Hard Starting Hot Big Block

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charger426 said:
So the tester I have is the old school resistant type tester (where you hold a switch on the bottom for 10 seconds and watch the gauge to see where it falls). I also used a larger group size battery for testing from my 04 Ram SRT10 and saw no difference. I don't have an ammeter, I have a volt gauge (all new wiring on this whole car. With a volt meter I get 12.8 at the battery and 12.7 up at the front. 1 wire power master 130 amp alternator and I'm seeing 13.3ish on the volt meter when driving (dial style autometer gauge plus driving so not like I'm able to check down the tenth of an amp in that situation).
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That will not work here. You need a variable load tester so that you can match the voltage which the starter pulls down to in order to read the starter current
 
In all your posts, I haven’t seen what your charging system is doing.? Also what timeline is it that it will not start. You say cold it fires up and cranks fine( 5 mins idle time or hour of driving time?). If the alternator is not charging properly then you may be down on your battery voltage after driving time
 
hemifiedbird said:
In all your posts, I haven’t seen what your charging system is doing.? Also what timeline is it that it will not start. You say cold it fires up and cranks fine( 5 mins idle time or hour of driving time?). If the alternator is not charging properly then you may be down on your battery voltage after driving time
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Tests have been letting the car idle with the hood shut for 20-30 min (been raining) which get the coolant up to 190. Voltage while running 13.2-13.6. Voltage when attempting the hot start is 12.8-13.1.
 
charger426 said:
Tests have been letting the car idle with the hood shut for 20-30 min (been raining) which get the coolant up to 190. Voltage while running 13.2-13.6. Voltage when attempting the hot start is 12.8-13.1.
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Running Voltage should be around 14.5. 2 1/2 volts over battery voltage. Possibly check your alternator, regulator
 
Did you remove color from the ground points at the chassis and block?
measure voltage drop of the wiring, that means measure voltage from pos bat terminal to the starter pole+ should read close to 0V during cranking. same with neg bat terminal to the starter housing, should be close to 0V. Is there excessive heat in the wiring or connections? There is the problem, dont burn your fingers!
 
plymouth4onthefloor said:
Did you remove color from the ground points at the chassis and block?
measure voltage drop of the wiring, that means measure voltage from pos bat terminal to the starter pole+ should read close to 0V during cranking. same with neg bat terminal to the starter housing, should be close to 0V. Is there excessive heat in the wiring or connections? There is the problem, dont burn your fingers!
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Yep I have... Going to add some more ground today (front frame rail and rear frame rail at a minimum).
 
Bewy said:
A fully charged battery is about 12.6 v, not 12.0 v.
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Agree. My battery is at 12.98 (just checked). Hasn't been on a charger, that's just what it is sitting at after having the car run for 30 or so min a few days back while testing out starters.
 
67Dart273 said:
EDIT.........AFTER doing what Steve said above (OldmanMopar)

The FIRST thing you must do is to determine whether the 1...battery is defective, whether the 2...starter is drawing over-amps and pulling the battery down, or whether it is 3...simply voltage drop.

EG Voltage drop measurements will not tell you anything if EITHER of the other conditions exist. IE if the starter is defective and dragging, etc, it will exhibit system voltage drop, as well as low battery voltage


You need to get/ borrow a legit carbon pile load tester, like one of these.

You can test both starter draw as well as get an idea of battery capacity. "Generally" you start with a fully charged battery. You must have the problem acting up, in other words engine hot, then crank, or try to crank the engine for 10 seconds while reading the voltmeter on the tester.

Next you crank in resistance until the voltmeter pulls down and reads the same as the starter pull read. At that point the ammeter on the instrument will tell you the starter draw.

Conversely, you can load test the battery and also get an idea of how it's doing. Again, you MUST start with the battery fully charged.

View attachment 1716306038
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So I just ordered one of these, should be here tomorrow. Am I correct that I can take this to the starter and draw the load right at the starter lugs using this tool and test for voltage drop vs having to have someone start it?
 
What I can tell you about the old starter cranking slow hot, is the armature bushing wear out and let the armature drag on the fields.
They work great cold but hot, things expand and armature drags, the hotter or more magnetism/boost, just makes it drag more.
If it's a big starter, break it down, armature will have shiny witness marks on armature.
Bushing are just a few bucks,.
Check the electrical " stud and contact " condition
Good luck.
 
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charger426 said:
So I just ordered one of these, should be here tomorrow. Am I correct that I can take this to the starter and draw the load right at the starter lugs using this tool and test for voltage drop vs having to have someone start it?
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You can IF you can get the clamps on there, but that is not the normal use. What you need to do is get the problem "showing" (engine hot) and measure battery voltage or rather voltage right at the starter as the starter is trying to crank. Then apply the load tester and draw the battery v down until it is the same as the starter was cranking. At that moment, the instrument will be drawing, and will show on it's ammeter, what the starter is drawing.

As OldManMopar has said implied in his post, tho, this does not tell you whether:

the starter is dragging because of an internal problem, either mechanical or electrical, or whether the engine friction / bearings/ rings/ other clearances are too tight.

I do realize that a trunk mount battery can certainly complicate troubleshooting this problem for the very reason in this post---access to the starter terminals.

It may be helpful to get or build a short eyelet to eyelet cable, about a foot, out of the largest gauge you can get, to bolt onto the starter post for better access for such testing.
 
Ok I'm calling the car fixed!

Let it idle for 20 min then soak in the heat for 10 and it cranked right up.

What I did:
Changed the starter to an OLD mini start off the shelf which helped but I also didn't want a 20+ year old starter on the car so I ordered a Summit brand one

Added another ground down to the frame rail to the battery,
Ground wire to the front frame rail to the bus bar in the front
Grounded the alternator with a wire from the case to the block. (got back that 1v I was missing when running)

Dips to 10.5-11v now when cranking hot.
 
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