no power

[nrp]

I have a 260 with 240 carbs and 6-branch manifold/sports exhaust, my problem is that when I try to pull away the car immediately looses power even durining normal driving,the only way I can get round this is by using the choke or if I`m at a junction &nbsp;hitting the gas hard resulting in much smoke and squeeling of tyres. the cars been tuned to no avail the only thing iI have done is clean the engine breather hose which improved the situation. Anyone got any ideas I`d be greatful I use this car every day <img src="http://www.zclub.net/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>

 

[Mr.F]

1. Has any work been done recently - head removed, cam timing disturbed? Or, has the car always been like this since you have owned it? One possible cause could be incorrect camshaft timing during engine assembly. This is a much more common problem than you might imagine.
2. 240Z carbs have a problem with sticking nozzles. These get pulled down when you apply the choke and should then slide back into place when you release it. In older carbs, the facing material on the nozzles wears and they can stick open making the idle and initial off-idle response very rich. You may need to consider a carb rebuild.
3. Is the vacuum advance can on this distributor working properly? Pull the pipe off to suck it and see. If bits move inside the distributor and you can hold the vacuum with your tongue, then all is probably O.K. Is static advance correct? Does the mechanical advance curve of the distributor come in smoothly? Use a timing light to investigate how this is behaving. It is common for the weights in the bottom of the distributor to either stick, or lose their springs.
4. Any air leaks around the carbs or manifolds?

 

[pmac]

The Bearded one is spot on here with his comments about cam timing &nbsp;faults being much more common than you would assume.
I had this problem recently on an import car. Just couldnt get the mixture / timing right to make the bloody thing run well through the whole rev range. &nbsp;Took off the Rocker cover and checked cam sprockets and bright links on chain. &nbsp;Bingo there it was . ONE link out. Reset as per book and away she purrs. All the other "problems " gone <img src="http://www.zclub.net/iB_html/non-cgi/emoticons/sad.gif" border="0" valign="absmiddle" alt=''>