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I was taught, many years ago, NEVER clean the tip of the rotor OR the probes in the cap. The "gap" as its called, is basically an "air gap", and cleaning will widen that gap, and the spark has to "jump" too far, thus loosing energy for the spark plugs. Served me well for a very long time.
Since you have found NO spark at the plugs, I suggest:
Remove one of the HT leads coil to cap, atthe cap end, probably already off, since the cap is off.
Hold the exposed end ofthat lead near a metal earth point, get someone to crank the engine. IS there spark coming OUT of the coil.
You mentioned NO spark previously. Establishing where the spark starts and stops is needed.
If there is NO spark out of the coil, or coils, in your case, then the possible culprits are limited.
Modules, on the radiator panel, but 2 to go AWOL, rare.
Coils, same rarity for 2 to die.
Crank Angle Sensor, HA, gets back to that front one every time from what I READ on Mareli, NOT what I know.
I was taught, many years ago, NEVER clean the tip of the rotor OR the probes in the cap. The "gap" as its called, is basically an "air gap", and cleaning will widen that gap, and the spark has to "jump" too far, thus loosing energy for the spark plugs. Served me well for a very long time.
Since you have found NO spark at the plugs, I suggest:
Remove one of the HT leads coil to cap, atthe cap end, probably already off, since the cap is off.
Hold the exposed end ofthat lead near a metal earth point, get someone to crank the engine. IS there spark coming OUT of the coil.
You mentioned NO spark previously. Establishing where the spark starts and stops is needed.
If there is NO spark out of the coil, or coils, in your case, then the possible culprits are limited.
Modules, on the radiator panel, but 2 to go AWOL, rare.
Coils, same rarity for 2 to die.
Crank Angle Sensor, HA, gets back to that front one every time from what I READ on Mareli, NOT what I know.
One new coil, one old coil, no spark from either one, just now checked.
I recently had a situation on my 1990 Marelli car where at the point where the 6 (yes 6) wires are joined 12v lead delivering power to both amps, both coils and something else was suffering a terrible and corroded connection. To this day I still don't know if the connection I found (in the loom that carries wiring to the ignition amps on the LH side running right next to the rail, FInjectors) was factory or a rig up by a PO...
For me the terrible connection was affecting (if I remember) only the A Bank and I was getting all kinds of false readings in the tach (the Marelli tach is fed by the A Bank side of the ignition amp system), near stalling, power loss and the like. Maybe occasionally running on just 6 cylinders. I think the high resistance in that 6 wire connection created enough resistance to burn out the A Bank amp. Had to replace the amp.
Redid the wiring and replaced the amp, problem to the coil, tach etc was solved.
This is the connection that was ratty... I'm wondering what and how this connection is done on others Marelli cars
I'll echo Grant, it looks ok to me. It appears you have something preventing any ignition rather a partial failure like a cap issue. Which is why I thought it might be sensor or relay related. The other issue could be a wiring fault, which after 30 years isn't unheard of.
The cap looks perfect. As Grant so wisely said, the next step is to find out where the spark is getting to, or if there is no spark at all. I am pretty sure that the coils are either:
not getting the signal to fire for some reason, or
do not have 12 volts at the coil positive terminal.
I would check that there is 12 volts at the coil positive terminal, ignition on.
If there is, then we know the fault is somewhere in the coil triggering circuit (ie, crank shaft sensors, or amp wiring, etc).
The cap looks perfect. As Grant so wisely said, the next step is to find out where the spark is getting to, or if there is no spark at all. I am pretty sure that the coils are either:
not getting the signal to fire for some reason, or
do not have 12 volts at the coil positive terminal.
I would check that there is 12 volts at the coil positive terminal, ignition on.
If there is, then we know the fault is somewhere in the coil triggering circuit (ie, crank shaft sensors, or amp wiring, etc).
Looking at JayJagJay's ignition diagram, the connector that plugs into coil, is the (W) the positive wire that I need to connect to my 12 volt light tester too.
Looking at JayJagJay's ignition diagram, the connector that plugs into coil, is the (W) the positive wire that I need to connect to my 12 volt light tester too.
Brother, I am sorry that I simply am and can be only a provider of partial/limited information, that said, I'll chime in on your last statement just above...
I think (unless something is terribly wrong) you will get/see 12v at any of those white wire feeds (the ones in my photo and in the ED)... The 2 to either coil and the two to the amps. The white wires are 12+volt positive leads that pretty much should be HOT whenever the key/ignition is in the II or III position at the key. Its one of the same main white wires that feeds power to the coils and ignition amps (if I am right) and is representative of the white (hot 12v) wire that can be found in several areas of the car that gets 12v when the ignition/key is in the II or III run position... feeding 12v to many of the relays and fuse boxes.
Where what might be missing (if you are getting 12v at the white wires),,, is the part of your ignition system that triggers the coils to pour their juice into the cap and triggers the amps to fire and signal the coils... And AGAIN, my understanding is limited, I'm still learning here, and I could be wrong. That signal is dealt with by crank sensors, the Marelli ECU - and stuff I don't know yet.
Here's a wild shot... Is the bright orange vac tube that comes off of the back of the RH manifold connected at both ends? Connected at both the manifold and the ECU in the RH foot well in the cabin? I don't mean to send you on a goose chase but it's a pretty easy check. Use your mouth to pull a vac on the bright orange line and then use the tip O your tongue to see if it holds for a few seconds.
Brother, I am sorry that I simply am and can be only a provider of partial/limited information, that said, I'll chime in on your last statement just above...
I think (unless something is terribly wrong) you will get/see 12v at any of those white wire feeds (the ones in my photo and in the ED)... The 2 to either coil and the two to the amps. The white wires are 12+volt positive leads that pretty much should be HOT whenever the key/ignition is in the II or III position at the key. Its one of the same main white wires that feeds power to the coils and ignition amps (if I am right) and is representative of the white (hot 12v) wire that can be found in several areas of the car that gets 12v when the ignition/key is in the II or III run position... feeding 12v to many of the relays and fuse boxes.
Where what might be missing (if you are getting 12v at the white wires),,, is the part of your ignition system that triggers the coils to pour their juice into the cap and triggers the amps to fire and signal the coils... And AGAIN, my understanding is limited, I'm still learning here, and I could be wrong. That signal is dealt with by crank sensors, the Marelli ECU - and stuff I don't know yet.
Here's a wild shot... Is the bright orange vac tube that comes off of the back of the RH manifold connected at both ends? Connected at both the manifold and the ECU in the RH foot well in the cabin? I don't mean to send you on a goose chase but it's a pretty easy check. Use your mouth to pull a vac on the bright orange line and then use the tip O your tongue to see if it holds for a few seconds.
It is getting spark at coils now.Cleaned prongs on CPS. Your Diagram came in handy, thank you.
10-11-2020, 07:58 PM
