Why wont it run properly?

N

No Hands

Well-Known Forum User
Worked on my Z today, but its got issues i cannot fix without help..

It starts, it kind of runs but if i put my foot on the gaspedal it stalls. What do i need to check and fix to solve this?
 
Yes it has a brand new fuel filter, transparant, so i can see if there is dirt/fuel in it.

Sure i can take it to a garage but ill bet they know as much from Z's as i do.
 
I has been standing still for 18 years in a dry garage.
picked it up a few months back, checked points, distributor, rotor, plug wires, spark plugs, cleaned the tank, blew air through the fuel pipe from tank to filter to make sure it was clean, installed new transparant filter and got it running on idle.
Today i got the clutch working, pried the clutch plate off the flywheel, started it and tried to make a few meters in the garage. but as soon as i put the pedal down it stalls. there is fuel in my filter.
 
How old is the fuel?
What's the plug gap, it should be around 0.28, too wide a gap and it'll kill the spark.

I once had my leads on the wrong plugs which gave me a similar problem. doh!
 
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Which carburettors have you got on the car?? standard Hitachi??

Does the piston move in the dashpot and is there oil in the piston damper??
 
I would start with zblokes suggestion above. It's really simple to check, just remove the bell housing and see if the piston inside is free to move.It should move very smoothly. Just be careful of the needle. Lol
 
Make sure that the float bowls are filling (there is a sight plug on the Hitachis) and that the rubber transfer pipe under the carbs has not perished / collapsed.
Obviously check that you are getting a good strong spark at the plugs.
 
The fuel is brand new, put it in after cleaning the tank.
Took one of the std. 260z carbs apart to see if that had any problems, looked all clean and tidy to me.
will check the spark plug gap tomorrow, the plugs were already in there so that might be an issue, the spark plug wires were already on the engine when i bought the car, ill see if they are on the correct plugs :)

Since my fuel filter is transparant i noticed it isnt completely filled with fuel, there is some at the bottom and some at the top were it goes to the carbs, but the middel seems to be 'empty' Shouldnt it be completely full?
Maybe i just have a bad fuel pump?
 
no, the filter doesn't need to full, although I can't picture some fuel at the bottom and some at the top - do you have a photo?
 
std. 260z carbs
Click to expand...

That'll be your problem...:p

Most users in the UK have junked them in favour of 240Z Hitachis or SU equivalents...(cue Ian P to rally support for the originals...)
 
Yes i know they are changed for other stuff but if nissan put them up from brand new and the Z's drove the streets with them sure we must be able to make them work properly?

I have a few sets of 240z carbs, is it a lot of work to change the 260 ones with 240 ones? Or is it just undoing 8 bolts and 2 fuel lines?
 
Yes i know they are changed for other stuff but if nissan put them up from brand new and the Z's drove the streets with them sure we must be able to make them work properly?
Click to expand...

A little naive at best, ditch them, at the very least they will require a complete overhaul with parts being harder to aquire that the Hitachi units even then they tend not to perform as well.
 
Are some people confusing the ( European market ) HMB46W carbs with those fitted to North American models during the same period? They are not the same thing at all, and yet the 'Euro' ( and Japanese ) market carbs get slagged off on the reputation of their North American market cousins....

No Hands,
If your carbs were OK when the car last ran, and they are clean, free of gummy residue from ancient fuel and have not been full of moisture / water since heaven knows when, then there is no real reason to junk them. They will work perfectly well if they are perfectly well.

By all means bolt your '240Z' carbs on there if you want to have another unknown to deal with...
 
Couple of things that helped with mine were making sure the dash pots were filled with 30 grade oil and a squirt of wd40 in the distributor and make sure the weights are capable of advancing the timing.
 
Albrecht: i dont know if the car was running fine before i bought it, i bought it when it had been standing still for 18 years, i took one carb apart and that was all clean and nice. It was stored in a dry garage so no water could have gone in it. I really dont see the need of swapping to 240z carbs, the 260z ones should work just fine, they are european carbs so no emisiion stuff etc.

But i dont think its the carbs, i am guessing its the fuel pump becuase of the transparant filter. I have the same filter on my 510 and that filter is completely filled with petrol. even wehen the engine is not running. The filter on the z is not even completely full of fuell when i try to let it run, ill see if i can get a new fuel pump, or at least rebuild the current one and see if that helps.

If the pump cant pump enough petrol to the carbs they will never work properly.

pics of carbie i took apart:

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7945409172_998b795ae2_c.jpg


7945410474_9f7dec15b1_c.jpg


7945411618_16a4de0b6e_c.jpg


Looks o.k to me.
 
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