No spark from distributor with good coil.

I have a dead "bank"(cylinders 1,2,3,4) on '86 Mondial 3.2 l, based on previous POST ("Little gas out of two tailpipes." where readers made suggestions). Having narrowed the source of the problem I want to start a new POST for clarity. Both the coils are good (I switched them). All plugs are good (I switched 4 and 5). I use an in-line plug tester which flashes when it gets a signal. Today I removed distributor cap on bad side and saw what appeared to be metal "filings" on inside of cover. I plan to clean and replace the cap and test spark on 1,2,3,4. Does anyone have suggestions? Can a cap just wear out? Does the fact that all cylinders 1,2,3,4 are out suggest anything. Why would they all "wear out " at the same time. Or could it be the rotor? If this approach does not work does it make any sense to find a replacement cap and rotor/.

 

Update. Originally cylinders 1,2,3,4 gave no spark with plug tester which flashed when in line. Cylinders 5,6,7,8 all sparked. Switching coils, cylinders 5,6,7,8 again sparked, cylinder 4 did not (did not check1,2,3). Coils remain switched. Distributor 5,6,7,8 more difficult to get to so postponed switching caps/rotors for the moment. Cleaned out 1,2,3,4 distributor cap of what may be gritty carbon specs and lightly rubbed contacts with nail file. Checked contacts between the four HT terminals inside the 1.2.3.4 cap and end of HT wires at spark plug. Cylinders 1,4 HT leads showed no resistance using ohmmeter at 20K. No electrical conduction for 2,3. Removed 2,3 HT leads from engine. Again no conduction from one end to the other. By repeatedly poking ohmmeter sharp sensor through HT insulation to touch the wire I determined there is a break in conductivity of HT leads near spark plug end of #2 lead and the same with #3. WIll check availability of new leads. I have no idea how a "break" can occur in these lines. There is no sign of damage. I guess I could try starting engine without HT leads 2,3 which were no good anyway to see if 1,4 are now working with cleaner distributor. If not working I could move on to switching distributor caps/rotors or maybe buy if not an arm and a leg.

 

Update. 1986 Modial 3.2 L Cabriolet. No sparks in cylinders 1,2,3,4. I replaced broken HT wires to cylinders 2 and 3 using new wire from O'Reilly's. Bank 1,2,3,4 still won't fire. Both coil bodies are good since I switched them. Each coil has 5 electric leads entering top of coil through a plug. i pulled off plug to bad bank 1,2,3,4 and put into good bank coil 5,6,7,8 which it can reach. Car would not start so there is a problem with electric feed to top of coil 1,2,3,4. Then in a separate experiment, I rerouted HT wire from bottom of coil 1,2,3,4 into coil 5,6,7,8 and car would not start. Signal is good out of bottom of coil 5,6,7,8 because these cylinders fire but this good signal will not fire 1,2,3,4. Distributor 1,2,3,4 has been cleaned.I concluded I cannot reach distributor 5,6,7,8 because of location to get to bolts, remove it and switch with distributor 1,2,3,4 unless someone knows how to increase access to the 5,6,7,8 distributor.

If I could fix electric problem at top of coil 1,2,3,4 I could check spark out of bottom of coil 1,2,3,4 as someone suggested, If a spark exists then distributor 1,2,3,4 must be bad. I could just replace it. I have never got a spark in cylinders 1,2,3,4 HT lines using my in-line meter throughout this problem. Does anyone know where I might purchase a distributor. Does anyone know why the 5 wire electric input into top of coil 1,2,3,4 would not drive coil 5,6,7,8? Are not these two 5-wire inputs the same, with similar constant voltages.? Should not they be reversible? Why would the car "know" the difference?

 

I have in-line plug tester. Is it OK to connect plug tester to bottom of coil and hold other end of tester close to or against ground? This is to test whether I am getting a signal out of coil on dead bank side of car which has no sparks on cylinders 1,2,3,4. JMcScotty

 

Jeka. Thanks for advice. I attached HT lead to bottom of coil (cylinders 1,2,3,4) and added an in-line spark plug tester and then a new spark plug which I laid against the engine block. I started the engine. Cylinders 5,6,7,8 started as usual and the plug tester and the plug both sparked. THerefore I am assuming the reason cylinders 1,2,3,4 do not spark is the distributor on that side. I will buy a replacement distributor cap and rotor for this '86 3.2 L Mondial Cabriolet. Cleaning the existing one did not work. Does anyone know where I can find these?. JMcScotty

 

I checked electrical connection between rotor contact and engine body on the dead side and found conductance. On removing the rotor I discovered a carbonized hole in the back which had been conducting electricity to the metal shaft on which the rotor is mounted. I live in SF Bay Area and in Carson City NV but will look for this Magneti Marelli part on line for my '86 Mondial 3.2 L Cabriolet.