No Spark

[Jason1975]

I've been fighting an ignition/spark problem for the past couple of months on my 93 with 253k on it. About 10 years ago, I replaced the fusible links with a new fuse box. I've been having charging issues for about the past 10 years as well. I've been through about 6 alternators from Autozone. After about the 5th rebuilt one, I returned it and exchanged it for a new one. It starts off at 14 volts when I first start up, but then after I'm driving for 15 minutes, it's down under 12 volts. If I'm running the lights, it gets down to 10 volts. This is an ongoing issue that may or may not be related.
About a month ago, I was driving, and it just died. When I got it home, it had no spark and I ended up replacing everything ignition related. It needed a tune up anyways, so it got new wires, plugs, distributor cap, and rotor. I also replaced the Ignition control module, ignition coil, as each time I replaced something, it worked for a few days, and then quit again. I finally realized, I was intermittently getting 12V on the yellow/black to the crankshaft position sensor on the distributor. When it failed a month ago, it was only getting 3-4V at the CPS. So, I ran a wire from the yellow/black on the empty 6 plug near the firewall to supply the power to the CPS. I thought problem solved, until today. I stopped at my dad's house and it wouldn't start. After some evaluation, the power from the yellow/black from the empty 6 plug near the fire wall is now down to 3-4 volts. I then ran my newly created line to my fuse box, and put a 5 amp fuse in it. I confirmed that 12 volts is getting back to the CPS. No "signal" is being sent back to the ignition control module or coil, therefore, no spark. We did get it to fire up a couple times, but it appears that it is dead for now.
Could my CPS be burning out the power supplies (yellow/black) to it?
I looked around, and have CPS's gone bad before? They don't seem like much could go wrong with them.
Looking at the wiring diagrams, it looks like the CPS goes through the computer, so there's no way I can wire directly from the CPS to the ignition control module?
Anyone have anything similar happen before?
Any recommendations would be appreciated. Thanks!

[tooldude]

Assuming the battery is good & charged: If there is low/no voltage on the Y/BK wire that condition will appear at the CKP sensor, ISC, Injectors, 6 terminal connector, and/or Ign Coil (on that other Y/BK wire). Most likely culprits are burned contacts in the Main Relay (make sure the Engine Fuse is good) or a connection problem in the Main Fuse Box. Alternately, there could be a bad splice connection in the wiring or bad battery cable connections (Gnd also). With the key on: Check for a serious voltage drop from the battery negative post to the W/BL wire exiting the fuse box; and from the battery negative post to the Y/BK wire exiting the Main Relay, (and verify at a couple of the above items on the Y/BK wire). That will show if one of them is bad, but you will need to quickly check between the battery voltage and test points to make sure the battery voltage is not falling rapidly. If it is you could jump the battery. Also, make sure the engine ground cable is on and has clean connections.

[Rick the Quick]

Sounds like your distributor is the problem. I am not one to change or replace parts without first testing them to confirm that they are bad but when I bought my '93 it was plagued with the intermittent spark problem. There may be ways of testing igniters and distributors/crank sensors if you have the procedures, knowledge and required test equipment but in my case after doing preliminary testing with a volt ohm meter I was reasonably certain it was in the igniter or distributor. These parts ran me $30 for both and I also figured if I didn't fix the problem I would at least have good back ups to carry in my car. I replaced the igniter first and the car fired right up only to die within a few minutes. Then I tried the replacement distributor and it fired right up and has since run with no more spark related issues. Good luck, let us know what you find.

[tooldude]

^Good advice from RTQuick about having a spare distributor to keep from getting stranded and to check for an on-car failure. However, your information does not seem to indicate a bad CKP sensor necessarily, but rather a low voltage problem - so low the engine won't start. There is a low voltage threshold below which an electronic component (CKP, ECA) is not going to function, as well as electrical (Injectors, Coil). Is the battery (and alternator) good? If you jump the battery will the engine start? The CKP sensor can be tested with a volt-ohm meter but you have to be testing the right connections. My schematic shows two Y/BK wires at the distributor. With the harness disconnected and looking into the connector with the retainer at the top, the terminal order from left to right is (1) GND, (2) VPWR, (3) CPS - signal, (4) unused. Are you checking for battery voltage at terminal (2) {to frame GND or NEG battery post} - that's where you got 3 to 4V? If so, I refer you back to my first post. If you get correct voltage there, then the CKP sensor needs testing (and the distributor to be checked for oil getting inside which may cause the CKP to malfunction) - or try a substitute distributor. Regarding your first statement about charge voltage rising, then falling, did you measure that at the alternator output terminal or at the battery?

[Rick the Quick]

