Main Relay painintheassery - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 04-17-2013, 05:42 PM   #1
Elite Member
Thread Starter
iTrader: (2)
 
Join Date: Jun 2009
Location: Istanbul, Turkey
Posts: 2,050
Total Cats: 433
Default Main Relay painintheassery

My engine started just quitting recently.

It does not sputter or stumble, but just stops.
This happens under load, and mostly when I am just getting on the gas. I could be leaving a parking spot, or flooring it to overtake someone, and the engine just cuts out.

All dash lights go dark when this happens. Cranks with no response.
It only fires IF I cycle the key.

All this pointed to a main relay issue - the green one under the hood. I pulled the main relay, and it was too hot.
On a whim, I bypassed the relay for my aftermarket immobilizer system which feeds the main relay.
Things seemed to be OK for a while.

The car died a couple times today, once at 15 psi. That was scary.

I know Reverant was talking about installing a solid state relay on his car at one point, after having a few main relays fail on him.

My theory is, with 4 Toyota COPs and 4 650 cc injectors, there's a whole lot more electrical load (current) on the green relay. I mean, you should have been there to see how hot the relay was.

Are any of you guys experiencing similar problems to mine?

Would you guys please explain what sort of a solid state relay I can use in its stead?

I am thinking if I can get my hands on a powerful relay, I can easily modify/adapt the terminals to make it work.

Any thoughts?
Godless Commie is offline   Reply With Quote
Old 04-18-2013, 01:48 AM   #2
Supporting Vendor
iTrader: (10)
 
Reverant's Avatar
 
Join Date: Jun 2006
Location: Athens, Greece
Posts: 5,440
Total Cats: 197
Default

I replaced mine with a standard type 40A(?) relay, and it has been fine ever since.
Reverant is offline   Reply With Quote
Old 04-19-2013, 07:31 PM   #3
Elite Member
Thread Starter
iTrader: (2)
 
Join Date: Jun 2009
Location: Istanbul, Turkey
Posts: 2,050
Total Cats: 433
Default

Just ordered a main relay.

It's a waiting game at this point. I'll wait and see what happens, or doesn't.
Godless Commie is offline   Reply With Quote
Old 04-20-2013, 04:49 AM   #4
Supporting Vendor
iTrader: (10)
 
Reverant's Avatar
 
Join Date: Jun 2006
Location: Athens, Greece
Posts: 5,440
Total Cats: 197
Default

Not worth it. They are like $40 new over here from Mazda. I can get 10 generic 40A relays for that kind of money.
Reverant is offline   Reply With Quote
Old 05-11-2013, 09:10 PM   #5
Junior Member
 
Join Date: Jul 2010
Location: Camp Pendleton, CA
Posts: 93
Total Cats: 2
Default

How did you wire in the solid state relay? I'm getting ready to order one and wasn't sure how you mounted it and wired it.

I've been using jumper wires in place of a main relay for a few years now, but I'm getting tired of going under the hood every time I start or stop the car.
Darthteddy is offline   Reply With Quote
Old 05-11-2013, 10:28 PM   #6
Elite Member
Thread Starter
iTrader: (2)
 
Join Date: Jun 2009
Location: Istanbul, Turkey
Posts: 2,050
Total Cats: 433
Default

Well, the main relay did not solve the problem.
The car died under power today on the freeway.. I was carrying enough speed (100+ mph) so I did a quick restart.
It does not even want to start unless I cycle the key off and on when this happens.

I'll start troubleshooting wire by wire. Argh.
Godless Commie is offline   Reply With Quote
Old 05-16-2013, 06:56 PM   #7
Elite Member
Thread Starter
iTrader: (2)
 
Join Date: Jun 2009
Location: Istanbul, Turkey
Posts: 2,050
Total Cats: 433
Default

Gentlemen, I need your help please...

This problem is not going away.
Let me give you guys an itemized list of what I have done so far:
  • Installed a brand new relay, to no avail
  • Removed the MS and wiggle tested all wiring, no dice
  • Checked all the fuses, wiggled and banged on relays and wires underhood, still nothing
  • Completely bypassed the aftermarket alarm immobilizer - meaning, I restored the IGN wires back to their original configuration, still dies
  • Installed a heavy jumper in lieu of the green main relay under the hood, and the damn thing still died on me
  • But, I captured the ever so frustrating event in the form of a datalog... I kept looking at the said datalog file for a while, but made no sense to me. It is attached.

