fuel pump and vacuum advance

[zztom]

Hi all and Happy Holiday,

Can a mechanical fuel pump be repaired or checked out? I'm getting a lean pop from my carbs. I blewair through the fuel lines and they seem clear. I also checked the fuel rail..clear. The carbs are new Z-Therapy units. Idle is fine but giving it hard throttle pops through carb.

I also would like some info on vacuum advance. Are they adjustable, repairable or disposable? How do you check to see if one is functioning?

The only other thing I can think of is the fuel pickup. Even though I hear bubbles when I blow on the fuel line, can the pickup be blocked?

Everyone here has great opinions and comments to help others. I make sure that I stop by every day to see what the next topic is. Now if we can get those wiring harnesses from ZHADMAN we will all be on cloud nine.. Thanks to all. Tom

[2ManyZs]

The mechanical fuel pump can probably be repaired or checked, but since it's an inexpensive item, it's probably cheaper and easier to just replace it......

You can check the vacuum advace by removing the cap and rotor, and using a vacuum pump or doing it the "old fashioned way" by putting a longer hose on it and up, you guessed it...see if the advance plates move at all...

Another thing, be sure to check the movement of the advance plates, just to be sure the little bearings aren't gone.....

Yes, the module is replaceable, but not adjustable if I remember right.....

Before you do anything, I'd double check your static timing... it's possible it could be advanced just a couple degrees too much and is causing the pop through the carbs......

[frank13]

Hey zztom. If you are getting a lean misfire, you could check you'r fuel line(main feed) from the tank to the hard line in the back. If it's old and chracked it will still run put under load will also suck some air in and kinda give vapor lock or fuel starvation syptoms. you could also check your shop manual for the amount of fuel the pumps should put out while cranking. Then disconnect the out line from the pump and get a cheap measuring cup or the sorts, crank for the amount of time the test calls for and compare. It might also be good to check your advance cannister with a vacum pump/gauge to make sure that your holding vacum and that your advance cannister is not bad. But surely check your timming too.:devious:

[Alfadog]

Originally posted by 2ManyZs

The mechanical fuel pump can probably be repaired or checked, but since it's an inexpensive item, it's probably cheaper and easier to just replace it......

Inexpensive??? Dunno what you define as "inexpensive" but I just bought one for 150 bucks from Repco.. (aud)

[Bambikiller240]

Originally posted by Alfadog

Inexpensive??? Dunno what you define as "inexpensive" but I just bought one for 150 bucks from Repco.. (aud)

Last one I bought (3/4 yrs ago) was under $50 USD

[motoracertx]

Well if you really wanted to take care of the problem. Do what I did on one of my early 240z's. I got a plate to block off the old mechanical pump and installed a electric pump back by the tank along with a pressure regulator and a pressure gauge under the hood. It always supplied the perfect ammount of gas. And was not to costly to do.