Hey, you guys might remember me I posted last week about the stolen recovery 87 NA. Anyway, I've spent hours and hours just reading. I love to read anyway, so to me it's fun. I've got a thirst for knowledge, which is why I love this car already

Well... I got a leading coil, plug wires, etc. I figured out where all the random missing connections went. I got the whole thing put back together. Oil change, tranny fluid change, etc. Remember, the ignition is destroyed, so I'm hotwiring this thing. I connect the on wire to the power wire, so the car has power. I can hear the relays energize, the dash lights come on, the turn signals work, etc. Then I connect the actual ignition wire to crank over the engine. At first it was a little hesitant to crank (Read: *click click click...*) So, after throwing a few wrenches at it and punching a rather nice hole through the already cracked windshield, I came back inside to read more. Found some things, troubleshooted, ruled out bad connections and bad starter and solenoid. I figured that it's been sitting for awhile and had carbon buildup inside (I read that here somewhere). So, I pulled a spark plug and put a little ATF in it, then I ripped off the fan and shroud and took a breaker bar to it. It took a little effort but I turned the engine over by hand, then it turned over nice and smooth. I gave it a few full revolutions to make sure it was smooth through it's whole cycle.I guess over the years it just kinda froze. It doesn't make any grinding noise or anything bad. Now, when I hotwire it, it turns over and sounds pretty nice actually. It's getting fuel, I can smell it coming out of the pipes, and I can actually see the fules coming out of the pipes. It also makes a slight popping noise from the pipes as it cranks (Sounds like nice compression).

But....

No spark :'(!! I pulled off a plug wire from the leading coil, stuck a screwdriver inside and made sure it had a nice ground (to my hand of course). So if it was going to spark, it should've shocked the hell out of me. I taught a friend how to hotwire it so I could check for spark. The engine cranked, but no spark. I checked both coils the same way, and still no spark. I took a 5 min break and read some more on troubleshooting coils. I checked their resistance and they both have under one ohm. So the coils should be good. I checked the main relay. It clicks when the "ignition" is set to on. I checked continuity between the 4 terminals on the relay, and they're making good and solid connection. Like I said earlier, gas is getting to the engine, so I kinda ruled out that relay anyway. I checked power going to the coils while the ignition was set to on, and while it's cranking. This is where I get confused...

If the ignition is on and I check voltage across the two terminals in the little white connector going to the leading coil, it gets no voltage. However, if I check it from one side to ground it gets 12 volts, and if I check the other side, it gets anywhere from 0 to 6 but no more. I think the coils are ok, they're just not getting enough voltage. If I check from those same terminals to ground while it's cranking, the voltage just fluctuates between 0 and 6.

What's the next step? I've searched like mad through these forums and read a bunch of manuals and other texts, but I can't find anything similar. Anything I do find, I try. I've also cleaned the grounds, and the battery does have enough juice. Through all these tests I've had jumpers attached to the RX7's battery and my running S10. So it's getting around 13-14 volts.

I found some threads mentioning checking the ecu, but I haven't found anything really saying how. If somone can point me in the right direction or give me ideas, I'll really appreciate it.

Sorry for the long post, I'm trying to kill time before the drags tonight

Thanks...

 

wayne?

 

i would say just check the fuses. just to start things off. who know it could be something as little as a fuse.


(mumbles to self damn fuses)

 

I checked those, too. Earlier in the day I lost all power. I thought it was the main 80 amp fuse because it looked a little burnt. I replaced it with a new one, but the car was still totally dead. The headlights wouldn't lift up, nothing would work. So I checked all the fuses under the driver's dash. I found one 10 amp fuse that was blown. I changed it and everythign worked again. It was kinda weird that a 10 amp fuse would disable the whole car, but whatever. Maybe it went to the computer...

Anyway, fuses are good.

