runs and idles great for 5 to 10 minutes then shuts off

[Hendogg]

Have you checked the bran under the driver seat? You mite unplug it and plug it back in with some new elc grease. I had a 86 that was doing about the same thing as this one and it was the bran under the seat.. I unplugged it cleaned the terminals on it and then put new terminal grease on them and it fixed the problem.. And just cause you got a new dizzy does mean it doesn't have a bad module in it.. A few yrs back I bought a new Dizzy for a mustang and put it in and worked grate for like 2 days then it would just die for no reason. and I changed coils, Bran box's and 1st one thing then anther. To find out it had a crack in it and would quiet for a bit. ended up putting anther one in it and that's all it was.. Hope this helps..

[SlammedhappySteveO]

Thanks for the reply Newbie...

ill have another look at the brain ... Green light shows thumbs up! curious tho..... when it dies and i try to restart the light goes out and doesnt come back on unless you re cycle the key... meybe something to look at.... curious bout fuel pressure on this 85 nissan 720, anyone know how much fuel pressure were supposed to be at on this??

 

Oh, n as far as the dizzy goes.... it was replaced, because i thought that was the problem to begin with.... as it turns out there is / was no change with replacing the dizzy.... And both ignition modules were tested and retested...

 

sooo as of today were still sittin in the driveway (well blame it on the rain), still puzzled.

[datzenmike]

Dtazenmike

... The siteglass is 3/4 full... Fuel pumps runnin... Relays r workin n have spark....

When it dies it shuts off as though someone turned it off.....

 

 

Fuel pressure does not seem to be the problem if it is 3/4 full.

[datzenmike]

I would to retract my last post..... For ish n grins i popped back out n gave er a bump... NADA.... WONT START... Pulled the coil wires n got no spark.... The coils r bran new.... Dizzy is new..... Ig. Module new.....

Being completey frustrated.... Priceless

E

 

Engine quits but it has fuel no spark. Distributor and coils changed.

 

 

Get a meter or $5 test lamp and see if there is power to the + side of the coils when it won't start and the key on. Try when cranking too. There may be no power coming from the ignition switch.

[SlammedhappySteveO]

thoroughly disgusted... sooo been a day of side work..... headgaskets n what not..... other peoples ish.... been driving the 720 allllllll day..... and its been faithull n tru...... done with  mobile repairs for all else.... im home for n hour and gd truck wont efn start..... confused angry n  a bit but sore..... i have done all suggested... while driving , running, i have had no problems.... not a misss, not a skip..... tried n tru...... bout i go to leave jus now.. i got nada..... wont start........ bout to off this beeeotch...... sic to my stomach n need this ish runnin........ jus los jobn, and my house...... i work on everything.... but this m.f. gotta get right.......shits flawless when ru nnnin....... clueless n angry

[datzenmike]

When there is no spark do you have power at the + side of the coils???

 

Has to be this. Maybe the ignition switch. Plug to ignition loose. Unplug and plug it in several times to clean the contact parts.

 

Run a temporary jumper wire from battery to both + terminals on coils. You will have to remove them when not running but this should get around any problem with the ignition switch.

[SlammedhappySteveO]

Datzenmike, on the jumper situation, start the truck and then connect the jumper, or hook up the jumper and then start it?

Jus caught a layoff sooo with that said im going to redirect some needed attention the 2 tone turd 720...

 

Appreciate all of the posts / responses but the ghost is still in the machine!

[datzenmike]

Well the non restart seems to be no ignition or spark. You can crank all you want but won't start. If you wire 12 volts directly from the battery to the + on both coils and it fires up then it's not getting power from the ignition switch.

[SlammedhappySteveO]

so obviously I should disconnect the existing positive side terminals before hooking up the 12 volt jumper? guess I'm worried about frying something ... well give her a go

[datzenmike]

No there can only be power from the ignition on that side... or lack of it. If this gets it started then there is a power supply problem.

[izzo]

I think he meant should he disconnect the stock positive wires off the coil before running a jump.

[datzenmike]

NO I don't see why. The intake side goes directly to the ignition switch, the exhaust coil goes to the fuse box and then from it to the ignition switch. Since it would start on one coil or the other the supply from the ignition switch is suspect. Possibly the fusible link that supplies the switch is part melted and warms up and breaks contact??? Have to narrow it down.

