[dB Zac]

I have a 85 Nissan 720 with a rebuilt z24 engine but the carb and or computer is not right. the engine idle speed is erratic, it dies if I turn the idle down and it races if I don't.

I have a 86.5 donor d21 truck that has the z24I engine. Is there a website, book or has anyone on here converted a carb 720 z24 to EFI

 

[CMax03]

The Z24i is a good engine but the injectors are expensive and not rebuildable and the TBI is a bottle neck in the performance aspect. My dream is to get a Weber Sidedraft intake Manifold and install individual Throttle bodies, controlled by either a SDS or Electomotive standalone ecu. I'll definitely have no problem putting down 220 whp. checkout www.raceengineering.com

 

[dB Zac]

that's all well and good but I w3ant to end up with a CA smog legal truck that has good drivability.... thanks for sharing LOL

 

[Peterdaniel]

Honestly, I would just look for a stock D21 truck.. There are plenty out there.. If you did what you wanted to do, it would be a nightmare.. Most likely, you would need a new fuel tank, fuel pump, new wiring harness, computer, head for Fuel Injection, possibly new exhaust manifold and definitely all the top end stuff... THEN you have to convince the EPA ( the environmental pollution agency) in CA.. also know as CARB to give you a waiver.
Way too much work if you ask me.. unless you have a lot of time on your hands.

 

[Peterdaniel]

It also sounds to me like you have a massive vacuum leak in your 85 720.

 

[dB Zac]

I checked for vacuum leaks and found none. When I have the truck in neutral and the clutch engaged (not disengaged) it idles down somewhat. I know the computer sees the clutch switch and there is a "neutral" switch in the trans too. I am guessing that it has something to do with when the exhaust plugs fire, but why it would affect the idle I have no clue.

I have a d21 motor, wiring harness, and computer. I also have an inline fuel pump that carter make specifically for putting EFi motors in carbureted cars and trucks. I just need I little help sorting out the wiring

 

[brookwood61]

If you decide to got with the TBI, make sure your rubber fuel lines and clamps are going to handle the extra pressure.
I had a choice of keeping an 85 longbed,or an 86 king cab TBI a while back when we shut down our business.Many times I wish I had kept the carb set-up. I know where an 85 is sitting,if you need any hard to get parts.

 

[tzdust]

the vaccum and overall setup on both the z24 and z24i experience idle problems all the time. you may convert and still have the problem. i've been chasing vac lks for years in my trks. 720 & d21. if you just want convert i understand but i think you would be best advised to plug vacs and install a webber. you get better hp and a consistent idle. you can rebuild your carb (if u r pos it is nt vac reltd) or get a good used one. bad carbs are a dime a dozen and good ones are priceless

 

[CMax03]

Honestly, I would just look for a stock D21 truck.. There are plenty out there.. If you did what you wanted to do, it would be a nightmare.. Most likely, you would need a new fuel tank, fuel pump, new wiring harness, computer, head for Fuel Injection, possibly new exhaust manifold and definitely all the top end stuff... THEN you have to convince the EPA ( the environmental pollution agency) in CA.. also know as CARB to give you a waiver.
Way too much work if you ask me.. unless you have a lot of time on your hands.

Heads are the same, Exhaust manifold has AIV air injection port on the Z24i engine. With a SDS engine management and 4 individual throttle bodies, can be tuned to run like a champ. By the way once the vehicles 25 yrs old here in Texas it's excempt from emissions and I'll probably go Webers side draft just for the hell of it... No need to invest $5000 in a $500 ride (BBV)!