distributor voltage??

[nissanprerunnerdavid]

So recently i had my ICM module inside the dizzy go bad. So i bought a new whole distributor assemblemy on ebay. I just got it. Put it i. And she fired right up. After about 8 miles of driving i turned her off to get gas and now she wont start again. She cranks over for days but just isnt getting spark?? I was think that maybe if the dizzy is getting too hot or reciving too many volts that it would frie it. I changed nothing between dizzy swaps. Same cap wires and coils. Any help is good help. Thank you!!

[datzenmike]

Did you test for spark or not, you say:

She cranks over for days but just isnt getting spark??

with ???? marks.

 

Get two old plugs and stick in the #1 intake and #1 exhaust side coil wires. Lay on a well grounded surface and have someone crank the motor. Be sure they are grounded. You can do them one at a time if easier. SPARK???? yes or no?

 

 

You can only get 14.8-15 volts from the alternator so this isn't a problem.

 

Heat will not 'fry' them. They may stop working or become erratic, but will resume once they cool down. The module is inside the distributor so heat from the exhaust is not a factor as it is well protected from it.

 

 

More info needed.... do you have stock coils??? or have you swapped in some aftermarket wizz bang, lightning bolt, super duper, accell, MSD super 800 killovolt coils??? After market coils may draw more current to produce a higher voltage spark. Too much current drawn through a module might fry them but I have yet to see a verified blown module. They are very tough.

[Alec 720]

I've heard about sometimes something like grease going between the points and grounding them with each other.

Being its a new distributor its possible it has grease or something inside.

 

Not sure how likely it is, but it maybe worth checking out.

[datzenmike]

Well this is an EI distributor or electronic ignition that has no points. Also known as a breakerless distributor. It uses solid state parts to do the same job as points but can handle much higher current loads than points. Because of this, a special higher output coil can be used to produce a higher output voltage that would burn out the old style points. All N Am Nissans since '78 have used them.

[datzenmike]

I might add that you be sure that the dizzy is firmly bolted down and well grounded to the block.

[nissanprerunnerdavid]

no grease anywhere on the inside. stock coils and same wiring i had in my last one. one i get off the side of the road i will test for spark. thanks for all the helps guy. always count on ratsun.

[datzenmike]

So recently i had my ICM module inside the dizzy go bad. So i bought a new whole distributor assemblemy on ebay. I just got it. Put it i. And she fired right up. After about 8 miles of driving i turned her off to get gas and now she wont start again.

 

So how did you determine that the module was bad? When something is replaced and it doesn't fix the problem it make me think that it may not have needed replacing.

[I'm BLUE]

(1) Check power wires lleading from engine harness

(2) Check for "pulsing" feedback from module with a multi-meter or test-light (should be possible)

(3) Test and verify ignition coil specs. They do go bad.

*** Always make sure to use new butt-connectors or cleaned-connections when fiddling with ignition stuff :)

 

What brand/product was purchased then installed ?

Some of these aftermarket ICM setups require a filter to shield the ICM from voltage spikes ( speaking in general )

 

Test your coil as well ...

Bro's "Brand New" Mallory Pro-Master ignition coil was bad right out of the box :rolleyes:

The insulation was broken on it from shipping .. ( glass-filled polyester casing )

[nissanprerunnerdavid]

@ datzenmike, i determined it was bad because i printed the mitchell on demand tests for the distributor, and i was passing all the resistence tesst through the wires and whatnot until i got to the distibutor. the B terminal on the ICM should have power to it when the ignition is on and on my old dizzy there was no voltage coming from that terminal at all. so therefore i thought it was bad. and i got a new dizzy from an 84 and she fired right up. so it did fix the problem only temporarily.

@DTP i will check all those things and thank you. that information is very helpful, however, the product i got was a dizzy from a 1984 720, OEM. and maybe that makes a difference because mine is a 1985?? as for my coils they are OEM and i will do all the voltage tests and resistance tests in the morning. and the voltage coming to the dizzy is suppose to be no higher than one volt below battery cranking voltage and no less then 8.6 volts. so i will know by tomorrow what the culprit is.

 

thank you all again for your help!!!

[datzenmike]

@ datzenmike, i determined it was bad because i printed the mitchell on demand tests for the distributor, and i was passing all the resistence tesst through the wires and whatnot until i got to the distibutor. the B terminal on the ICM should have power to it when the ignition is on and on my old dizzy there was no voltage coming from that terminal at all. so therefore i thought it was bad. and i got a new dizzy from an 84 and she fired right up. so it did fix the problem only temporarily.

 

 

thank you all again for your help!!!

 

 

The B terminal on the module does not produce any voltage. It gets its power from the wire attached to it that comes from the ignition switch. I think that test is for the wire on the B terminal. It should have 12 volts with the key on.

[nissanprerunnerdavid]

copy. now that i look at the sheet your right. and what is the order of the terminals? i belive it has the letter b, i, e and two others. what are the letter terminal labels and the orders??

[nissanprerunnerdavid]

i just finished doing tests with the dmm and the coils are just barley out of specs and i checked power. i have power to the b terminal but no other ones. so i checked dizzy grounding by attaching the negative lead of the dmm to negative terminal of the battery and the positive lead to the distributo housing and cranked the truck. mitchell said if voltage is below .5 volts replace ICM. i was reading 200-300 mV. so its the icm module. but why would it go bad right after i put the new one in?? there is a in line resistor for 2.2 K ohms and i checked it and its good. fuses are good. relays are good. any other ideas??

[ggzilla]

Aftermarket ignition control modules don't last very long, sometimes just weeks or months. The original Datsun/Nissan equipment were very reliable (Hitachi and Mitsubishi). Which is why Nissan charges over $200 for the module, because they are very good.

[nissanprerunnerdavid]

hmmmm. ive only got the oem distributors though?? just used.

[ggzilla]

Corroded connections.

 

i checked dizzy grounding by attaching the negative lead of the dmm to negative terminal of the battery and the positive lead to the distributo housing and cranked the truck. mitchell said if voltage is below .5 volts replace ICM.

That does not make sense. If the voltage between NEG and DIST HOUSING is below .5 volts, that is good.

[nissanprerunnerdavid]

when you crank the engine?? and thats just what the mitchell on demand test said. i dont know how that would work.

[datzenmike]

The 2.2K resistor is for the tach signal.

So recently i had my ICM module inside the dizzy go bad.

 

Lets revisit this.... How do you know the module was bad? Could it not have been something loose or poorly grounded that was corrected when a new module was installed?? Now it has gone back to not working again.

 

I guess the question to ask is: Is there spark from the coils????

Pull the coil wire off the distributor cap. Stick a spark plug in the end and lay it on a grounded surface. Crank the motor and look for spark. So is there spark or not????

[ggzilla]

He determined the ICM was bas based on "what the mitchell on demand test said"

But I think it was an incorrect determination.

 

NPRD, do what Mike suggests. Then you can see with your eyes if there is spark or not.