Misfiring And Affecting Acceleration After 10 Mins Traffic Jam On My 240Z

[d3c0y]

Jeeze, it almost sounds like your mixtures leaned out like we've told you in all your other threads. Here's an idea, have you tried refitting the old system to see if the problems go away?

[jalexquijano]

Which damper oil is recommended for hot tropical weather then? my problem is at idle not during cruising at the highways.

Edited November 30, 2017 by jalexquijano

[jalexquijano]

no i have not. surely it will go away.

[1600dave]

Damper oil will have absolutely no effect on anything at idle. It only changes the rate at which the piston rises or falls when engine vacuum changes. Vacuum doesn't change at idle, piston position in the carb doesn't change, therefore whatever oil you run won't change anything.

[d3c0y]

Seriously keep all this crap in the one thread.

 

The temperature is the same in Australia and it gets that hot in America too.

 

You do not have some sort of special situation. 

 

Use the factory stated oil or ATF. 

 

</close thread>

[d3c0y]

I don't know why i bother replying but anyway:

1. Is this still a problem?
2. Did you replace the fuel filter right now?
3. Did you check the fuel pressure right now?
4. In your idle thread you said it runs fine on the highway is this not the case now?

If the choke fixed this, you added more fuel, which means your are running lean, which is what we have said all along. If this is the case you need to richen the carbs.

 

After you have performed/answered the above questions, you need to go through this guide step by step and purchase some sort of airflow meter for your carbs:

 

https://www.z-car.com/blog/cars/tuning-su-carburetors

 

If you can't get it right after following the guide, the way i see it is you have two choices:

1. Take it to a mechanic run it on a dyno and get them to set your mixtures
2. Return carbs to original settings and refit the exhaust it ran fine with and move on with your life.

Now this is the most important step of all, don't start a new thread until you have posted before until everything above has been completed.

 

Good luck.

Edited November 30, 2017 by d3c0y

[jalexquijano]

This is not crap. This needs to be addressed logically.

[Agno]

I really should stop reading this guys threads but I love how he keeps coming back with the same questions after ignoring what everyone says.

 

RICHEN YOUR DAMN FUEL MIXTURE

[d3c0y]

But you refuse to address it logically and you create multiple threads for the same issue with different titles.

[gilltech]

Ditto what everyone else is saying. Your car is starving for fuel. The effect of pulling the choke on makes that clear.

BTW, leave the ATF alone, don't mess with it, as long as the correct quantity is in there then that's got nothing to do with it.

[jalexquijano]

Thanks i ll follow your advice.

[d3c0y]

I doubt it hahah 

[jalexquijano]

i have richened both 3 Screws SU Carbs mixture to 2.70 turns clockwise and since my camshaft is not stock but a Schneider 274F cam, i have set the rpm to 1,100.

 

http://schneidercams.com/274FL6.aspx

Edited December 1, 2017 by jalexquijano

[jalexquijano]

In conclusión it is irrelevant if i use any Brand of ATF?

[jalexquijano]

your location says Panama?

How hot and humid is it there? are you using an ethanol mix fuel?

Reason I ask is ethanol fuels absorb moisture, particularly if its been sitting in a tank for a while, if the moisture content is high in the fuel it'll be more likely to 'boil' and creste a vapour lock in the lines.

Is there possibly another way you can reduce underbonnet heat? Vents maybe? or drive with it popped open? (but still with the saftey latch)

IIRC the 280zx had a fan setup to blow cool air over the injector rail, maybe something like that coud help.

not sure on your location or what the local cops would think, but if you can consistently get it to fault, maybe try replicating but with the bonnet removed completely, temporarily of course. Im thinking that if it still does it with the bonnet off completely its going to be a deeper issue than underbonnet temps.

 

Your heat wrapped rail is usually a good working solution, the extra heat shields are definitely not going to hurt the process either.

Gasoline in Panama has no Ethanol. I use 95 octanes.

[1600dave]

If your problem is at idle, yes it is irrelevant

[jalexquijano]

Need to solve my problem at idle during long traffic times where my car tends to stall.

[gilltech]

Could be getting vapour lock due to excessive heat under the bonnet.

How good is your cooling system?

[gilltech]

You've got three threads going on what is basically the same issue, how about dropping two and combining them?

[C.A.R.]

Jalexquijano, your issues are utterly impossible to diagnose over the internet. And starting a 3rd thread isn't going to change that.

Find yourself a chassis dyno & run the car up on it to check what it's doing.

[gav240z]

I believe all threads are now merged.

 

Carry on...