Where can I track down an ignition module?

[Jerkovadovich]

I have an '83 Marquis, and it has been experiencing issues with acceleration (as well as starting). After a few years of testing EVERYTHING on the car, I believe the ignition module is bad - but I can't find a new/used one anywhere local or online to switch out with the old one.

I think the module should be EECH III, but I'm not 100% sure. Any help would be greatly appreciated!!

[kishy]

The ignition system with EEC-III is Duraspark; these modules are available in retail channels.

Unless I'm missing something, RockAuto.com sells an ignition module for this car (as do retail auto parts stores, but RockAuto will be the cheapest usually - don't forget to search around for a discount code). I checked my '83 electrical manual and EEC-III CFI uses a 2-connector Duraspark module, you just need to buy the one that has the right colour grommet around where the wires exit the module. Blue or brown look to be the options.

As for determining if the module is your actual problem or not, I can't really help much with that. But your module is definitely available.

[gadget73]

Is that a 2 plug or a 3 plug? Either should be easy to get, you just need to know which yours uses.

[Jerkovadovich]

Thanks for the tip, kishy! I tracked one down on RockAuto.com. It was relatively easy once I figured out the part number for this specific ignition module (which was only made for one year). I've got my fingers crossed that this will fix the acceleration issues!

[kishy]

Is that a 2 plug or a 3 plug? Either should be easy to get, you just need to know which yours uses.

Well, funny thing about that...

'83 EVTM shows "Canadian and Police 5.8L MCU Engine" use a 3-plug module, and "Electronic Engine Control" use a 2-plug module.

CFI is 2-plug. But (not relevant to this thread but maybe useful to put in writing somewhere) Canadian factory carb 302 is also 2-plug. They've kind of screwed that up in how they've identified the diagrams.

The third plug is for feedback carb MCUs.

Thanks for the tip, kishy! I tracked one down on RockAuto.com. It was relatively easy once I figured out the part number for this specific ignition module (which was only made for one year). I've got my fingers crossed that this will fix the acceleration issues!

Happy to help, just hoping it's the right direction. Hang onto the old module, if you keep a kit of roadside emergency type stuff in the trunk, you at least know the car runs with it, so it's good for that purpose.

I think the typical DS2 (Duraspark II) failure is the modules start to overheat and misfire or just stop working until they cool off (roughly the same failure mode as a TFI ignition module). My Ranger uses this ignition system also and the potting compound they seal the module up with has all melted out and ran down the fender apron.

[Jerkovadovich]

Is that a 2 plug or a 3 plug? Either should be easy to get, you just need to know which yours uses.

Well, it's a five-wire module, with one three-prong plug and another two-prong plug. Apparently the grommet color is an important indicator of the module as well (the ICM for my '83 has a brown grommet)

[Jerkovadovich]

I think the typical DS2 (Duraspark II) failure is the modules start to overheat and misfire or just stop working until they cool off (roughly the same failure mode as a TFI ignition module). My Ranger uses this ignition system also and the potting compound they seal the module up with has all melted out and ran down the fender apron.

I was under the impression that ignition modules don't break down too often, but from these forums it sounds like it's more common than I originally thought.

[gadget73]

They can get thermally stupid, but usually it seems they work or they don't.

The 3 plug one has spark retard. I knew the MCU cars had that because they also had a knock sensor. Wasn't sure if the EEC-III CFI used the spark retard for something as well.

1983 was the last year for Duraspark on the 5.0. Most of what you read on the forums will be the other style ignition module, which mounts right on the side of the distributor. They can fail, but they're more cranky about heat. Only time I ever lost one was the day after overheating the car from a blown water pump gasket.

EEC-III is sort of it's own demon. It has a crank sensor in the mix too, and if the connection for that is bad it will run stupid. Whats it do exactly?

[Jerkovadovich]

EEC-III is sort of it's own demon. It has a crank sensor in the mix too, and if the connection for that is bad it will run stupid. Whats it do exactly?

It pauses when I try to accelerate; I have to flutter the gas pedal to get the engine to engage. I've ran through the vacuum tubes, sensors, TPS, fuel pumps, injectors, etc - everything seems to be in working order. So I'm now hoping it's the ICM, because otherwise I'm at a loss. Actually, the EGR sensor is acting a little wonky, but it shouldn't be causing the engine to act the way it is.

This Marquis only has 31,000 miles, so I'm really trying to save it (instead of selling it in frustration).

[gadget73]

You could always trade the control system for something thats not braindead. Multiport and carb conversions have been done, and its an option.

If the EGR is open when it shouldn't be you'll get a hesitation. Might be worth unhooking the vacuum line just to see if it changes. I had problems with mine doing this, turns out it was the egr regulator not actually regulating. It went full open just off-idle and hesitated as a result.

Another point, these had a timing set that used plastic on the cam gear. It wouldn't be the worst idea to make sure the chain isn't sloppy. Pop the distributor cap and rock the crank back and forth to see if the rotor follows. If you get a noticeable amount of crank movement without rotor movement, the chain is done. This doesn't drive the injector or ignition events off the cam position like later ones but if the valves aren't opening at the right time its not going to perform well.

[Jerkovadovich]

You could always trade the control system for something thats not braindead. Multiport and carb conversions have been done, and its an option.

Believe me, that will be my next move assuming I can't figure out the hesitation issues!! I've got a new EEC III in the mail, and will be able to test it out next week.

As for the timing chain, it checks out; unhooking the vacuum line also does not result in any changes. HOWEVER - the engine will sputter and die when the EVP sensor is unplugged, which I can't figure out why. Out of the four separate components that use the reference voltage, the EVP sensor is the only one that kills the engine (hot or cold) when it's unplugged. Any idea on why it's doing this?

[gadget73]

hm, that doesn't sound right, though I do not know the EEC-III wiring scheme. On EEC-IV, the EVP has vref in, sigrtn (ground) and the sensor output wire back to the ECM. Unless its much different, I don't see why unhooking that would change things.

Unless maybe the sigrtn ground connection is bad, and unhooking that sensor alters the ground voltage level, causing the ECM to see suddenly different values for all the sensors? EEC-IV has several grounds, one is straight to the battery, one is to the engine block, and there is another one to the body. I believe the engine and battery one are what it uses for sensor ground reference. Thats intended to allow for crusty connections between the battery and engine to not screw with sensors. If EEC-III doesn't have that, maybe cleaning your grounds would be of use. Also worth making sure any grounds its supposed to have are actually connected, clean, tight, etc.

Just a guess, again I don't particularly know EEC-III.