Need help diagnosing a no-start situation

thaxman

Mazda5 the Anti-Van
2 weeks ago I put the Mazda5 up on ramps to replace the water pump b/c I thought it was weeping and was about to fail. It was not the pump, but the thermostat housing, which I took care of after removing the alternator and the tensioner and tightening the WP back down after failing to pull it out due to clearance issues (see my WP post from 2 weeks ago) Because the WP doesn't touch electrical, I never disco the batt, so when I began removing the alternator, I made a ground connection with the block for 1/2 sec. So I pulled the neg post of the batt, and did the tstat housing, and put it all back together. I also drained the FL22 from the system while I was at it since its been 11 years. Top off the coolant as per manual and went to start it, but only got a loud click from the starter solenoid and no start. Got it running with a push start and took care of the coolant level after running up to op temps to get the tstat open. It HAS NOT started from the starter since. I have been able to push start it, and the 3rd run around the block proved the batt was bad because I started getting idiot lights all over the dash then the elec steering pump failed to produce pressure. Replaced the batt, still no start. You can then cruise back to my DIY starter removal post to see that this was the biggest PITA I have ever experienced with a starter. Not the starter. The OE unit tested good at the store and I put the reman in just in case. Nope, not the starter. Not the clutch position sensor as far as I can tell b/c trying to start w/o pushing the pedal yields nothing, but pushing in the clutch gets the starter click. Don't think it would be the immobilizer or ignition b/c I get a solid click not a no spark situation since I can push start it and it runs fine.

I am at the end of this rope. Any direction someone can point me in would be greatly appreciated!!!
 
Going back to my previous comments on using a multimeter to do some actual testing. Or at least a test light.

The big wire going to the starter should be 12v all the time with key off. If not, you probably fried the main fuse. Otherwise when the key is turned it should not drop below 9v.
The small wire circuit going to the starter is the ignition switch path (which includes relay, clutch switch, small fuses) should also be 12v when key is turned. per wiring diagram is red/yellow.
 
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I never disco the batt, so when I began removing the alternator, I made a ground connection with the block for 1/2 sec.
I believe Mazda uses fusible link instead of standard fuse as the battery's main fuse. The section of the wiring harness near the battery is built to a specific AWG to blow at a certain amperage, like a fuse. IIRC (been I while so I may not recollect correctly), when this gets blown, there are other power source wires that still draw power to run in car electronics while the fusible link connects to the starter. You can jump this section/add-a-fuse or replace the whole harness (technically the integrity of the cable could be compromised from the sudden high current draw but I doubt it). Google/YouTube "mazda fusible link". Worth taking a looking at.
 
I believe Mazda uses fusible link instead of standard fuse as the battery's main fuse. The section of the wiring harness near the battery is built to a specific AWG to blow at a certain amperage, like a fuse. IIRC (been I while so I may not recollect correctly), when this gets blown, there are other power source wires that still draw power to run in car electronics while the fusible link connects to the starter. You can jump this section/add-a-fuse or replace the whole harness (technically the integrity of the cable could be compromised from the sudden high current draw but I doubt it). Google/YouTube "mazda fusible link". Worth taking a looking at.


DING! DING! DING!

I nominate this the best post of 2017

After prying off that really stupid clear plastic cover that is of course no longer clear, there it was - broken link. You saved me a diagnostic trip to the dealer plus their asinine cost to replace it!
 
I'm glad you got the answer on this one, but don't miss the bigger opportunity here which is learning how to problem solve without guessing. The starter had no power running to it. A simple test light check would have saved countless hours, frustration, and money (battery and starter replacement). Not trying to add salt to the wound but instead encourage a methodical approach to troubleshooting. Nowadays you can learn quite a bit online about anything in a short amount of time, including basic electrical.


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Glad you have it narrowed down! There's nothing in the post that's original to be best of anything. Hope this reminds everyone to disconnect their battery when working on electrical..
 
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