No spark through my plug!

[Steve M]

Ok to make a long story short, spoke to Tom I finally found that the reason my engine doesnt start is cause there is no spark through the plug. I am getting a weak spark through the wire itself, I checked points gap and readjusted it (.016). Set the timing so that the leading edge of the rotor is just on the notch on the distributor. What would cause this? I am open to any and all suggestions. Could it be the temp sensor? or the relay board? the spark from the coil itself seems healthy but its not blue like the one coming to the spark plug wire. I had checked continuity at the relay board for both wires that connect to terminal's 1 (negative) and 15(positive if memory serves me right). The purple and black goes to the negative along with the condensor or capacitator (that ballast thingy on the side of the dist). and the plain black one to the positive. However when I did check continuity for purple and black wire (terminal 15) I was getting it for the other terminal as well!, is this normal?. Also I had was getting continuity for a few other wires as well on the same harness leading to the purple and black wire. Meaning that my multimeter was beeping at me telling me that just about every wire on that harness was giving me a connection to the purple and black wire (just wanted to make sure I'm understood). Again, is this normal?. I also tried reversing the order in the wires on the positive and negative and the condensor, but no spark at the plug. So what do I do about this no spark at the plug thing. The plugs are pratically brand new Bosch brand as are the spark plug wires. The coil is the Bosch blue one rotor is clean and so is the cap. Points are as well and I had replaced the condensor. So you cant get me on that, at least I dont think so. I'm still open to suggestions of any kind, thank much.

[This message has been edited by Steve M.]

[JP Noonan]

The blk/purple is the trigger for your tach. Try disconnecting it. As for the continuity my guess is that your tach wire may be grounded because of "chafing" somewhere in the harness. Not a total short so the coil still works, but enough that the meter senses it. Or it may be normal (I'm too lazy to check it out on my car plus my car is FAR from normal). Both my main 914 and my parts car had fires in the wiring harness sometime in thier lives. My main 914 had house wire replacing the burnt out sections!!!! So I went to NAPA bought the appropiate color wires and rebuilt the harness from the 12 pin connector on. If you take apart the connector and pull out the wires you can use a solder gun to heat up the connector at the end and transfer it to another wire. I'm telling you this because you mention REVERSING the wires to the coil. I did this inadvertantly, +12 to the neg side and nothing to the pos side. Well as I smelled something burning I disconnected the batt. and saw smoke bellowing out from under my cap. The wire to the points was red hot and burnt the insulation. So DO NOT REVERSE THE WIRES!!! The other thing is if the car was running before try putting the old points and condenser back on. Bosch is not perfect (there 30 DPDT relays have something like 1 in 200,000 failure rate, but if you have that 1 then life ain't so grand). Another thing is for some reason I allways have a problem putting the dist back on. It always seems to be on right then I play with it some more and "click" the cam drops into the drive mechansim. The rotor should only turn 15-20 degrees with light pressure, any more and it is not seated right. Good luck and don't trust anything about these cars, after 20+ years it has more then likely seen at least one "hack" mechanic (myself included).

[Steve M]

Thanks for your help I did find out that I shouldnt take anything for granted in this car just like you said. I went to work on it earlier this morning and decided to pull all the plugs. Well, my grandpop got one look at plugs 3 and 4 and he knew right there and then why the car wasnt starting. Apparently what had been happening was the pressure sensor had been running the engine rich all this time and fouled the plugs to the point were they wouldnt fire. I had already replaced the pressure sensor (which by the way I had bought from Pelican Parts was able to determine that it was faulty in the first place from their great website and links) but didnt bother taking the plugs color seriously enough. Now mind you this car has been sitting in the garage for the past 4 years being 'restored'. I had the engine rebuild by FAT performance in CA. They did a great job cause this thing loves to rev. Anyhow grandpop has one of those portable plug cleaning thingys that you hook up to an air hose. So we hit all of them, put them back in and....whammo!, ignition!!. That puppy revved up to about 1500 rpm at first and then settled down to a nice and lesuirly 900 rpm just like god intended. The engine has been bored out to a 2.1 and has a slightly more aggresive cam so it idles a little rough. But that just makes it more fun. Now I need to deal with its insistence on surging when I nail the gas. It simply wont take. But if I do it really really really light and nice it just may rev. I think it may be a vacum leak. And there is also its not wanting to start when hot. Yes I put the fuel punp in the front. I found that the auxilary air valve is defective, I was able to take it apart but I dont know how to put it back together?!?!. Anyone?

[This message has been edited by Steve M.]

[This message has been edited by Steve M.]