I also conducted a test hoping to pinpoint the problem:
(The test yielded no solid results, but an interesting observation)

Like I said, I made a heavy jumper out of 3 mm wire and a couple of male terminals to bypass the main relay. As I did that, I also made a light circuit with a long lead, and attached the ends (with male terminals) into the other two terminals of the relay socket.
The idea was to monitor the IGN line that triggered the relay. I extended that "test light" into the car, and the light came on as I turned on the key. (meaning, it would trigger the main relay if it was there).
If the car died and the light went out, I would know the main relay was no longer triggered, and that would be the cause of the engine dying. In that case, I would look for the problem in that area.

So, I started logging, and created the conditions where the car was dying on me.
And, just like clockwork, it died halfway into 4th gear under high load. (please see attached log for details)
Funny thing is, the "test light" I had extended into the cabin remained lit. That meant the IGN circuit was not at fault.
Funnier still, the car would not restart...

I had to get out of the car, and remove and reinsert the jumper I was using in the main relay socket, just like cycling the key all the way back to OFF...
That made no sense, at all.
Once I did that and got back into the car, it started instantly.

Joe, Dimitris, Scott, my fellow citizens, soldiers, Romans... Today is the day I need this forum's collective brainpower to solve this thing.

And, you know what really hurts me in all this?

There is a track event on Sunday which I really wanted to attend. And I can't.
It's not just any trackday. They are making Istanbulpark, the genuine, bona fide, real Formula 1 track available for the likes of me for timed events. And I am missing all that for a stoopid electrical problem.

(Yeah, I could get up to speed till it cuts out, and coast the rest of the way on the track, I suppose...)
Attached Files
File Type: msl Hakan Engine Cut.msl (99.7 KB, 91 views)
File Type: msq CurrentTune[1].msq (56.7 KB, 65 views)
Godless Commie is offline   Reply With Quote
Old 05-17-2013, 04:20 AM   #8
Supporting Vendor
iTrader: (10)
 
Reverant's Avatar
 
Join Date: Jun 2006
Location: Athens, Greece
Posts: 5,440
Total Cats: 197
Default

When this happens, does the speedo gauge (not tacho) also drop to 0?
Reverant is offline   Reply With Quote
Old 05-17-2013, 07:51 AM   #9
AFM Crusader
iTrader: (18)
 
olderguy's Avatar
 
Join Date: Oct 2004
Location: Wayne, NJ
Posts: 4,437
Total Cats: 84
Default

Have you tried pulling apart the ignition switch to look at and clean the contacts?
olderguy is offline   Reply With Quote
Old 05-17-2013, 09:18 AM   #10
Elite Member
Thread Starter
iTrader: (2)
 
Join Date: Jun 2009
Location: Istanbul, Turkey
Posts: 2,050
Total Cats: 433
Default

Quote:
Originally Posted by Reverant View Post
When this happens, does the speedo gauge (not tacho) also drop to 0?
I honestly do not remember - it's not the calmest of events when that happens.

I will recreate the conditions and watch for that this evening.
Godless Commie is offline   Reply With Quote
Old 05-17-2013, 09:21 AM   #11
Elite Member
Thread Starter
iTrader: (2)
 
Join Date: Jun 2009
Location: Istanbul, Turkey
Posts: 2,050
Total Cats: 433
Default

Quote:
Originally Posted by olderguy View Post
Have you tried pulling apart the ignition switch to look at and clean the contacts?
Short answer is, yes.

I also went as far as completely bypassing the ignition by installing a jumper across the main relay terminals.
I also monitored the IGN circuit by installing a light on the circuit and extending the said light into the cabin. The light never went away when the engine died.
Godless Commie is offline   Reply With Quote
Old 05-17-2013, 09:25 AM   #12
Junior Member
iTrader: (6)
 
Join Date: Jun 2008
Location: Lansdale, PA
Posts: 462
Total Cats: 3
Default

I had an issue where the contacts in the fuse box that the relay plugged into were loose.