 

If you're getting 12v DC at the black/yellow wires (to ground) of each coils' plug, you're good there (there are two at the trailing coils, one for each)...The other wire you're reading is one of the following: 1)at the leading coil's plug, the green/yellow should be about .8v at idle (I realize you're only cranking here) 2) at the trailing coil, the blue/yellow is your .8v timing signal; the brown/yellow your select signal from the ECU (at 4.4v key on, this is probably what you're reading); and, the blue/red should have less than 2v on it...

You sound like you know what you're doing as far as troubleshooting, so you might as well get to the ECU to check your CAS inputs (while cranking) to rule that out.

Also make sure you're not totally flooding her out. If she's been sitting awhile, your injectors' spray patterns may not be very pretty...Pull the plugs-if they're soaked, use the unflooding procedures I'm sure you've read about...

See if this helps for the ECU checks-

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/troubleshooting-your-car-ecu-340578/

 

CAS - Crank angle sensor? I was thinking about that, but I wasn't sure. That thing has been pulled out a few times already, so I'm sure it's way off. It's also missing the cap that goes on it, so the gear and everything are exposed and rusted as hell. I cleaned up the contacts a little with sand paper, but I'm still unsure how that works. I know it tells the computer where the crank is, and the computer decides which spark to send based on that. Does the timing need to be close to accurate for there to be a spark? You'd think it would still send one (although way off). If that sensor is bad, would that cause my problem? And, based on the resistance I got at the coils, do you think I can rule them out as being bad?


I was planning on replacing the CAS anyway, I just want to get the car started!!!

 

If the CAS is bad, you'll get no spark, true...You should also be getting a code (you probably haven't rigged up a code checker yet, I'm guessing). There are procedures to align the CAS with the timing marks on the front pulley before installation. To paraphrase, align the right mark (looking from the front of the engine) on the main pulley with the pin sticking out of the front cover. Now align the CAS marks, near the gear (the dot & the "arrow"), and carefully reinstall the CAS as to prevent gear rotation. You should be close enough at this point for her to run, final timing adjustments can be made should she start...

The surefire way to verify CAS operation is from the ECU, this will also check all wiring between the two. If you're getting the input voltages (a little less than 1v to ground at the 4 pins-see the charts the guys posted on the ECU write-up for pin locations), then your CAS is good. If not, then the CAS (or the wiring) is bad- simple, eh?

 

Thanks I'll check that out tomorrow. I did pull the carpet back from the ECU earlier today. The bolts that hold that metal guard were already taken off! I guess the guy I bought the car from did that.

Thanks again I'll report back tomorrow after trying everything. I've got some spare 12V LEDs laying around, so I might make up a quick diagnostics checker.

As for now... Off to the drags. Anyone in AZ interested, check out 19th ave and Deer Valley. I'm the dude in the loud white S-10 blazer wearing the red OSU hat.


'Night

 

Ok, back again. Couldn't troubleshoot the RX7 yesterday, so I did it today. Anyway, I checked the CAS and coils at the ECU.

For the CAS all 4 inputs (1N, 1P, 1Q, 1T) were at around 1.6 volts. The FSM says they should be under 1.0v but I don't know if that matters that much since as far as I know the CAS sends its signal through induction (current induced by magnetic fields). To me that would mean it's working better than ok.

1M = ~6.5v (should be < 2.0v)
1U = ~4.5v with ignition on, and ~2.5v with it cranking
1X = ~0.5v on; ~1.5v cranking
1V = ~0.1v on; ~1.0v cranking

1M is way off, the others are a little off, but I don't know what that means. I'm using a Fluke 322 digital multimeter. It's the same one I use for work, and it's always right on with what it's supposed to be, but that's usually AC. I'm assuming its DC function is right on too. Everything I've read here says to use an analog meter. If you think that would be more accurate, I'll try and dig one up. I've got one that's like 50+ years old around here somewhere...

 

 

bump

Wayne, where'd ya go? I need that brain of yours.