Car not starting randomly? READ THIS (30 Amp Starter Relay Mod)
- Thread starter Idealsupra
- Start date
Thanks Aaron... this is both good and bad news for me... bad cos it means no easy fix with a relay... bad cos it means i'm probably looking at a new starter...
car is a factory JZA70, battery is brand new (put it in yesterday to eliminate that possibility) 600cca AC Delco jobbie, fully charged. when turning the key the trigger wire on the solenoid gets 12.5v and when you check the voltage on the starter wire it has 12.7v (battery voltage)
unless anyone has any more suggestions, i'm going to go with a bad starter, and try to source one to replace it... not looking like a fun job on a jza70 manual either...
well it Does say "repair starter" in that table....could always take it out and try to clean up the electrical internals. also i've seen a shady way of doing it - removing the starter, gutting it, replacing the guts with the one you bought at the store - then return the starter. haha...i've never done it myself - but some people.....
you do get a core charge rebate...if anything.
you do get a core charge rebate...if anything.
i had been running into this problem for a while now too
and this mod definitely fixed the problem
the car now starts with no problem
and this mod definitely fixed the problem
the car now starts with no problem
I'm very curious to know JetJock's solution.
Why some of you argue that this is a solution is beyond me. Having to add anything to a car to make it operate normally is incorrect, It's simply (as stated from the beginning) a band-aid fix. It means something already in the car must be repaired. I understand that most of you accept this and choose to do the relay mod still, this is fine, however I like everything under my hood and under my car to be 100% neat and as it should be.
I don't like cutting any corners, if I don't have to. Not knocking those who have done this. As with anything, you can get it done, or you can get it done right. I don't know why some of you feel you can argue with the man, he's obviously good at what he does.
Sorry if I come off rude, but it really is getting out of hand with the kids saying "NO, IM RIGHT!". I still give the original contributors to this thread their credit, they took ambition and found a work-around to a common problem, there's nothing wrong with that.
-Mike
Why some of you argue that this is a solution is beyond me. Having to add anything to a car to make it operate normally is incorrect, It's simply (as stated from the beginning) a band-aid fix. It means something already in the car must be repaired. I understand that most of you accept this and choose to do the relay mod still, this is fine, however I like everything under my hood and under my car to be 100% neat and as it should be.
I don't like cutting any corners, if I don't have to. Not knocking those who have done this. As with anything, you can get it done, or you can get it done right. I don't know why some of you feel you can argue with the man, he's obviously good at what he does.
Sorry if I come off rude, but it really is getting out of hand with the kids saying "NO, IM RIGHT!". I still give the original contributors to this thread their credit, they took ambition and found a work-around to a common problem, there's nothing wrong with that.
-Mike
Not in all cases (good example is a headlight rewire with relays), but in this case the circuit already has a relay....
radiod;1464021 said:
fair enough
i bypassed the problem
i do have a question tho
has anyone identified what the real issue is, and why so many of us have this problem????
With mine it was the starter itself (had a brand new starter NOT REBUILT that died on me after 3 months of use), so IF I had gone ahead with this solution (which I was seriously considering to the point of already had the wires/connectors/relay ready to go) I would have just ended up cutting in to my wiring harness for nothing.
Here's what I can come up with just taking a look through the TSRM starting system wiring diagram. Someone please correct me if I'm wrong, hopefully this will help people diagnose and repair their vehicles WITHOUT cutting in their harness.
If this mod does in fact work for you the problem likely exists in or connecting to one of the following:
White wire between battery positive terminal and fuse box (Ignition is fused by the 40A AM1 & 30A AM2 fuses)
White wire between AM1 fuse and ignition switch
Ignition switch
Black/white stripe wire going between the ignition switch and the starter relay (auto only)
Black wire going between ignition switch and clutch start switch (manual only)
Black/yellow strip wire going between clutch start switch and starter relay (manual only)
Starter relay (located under the passenger side kick panel)
Black/white stripe wire between the starter relay and neutral start switch (auto only)
Black/blue stripe wire between the starter relay and the starter solenoid (little plug on the starter itself that you installed your new relay on to)
Grounds
Other places to check with starting issues that are NOT fixed by this relay mod:
Blue wire between the positive battery terminal and starter
The starter itself
By measuring resistances/voltage drops between each of those sections you should be able to find where the problem exists and fix it. It will take a little bit of time with a test light and a multimeter, but it's very doable and will solve your starting issue without having to cut in to your harness. If you need numbers for what is considered "significant" voltage drop, I got this with my starter and it gives some pretty good instructions for checking voltages on the starter...
http://www.boschautoparts.com/Technical Resources/Alternators and Starters/StartingSystems.pdf
How to test your starter relay:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=ST&P=12
Clutch start switch test and adjustment:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=CL&P=4
If anyone sees anything wrong, let me know and I'll edit the post. Other than that, good luck with the testing and hopefully this will help at least someone find their problem.
....I hate electrical problems :: hommer :::: facepalm ::
Here's what I can come up with just taking a look through the TSRM starting system wiring diagram. Someone please correct me if I'm wrong, hopefully this will help people diagnose and repair their vehicles WITHOUT cutting in their harness.
