87 7MGE Won't Start

[RNEMESiS42]

Well, about a month ago I woke up one morning and my car didn't start. It turned over, but won't start. I put some gas in the tank, and tried again, nothing happened. I found a way to work, worked all day, then got back to my car. I cranked it for about 15 seconds and it caught. I filled up the rest of the tank with some good gas, and I was on my way. It worked fine for about a week or two, before the same problem started again. If I let it sit for two days it'd miraculously work again. It sat for about a week and decided to work again. It hasn't started in about two weeks, but yesterday it decided to again.
I checked a my first spark plug, and it sparked, weakly. I tried it again today and it doesn't spark at all. I put in a spare plug and that didn't spark either. I checked the ignition coil with a multimeter and it's reading correctly, just on the low side.

I just got a new battery about two months ago because it wouldn't start. I figured it was electrical because it didn't turn over at all. People were telling me it my be the cullinoid or starter, but the battery fixed everything. I also got a new alternator about six months ago, so I knew that wasn't the case.

sorry for the long post, but this sucks! I want to get it at least started up temporarily so I can get it somewhere to have someone look at it. I don't want to pay 200 bucks to have it towed to a place, heh.

 

[Supramatt90]

Did you check your codes. If you have any they will lead you in the right direction because there are many things that could be causing it.

 

[supraman7mgte]

when you noted it would not start,were you getting power to everything else?

 

[Nick M]

I would look for a loose ground or bad connection with your intermitent problem. An igniter going bad has your symptoms also. Engine heat will slowly kill it.

 

[RNEMESiS42]

Yeah, I get power to everything fine.

I'll check my codes.

 

[bluemax]

Sounds like an ignition problem.
Igniters will kill the ignition. And when igniters go, its usually intermittent but not all the time. I've had one (acutally my girlfriend, now wife) go on an old 7M Creseda intermittently. A friend of mine at work had his go out on his pickup. He trouble shot the thing for a week before asking me.
If you talk to the dealer, they say igniters never go out. Thats what they told me when I replace my gf's.
I replace them before 100k on all of my Toyotas. It could leave you stranded on the road.
I don't know of any way to test them.
I'm not sure why Toyotas need them, none of my American cars have 'em.
The ones I've replaced, were expensive and Toyota won't take them back if you try to return it. If you can borrow one you'll know for sure.

The ignition doesn't really use a lot of current. On a fresh battery you should be able to run for miles and miles before it gets too weak when the alternator goes out.

 

[RNEMESiS42]

I'm checking my codes after work today, but in the mean time I'm thinking about the ignition stuff you just mentioned.

On ebay I found both igniters and ignition coils for under a hundred bucks each. I'm pretty sure my coil is still good since I checked it with my multimeter, but my multimeter has been acting strangeley, also, heh.

After code checking I'm picking up some new spark plugs, and looking into buying an igniter off ebay...if that doesn't work I might as well pick up a new coil, too.

 

[bluemax]

Checking to see if you've got a code is the first place you should check. It could save you a lot of time trouble shooting and send you to the right place to look. Keep us updated.
I'd be careful about buying an igniter on e-bay. You don't know how many miles may be left before it goes bad. Unless of course you don't plan on keeping the Supra much longer.

 

[RNEMESiS42]

Hmm, so, I can't even get any codes to show. It should at least flash once to show that everything's normal, right?

I shorted out E1 and T...turned on the power with the key, and nothing. Listened to the CD I had in the CD player a bit : P
The diagnostic box is covered in some greasy creamy stuff...I assumed that it was some anticorrosive or something. Is that screwing everything up? I can't even get any codes!

 

[Nick M]

If you talk to the dealer, they say igniters never go out.

Im "the dealer" and they do go out. Electronics dont belong under the hood.

 

[RNEMESiS42]

So...today I didn't have work, so I was able to replace all of my spark plugs (annoying that I had to take off part of the throttle body...) I get everything back together, and try to fire her up. Success! The engine idled nicely. I turned it off and tried it again five minutes later, beautiful again. I go put all my tools away and try again to go get a good wash. Nothing...: /
I'm guessing now that either I have some bad grounds, it IS my igniter/ignition coil, or possibly my ECU?

If I got a newer igniter from say 91' it should work, right?

 

[mkiiSupraMan18]

If not, I got an 87 I'd sell for cheap.... :icon_razz

I'd have to agree with the grounds issue..... something that intermittent.....

Also, see if I caught this right.... you have a mkIII that isn't spitting out codes? wtf? :icon_razz

 

[RNEMESiS42]

Yeah, I got some wiring diagrams so I'm going to check everything in my ignition to see if it's getting power or not...
The only electical changes I made to the car was for the CD player, and sub woofers I put in, but I don't think if a ground for that came lose it'd mess up my ignition??

And yes, no codes of any sort. Not even the one that tells you everything is fine. definitely wtf, heh.

 

[Psykodelik]

I think I had the same problem you did. I took it to my mechanic and he replaced the TPS sensor. So it might be that. I don't know how to check those, so I'm not sure if it's the same problem as yours. Just something to check for also, ya know.