v on one of the ends of the relay.
Shouldn’t have doubted you. Was focused on a different link. I think I found the culprit.
Click to expand...
It could be fried, or it could just be the condition of the contacts/terminals; if you clean them up you may be able to keep using it temporarily.
 
You must log in or register to reply here.
Top