If this mod does in fact work for you the problem likely exists in or connecting to one of the following:
White wire between battery positive terminal and fuse box (Ignition is fused by the 40A AM1 & 30A AM2 fuses)
White wire between AM1 fuse and ignition switch
Ignition switch
Black/white stripe wire going between the ignition switch and the starter relay (auto only)
Black wire going between ignition switch and clutch start switch (manual only)
Black/yellow strip wire going between clutch start switch and starter relay (manual only)
Starter relay (located under the passenger side kick panel)
Black/white stripe wire between the starter relay and neutral start switch (auto only)
Black/blue stripe wire between the starter relay and the starter solenoid (little plug on the starter itself that you installed your new relay on to)
Grounds
Other places to check with starting issues that are NOT fixed by this relay mod:
Blue wire between the positive battery terminal and starter
The starter itself
By measuring resistances/voltage drops between each of those sections you should be able to find where the problem exists and fix it. It will take a little bit of time with a test light and a multimeter, but it's very doable and will solve your starting issue without having to cut in to your harness. If you need numbers for what is considered "significant" voltage drop, I got this with my starter and it gives some pretty good instructions for checking voltages on the starter...
http://www.boschautoparts.com/Technical Resources/Alternators and Starters/StartingSystems.pdf
How to test your starter relay:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=ST&P=12
Clutch start switch test and adjustment:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=CL&P=4
If anyone sees anything wrong, let me know and I'll edit the post. Other than that, good luck with the testing and hopefully this will help at least someone find their problem.
....I hate electrical problems :: hommer :::: facepalm ::
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whitemike;1464106 said:
My solution is to keep quiet. The reason for that is it can be several things...but not the wiring. At least I've never seen it be the actual wiring. Since it doesn't make sense it would be that's no surprise to me. Nor should it be a surprise to anyone who is electrically competent. But my main reason for keeping quiet is amazement that of all the people here 99% seem unable employ the simple and common troubleshooting techniques used for finding such problems, although I see from the post above limited progress is being made...
I would agree with jetjock. Wiring doesn't just go bad like that, and 99% of the time will not be the problem. There aren't too many things in the loop between the battery and the solenoid and/or starter either, so the culprit shouldn't be something terribly hard to track down.
I'll tell you what I do: I load the circuit using either a solid state electronic load (a couple of headlamps will also work) or a constant current power supply in place of the battery (ground the starter signal wire) to above what the solenoid normally draws and then step through it using one sided drop testing. That means setting the meter on millivolts and going along the line from the source (or from wherever I think the problem is downstream) by measuring the positive side only ie; the meter never gets connected to ground. When the high resistance area is reached it'll be obvious. Course, I verify block and starter grounding first. Simple and fast. Don't have that gear? Don't even have a meter? A jumper wire will net the same result. After all, the mod is exactly that: a jumper wire in sheep's clothing...
Well, if it's no big revelation why are you asking and why haven't you done it? 
I've said it before: drop testing is one of the most valuable skills car people can learn. Constant loading of this particular circuit and what I usually find as the culprit is the real secret though.
Keep in mind the starter itself can also be at fault (bad solenoid contacts or worn commutator brushes) but it's easy enough to test separately. Another thing to remember is the mod can overcome worn solenoid contacts by allowing extra current into the solenoid because even with a pristine starter circuit the mod offers a lower resistance path. Worn contacts are why the mod "works" at first but some owners find themselves back at square one in a few weeks or months, only to change the starer (or contacts, they're cheap) and have the problem disappear...
I've said it before: drop testing is one of the most valuable skills car people can learn. Constant loading of this particular circuit and what I usually find as the culprit is the real secret though. Keep in mind the starter itself can also be at fault (bad solenoid contacts or worn commutator brushes) but it's easy enough to test separately. Another thing to remember is the mod can overcome worn solenoid contacts by allowing extra current into the solenoid because even with a pristine starter circuit the mod offers a lower resistance path. Worn contacts are why the mod "works" at first but some owners find themselves back at square one in a few weeks or months, only to change the starer (or contacts, they're cheap) and have the problem disappear...
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I agree about the drop testing. People locally come to me with electrical questions, the methods they use determine the problem usually consist of:
1) Replace the non-working item (aka, starter)
2) If that doesn't work, randomly replace things in its path (aka, relays + fuses)
3) If those don't work, bypass it, hardwire it, etc
They skip the crucial first step .. finding the source of the problem. They move straight to fixing the problem. Drop testing isn't difficult to learn, and certainly isn't difficult to employ.
People diagnose that the issue is electrical and fix it anyway possible, then plead ignorance as if a degree is required to solve such a problem.
Folks, Google is at your fingertips, use it.
Nevermind, here you go: http://www.lmgtfy.com/?q=Voltage+Drop+Testing
Anyways, thanks again JJ.
-Mike
1) Replace the non-working item (aka, starter)
2) If that doesn't work, randomly replace things in its path (aka, relays + fuses)
3) If those don't work, bypass it, hardwire it, etc
They skip the crucial first step .. finding the source of the problem. They move straight to fixing the problem. Drop testing isn't difficult to learn, and certainly isn't difficult to employ.
People diagnose that the issue is electrical and fix it anyway possible, then plead ignorance as if a degree is required to solve such a problem.
Folks, Google is at your fingertips, use it.
Nevermind, here you go: http://www.lmgtfy.com/?q=Voltage+Drop+Testing
Anyways, thanks again JJ.
-Mike
First off good thread 30 amp relay fixed the problem write up and diagram were awesome took all guess work out of task. I was also wondering is this the only fix for the problem? Is there a way to repair the factory system so that it functions the way it did when it was first built?