Experiment.Seven

This is a follw up thread for my carb troubles.

I have stripped the Nikki of the following parts:

TPS
Cruise Control Linkage
Hot Start Linkage
AAB Valve

I've plugged all holes where a vacuum leak could be present.



I have the floats set to factory OEM specs:

16mm +/- .5mm
51mm +/- .5mm


I have brand new seats and needle valves as well. I polished the seats lip with a dremel and polishing compound. Polished VERY LIGHT. I also polished the tabs on the floats to make sure no binding could occur. I worked the needle vlaves up and down/in and out 50 times each to take off some of the micro-film.

Car started perfectly.

I adjusted the idle adjust screw to 750 RPM. Also adjusted mixture to spec. Then tuned slightly richer. (1/2 turn richer)


Inspected float level heights, the front most float bowel was dead on. Can't see the rear float bowl levels due to linkage/choke/brackets.



Test drive time:
Everything went smoothly under low load. Could cruise up to 7K and there was no problems whatsoever. I was getting overly enthused so i decided to take the real test: WOT.

I got to a stoplight....deserted of people and cars so i could speed. Light turned green - I floored it and squealed my tires for a moment. 5000, 6000, 7000 SHIFT to 2nd: 5000, 6000, 7000 SHIFT to 3rd: 4000, 5000, SPUTTERING and bucking like a retard in a candy store. I let off throttle and it revved down nice and slow....smooth though. Came to another light and it was idling normally: 750 RPM. Took off again to test it once more before i headed home. Same thing. It got me even more curious so i decided to do another test.

Got onto the highway and eased on at about 60 in 3rd gear. I wanted to test how long before it stared bucking in WOT. I floored it in 3rd: I got up to about 80 MPH and then it started sputtering and bucking yet again. So i shifted to 5th. It was fine as soon as I gave it throttle again in 5th. I WOT in 5th going 70 and it was fine.


SO...i am thinking it's something to deal with my fuel system. I am going to replace my plugs asap to see if MAYBE it's just the plugs. Which i really don't think it is. I have JUST replaced the fuel filter two days ago and haven't drove her until now. EVERYTHING is hooked up to OEM standards. I.E. Fuel lines are hooked up correctly, vent solenoid hooked up. Throttle linkage all fine, everything is hooked up correct.


I am contemplating dropping my tank and cleaning it asap and getting all the crap out of the bottom of it. Under hard acceleration would the crap in the bottom of my tank be sucked up more readily then when i'm just cruising?

If there is any thread with these symptoms in it feel free to direct me to it. I really didn't know what to search for.

Thanks in advance.

- Eric

Experiment.Seven

Any shops in Reno you guys know of? I am thinking just having a mechanic look at it for me.

I'm saving for a Sterling though. =]

- Sterling Carb
- Holley Pump
- Holley FPR

Add those together = FUN :]

Experiment.Seven

Waiting for an educated reply...

t_g_farrell

iTrader: (1)

Sounds like your carb is working and its a fuel delivery problem. Could be a number of things:

1. As you suggested, gunk in the tank.

2. Along with that possible clogged filter back by the tank or now in the carb inlet (theres a screen in there)

3. Old hoses. Replace all the rubber hoses, the old ones start disintegrating as they age, just ask Jeezus he had a similiar issue for a long time.

4. Fuel pump can't keep up. Since its a stock nikki its probably not an issue but you could attached a fuel pressure guage and tape it to your windshield and make sure the pressure is adequate as you go to WOT in the higher gears.

Sounds like you took Sterlings advice from the other post and cleaned up the carb.

Experiment.Seven

If i did have clogged screens wouldn't it make it a lumpy idle?Well it COULD but yes i understand. I will check out the strainers when i pull off the carb again.

Are you referring to the fuel inlet/return hoses? Oh and also when i inspected the bowls the last time i took the carb apart i found several wierd, chalky white pieces in there. o_O

What could that have been?

yetterben

Sounds like fuel filter woes for sure!!!! Couldnt hurt to ake your tank down and have it serviced either. i mean the car is 20 some years old. Who know's what accumulated in the bottom of that tank. That was one of the first things i did to my car when i got it!!!!

t_g_farrell

iTrader: (1)

Sounds like your getting contamination from something for sure. Replace all the hoses that the fuel travels through, including the return ones as well. Hose is cheap and if they are 20+ years old I'm sure they are deteriorating. Replace any filters and clean any screens.

Also, you can try running the fuel pump with the output into a bucket right under it and see if any foriegn material shows up. If it does then its coming from the behind the fuel pump. If thats clear go up from and do the same with the hose on the off the inlet to the carb and run that into a bucket and see what shows up.

dj55b

iTrader: (2)

Another +1 for fuel starvation. If you do get hoses might aswell by the FI rated ones. I would also try pouring some seafoam in the tank to clean up the hard lines and the carburator. Actually I used to pour some directrly in the carb too. Let it sit for about 1/2 a days, it will be hard at first to start up but once she goes she'll go strong.

Experiment.Seven

Well thanks for all the feedback guys...i just wanted some confirmation that it's fuel starvation of some sort.

Thanks...


- Eric