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1978 fury with lean burn 360 will not start

12318 Views 43 Replies 7 Participants Last post by  dopus
A friend of mine has a 78 fury with 360 engine. She told me it was a leanburn enginge ( Actually had to google it to find out what "leanburn" engine was) So this has a electronicly controlled timing.

The problem was that the car stalled when she put it in drive or reverse. I told her i could take a look at the engine, But when she was suppose to show me how the car stalled when put in gear it would not even start. Still does not start.

So what we have checked:

: power to coil is ok

a test light from coil minus to ground confirms that the distributor is triggering the coil. the testlamp it should work.

With a timing lamp we have found out that only 3 of the plugwires get spark when she trying to start the engine (the starter is running)

We have changed rotor and cap ...still the same..only 3 spartkplug wires get spark

I am beginning to belive that the leanburn ecu is the problem.

Is it possible to wire the distributor directly to coil /battery (disconnecting the leanburn ecu and running 12v from battery to coil), if this is possible how do i wire the distributor for testing purposes: I know one of the two wires from the distributor goes to the coil minus, and the distrbutor is grounded through its housing, so where do the second wire from the distributor go? One wire is grey and one is black. Is it the black wire that goes to the coil minus???

I have borrowed a distributor for a non leanburn 360. This one also have two wires. So how do i wire up this one ( to run without a leanburn ecu)

Can the spark problem also be the reason why it dies when put in gear ( before the non start problem kicked in)

Any help /good advice is much appriciated.

Pardon my bad english. English is not my native language.
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If only 3 wires are showing spark, it sounds like the wires are bad. I would replace all the wires and the plugs if they have not been done within the last 30,000 miles.
Hmm. I did move the sparkplug wires around. So one working changed with one not working. The cylinder that got one of the three sparks still got a spark with a sparkwire from one of those cylinders that did not get a spark. And the "good" wire did not get a spark in a non spark connection on the distributor. Concluction..wires might not be new, but they work.
It's possible that the wires are no longer in the right order. Make sure the firing order is correct, it should be 1-8-4-3-6-5-7-2, with cyl 1 being the driver's side front, odd numbers on that side. Even numbers go on the passenger side front to back.
Checked it twice actually..the firing order is correct.. chekced it twice after changing the distributor cap.
Sounds like a ballast resistor to me. Happened to me once. I believe that motor uses the 4 prong resistor, and either the top or bottom resistor is bad. Try replacing that next.
Actually there only a single ballast resistor. If I remember correctly Ithink it gets 12v power to the coil from the starter relay. So it have 12v and stroger spark when starting...I might be wrong, but it sounds logical when I know that there is only a single ballast resistor. Can any standard ballast resistor be used for testing purposes?.

So if I feed the resistor with 12 v on one side, and test the other side with a much voltage should i read?6V? If the resistor is bad,will there be to low voltage?
We have been feeding the coil v 12 v from battery,when we have tried to start the engine. 12v shoud not kill the coil? 12v to the coil is ony connected for half a minute or so.

But still. wondering. if one of the distributor wies goes to the coil minus. where does the other go...its not earth....the distributor casing is the earth connection ( through the engineblock)..and what wire color is the one that goes to coil minus...( the wires from the distributor is black ang grey)
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Electronic ignition used a dual ballast resistor. If there is only a single one underhood, it may be the wrong one. In the dual setup, one resistor is used during cranking, and one while running. These coils are the same coils used when cars had 6V electrical systems, they are not truly rated for 12V. Therefore, they need a resistor to drop it to about 8V while running.

The positive wire to the coil is the power. The negative wire is what gets switched to fire the secondary winding of the coil. It goes to the distributor.
Well. Its not a dual ballast resistor, Ill check if it gets power from the starter relay. I know that the coil gets its power from the coil plus side...thats the side we have been hooking up to the battery to get it to start without that "crappy" lean burn computer. I know as u say that it is the negative side of the coil that get the trigger signal from the distributor. I have tried with the original and the borrowed distributor connected to the orignal 2 wire distributor contact and it looks like it gives the trigger signal ok(test lamp built in to my multimeter, with the multimeter connected to coil negativ and battery earth. But when i try to connect one of the distributors wires to the coil negativ, and feed the coil with 12v on its plus side with 12v from the battery it does not give me the trigger signal from the coil. In my opinion it should have. So what is the second wire from coil used for? It works when connected to the original 2 wire distributor connector, but not when i try with it connected directly to the coil . I am not very familiar with mopar engines, but I have worked on older euro cars with distributor an coil, and this setup works on those ( but they only have one wire from distributor going to coil negativ if remember correctly.
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Found this picture of a leanburn2 system online:

It looks to me like the 1 wire from the pickup suddenly becomes in that case, for test purposes i can wire both to the coil negativ. Two wires, hmm must have somthing to do with starting mode and run mode.????
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Did som testing today. both with old and a new coil. Same problem. with leanburn computer connected it triggers the coil. but only get spark on a couple of cylinders. With lean burn computer disconnected. One wire from distributor to coil minus and 12v feed to coil positive, nothing, nada . No signal at all.