I would have random issues where the car would cut out (no power to the ECU) and then kick back on. Sometimes it wouldn't kick back on until I fiddled around with the relay, which is what made me look at the contacts.

I tightened them up to grip the relay harder, haven't had an issue in the two years since.
BradC is offline   Reply With Quote
Old 05-17-2013, 09:46 AM   #13
AFM Crusader
iTrader: (18)
 
olderguy's Avatar
 
Join Date: Oct 2004
Location: Wayne, NJ
Posts: 4,437
Total Cats: 84
Default

Does this only happen since the MS install?

If it happens at night, do the lights stay on?

Check the two screws holding the main 80 amp fuse?
olderguy is offline   Reply With Quote
Old 05-17-2013, 10:10 AM   #14
Elite Member
Thread Starter
iTrader: (2)
 
Join Date: Jun 2009
Location: Istanbul, Turkey
Posts: 2,050
Total Cats: 433
Default

Quote:
Originally Posted by olderguy View Post
Does this only happen since the MS install?
Yes

Quote:
Originally Posted by olderguy View Post
If it happens at night, do the lights stay on?
Yes, lights stay on

Quote:
Originally Posted by olderguy View Post
Check the two screws holding the main 80 amp fuse?
Do you mean bolts? It gives me no trouble elsewhere (I am powering a couple relays, like my LCD gauge panel off that line, and they stay on.)

Even then, why would it require depowering and powering up the circuit fed by the main relay?
Godless Commie is offline   Reply With Quote
Old 05-19-2013, 10:56 AM   #15
Elite Member
Thread Starter
iTrader: (2)
 
Join Date: Jun 2009
Location: Istanbul, Turkey
Posts: 2,050
Total Cats: 433
Default

As a proud atheist, I hereby proclaim that

There is a God, and his name is Dimitris.


Ask no more, have faith.
Godless Commie is offline   Reply With Quote
Old 05-19-2013, 11:33 AM   #16
Senior Member
iTrader: (1)
 
Join Date: Jun 2006
Location: Sweden
Posts: 1,391
Total Cats: 58
Default

Which "wire" did he wiggle to get results?

I'm grasping after any black-magic to get my project started...
NiklasFalk is offline   Reply With Quote
Old 05-19-2013, 08:06 PM   #17
Junior Member
 
Join Date: Jul 2010
Location: Camp Pendleton, CA
Posts: 93
Total Cats: 2
Default

Im having an issue where Im not getting the switched 12v at the relay. I have constant 12v at one lead, but regardless of key position I get nothing on the other side. Works fine when I jumper them. Any ideas?
Darthteddy is offline   Reply With Quote
Old 01-27-2015, 01:43 PM   #18
Ian
Junior Member
iTrader: (2)
 
Join Date: Jan 2012
Posts: 163
Total Cats: 4
Default

What was the solution here?

I just lost my 4th main relay yesterday since installing the MS, and I just want the car to work again.

Tach intermittently dropped to 0 before failure - was not looking at speedo. Also could not connect to DIYPNP.

Last edited by Ian; 01-27-2015 at 02:22 PM.
Ian is offline   Reply With Quote
Old 01-27-2015, 01:55 PM   #19
Supporting Vendor
iTrader: (10)
 
Reverant's Avatar
 
Join Date: Jun 2006
Location: Athens, Greece
Posts: 5,440
Total Cats: 197
Default

Replace the relay with a higher-rating relay.
Reverant is offline   Reply With Quote
Old 01-27-2015, 02:22 PM   #20
Ian
Junior Member
iTrader: (2)
 
Join Date: Jan 2012
Posts: 163
Total Cats: 4
Default

Quote:
Originally Posted by Reverant View Post
Replace the relay with a higher-rating relay.
Thanks Reverant, I am reading that thread now and will proceed accordingly.
Ian is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 01:25 PM
Walbro 255lph Fuel Pump $50 lsc224 Miata parts for sale/trade 2 10-01-2015 10:17 AM
Are my coils failing? viriiguy General Miata Chat 5 09-28-2015 08:39 PM
Help installing DDM HID kit thumpetto007 General Miata Chat 8 09-04-2015 06:25 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 09:19 AM.