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1984 Nissan 720 4x4 Weber Carb Problems


RatsunSam

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 So I got the alternator to work my dad accidentally bumped something around the fusible links and it started working and then we tried testing it and all was good.  We turn on all the accessories and heard something then the alternator stopped working .

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Good question. They are rated by the amperage they carry.

 

siravgI.jpg

 

Try auto supply store. A fuse will work but the advantage of a fusible link is they don't blow instantly but heat up over about 5 seconds and then melt. This would allow a short (pun intended) duration over current draw without blowing. They have a special (hypalon) coating that resists catching fire. Often when they blow it's not evident to look at.

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Alright thanks for the info Datsunmike I am still looking for a fusible link can’t find one. Also my truck is getting still bad gas mileage not as bad as before. What could cause it to run rich? I keep asking but since the fusible link is no good the  alternator doesn’t charge so therefore I’m not getting 12v therefore the choke and  electronics not working  which is causing it to run rich?  

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 I got some fusible link wire does the gauge of fusible link wire apply to the certain amps that I need as shown in the table you sent me before.  Since when I go to the auto parts store there is no green fusible link wire is just a Nissan thing?

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On 8/13/2019 at 11:18 PM, RatsunSam said:

Also DIY 1985 I am not running my vacuum advancing  distributor could that be causing it to run rich?

I'm not running vacuum advance.  But, I kinda wish I was for cold starts.  My Z24 performs great, I measured 32 mpg on the highway this last weekend.  I've consistently got about 29 mpg in the past, but that was mountain driving.

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The TVV (thermal vacuum valve) prevents ported vacuum from getting to the distributor during cold start up and warm up. There is a wax pellet inside that melts at a specific temperature and this closes an air bleed that destroys the vacuum signal. This same valve prevents EGR when the engine is cold. Maybe what you need is the choke adjusted richer? 

 

Also, do you have your ATC (ait temperature control) working? It directs exhaust warmed air to the air filter snorkel when outside air temperatures are low. Cold and warmed air are mixed by a thermostat regulator in the air filter housing to keep the carburetor air at a more constant level No matter the time of year the carburetor thinks it's summer out.

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Vacuum advance only works , or primarily works on part throttle or cruise on the highway, not at all at idle and for all intents and purposes not at full throttle. It improves combustion efficiency by advancing the timing as needed when the cylinder is not completely filled.

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Yeah I finally fixed The fusible link wire  my alternator is now charging I am getting 14.6 V. It’s still running rich I’m gettting about 18mpg which I think it should be getting more. Can you show a picture Datsun mike where the vacuum advanced should go to from the carb.

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On 8/2/2019 at 11:53 AM, RatsunSam said:

 

Quote was a mistake.

 

Sam from what I can tell is you have a 1984 720 King Cab Z24 4x4.  The 1984 720s did not have a feed back carb originally.  Your carb electrical plug only has 2 wires.

 

What fuel pump is on your truck?

 

If your charge light on your dash stays on all the time then either you have a bad alternator or the wire/connection is bad for the charge light.  If the wire is good and connected to the alternator corectly then the alternator is bad.  The light wire excites the alternator to start charging and when the alternator is charging the light goes out.

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 I just realized that my vacuum lines are all hooked up wrong, I don’t have any vacuum going to the distributor which is not advancing it when I give it gas which in return is making me have terrible gas mileage.  So I’m going to fix that have another question can my truck handle 31‘s tires? What my trucks gear radio?

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1 hour ago, RatsunSam said:

 I just realized that my vacuum lines are all hooked up wrong, I don’t have any vacuum going to the distributor which is not advancing it when I give it gas which in return is making me have terrible gas mileage.  So I’m going to fix that have another question can my truck handle 31‘s tires? What my trucks gear radio?

 

On a 1984 Nissan 720 4X4 there is a tag on the passenger inner fender well near the firewall, in the bottom right corner of the tag there will be a number, it will likely be 4.1, but I suppose it could be another number also, what number is in your tag?

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2 hours ago, RatsunSam said:

 I just realized that my vacuum lines are all hooked up wrong, I don’t have any vacuum going to the distributor which is not advancing it when I give it gas which in return is making me have terrible gas mileage.  So I’m going to fix that have another question can my truck handle 31‘s tires? What my trucks gear radio?

 

Vacuum advance is engine load dependent. The more you step down on the throttle the less vacuum advance. Vacuum advance increase efficiency during part throttle and steady cruise speeds.

 

 

2 hours ago, bottomwatcher said:

Gear ratio on door jamb. I run 31s 4 inches of lift. A dog with the z24, also the b series trans will keep blowing countershaft bearings. Running a ka now with a c series trans, so far so good. I went through 4 b series they just can't take the extra load of big tires.

 

Inner fender, right side under the right hood hinge. Bottom right corner where HF38 is stamped. 

buF8TkE.jpg

 

If build date is before Jan '83 it should be an H-190 and 4.375 or HF43... HF stands for H-190

From Jan '83 on it will be a stronger C-200 and 4.11 ratio. I don't know the prefix for the C-200 but it won't be HF.

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