# 1986 hardbody xe z24 questions



## BigChewy (Jan 15, 2015)

Hey guys and gals,
Im new to the forum and also new to the hardbody truck i have an 86 d21 hardbody with the tbi z24 engine and my dad has a 95 and little brother has a 91 and im new to the performance and mod world of trucks/cars. my first issue with the truck is i think it has a speed goevernor/limiter and would like to remove it if possible so my question would be how would i do so, the reason i say i think its governed is because i was on the interstate and truck drove fine till i hit 75mph around the 3500 rpm it started to bog out as if governed like a go kart, dirt bike, etc etc. The next issue of concern is in the morning on a cold start if i dont have time on my way to work to allow the engine to run for 10-15 mins and warm up ill go to drive and in 1st and second gears the truck starts to kick and buck as if the fuel pump isnt pushing fuel to the engine. what could be causing this. Also i am wanting to convert the throttle body injection to a carburetor any help on this such as what systems i would have to change as far as injectors intake exhaust would go etc etc i was always taught if your gonna do something might as well do it right the first time so thats what im wantingto do. any kind of info would be appreciated thanks


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## smj999smj (Jan 1, 2006)

Your problem isn't a governor issue. It sounds by your description that you either have an ignition problem or possibly a fuel injector problem that is causing both of your driveability issues. It could be one of the two ignition coils is cutting out, a bad ignition wire or a bad distributor cap. How long has it been since it was tuned up? If there are a lot of miles on the ignition system, I would recommend you replace them with NGK ignition wire and NGK spark plugs and a genuine Nissan distributor cap and rotor. I would also suggest you get a Nissan factory service manual for your truck as it's a wealth of useful information. Sometimes you can find paper versions on Ebay for around $30; they are worth every penny! The fuel injector spray can be viewed by using a timing light aimed at the inside of the throttle body when the engine is running. The strobe light affect makes it possible to view the spray pattern and I believe there was a TSB on fuel injector problems on these engines. Try looking in the "knowledge base" at NissanHelp.com or at Nico's forums for the TSB. 
You should also try check for self-diagnostic codes stored in the ECM. The procedure is here: www.troublecodes.net/Nissan

As far as replacing the TBI with a carburetor...WHY? The throttle body injection system is far more efficient than a carburetor, so why reverse-engineer the truck? It's a lot of work for no gain! You can a view a good article called "z24i, tbi to weber conversion" in the forums at Nico club. Just Google, "1987 Nissan truck z24i to carburetor conversion" and you should be able to find it.



My two cents: the Z24i was a very good engine. It wasn't much on power, but sufficient for the truck and a tough engine! It has a "hemi" head design and the dual ignition system designed for a lot of EGR and good emissions performance. There are some things you can do for better performance, but it's best not to get your dreams and expectations too high unless you are going to dump a lot of money into it. If you want a good, reliable truck with descent performance, keep it as stock as possible.


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## BigChewy (Jan 15, 2015)

Thanks for the info man I really appreciate it gives me some where to start. My reason for wanting to put the carb on it is just I have always wanted to have a carbureted hardbody but like I said im new to the "mod" world but thanks for the advice on the governor issue I work for a nissan dealership so usually getting the oem parts is nothing. And im also wanting to make the truck fast enough to compete on tge track and of course look good to comoete in car shows.


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## BigChewy (Jan 15, 2015)

well possibly had my head gasket blow today was doing some errands on my lunch break and out of no where white smoke just started barreling out the exhaust but only did it when i would accelerate and go to shift into the next gear any thoughts???


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## smj999smj (Jan 1, 2006)

Could be... Head gasket failure is not uncommon on the Z24 engines; they typically blow between the cylinders. It's not the worst job in the world. The most important part is to wedge the timing chain between the guides so it doesn't drop when you remove the cam gear. If the chain drops at all, you'll have to remove the entire front cover. Otherwise, it's mark your vacuum hoses, put engine on TDC, disconnect the front exhaust pipe from the manifold, disconnect the accellerator cable, etc., valve cover, head bolts, and lift the cylinder head/exhaust manifold/intake manifold assy. together as one piece. Make sure you check the head deck for straightness or have it checked at a machine shop. It'll probably run like new when you get her back together!


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## BigChewy (Jan 15, 2015)

yeah well hopefully the heads didnt get to screwed up if it did blow because i bought the truck roughly 2 and a half months ago and it had a blown head gasket then i had the heads worked at a machine shop where they worked 10 thousandths off the head when my father and i pulled the heads then there was some scarring we seen on the cylinder walls and my old man said that they worried him he thinks that there may be a crack in the block. We are gonna rip it apart tomorrow evening after the 2 of us get off of work and check it out if the block is cracked i havea friend of mine who has a 95 hardbody which has a blown engine and he said i can have the truck for parts. so lets keep our fingers crossed that the block isnt blown out if they are i already ordered new gaskets from work and will get them in a week from monday i work for a nissan dealer in FL and when we get the engine pulled im probably just gonna do a complete rebuild. but ill keep you posted with pics and vids. thanks for your help bro


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## Shut-Trip (Oct 18, 2012)

*carb versus fuel injection*



BigChewy said:


> Thanks for the info man I really appreciate it gives me some where to start. My reason for wanting to put the carb on it is just I have always wanted to have a carbureted hardbody.



In response to your interest in carb versus fuel injection. I had a VW pick up many years ago, that was a carb engine, 1.8 L 4 cylinder. and I was rebuilding it, but it took too long to complete, and my landlord had me get rid of it. I sold it to for $300.00 that was about 20 years ago.


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## BigChewy (Jan 15, 2015)

ok head gasket didnt blow head is not cracked and as far as my father and i can tell neither is the block but there is a throttle body issue, while my dad and i had the air cleaner housing off the top of the throttle body i put a towel over the top of the throttle body to try and choke it out which in theory would have worked but it did not choke out the engine so the throttle is pulling air from somewhere else found a weber progressive carb online for 300 bucks. We got everything back together, and found out the exhaust coil plug was no good so i got a new one and put it on so now all 8 of the spark plugs are sparking but when idling the engine is only operating on 2 cylinders and when i get moving it runs on all 4 any ideas on this issue??


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## smj999smj (Jan 1, 2006)

Are you sure two of the spark plug wires are not swapped? The ignition system, IIRC, runs the intake side all the time by only the exhaust side part of the time. You'll also want to make sure your coil wires are going to the right coils. The front coil is usually the exhaust coil. The distributor cap should be marked where all the wires go; the firing order for the intake side is not the same for the exhaust side. 
If it's sucking air some place, the most common areas are the throttle body gasket and the intake gasket; a bad intake gasket could also be the reason why you are missing on two cylinders. Try spraying carb cleaner around the intake gasket with the engine running and see if the RPM surges; this would be an indication that the intake gasket is broken or leaking. 
I still advice against the carb swap, but it's your vehicle to do with what you want. I believe you may have to replace the distributor, as well, for a vacuum-advance type. Do your research before dropping down the Weber.


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## BigChewy (Jan 15, 2015)

ok cool thanks SMJ for all the advice and ill do some more research before i officially say yes or no to the carb but thanks bro ill keep you updated on everything as it progresses


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