SlammedhappySteveO Posted March 17, 2013 Report Share Posted March 17, 2013 85 nissan 720 8 plug motor 5 speed, bone stock 2nd owner... Has been a solid runner but now i jus dunno... Outa the blue, starts, runs, idles and turns itself off after 5 -10 minutes running... Has spark, and the siteglass on the feedback carb is half o three quarters full... All the pertinents test out.... No breaks or exposed wiring all the fuses clean n in working order... Really kinda lost n now jus dunno which direction to go..... Any input or suggestions appreciated in advance.... Cant seem to post pics or anything from mobile for some reason.... Any suggestions there¿? Quote Link to comment
datzenmike Posted March 17, 2013 Report Share Posted March 17, 2013 With the air filter off, watch out for all the vacuum lines, while idling wiggle the connector with the wiring at the back of the carb. These are known to be a contact problem from internally broke wires. If it quits from this, that may be the problem. Did you look at the carb fuel level after it quit? If not, the next time it quits turn the ignition off and take a look. There is a fuel pump relay on the 720 that needs normal alternator output and oil pressure to remain pumping. Maybe the relay shuts the pump off and carb runs dry. Quote Link to comment
SlammedhappySteveO Posted March 17, 2013 Author Report Share Posted March 17, 2013 Dtazenmike I did check the barrel conector that supplies the idle valve, choke and so on.... And air cleaner is off free and clear.... 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..... I try to give it gas but does nothing jus shuts off... Doesnt even diesel..... Jus tried it again, fired right up n idled great then shut off.... Full siteglass... When u depress the gas pedal, fuel squirts into the primary.... More like a drizzle.... This looks to have the from factory fuel pump.... Looks like u can unscrew the body itself, meybe theres a filter in there? Doin more investigating now Quote Link to comment
SlammedhappySteveO Posted March 17, 2013 Author Report Share Posted March 17, 2013 Does anyone know? The frame mounted fuel pump, looks like it doubles as a filter housing? Ño local parts houses have this, is this something thats still avail? Or should i jus go with a new inline filter and an aftermarket fuel pump? Quote Link to comment
datzenmike Posted March 17, 2013 Report Share Posted March 17, 2013 As long as the carb is full of gas then the fuel pump is working and no need to change it. There is a filter in the very bottom of the pump that twists off. The part number is Nissan # 16404-28530 but I think available from Purolator/fram or something. An inline filter is fine before the pump to keep crap out of it. Quote Link to comment
SlammedhappySteveO Posted March 17, 2013 Author Report Share Posted March 17, 2013 No parts books show but how bout a filter at the carb? Fuel should be freely squirting out in the primary right? Not a trikle.... I wonder if somethings gaught in the idle cut seat? Seems odd to have spark, and have the siteglass full .... Damn thing runs like a kitten til it shuts of..... Not miss nada..... Miss my truck :-( I am forced to drive a Honda :-( :-( makes me sic Quote Link to comment
SlammedhappySteveO Posted March 23, 2013 Author Report Share Posted March 23, 2013 Again today to no avail.... Started up ran for roughly 5 min then promptly shut off... Ive got fuel, ive got spark..... What gives? Any one have any suggestions on where to go from here? Bone stock 85 720 , feedback carb , 8plug z motor..... I dont jus want to frantically bounce around chasin my tail! There is absolutely no warning or indication before it shuts off , purrs when she runs and idles smooth, no misses.... Atleast the sun is shining today ! Good day to wrench! Quote Link to comment
datzenmike Posted March 23, 2013 Report Share Posted March 23, 2013 No parts books show but how bout a filter at the carb?Fuel should be freely squirting out in the primary right? Not a trikle.... I wonder if somethings gaught in the idle cut seat? Seems odd to have spark, and have the siteglass full .... There will be no fuel squirting out the primary side unless you pump the throttle. Then the accelerator pump will squirt fuel to make the mixture richer coming off idle. Otherwise it is running on the idle circuit. Did you look at the carb fuel level after it quit? If not, the next time it quits turn the ignition off and take a look. There is a fuel pump relay on the 720 that needs normal alternator output and oil pressure to remain pumping. Maybe the relay shuts the pump off and carb runs dry. Just checking. When it quits is there fuel in the carb? Quote Link to comment
SlammedhappySteveO Posted March 23, 2013 Author Report Share Posted March 23, 2013 Ya thats what stumps me.... Siteglass is full ..... And theres spark! Quote Link to comment
datzenmike Posted March 23, 2013 Report Share Posted March 23, 2013 It has an electric pump so you have to get the ignition off fast or it may come on and fill the carb before you can get the hood open. Does it restart? Quote Link to comment
kelowg Posted March 23, 2013 Report Share Posted March 23, 2013 but do u have strong enough spark getting to all the plugs themselves. should be blueish/white spark. maybe the coils is not making strong spark. pull a sprk plug the moment it shuts off, wet,oily,dry? Quote Link to comment
