'77 FI Z has hesitation
 

I've done quite a few thinks to my '77 but ever since I put on some MSA headers it has had a hesitation problem.... I've changed the injectors and some leaking vacuum lines. It starts ok usually but only seems to only have three power settings. Idle, accelerate like hell and cruise. In between idle and accel it misses and backfires a little... any ideas on where I should look next? Also, the timing is dead on, both valve and ignition. I'm thinking thermotime switch/cold start valve, airregulator, or maybe the fuel press reg just don't what to throw them all at it if I can help it
thanks for your suggestions.:confused:

check your TP switch. when i first assembled my Z after restoring her, it really didn't have any 'pep' until i reached about 3/4 throtlle, then she took off. was cool for about a day, then got frustrating. the switch should close the off idle circuit at about 1/3 pedal travel. i drove around for a day or two with the wrench to loosen the bolts in my glove box so i could just pull over and tune it as i went. when she's in just the right spot, it's pretty cool... also, just as preventative maintenance, go through and clean all the electrical contacts on the sensors and injectors.

had the same problem
 

take a close look at the bottom of your intake where your EGR line used to be. When I put my header on I didn't close that hole good enough and mine acted the same way. Vac leak

I had the same problem!!!
 

did you use the msa intake and exsaust gasket??? if so, your gonna have to take it all back apart. See the msa gasket is made for 240's - 280's... so the holes in the gasket for the injectors to spray the gas in.. well there not cut out in the gasket. You are going to have to either buy a new gasket, or cut the holes in for the injectors. I thought i had a FI problem... so i went to carbs.. but after taking my fi off to switch to the carbs i found the problem with my gasket.

Re: I had the same problem!!!
 

WOW! That's crappy!!

I've learned always to double check anything I get from MSA.

I've been running the MSA header gasket on my 280zx for years and have no problems. I never did check to see that it has fuel injection cutouts.

FIXED!!!!
 

I finally removed the gasket material from the injection ports. What a difference, all the stuff I've done just for the wrong gasket!!!! Thank you all for your suggestions. And I will pay more attention to MSA stuff from now on. Thanks again.

hey!!
 

im glad you found it!!! :) i drove a whole summer like that. And then convinced that my fi was shot, i convrted to carbs.. in that process i found that out about the MSA gasket.. it really sucked.. glad you found it before you gave up :)

I suffered w/it for the last three years..... lol only on weekends though