Bad E.C.U.?

[monaco75]

whats up guys?

This is on the '78 d300..

Someone installed a points distributor long ago. I just finished installing a Mopar electronic conversion kit. All the stock electronic stuff was still there, but in miserable shape. Along with the kit, I also made a new under hood harness as all the wiring was shot as well (alt, regulator, ect.).

Well I got nothing.. engine rotates but no fire. I'm getting 12v to the positive side of the coil, as well as the negative side. I sanded the firewall down, and added a jumper wire to the negative post on the battery to make sure I have a good ground on the ecu. Still no change.

Idk what I'm missing. All wire is run the way it should be

Could it be the new ecu? Distributor? I get no pulse from the - post on the coil when starting. Thought the ecu might not be grounded good, but no change after the jumper wire..

 

[monaco75]

A couple pics. Excuse the crudity, not 100% done, and I'm no go with electrical (obviously)

Instead of using the 2 prong ballast in the kit, I stuck with the original 4 prong. I believe it's wired correctly?

Top left- starter relay
Top right- + coil
Bottom left- Blue ECU
Bottom right- Ignition switch

 

[65sporty]

Did you recheck your wiring to the ecu? The pick up in the dist could be causing your issue. Do you have another dist you can plug in and ground? Then you can spin it by hand and see if you have spark.

 

[monaco75]

I do have another dizzy somewhere. I'll give that a go.

I did check all the wiring. Everything seems to be in order, except for having 12v on the negative side of coil. I have 12v coming out of the coil to dizzy as well.

From the little I found online, thought the box might be malfunctioning with the 12v at both sides of coil.

 

[cantflip]

I do have another dizzy somewhere. I'll give that a go.

I did check all the wiring. Everything seems to be in order, except for having 12v on the negative side of coil. I have 12v coming out of the coil to dizzy as well.

From the little I found online, thought the box might be malfunctioning with the 12v at both sides of coil.

It's going to switch the ground side of the coil to make spark... which forces the electricity through the coil and plug gap to find ground. Ignition module isn't off the list yet... but 65sporty hit it with the distributor idea... that came from traintech in the past didn't it? Either way, an excellent idea for a quick elimination of the pickup... as long as the other distributor is good.

 

[Dobalovr]

Don't the dual ballasts run different resistances between the two sets of contacts?

 

[monaco75]

I'll try the other dizzy tomorrow. Had to walk away from it. Running me up a wall. Seems like every time I fix something, 10 more things go wrong.

I did see that about the ballast on another page. Would it cause this issue? I didn't see any markings on this ballast. Can also try to swap them around. The wiring diagram that came with the kit had the the same wires going into the top, and bottom. Just tied together to go onto 1 prong together.

 

[traintech55]

Just a couple of things. First is your new ECU a four pin, or five pin? If it is a four pin you do not need the second side on the ballast resistor. Second, if another distributor will give you spark, check the gap on the pick up coil and reluctor. Many times the new ones don't have the gap set correctly.

 

[monaco75]

Is this how you guys mean? Took the other dizzy with a ground wire attached straight to the NEG post on the battery. With the key on in run position, turned the dizzy by hand. Got nothing out of it.

Dizzy has spark going to it (11.75v) as battery is getting a little weak. Took some readings from the ballast. The left side (starter relay, and blue wire to ecu) has 1.3v. The right side (+ coil, and ignition switch) has 11.75v.

Also the male connector to the dizzy from the box has .4v. Female read nothing.

 

[monaco75]

Just a couple of things. First is your new ECU a four pin, or five pin? If it is a four pin you do not need the second side on the ballast resistor. Second, if another distributor will give you spark, check the gap on the pick up coil and reluctor. Many times the new ones don't have the gap set correctly.

It's a 5 pin. Has a green wire that is not used, making it a 4 pin theoretically.

 

[commando1]

I need visuals to understand what people are saying

 

[monaco75]

I need visuals to understand what people are saying

Mines set up just as the bottom pic, only with a 4 prong ballast vs a 2.

 

[commando1]

Mines set up just as the bottom pic, only with a 4 prong ballast vs a 2.

so change it to the top diagram...

 

[monaco75]

 

[commando1]

 

[commando1]

Zac, you made my night.

 

[monaco75]

Glad to be of service.

lol

Think the truck is getting towed in the AM... haha

 

[monaco75]

Idk if I could set it up that way. The wires don't match up between the 2?

 

[commando1]

Idk if I could set it up that way. The wires don't match up between the 2?

Whats the problem?

 

[300rag]

...Think the truck is getting towed in the AM... haha

To Sebring?