'88 Mariah 351-W, no spark, wiring question

[hotgrips]

My 1988 Mariah with 168 original hours on it (has been sitting in storage for many years) has no spark when cranking over the engine. I replaced distributor cap, points and condenser, spark plugs and their wires, coil primary wire to the distributor, checked voltage coil on primary and secondary windings and ohms checks out within spec (8060 ohms and 1.6 ohms) Replaced stuck starter relay but puzzled as to why I find only one of the small terminals has a wire to it, with the other one empty. Is that normal? The relay I got from skidim.com has 3 of the 4 terminals copper colored and the 4th is silver colored. I may have lost track of which wires go where on it. Does it matter if you have the battery cable and the heavy power cable to the starter reversed on the new relay? Does the colored terminals mean that I should use the copper colored ones, and not the single silver colored one?

The neutral safety switch is ok and hooked up. I removed the wires to the ceramic resistor and it is about 2 ohms- what are they supposed to be. I figure if it is an open circuit or a closed circuit when tested that the resistor is bad, otherwise 2 ohms is probably ok? Please advise on it.

My rebuild kit for the distributor included a little square white felt pad and a red capsule of grease. I know that the grease goes on the 8 lobed distributor shaft to reduce wear on the points actuating against it, but don't know what the felt pad with the slit in it is for. I didn't find one in my old distributor.

How can I tell which is the plus sided and which is the negative side of the small terminals on the voltage coil?

How would I test to see if the small wire going to the distributor is grounded out...I ask because a motorcycle mechanic buddy mentioned that is a common problem in diagnosing for no spark. Do I just check for continuity with an ohm-meter between the wire where it connects to the points against engine ground? Do I do that test with the engine cranking over or still?

I had a defective circuit breaker switch on the dash just to the right of the ignition key, which was required to be in to get the dash to light up. It was the type that latched either as a closed circuit or an open circuit. So I ordered a new 20 amp one from skidim.com but it seems to work differently, though appearance is the same externally. The one from skidim.com seems to be always a closed circuit, so perhaps it is designed to only open circuit above 20 amps? One little difference is that it doesn't have that small white band on the shaft that my original one had. Did they send me the wrong type of circuit breaker? Or is current wisdom that you should use their new type.

When inspecting the wires behind the left dash on the ignition key side I found several unconnected black and blue wires and I assume that is normal and merely for hooking up to auxilliary gauges for their light...is that it? I also found a disconnected pink wire which when I connect it to 12v power will cause the starter to constantly run even when the key switch is not moved into the actuate starter position. IN other words the starter cranks as soon as I turn the ignition key to the first position (lights up dash). Any thoughts on where the pink wire might go? There was a loose green wire and I noticed when I touched it to 12v the radio went on, so I assume that is not important at this point and taped it up. The dash electrical connectors that allow you to hook up more than one wire to the same point seem brittle and broke easily, but Autozone didn't have that kind in stock. Any good source for them? I just soldered where that happened to complete the connection for now.

All dash functions work ok, the bilge blowers turn on, gauges all light up. I am worried that I might have got some wire connected incorrectly behind the dash that might be causing the no-spark condition, so if someone could reassure me that probably is not the case if it cranks over normally that would be a relief.

Since the coil is the only electrical items I haven't replaced, when I tried to get a replacement ignition coil just to be sure (even though the ohms checks on it are ok) at Autozone, the parts guy didn't have a clue. They can only check automobile database year, model, engine, etc. Should I just be patient and restrict my order of the coil to skidim.com? Or is there an acceptable replacement coil from NAPA or Auto Palace, Autozone by part number that one of you can advise me on?

I know there are a lot of questions. Hope some of you can be patient with me and give me advice on each. I am looking forward to getting it back on the water again. Have already put on 4 new trailer tires and got trailer and boat registration for 2012.

Thanks all in advance on your input. You have a great site for Supra owners and their questions.

Jim in New Hampshire.

[wotan2525]

Someone may chime in with more specific/helpful information, but I know I won't be the only one that says -- ditch the points and move to an electronic distributor. It will be much easier to trouble-shoot and diagnose, and when it does run again, it will run much better.

Your first photo shows some wires disconnected from the ignition switch? Has that been rectified? With the key on do you have voltage to the coil?

[OUI]

Send me your email address and I'll send you a couple of wiring diagrams. The felt piece goes into the hole on the top of the distibuter shaft. To check your ballast resistor check voltage coming out. I think you need to be about 7 volts as it goes into the coil. If your circuit breaker is bad nothing would work. Any 12 volt, external resistor coil will work.

[hotgrips]

With the key on, when I place a 12v automotive test light on either small terminal of the coil (+ or - side) and ground the automotive test light, it lights up almost the same on either terminal, though the buzzing sound slightly changes. That in itself puzzles me because if one is supposed to be positive and one supposed to be negative, shouldn't using a test light on the negative terminal give no light nor buzz, since you are just grounding to a negative point on the coil?

The black and blue wires were found disconnected like that and I noticed the same colored wires go to each gauge illumination bulb, so I left them alone. The pink wire I don't know what it is for, but when I connect it to 12vdc positive on the ignition switch the result is instant starter cranking and it won't stop cranking the starter until I shut the key off. In other words the starter is energized despite my NOT having yet turned the ignition key to that spring-loaded normal "engage starter" position we are all familiar with.

Some of the wire terminals where they share a connection on the back of a circuit breaker or gauge were brittle enough so they failed with the slightest touch. So as each of those failures happened I tried to keep track of them and make the connection some other way, since I had no replacement double male terminal fittings on hand. I hope I got them all correct, but possibly I made an error. I did find a generic schematic from Supra online but it isn't close enough to my dash to have a lot of confidence in it. For example all of their right gauges are on the left, and the left gauges are on the right. The generic Supra wiring diagram I located doesn't show the starter relay and ballast resistor unfortunately.

Thank you in advance for any guidance you can offer.

Jim in NH


Someone may chime in with more specific/helpful information, but I know I won't be the only one that says -- ditch the points and move to an electronic distributor. It will be much easier to trouble-shoot and diagnose, and when it does run again, it will run much better.

Your first photo shows some wires disconnected from the ignition switch? Has that been rectified? With the key on do you have voltage to the coil?

[hotgrips]

I tested with a VOM tonight and find with the the ignition key on, that I get 12.45 volts at BOTH small terminals on the coil, and on BOTH sides of the ballast resistor.
I also intentionally moved the shift lever into forward and reverse and the starter motor was not not defeated, so something is wrong there too. I did not defeat the two white wires going to the neutral safety switch, so something is wrong elsewhere on that issue.


Someone may chime in with more specific/helpful information, but I know I won't be the only one that says -- ditch the points and move to an electronic distributor. It will be much easier to trouble-shoot and diagnose, and when it does run again, it will run much better.

Your first photo shows some wires disconnected from the ignition switch? Has that been rectified? With the key on do you have voltage to the coil?