Ignition and Starting Diagnosis

Joined
Jan 17, 2017
Messages
320
Location
Seattle, WA
Hi all,

I am on a slow baseline of a new to me truck (details in signature) that is parked for the winter where I have a chance to work on it every 2 weeks. Well, I changed the fusible links and put in a new battery last week but a starting issue remains Here's a video: 19_0218_nostart.MOV

I have read a lot of threads on no-starts, slow-starts, or intermittent starting issues. I don't know how to classify mine because with the old battery, I thought it was just a slow start, but after I installed the new battery and fusible links, it still took about 4-5 attempts, which is intermittent, and now I'm back to no start as in the video. Would starter be your first guess and if so - how can I test to make sure it is the starter?

I have a reman Denso starter that I was planning to swap in anyway, but before I do, I want to thoroughly asses and understand the entire starting/ignition pathway because I am trying to get ready for multi-day trips and don't want the issue to keep coming up. Plus I am getting ready to order plug wires and distributor stuff and it's easier to diagnose when you are only making one change at a time.

The other reason I bring this up is that many others @jvazquez53 @SUMMIT CRUISERS @martyjayFJ62 have had success wiring in a Ford Solenoid between which seems to be a way of working around old wiring between the ignition switch and starter. So I'm keeping that in the back of my mind but electronics are a severe weak point for me and I think going through some troubleshooting will help me learn the circuit and how to test different points of failure.

So based on Emergency FAQ, I plan to go through Scenarios 1 and 2 first. The crux of it seems to be verifying battery voltage and connections to the starter as well as ground points for both. I pulled up EWD - Starting and Ignition (p. 54)
1912822


Please correct my understanding if wrong but it seems like the starter always has 12V at the big post (on the solenoid) and turning the key forward, completes the switch and delivers 12V to the starter motor itself, correct?

So what's a good way to measure with the starter installed by myself...or should I pull it out. And if so, how can I test the wiring both to the large post and the connector (think it's called the solenoid pin - the black connector)?

Am I trying to measure between the large post and frame to see a constant 12V with the key off?
With the key on, where am I connecting my leads - do I take off the solenoid connector and check the wire or the connector or ?

Lastly, since ground points are really important, does anyone have a picture of where the EC ground is from EWD pg. 30?

1912863


Since cables could be bad inside insulation I also plant to do the following which I took from Voltage Drop Testing:
  • Check the negative ground cable from the battery to the engine (should be 0.2 volts or less).
  • Check between the negative battery post and starter housing (should be 0.3 volts or less).
  • Check between the engine block and starter housing (should be 0.10 volts or less).

Sorry if any of these are amateur-ish questions, clearly I have too much time when away from the truck. But I also had a really weird one-time episode several months ago where I went to turn off the truck ... and it wouldn't turn off. Which makes me really want to understand what could be happening ignition wise.

So my goal here is to expand on the procedure in the Emergency FAQ and perhaps we can get some diagrams or pictures added.

Lastly, I know I will have to verify spark as well as check on the Neutral Safety Switch if none of the above help me.


Helpful Links
RockAuto Denso Starter Diagnosis
Voltage Drop Testing
 
Joined
Jan 17, 2017
Messages
320
Location
Seattle, WA
Found most of my answers in this post here, plan to add diagrams and post results of my tests anyway: Turn key - Click no start

Bench Test Starter (this process is also in FSM and a simplified version in the youtube video linked in the post above - really good video, thanks @martyjayFJ62)
  • If your solenoid is broken then the gear teeth will not move forward and spin when you give 12v to the small pin.
If it is all working properly from your bench test
  • Check the voltage coming from ignition wiring to solenoid pin wire
    • Diagram incoming
If you're getting correct voltage then that leaves a bad ground connection on the starter (usually starter is grounded by bolts into engine) check and clean all grease and rust / dirt / corrosion around the mounting bolts.

Then after that check that the thick heavy duty wiring going from your battery positive terminal to the input terminal of the starter is all good, no cracks in the insulation etc.

If all that is good then it could still be issues with the Neutral Safety Switch under the car mounted on the transmission.

Or it could be a wiring issue with your ignition, but if you're getting the 12v signal to the starter small pin when you turn the key, then it shouldn't be that.
 

flintknapper

SILVER Star
Joined
May 22, 2004
Messages
7,771
Location
Deep East Texas
 
 
 
I think 'for now' you are making this way too complicated.

First (ALWAYS FIRST) check the condition of your battery terminals AND the cables themselves. Next...be certain you have a good connection AT the starter. Check ALL ground wires.

IF all those things are good, pluck the old starter, install the re-man that you have and try to crank it.

IF it starts...then your old starter (most likely the contacts on the solenoid) need some attention. Repair the old starter and keep it for a spare.

IF the re-man starter doesn't crank the engine THEN...you can go on to other troubleshooting.
 

SUMMIT CRUISERS

SILVER Star
Joined
Mar 25, 2005
Messages
2,097
Location
Edmond, Oklahoma
 
 
 
Word of advice here. When you get tired of changing starters, changing contacts and plungers, tapping on starters, you will then add the Ford solenoid and your worries will be over.

The power to the ignition switch, the switch itself and or the wire to the starter from the ignition switch is probably 25 years old and has degraded. You may measure 12v under your test but under adverse conditions the power/ amp draw may degrade to a no start click scenario.

Adding the Ford solenoid sends direct battery voltage to the starter solenoid ultimately eliminating the voltage/amp drop through your old wires, switch, etc. It just works and that’s all I need to know. Thanks to @jvasquez53 for coming up with this solution to our no start issues.
 
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