Hey all,

for some time now my 1990 has had an issue but goes away when it is warmed up and at operating temp after a few minutes.

issue. Cold start morning driving the cooling fans kick on and the car looses electricity doesn't full shut off but I can hear relays clicking. After it warms up the issues goes away. Today the car completely shut off, it would crank but didn't turn over and eventual lost all ignition when I turned the key.

Pushed it off the road waited a few minutes and cranked over and drove back home.

I had duel spal fans and when they kicked on the amp draw was massive it felt like the engine got a shock and the rpm's dropped so I switched to soft start fans thinking that was the cause but the problem continues( soft start fans don't have the massive amp hit rpm's don't change). As the car reached operating temps and the soft start fans kick on I loose power and goes away after reaching operating temps. I'm not sure if it's a relay issue or something else. From best guess the relays are original to the car. Should I get a new fuel pump relay and other relays or is something else going on?

 

Almost certainly the main relay.

I don't know if anyone other than Mazda makes the part, but IMHO it would be worth buying the genuine part anyway.

Note that the relay is bolted into place, so don't try to just yank it out and don't destroy your relay box by prying on it like a caveman.

I don't typically link to vendors, but FM does a good job explaining this issue. Probably because Keith lost out on a Targa Newfoundland win because of a bad one (IIRC, it was a while ago).

https://flyinmiata.com/products/stock-main-relay

They also have an upgraded version for way more moolah

https://flyinmiata.com/products/main-relay

 

i will order a new relay from Mazda it'll be here this Wednesday. I will keep you posted.

 

i put in a china relay out of curiosity, denso one will be delivered tomorrow. Issue remains short video of what happens does it a few times not just once.

 

The issue is become more common and not just a fan issue. I am all out ideas, anyone out there with a possible cause? I have a new main relay I can't find any loose wires or bad ground.

 

Can you take a log of it happening?

 

here you go. Happens just before the log ends 2 times.

 

I believe that's loss of trigger. I think you're feeling the red circles in the picture below, complete loss of RPM, which would result in a complete loss of power, but even the yellow circles are indication that it's having issues. Those happen 5-6+ times in that log.

If you're running a 36-2 wheel, I've found MS does not like the factory gap, which is something like .020-.025, I run more like .010-.015. Inspect for a loose sensor, cut wires, or otherwise, then try the smaller gap.

 

Wow thanks that's very useful I am doing that now. I noticed my vvt cam angle was pinned all the way to 280. I checked the solenoid by feed power to it and it worked. I plugged the connector back on and went to the ecu options port disconnected from the MS and fed 12v directly to the vvt solenoid. I was expecting only the vvt solenoid click butttt all the relays and fuel pump came on. There is definitely something loose. I'm checking my fuel injector/vvt harness right now for any breaks and going from there.

thanks.

 

If I recall correctly, this has not been your only electrical gremlin, I might suggest taking your options plug harness into someone local and having them probably wire/crimp/loom it.

 

I definitely have, it's not technique it's the supplies. Amazon questionable branded connectors. I need to redo it with quality.

 

Probably the crimping tool and method, not the supplies. I use bare crimps and adhesive heat shrink.

here’s the crimper I use, using the 3rd jaws from the left.
https://a.co/d/fpDQ0JE

Not my exact crimps, but really similar, 10-12 crimps:
https://www.digikey.com/en/products/...0369-2/2259455

thats equivalent to the “yellow” heat shrink splices, get 16 and 20 for blue and red respectively.

 

I have noticed that my VVT gauge in the TS dashboard is pinned to 280 even when the engine is running. My camshaft position sensor and trigger wheels sensor wiring seems to be in good condition.

Waiting on the parts you suggested to be delivered. I didn't put a new OEM trigger wheel sensor when I overhauled the engine could it be going bad and it's the culprit?

 

Was the crank gap checked? Id ignore vvt errors until that has been done. Also, “vvt gauge” tells me nothing. Target? Advance? Other?

 

used the parts you suggested here's a log. Did not have those symptoms when the fan kicked on.

 

That log looks much better. As long as RPM isn't dropping out, no need to close the gap, however I've found it necessary with 32 tooth wheels.

 

I went to .10.