SlammedhappySteveO Posted March 23, 2013 Author Report Share Posted March 23, 2013 Yeah, stock fuel pump, turn the key on n its on.... And hood is alwzys open lately since i cant figure it out.... I have my son turn it over, it fires up .... Runs for 5 min and shuts off Fuel pump still runnin but truck jus shuts off.... No dieseling, hesitation or warning, jus like someone turned it off... Smh :-( As far as restarting, ya thats a no itll crank but wont start.... Come back 10min later and fires right up don have to pump the pedal or nothin , turnkey... I always get the super possesed stuff , somedays its enuf to drive me bonkers! Quote Link to comment
datzenmike Posted March 24, 2013 Report Share Posted March 24, 2013 Have to have spark and fuel to run. Take away one and it quits and won't restart. SPARK... When trying to restart, have you checked if there is spark?? On both coils? Quote Link to comment
SlammedhappySteveO Posted March 24, 2013 Author Report Share Posted March 24, 2013 Thats what i thought it was before... Replaced both coils... Check n re check yes sir spark intake and exhaust.... Ignition module? Although seems unlikely... Quote Link to comment
datzenmike Posted March 24, 2013 Report Share Posted March 24, 2013 But does it spark right after quitting? This could be why no restart until the module cools down. Quote Link to comment
Hyspeedz Posted March 24, 2013 Report Share Posted March 24, 2013 Watching this topic because I have similar issues. I ordered a fuel pump and new filter because mine will just stop running randomly. Had 400lbs of dirt in it last week, and started it up to come home, drove a block, and it was like I ran out of gas. Waited 10 minutes, and drove home (5) miles without a hitch. It seems like the pump mechanism gets hot and shuts off, then cools down and starts up. Good luck, friend. Quote Link to comment
datzenmike Posted March 24, 2013 Report Share Posted March 24, 2013 Good point, but if the electric pump had a thermal overload switch it would quit and the carb would run dry. I'm still trying to find out if it's out of gas when it quits or if the spark stops. Quote Link to comment
SlammedhappySteveO Posted March 24, 2013 Author Report Share Posted March 24, 2013 side tracked by liquor n tattoos yesterday.... Full tank fresh gas , the fuel pump continues to run when the truck shuts off and the siteglass on the carb is full... Sooo gonna grab the kid n a couple drivers n do an ignition spark test n see whats good :-) Quote Link to comment
Hyspeedz Posted March 24, 2013 Report Share Posted March 24, 2013 My carb was totally dry. So, I'll let you know. Too much snow on the ground right now. Quote Link to comment
datzenmike Posted March 24, 2013 Report Share Posted March 24, 2013 side tracked by liquor n tattoos yesterday....Full tank fresh gas , the fuel pump continues to run when the truck shuts off and the siteglass on the carb is full... Sooo gonna grab the kid n a couple drivers n do an ignition spark test n see whats good :-) Maybe a loose wire or making poor ground contact through the housing to the block. Check the plug to the dizzy. Make sure the dizzy is snugly bolted to the timing cover and the adjustment tie down for setting the timing is tight. Assume the spark quits then. Get a can of http://www.fastenal.com/web/products/detail.ex;jsessionid=Qvp1RPpXphGyyB2L4LxnjQpVfjv3qc4nd1npt0jBWvTWzFxTwMX1!2092185562!926578551?sku=1014505 It will quickly cool down the module under the rotor. If it restarts then there is a thermal problem. Quote Link to comment
SlammedhappySteveO Posted March 24, 2013 Author Report Share Posted March 24, 2013 Ooooookay soooo now im shaking my head.... Went out to check out the spark situation, fired right up... Love it.... And its been running ever since, hasnt shut off . Thats a go for spark ! I even shut it off and started it back up and it started... Sooo I JUS DUNNO Quote Link to comment
datzenmike Posted March 24, 2013 Report Share Posted March 24, 2013 What did you do????? :lol: :lol: :lol: Ah sometimes it's like quantum mechanics where just observation changes the rules. Quote Link to comment
SlammedhappySteveO Posted March 24, 2013 Author Report Share Posted March 24, 2013 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 Quote Link to comment
datzenmike Posted March 24, 2013 Report Share Posted March 24, 2013 You changed the module? Or the dizzy is new? Could be loose wire under rotor. Quote Link to comment
SlammedhappySteveO Posted April 1, 2013 Author Report Share Posted April 1, 2013 Got some time and money into it and situations better, but not perfect..... What i found, i had 2 o rings on the dizzy assy.... As well as the leads that attach to the ignition module were very loose.... So i cleaned the connections and made the terminals tighter by squeezing them with electrical pliers... Ive also, checked bot coils, running and not and were good there.... I also double checked the ig. Module and were good there. I running longer now, and have driven it a bit but bout to lose my AAA if i gotta have it towed again! But alas were still intermittantly shuttin off with no warning... Only now i can restart it almost immediately, although it may still die immediately... Idle is great, smoothe and even.... And there is no miss .... Still fuel in the sightglass So far to date, all fuses have been replaced,and all check out..... New fuel pump relay (pass side bhind dash)... New fuel filter.... Plugs, wires, rotor and cap, as well as complete dizzy... Been goin thru checkin grounds and wiring but all looks fine..... Either way ive cleaned and re established grounds in the engine compartment.... Soooo thought and suggestions ANYONE? STILL FRUSTRATED but will still push on And direction or advice greatly thankful for in advance! This has really sucked thus far! Quote Link to comment
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