We have decided to eliminate the whole leanburn system, and get a leanburn elimination kit from summit.
Before you do that, have you set the reluctor gap properly - to 0.008 inches with a non-magnetic feeler gauge?
No. I have not. But I have tried two different distributor, one leanburn and one vacuum advance. Both distributors get sparks to the same cylinders, and are missing spark on the same cylinders. When i cheked the trigger signal from the distributor it looks good. the amount of time between the signals looks to be ok(no irregular pauses in the blinking). But when i check the coil with a timing lamp. it begins with two blinks...then a pause then a blink and blink then a pause, like its skipping cylinders. when the trigger singal is ok, but the spark is not and the spark is controlled by the lean burn ECU, my logical conclution is that the ECU is the source of the problem.

I might be wrong, and the ecu works, but to test the ecu is far beyond my knowledge, and to take it to a workshop or a dealer ( where they dont know anything about leanburn anyway,), is more expensive the to order the mopar ignition kit , even with postage and import taxes in my country...the kit still does not cost more then two hours in a workshop/garage.

installing the new kit should not be to hard. crossing my fingers hoping it will solve the problem.

One more question. I know the carb will work with the new ignition kit, but should it be jeted up, to get the mixture richer?
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Take a moment and since you know how long it take between sparks on an individual wire, pull the plug wire and you should get 8 sparks every rotation of the distributor. Then you will know if it is in the top or bottom of the distributor that you are having issues. It sure sounds like gap issues to me. You say it is the same three wires that spark. Which ones? May tell a story.
Could it be gap issues? Even when tested on two different distributors?? Both distributors appears to be working( sending trigger signal to the coil. gap issues should have been on the trigger signal side to i,f the gap between the wheel and the magnet is to big or small????
One way to find out - set the gap. Check the gap at each tooth to make sure that the shaft is centered and there is no wobble to it. If the gear that drives the distributor shaft has wobble, it can cause this issue where the gap is different at certain cylinders - the same ones every turn. You can only tell this when the distributor is installed. Rotate and check each tooth with the dist in.
I cheked the gap and it looked ok. The owner have decided that she will get a electronic iginiton kit ( like the mopar/jegs/summit/proform kit wht distributor, computer. resistor and wiring harness) and new spark plug wires It is on its way from Summit., delivery takes about around 7 days ( I live in scandinavia, Europe), So next weekend we will try to wake up the 360 with the new ignition kit and plug wires.

One question, with this new kit, can i stil use the mopar coil in the car or do I have to get a new one?
dopus said:
I cheked the gap and it looked ok. The owner have decided that she will get a electronic iginiton kit ( like the mopar/jegs/summit/proform kit wht distributor, computer. resistor and wiring harness) and new spark plug wires It is on its way from Summit., delivery takes about around 7 days ( I live in scandinavia, Europe), So next weekend we will try to wake up the 360 with the new ignition kit and plug wires.

One question, with this new kit, can i stil use the mopar coil in the car or do I have to get a new one?
Living overseas does put a different light on things; especially that the 1970's Electronic Lean Burn systems basically 'sucked' whereas the newer ones are tolerable. Unless the owner was 'obsessed' at keeping the car 100% original, I to would convert to the vacuum advance style ignition. For that matter: the early ELB's were so bad that even our EPA turned a blind eye towards such ignition conversions.
We could get a local parts shop to order it for us , but they bulk order from summit or jegs anyway. So by ordering the kit directly from summit racing instead of throught the local shop, the owner of the car gets the kit and new spark wires, and saves about 80$ (even after adding postage and import taxes). Finding LeanBurn parts localy is almost impossible. Lets just hope that installing the kit and removing that leanburn computer fixes the issues. Its the only logical solution, everything that has to do with the ignition will be changes ( even got an extra coil, if the mopar one will not work with the new system.)
You will need to change the carb as well in most cases. First the carb may have electronic controls that interact with the lean burn and when the lean burn is gone the carb won't behave properly. Second, the carb likely does not have the provision for the vacuum advance on the distributor.

The best thing would be to order a carb for the same engine from say 1973.
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