new guy, tbi z24i question

1980-1986 Datsun 720 forums. All 720-specific topics and discussion can be found here.
billygoat22
Posts: 2
Joined: Sun Aug 06, 2017 3:51 pm
Car: 720 z24i, 720 z24

new guy, tbi z24i question

Postby billygoat22 » Sun Aug 06, 2017 4:06 pm

new to forum here. have been searching but have found some new questions rather than answers!


I have an 86 kingcab, z24i, electro injection on air cleaner. I hear that this was supposed to be a single injector setup but mine has two injectors, which is supposed to be a vg30i setup? advance auto site had a manual and some other sites have the same statement.

Problem I have is that engine is acting up, will idle fine and little rough until get on gas some or more gas at higher speeds, can feel a point where it seems to bog or loose power. Awhile back blew a gasket, replaced head gasket and intake/exh gaskets and ok for good while.

Started again (slightly) few yrs later and found stud on intake loose under aircleaner, tightened and ok again. 6 mo later starts again, started right after downshift to make a turn and starts out of turn. replaced intake gasket due to saw a little coolant in sparkplug recess, second back (#3 I think?). still acting up, but also at same time noted one of plugs on exh side had come loose and was melted against exh header, so replace with older set I had replaced when did head gasket.

Going to take it to mechanic wed, too busy at work to spend a lot more time on it, and little exp w/tbi. Even mechanic said its an odd setup and would challenge some due to age, # out there. Looking for input or manuals on this engine/ tbi.
looks exactly like a z24 setup, only w/tbi. looks like one of pics in sticky post, but has 2 injectors. also has the box under driver seat where you use screw to do diag mode.

thanks for any input. Truck has run fine otherwise, exp for 30 yr old machine.


billygoat22
Posts: 2
Joined: Sun Aug 06, 2017 3:51 pm
Car: 720 z24i, 720 z24

Re: new guy, tbi z24i question

Postby billygoat22 » Tue Sep 05, 2017 5:37 pm

got back from mechanic. replaced dist and rotor. recommended replace spark plug wires, since one was damaged.

not as bad as before, still has some stumbling or missing still. It seems to be related to the position of throttle. push pedal down over 2/3 way, and starts to loose power, seems like isn't firing.

happens more at higher speed. If shift down can maintain speed w/o issue, but if push pedal past 2/3, acts up.

xeroxcat
Posts: 4
Joined: Wed Sep 06, 2017 11:13 am
Car: 1986 720 4x4 King Cab w/ Z24i

Re: new guy, tbi z24i question

Postby xeroxcat » Thu Sep 07, 2017 10:27 am

also quite new here, and without many answers - but i think we have the same truck!
there is a service manual for the 720 z24 here, covering everything except the z24i TBI differences:
http://datsun510.com/index.php?%2Ffiles ... -manual%2F
this is the accompaniment manual that covers the z24i on the 720 ($200):
https://www.diyrepairmanuals.com/prodde ... 6aNisTruSp
I haven't taken the plunge on the TBI supplement manual but really considering it since i need to pass CA smog and my vacuum lines are all screwed up.

Have you had any luck finding a vacuum diagram for these guys?


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