[SlammedhappySteveO]

So i removed the power wires from the coils , wired up the jumper and turned it over , fired right up and hasnt shut down once, infact still running right now... I turned it off and on a few times and zero hesitation !

Sounds like were thinking ignition switch? Ive got one on my 84 I could swap! :-)

Would soooo nice if is the issue!

 

Getting jealous watching everyone drive theyre datsuns :-(

[datzenmike]

Battery >>>>

 

fusible link >>>>>

 

Ignition >>>> Fuse box >>> exhaust coil

 

and directly to >>>>

 

Intake coil

 

 

Well try the switch but if not then try the fusible links. After that I'm out of ideas.

[SlammedhappySteveO]

So ive been able to drive this thing 2wice in the last coue weeks... But now same story.. Wont start... Replaced fusible links... Have 12 volts at coil, all new fuses new fuel filter at tank ( i still havent replaced the o.e.m. Fuel pump or filter inside)....

 

Ive got spark all day and the siteglass is full on the carb.... Had it run for a few today, then it shut of, so i turned the key off.... Then back to on position ( but not cranking motor) and it backfired.... Just turned the key to the on position...

 

Datzen mike.... I did directly wire coils to battery and had same results...

Im thinking fuel delivery? Getting fuel, but not enough?

Wanna check the fuel pressure when i get home....what should ir be and where is the best place to check that?

[SlammedhappySteveO]

And is there a fuel filter on the hitachi carb itself? On the inlet housing?

[datzenmike]

I think there is a fine brass mesh screen filter at the inlet of the carb inside the banjo fitting. You say the carb is full of fuel so pressure and filter don't seem t be a problem.

 

Did you swap the ignition switch yet. Just to see if this fixes it?

[SlammedhappySteveO]

Im playing with it now, n yes sir replaced ig. Switch too, almost new truck now!

I noticed now when it dies , if i furiously romp gas pedal it tries to run.... Then dies.... Hitachi take a poop? Seems unlikely, runs and idles great , perfect , when it wants!

[SlammedhappySteveO]

Jus had hef runnin, idleing.... Then it died and spewed fuel everywhere outa the carb

[datzenmike]

Sight glass over full?

[SlammedhappySteveO]

Actually, yes.... Looks like a midway dot for eyeball..... But its full to the brim.... Overfueld, so im sure im fouled out at the moment.... Time to pull plugs! I believe were in the right direction

[SlammedhappySteveO]

So im guesz im confused why it still drives from time to time and has zero issues.....

Are these hitachi carbs hard to rebuild.... Ive rebuilt lots of different carbs but looks like a bit to thiz one....

Is that the thinking the datzen mike? Sediment and debri in the float or something and thats why the bowls overful? Fuel level should be sitting at the dot or just a bit above ya?

Ive got a webber i can slap on there, but im curious about the jetting and wether or not its right.... I believe its a 32/36 but ima have to drive out to gig harbor tonight and pull those numbers....

And grab the othef box of hitachi carbs n see if we can get something to work....

Frustrated :-(

[datzenmike]

I had n old 521 that would run fine. But if I really drove it hard or hit a large bump it would act up. If I stopped and shut it off and counted to 5 I could start it and it ran normally again. Turned out to be a flake of 'something' that would get sucked up and block the primary jet. Shut it off and it would drop down and was fine. Took the carb off and found it.

 

Yes could be the needle valve sticking or dirty and the carb will over fill. Does this only happen at aide and low speeds?

[SlammedhappySteveO]

Original owner said it would do it to him all the time and at 70 he Jus wanted to off it... I put almost 2000 miles on it before it shut down on my SEATTLE commute.... Now starts intermittently and won't stay running.... The other day I was able to drive it and it cut out a couple times but didn't die, now I got it home and it'll start run, then die - IM really thinking fuel , all it can be

[Zlich]

your carburetor might be on its last legs mine was doing the same thing before it died except itd leak fuel everywhere i managed to start it and get it home but it wouldnt fire up after that. also check the hoses coming from the fuel filter they might have cracks in them which lets it fill the float bowl up but when it starts running the pump cant keep up with the amount of fuel puming out. as for the fuel filter you should have one right on the frame by the fuel filter.