[Tanya]

This problem developed about 3 weeks ago when it was really hot outside: all of a sudden the engine shuts off without warning, no sputtering or anything, just dies. then the tachometer needle jumps around wildly even though the engie is not running. pop the hood and find that the EFI relay in the fuse block is blistering hot! So let it cool, 10 minutes, engine starts up and runs OK. I replaced the relay about 2 weeks ago, and it was fine for a couple of days while the weather was wet and cool. then it6 got hot outside again and it's been cutting the engine off. today was the worst. I was stranded for 3 hours in the boonies w/ my kids. we'd cool off the relays, drive the car and within a minute the engine shut off again and the tach would jump around. the relay wasn't hot, but yet it was still not running. sit there for 10 minutes and we'd get the car started and driveable for another minute or 2, then die. we must have driven 5 miles within 2 hours! after being towed home, we ohmed out the ignition coil... the book says 0.4-0.5 ohms... my coil ohmed out at 0.3 which isn't good, but I don't know if it woulod cause4 what's happening or not. anyone have this happen before or5 know what this is about? thought she dropped a ground wire, but all wires look OK

~~Tanya~~

 

[Dave A.]

Which EFI relay is it that you're referring to? EFI main relay no.1 or no.2?

 

[Tanya]

the relay in the fuse block that says "EFI" the "Main" relay gets hot as well, but when I* replace just the EFI relay, it works good for about a week or so

 

[Dave A.]

Hmmm, what size fuse is installed for the "EFI" fuse in the same fusebox. The EFI fuse should be a 15 amp fuse and I'm wondering if someone may have installed a fuse with a higher rating. Check the rating of the "IGN" fuse as well. Should be 7.5 amp fuse. The fact that replacing the EFI relay with a new relay temporarily fixes the problem leads me to think that something is drawing excess current through that relay and damaging it with time.
Try shorting the fuel pump check connector and turn the ignition switch On. Then let the fuel pump run for a couple of minutes and see if the EFI relay gets hot . Let me/us know what you find with this test.

 

[Dave A.]

I forgot to ask which car is having this problem, your 82 or 85? The measurement of 0.3 ohms on the ignition coil would be for the primary winding. Check the secondary winding resistance and see what your meter reads. The reading should be 8.5 - 11.5K ohms on the secondary. Page IG-6 in the 85 TSRM. The EFI relay no. 2 feeds the ignition coil primary, the igniter, the injector resistor pack, and the fuel injectors. The relay contacts on the no. 2 EFI relay are overcurrent protected by a fusible link and not a fuse so it is possible that your ignition coil could be crapping out when the underhood temps. go up. The ignition coil on both cars I believe have built-in thermal overload protection which would explain the erratic tach. needle movement and the ability to restart after things cool down. If the coil draws too much current, the no.2 relay will get hot and the thermal overload protector in the coil will open causing the engine to just up and quit. Chances are that both the relay and the ignition coil windings are cooling down during the off period, but the coil could very well be the actual source of the problem!
HTH!

 

[Tanya]

1st of all, I don't have an '82. Haven't had one since January- only one mk2 now
2nd. I checked all fuses, all are correct amperage, none are broken, etc. Yeah, basically my guess was that maybe the EFI relay was getting hot trying to over compensate for a weak ignition coil. the primary resistance was only 0.3 ohms, 2ndary was OK- 11.3 ohms, BUT I know the simple fact that it is a yellow spark means the coil is weak. supposed to be bright blue and it isn't. I'm trying to get my butt to NAPA to get the coil but they close at 6, and I'm stuck w/ the kids until fiancee gets home, what a PITA! as soon as I get it I'll let y'all know, TYVM!
Tanya

 

[Shimmy Supra]

I would be very interested to know how you fixed that. I think the problem you had is very similar or the same to my problem. http://www.celicasupra.com/phpBB2/viewtopic.php?t=8014 I also noticed my relays got really hot as well. Anyway, it may help me narrow down what area of my car is shorting out.

 

[Tommy]

Two things tend to cause heat in load carrying electricals. One is a short to ground on the + side, and the other is not enough ground on the - side.
I doubt you have a short on the positive side cuz it runs sometimes. I suspect the relay (and maybe more) isn't grounded adequately

Ihth,
Jamie