Sporadic Low Voltage / No Start (1 Viewer)

[Halfpint]

'97 LX450

• toyota/ reman 80 amp alternator
• battery in good holding charge
• no cable corrosion- battery/starter/alt
• new ignition switch
• new denso starter
• fusible links are in great shape

I'm chasing a very infrequent no start situation and have tried numerous mentions here to fix. No start meaning single click heard when turning key (all lights/radio/air as expected) but no crank.

It comes and goes at the most inopportune times- but moreso a) when it's super hot outside b) after I've been driving aggressively c) when I need to be somewhere.

I'm not sure how to chase this one down.

What I have seen is that during these times, the volt on my ultraguage show a drop to 11~ which I'm sure is causing the issue. In the good starts, battery is in great charge and readings hold mid 13s at idle. When the no start occurs, I cannot jump off the car- which is more frustrating- my noco jump box is rated to kick over cement trucks (I've proved that!), but is unsuccessful at connecting properly during the no start period. So I'm assuming it's that weird ignition needs to detect a certain amount of voltage to activate the starter issue- but how is this still a thing after all the replacements.

I typically let the rig rest 30-45+ mins and retry and all is well (volts show perfect on UG and truck acts like nothing happened)- as you could guess, 30+ mins stranded in the NC heat or late for an appt makes wife angry!

So I want to focus more on the ignition to starter connections- is this where that voltage must have a certain reading to activate the starter? I'm wiring diagram dumb, and need Fischer Price level discussions...lol.

 

[jonheld]

When do you see the 11 volts on the UG? With the key just in the ON/RUN position or are you trying to crank the starter?

 

[gummycarbs]

What I have seen is that during these times, the volt on my ultraguage show a drop to 11~

That's normal when a starter is receiving current.

Did you try smacking the end of the starter with a hammer or wrench?

I had intermittent no-starts with my Denso rebuilt alternator from RockAuto. I replaced the solenoid contacts and seated them properly. Never had a problem since.

 

[Halfpint]

When do you see the 11 volts on the UG? With the key just in the ON/RUN position or are you trying to crank the starter?

on/run- UG powers up and only shows the low voltage...

Edit: Checked just now and it read 12.4

 

[Halfpint]

That's normal when a starter is receiving current.

Did you try smacking the end of the starter with a hammer or wrench?

I had intermittent no-starts with my Denso rebuilt alternator from RockAuto. I replaced the solenoid contacts and seated them properly. Never had a problem since.

I've got this mini pry bar in my door pocket that fits perfectly for starter whacking.

I've been thru 2 starters already...one Denso, one AC Delco...I have another Denso on the shelf Denso reman from rockauto...I don't want to change it out as the same problem has persisted.

 

[jonheld]

on/run- UG powers up and only shows the low voltage...

Edit: Checked just now and it read 12.4

You have a power supply problem. The OBD2 port +12 comes from the main fusible link through a 15 amp fuse.
When you say things like, "fusible links are in great shape", it makes me wonder how you are determining this. Did you use a meter or your eyeballs?
I would also put a meter across the battery terminals and get an actual battery reading.

 

[Halfpint]

You have a power supply problem. The OBD2 port +12 comes from the main fusible link through a 15 amp fuse.
When you say things like, "fusible links are in great shape", it makes me wonder how you are determining this. Did you use a meter or your eyeballs?
I would also put a meter across the battery terminals and get an actual battery reading.

Eyeballed the Fusible Links...I guess youre right, I had a '94 LC and when I checked them they deteriorated in my hands....the ones on the 97 dont appear to be at that stage- I have some spares and can replace it to rule it out.

I didnt think the Links would be a part of the connection as the starter has the direct connect to the battery- again I'm no electrician. Is the link at the posi the only one I should replace?

Battery charge was taken with meter at terminals - nothing connected (did this recently- as I had powered down to replace the alternator)

 

[jonheld]

New fusible links are $16 for the set of 3. Don't try to save money with this stuff.
They should be replaced with every battery change.

 

[Halfpint]

New fusible links are $16 for the set of 3. Don't try to save money with this stuff.
They should be replaced with every battery change.

No I meant I have 2 brand new in bags I carry in my parts bag.

I'm all about new if I'm putting in the sweat equity!

 

[jonheld]

I didnt think the Links would be a part of the connection as the starter has the direct connect to the battery-

The starter motor side is a direct connection to the battery positive.
The logic path is Battery +, fusible link AM1, fuse AM1, ignition switch, neutral start switch, starter.

 

[Halfpint]

The starter motor side is a direct connection to the battery positive.
The logic path is Battery +, fusible link AM1, fuse AM1, ignition switch, neutral start switch, starter.

So I forgot that I DID replace the fusible link about ~5 mos ago... because I cracked the one side of the case that covers the screw terminals and it fell off. Links are from Wits End- I still have one left thats unused...

I don't think that cover does much for connectivity, and the connections are not touching anything and coated in dielectric gel...what would be the next level to review. AM1 fuse? I assume it's good since it works well 95% of the time...

 

[-Spike-]

Battery voltage is only half the story. Have your battery load tested. If you have a load tester, connect it and hit the button for 5+ seconds, and see if the amperage/voltage drops and holds or keeps dropping.

Also, will the engine crank if you toggle the key to 'start' rapidly? If so, that might keep you from being late for meetings, and it indicates either a bad starter contact situation or a weak battery. Or possibly a bad connection, but it looks like you have eliminated that as the issue.

 

[Halfpint]

Battery voltage is only half the story. Have your battery load tested. If you have a load tester, connect it and hit the button for 5+ seconds, and see if the amperage/voltage drops and holds or keeps dropping.

Also, will the engine crank if you toggle the key to 'start' rapidly? If so, that might keep you from being late for meetings, and it indicates either a bad starter contact situation or a weak battery. Or possibly a bad connection, but it looks like you have eliminated that as the issue.

I conditioned the battery once on a Schumacher tender. And it reported fine .. maybe it is a battery issue. I'll explore the load testing.

Yes the rapid start attempts sometimes cranks it. But more recently I'm finding I hear the initial click get softer and softer ...

But again, 30 mins later, the truck acts like normal.