You made some good points there tooltude, without looking at the schematics in my Vacuum + electric trouble shooting Factory service manual which btw will give you detailed step by step troubleshooting instructions. Jason confirmed that "12 volts was getting back to the CPS" yet no signal was getting back to the control module. If my memory serves me right there is a wire coming out of the cps module that connects to the ecu and comes back out of the ecu and feeds into the igniter (also called the control module) and coil. If you have 12 volts getting to the cps (distributor) you should see approximately 12 volts pulsed coming out of the cps. If you don't see a pulsed signal coming out of the cps it indicates a defective cps/distributor. The guy that sold me the used parts (distributor + igniter) said that back in the day when somebody junked a non wrecked Festiva 9 out of 10 times it was a faulty distributor that caused it to end up at the junkyard.
Like I mentioned earlier I am not one to arbitrarily change parts in hope for getting 'er running however if you physically checked all the connections in the circuit for corrosion or obviously broken wires, including any taped wires that do not look factory you will probably find the distributor to be the culprit. If and when you find a taped wire that is obviously not "factory" do yourself a favor and remove the tape and see what it's hiding. I went through a similar problem recently on an '88 Toyota truck. It would start and run but was not getting any ignition advance. It turned out to be a wire that ran from the igniter on the drivers side inner fender back to the ecu located on the passenger side. This wire ran over the valve cover and under closer inspection the valve cover was missing a plastic guide that was intended to keep the wiring off the hot cover. The previous owner had a problem with the wire burning and decided to splice in a 3 inch section of speaker wire by stripping the ends and twisting them together and then covering the mess with 3 feet of tape. The twisted ends came loose on one end causing intermittent problems. Easily fixed without the need to use any test equipment. Also tooldude made a good point about checking voltages at the main relay and another place you may want to check is the ignition switch. One of my cars developed some weird intermittent electrical problems that I traced to worn contacts in the switch. These switches are fairly easy to disassemble at which point the contacts can usually be cleaned up with some very fine (600-1000) grit sand paper followed by wiping clean with rubbing alcohol. Use the 91 proof alcohol as it works better than the 70 proof. Back to the switch disassembly, there are some very tiny phillips head screws and some tiny springs that you will encounter. Don't attempt to work on the switch without good lighting and and something to put your parts in because if you lose anything these are not the things you will find at AutoZone.
As for going through 6 alternators it sounds like there may be some defective grounds on your car. Make sure you have a good ground from the engine to the body and it never hurts to run a heavy (at least 10 gauge or heavier) wire from a clean place on the body back to the negative battery terminal. If you look in the factory service manual you will find an entire section devoted to grounds. These cars are getting old and these grounds need to be checked and cleaned if they are corroded. What comes out of the battery must make it back there and without good grounds it wont work as intended.
One other point, you mentioned having schematics. That's a good thing. even a Chilton manual is better than nothing, however nothing beats the Factory service manual and the suppliment
Electrical Vacuum troubleshooting manual. I got both on eBay for $20Good luck and let us know what you find.

[tooldude]

I wonder where Jason is. Maybe he already got the problem fixed. So, RickTheQuick, is it appropriate to respond to your comments since Jason is not getting back right now, if ever? I think, yes, since others may benefit from this thread. Like you, my first thought was CKP sensor (so...distributor) or Ignition Switch. It's all or nothing with the Ign Switch. All it does for this part of the circuit is to supply enough current (because of enough voltage) for the main relay contacts to close. It does not control the actual amount of voltage available, but an intermittent Ign Switch connection is one of the various points that could account for the intermittent problem in that circuit, as could the CKP Gnd connections or ECA [^ RTQ's reference to all Grounds]. Critical to this is, where was that 3-4 volts measured? If it was on the Y/BK input to the ECA (computer), then that was the signal voltage. If at the Y/BK input to the CKP, which it obviously needs to be, then the supply voltage out ot the Main Relay is suspect and needs to be checked. Making a connection from the 6 terminal self test connector ["6 plug near the firewall"] to the CKP is misleading and inappropriate,because the Y/BK and everything connected to it is downstream of the supply voltage from the Main Relay. A definitive test for proper & continuous voltage would be a fused jumper wire from the battery positive terminal to the Y/BK wire exiting the Main Relay (effectively hot-wiring the ignition). Looking over all this, the first ignition complaint is that there is intermittent voltage at the CKP, so when that voltage is missing, just trace back through the connections for B+ and you should find where it has dropped out.

[Rick the Quick]

Jason 1975, did you get her going?

[Jason1975]

Sorry for the late response. I was out of town for two weeks + for the holidays. I got her running. Drove it a few times this week. I think I had two problems. First, I believe the plug to the VAF was loose. This was ultimately causing there to be no spark. In the meantime, i replaced the coil and ICM as noted above. Secondly, since my fusible links blew out about a decade ago, I've been dealing with ongoing voltage issues. I've probably gone through 5 alternators from Autozone since then. I'm now getting 12V now at the distributor, after I charge my battery.

Now when I start it, it starts off at 14.3-14.5 volts. If I drive for 20 minutes or so, I'm lucky if I have 12 volts.(I have an aftermarket voltage gauge.) I swear it quits charging after about 15 minutes. I'm also showing about a 0.5 volts drop from the back of the alternator to the battery when running. The other two wires in the plug for the alternator have 12V with the key on. It may also be worth noting that with the key on and engine off, the Charge light is slightly dimmer than the other lights (Oil, Engine, etc).

I'm about ready to return my 5th alternator to AutoZone. I also think I might need to replace the wire betwwen the alternator and battery.

[Jason1975]

So, I can't understand why I had 3-4V at the distributor the one day. I think my battery must have been low that day. I've had 12V every time since then. I don't think my distributor is the issue at this time.

I have a supplemental ground going from the negative terminal to the frame. I have the Haynes book but finding out where are the grounds are for sure? I'd love a list. Perhaps there's another thread with them?

[Jason1975]

I should also add the battery and the alternator are from 2019.

[Jason1975]

So, I think I may have figured out the problem. I the wires to my VAF were rubbing against the metal and may have pinched open. I think I may have have been shorting out a wire to the frame. A look in the good 'ole Haynes manual shows that the same yellow/black that goes to the distributor, amongst other places, also ends up as a "hot" green/red wire with the VAF. I've corrected the pinched wire situation, and my voltage is staying just above 14V at all times. It drops at idle and when I first turn on the lights, which is typical.

If you guys think of anything else, I'd appreciate it. Thanks for all of your insight and ideas to date!