PLEAESE HELP!!!Starting issue with fresh built redtop sr20 in 90' s13

[drftwel]

I have been having a starting issue for MONTHS ....... I have a 1990 240 with a 429 HP to the wheels sr20 redtop fully built with extensive mods too long to list for now....


If I roll down a hill and drop it in 2nd gear ( haven't tried any other gear) it starts right up like a champ.....but never any other time. I just got the car back from having bottom end and top end built and was starting up fine when I turned the key and out of nowhere with no warning I inherit this issue which sounds more and more like a riddle every time I try explaining the symptoms so I can get the right diagnosis, I'm slightly mechanically inclined.... So my first thought was the starter is bad, so of course I had to wait on a new one for over a month because it was on backorder everywhere ........


So I installed the starter, direct replacement so I know it is wired correctly, and when I turned the key, NOTHING.... checked all the fuses, which still didn't fix issue.....

Got alternator tested after I got it jump started.... Mind you, it WILL NOT take a jump from another car via jumper cables, and they said the alternator is good ..... So now I am LOST.....


I had my battery (cheap valuecraft ) which was a sidemount setup relocated in the trunk just rigged up with electric tape linking the lead wires from battery to the original terminal points, and had starting issues in past dealing with bad grounds, so assuming that rigged trunk mount battery could potentially be part of the problem, I ditched it for a duralast gold battery (instead of my preferred optima redtop I was a hair away from buying) because it has a 5 year warranty compared to the 3 year optima warranty......



But anyways after installing the miata duralast gold new battery in, and extending the fuel pump wire up to the front through the firewall and to the positive terminal, but I DID ADD AN INLINE FUSE thinking I did the right thing? Fuel pump kicks in nice and strong (I always allow it to prime up before starting the car with the turn key method which I would kill to just be able to do right now lol.....


But what else could be the problem? It is such a pain and dangerous to be trying to roll the car fast enough to crank by dropping it in gear where I live .... And I'm trying to save a boat load of cash from having to drive to my mechanic who did the build because although he is the closest distance mechanic who can work on sr's to me, we are almost an hour and a half apart l

[drftwel]

Could the Mazda miata duralast gold battery be the wrong polarity? Oh I forget to mention I HAVE AN APEXI POWER FC D-JETRO SETUP

[blkvrtswp]

The fact that using jumper cables does nothing but the car runs fine tells me that the main power may not be getting to the starter, or that the start signal may not be getting to the starter.

I would concentrate first on the thick wire that runs from the battery positive terminal to the starter. Battery in trunk often makes this connection very suspect. Make sure the wire is of correct thickness for the full length, and that all connections are very tight. Try jumping the car from the front, not using the trunk battery.

You can also buy an "under hood remote start switch" that will 100% bypass your ignition switch for testing. $22 at a local parts store, attaches with alligator clamps to the tab on the starter and your pos terminal. Push the button and the engine cranks. The ignition switch itself is like $16 on Amazon.com if you suspect it is bad.

Good luck!

[Harrythook]

You can also buy an "under hood remote start switch" that will 100% bypass your ignition switch for testing. $22 at a local parts store, attaches with alligator clamps to the tab on the starter and your pos terminal. Push the button and the engine cranks.

I would say diagnose before doing this route. One mistake with remote start (pushbutton) and you got a big problem. I have seen it done, car in gear, ignition on and hit that button. Car fires and your chasing it, or worse yet a finger or something is in the wrong spot when the motor catches.

Check for B+ voltage at main starter feed, with key in start position. Check for B+ at S-feed for starter in start position. Either there is no voltage (or severe drop) at the main feed for the starter, or you are not getting the required 12 volt (B+) at the solenoid. For either fault proceed backwards to diagnose.

Safety first, don't let that fresh build not starting make you overlook the basics. And the first step is always make sure your not gonna hurt yourself or others.

[drftwel]

Okay, I bought a new battery intended for a Mazda miata, because not much else would fit...... And INSTALLED NEW BATTERY UNDER HOOD . .. Got all my battery cable leads ran and terminals installed, and the Power FC is saying I have 12.3-12.4 volts.... But when I turn the key, nothing .... The only thing I hear is my fuel pump priming up before I attempt to start the car. And every 8-10 seconds I hear a slight "zzzzzzz" coming from around the power steering pump ( I don't have air conditioning BTW) I checked to see if it was coming from the fuse box and it wasn't.... I may end up having to post a video of what is going on ..... I also added a ground from the greddy top mount intake plenum to the battery tray...


[/quote]Check for B+ voltage at main starter feed, with key in start position. Check for B+ at S-feed for starter in start position. Either there is no voltage (or severe drop) at the main feed for the starter, or you are not getting the required 12 volt (B+) at the solenoid. For either fault proceed backwards to [/quote]

I am a novice mechanic (no training or experience other than watching my old mechanic drop in the motor back in 2004 and slowly but surely installing bolt ons here and there, which now..... 11 years later isnt too shy of a competitive drift car now that I got the engine full rebuilt and headwork done (keep in mind I don't mess with internal work, I leave that to the pros) but anyways...... My in-town mechanic who dropped in my engine over a decade ago no longer lives here so that is why I am having such a hard time and having to go through the whole trial and error thing, but can you please explain how I do this wiring diagnosis with a multimeter? As in where should I touch the black/red tester cables? and also what setting the multimeter should be on? What reading is good/vs. What reading is bad? Thanks for the help guys!