goin nutz! need help on 720 electrical :)

[dreadsiren]

I love my 720's and have worked on them since i was a wee one... but this one has me stumped... My husband and I own 3 trucks and have been making one extra nice one from the 3, we have the body from an 82, motor from a 85, and most parts from our two 84's. we put the best full wiring harness (working cherry on the 84, no spliceins) in the 82 since its was thrashed, put our ignition coils and dizzy (again from the 84 that ran) left the transmission and engine (from and 85) and swapped interior pieces to make the best one. now our ignition wont trigger right (best way to decribe our happenings) It was firing, then it stopped, now we have to hold the key to almost starter to get the fuel pump on, heater wont work (new motor and switch) and no spark?! checked all fuses (the one to the engine was blown,we replaced it but nothin... checked all our ground wires, made a better positive cable power connection, replaced battery and tried a new ignition... now we are at a loss... what else could possibly cause the ignition to not allow power to the coils? anyone? :wtf2: oh, our lights all work though, lol

thanks in advance

[dreadsiren]

well... going to guess that its the dizzy.. dont want to go there, it was working in the old truck... I forgot to put the condenser on the harness the first time I cranked it so I'm worried I damaged the module... any 1 have any ideas on it?

*edit: dernit... tested and it is the icm grrrrrr.... found out if they could get one at a parts store they want over 400 for it *gulp* any one have an idea for a makeshift/after market option for a 1984 z2.4 icm? part number lx555? (four wire. 'e, i, c, b') all of my spares are the 3 wire (e,b,i) kind

[flinterman2000]

Try changing the ignition switch for one of your other trucks.

[fastboatman29212]

They just parked a 1984 720 at my local salvage yard. If it's a 2wd do you want me to pull the ECM for you? I'm going there today. The price is $17 plus whatever shipping is.

**Update** Just got back from the salvage yard. Sorry, truck did not have the ECM anymore. I don't know when it was removed, but probably before it got there.

[dreadsiren]

durn it such a bumber!!! I tried switching for another one of my trucks but cant figure out how to rewire the module from 3 wire to 4... (harness is for 4 wire, others are z22 dizzys, 3 wire) just glad its too old for the under seat ecm or I'd probebly have to replace it too, lol. thank you anyway though

[flinterman2000]

Did you check to see if the ignition wire from the switch key has current? Check the colors of each of the wires, if they are the same forget about c and connect the rest. Then connect a wire from the ignition switch to c, try to start.

[PEZi]

Sooo..... There is some mild rumor I will be ridding of my engine, and *ahem* ECM... It's for an '85... but............

[dreadsiren]

Sooo..... There is some mild rumor I will be ridding of my engine, and *ahem* ECM... It's for an '85... but............

hmm... is the rumor a reality yet?? if so, is your dizzy a 4 wire?? and if thats a yes... how much

[PEZi]

I can give you pics of everything to make sure its exactly what you're looking for... but yes it is a reality, and I dunno... $75? $50?

[PEZi]

I just realized you have an ICM problem, not an ECM problem. Try our buddies at rockauto http://www.rockauto.com/dbphp/mak,NISSA ... l%2BModule

[dreadsiren]

got him all fixed now new icm and had to replace one coil for weak spark but going great! other than... fuel pump only works with key in start position... replaced all the relays and serviced black box, then replaced it with working spare... same problem, pump wont work in on or full acc positions causing starve problem. seems to work if I pull the wiper fuse... any one have this happen before? before I go postal and rip the dash back out and butcher the wiper delay module I figured I'd see if anyone else experienced this before and if the pump routes through the wipers at all... they do share a common fuse for acc position...