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how to replace fuel pump on 2.3 4zd1 engine.

33K views 11 replies 10 participants last post by  1986trooper2 
#1 ·
the manual will tell that you must remove intake manifold.... don't bother with the intake man. its just more time money and headache... so here is the easy way..... sorry no pics.

raise and support vehicle. remove front passanger tire. remove rubber/plastic skirt from between the frame and body.

tools: most the nuts and bolts you will encounter are 10mm and 12mm i used a 14mm once on the funny hose thing at the front of the valve cover on the passanger side. some needle nose pliers will be useful and lots of ratchet extensions. maybe a universal joint or two. don't forget the all important buddy system. usually best paid with food, money, and or beer. oh i aslo used one of those magnetic parts dishes.. ablolute life saver... i just stuck it to the fender every bolt or nut i took off just stuck it to that made finding the right hard ware super easy.

remove air cleaner assembly. (remove nut from carb stud, valve cover near oil cap, and bolt form support bracket. then carefully flip the air cleaner assembly so the top rests on the driver side fender and master cylinder. now remove all nuts and bolts that hold the wire loom in place and throttle cable support bracket. remove the three valve cover bolts and lift vavle cover off.... you can do this without removing the spark plug wires or throttle cable. just takes some effort...

now its time to rotate engine so cylinder #4 is at TDC of compression stroke. so remove the coil to distributor cap wire. and have a friend crank the engine untill the intake and exhaust vavles are visibly closed. then check the cam lobe for the fuel pump... the pump push rod should be on the shortest part of the lobe. if not rotate engine till this is acomplished.

NOW REMOVE + BATTERY WIRE!!!! you will be working with your hands and tools very close to the starter. electricity and spilt fuel is a bad combonation.... please use common sense.

open the fuel door and remove the gas cap. this will relieve the pressure inside the tank. so you don't lose all your gas on the ground when you pull the hoses off the pump.

now go to the passanger front wheel well. disconnect all hoses form the pump. there is a small diaphram looking thing that the hose from the tank goes through. i'm guessing its a back flow preventor the bolt to remove that is just abouve the engine mount.. remove the two nuts that hold the EGR pipe to the underside of the intake manifold. follow the small hardline coming out of the EGR adapter to a rubber hose, once the rubber hose is located disconnect it. now pull down the EGR pipe so you can easily see the pump mounting nuts. now to reach the pump mounting nuts i used three to four wobble extensions that i bought at harbor freight for $10. if you use a 3/8" ratchet with a couple long extensions and use a reducer at the end to use a 1/4" extension then a 12mm socket. this will ease with getting at the nut towards the front of the engine. now remove the old pump, spacer and gaskets. if you wiggle the pump out as far as you can. get the left side of the pump off the stud and swing it down and towards the front of the engine it will be easy gettting it off the other stud.

now use the new gaskets and spacer to reinstall. have a buddy hold the push rod all the way against the camshaft. and put the new pump on. and put everything back together. remember to make sure all fuel lines are tight and still in good shape. if they are questionable just replace em... its already easy to get to and fuel hose for carbed vehicles is cheap. hell i went to the local checker/ shucks/ kragen auto parts and got 28 inches of fuel hose and they just gave it to me free. thats why i always go back to them for my parts. also remember to put some RTV silicone on the corners of the hump for the cam and on the corners of the plug in the back of the head. once everything is back to gether start the engine and check for oil and fuel leaks..... if it won't start double check all your plug/ coil wires and fuel hoses and battery terminal. remember also that all the fuel that was in the line from the pump to the carb is not there anymore so your going to have to crank for a little while. if it starts and runs like $#!T don't be too surprised the pump needs to get broken in.... if it keeps running bad for more than about 5 minutes double check all your vaccuum lines that might have come off during the removal of the air cleaner assembly.

before i installed my pump i put on an inline pressure gauge. with the old pump the needle would go from 6 psi to 0 really really really fast. now with the new pump it stays really constant at 4-6 psi. ok well i'm sorry that this is such a long right up but heck if it'll help out someone else then it was all worth while. so good luck to all those that will tackle this project. also for all those that read this if i missed something or you have something to add go ahead the more information the better. :D

by the way gotta give a shout out to jerry thanks for the tips... took about 2 hours just like you said.
 
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#2 ·
this is probably a day late and a dollar short, but the best way to do is remove the rf wheel and go in through the fender well. I just change mine and I went to the isuzu dealer and spoke with a first gen mechanic and he said to never pull the intake for this. Go through the fender well and there is a pipe that is mounted to the under side of the manifold, I would recommend loosing this and drop it down, it makes access to the bolts easier, I didn't do this until I was putting it back together. If I would have done this from the start it would have been about a 1hr job, but because of that it took me several hours. Drop the pipe!!! If you have already done this maybe this will help you on the next one.
 
#4 ·
Hi, I'm new to this forum and so far it has saved my butt!!!
Thank-you! Thank-you! Thank-you!

I replaced my fuel pump today and wanted to share while it was still fresh in my mind. I tried to do it using the Hayne's Manual and got totally discouraged. They had me taking off stuff that didn't need to come off and I couldn't get the intake manifold to budge after removing the nuts/bolts and tapping it with a hammer and piece of wood. That's when I got on the internet and stumbled onto this site. I'm hooked now and will be cruising the archives to fix up my $350 pickup purchased from Craigslist.

Toolow87isupup pretty much hit it on the head as to how to do it, but I was able to do it without removing the valve cover.

First I removed the distributor cap and turned the crankshaft to top dead center and checked the distributor to make sure the metal tip of the rotor button was at @ 10:00 which is the compression stroke for cylinder #4.
This is where the pump push rod is at it's shortest point on the camshaft.

I had to remove the distributor all the way (don't forget to mark it with white out or make a mental note of it's position) to reach the back of the head to remove the bolt for the EGR pipe bracket. Just to make it easier to lower the EGR pipe, I disconnected the pipe from from the exhaust manifold also. My engine had a heat shield between the end of the EGR pipe and the fuel pump that had to be removed (one bolt). I was able to remove the fuel pump nuts with a long extension, a universal joint, a reducer to 1/4" drive, and a 12mm socket going through from the wheel well.
I dabbed some grease on the tip of the push rod before installing the new pump. I dropped the nuts about six times trying to put them on the fuel pump studs. Each time they fell between the motor mount bracket and the block (a place fingers can't reach).

I laughed, I cried, I wept, and thought for a while that the Japanese auto engineers hated us, but I got over it and finally, it went together. It took about 4 hours for me Mr. butterfingers.
 
#5 ·
When I i mine on my old 87 I did it the lazy way. Blocked off the mechanical pump by sticking the 2 hoses together an put in an electrical pump right after the filter. Took 15 minutes and costed 14 bucks
 
#7 ·
Russell89 said:
When I i mine on my old 87 I did it the lazy way. Blocked off the mechanical pump by sticking the 2 hoses together an put in an electrical pump right after the filter. Took 15 minutes and costed 14 bucks
thats how my dad has his pump on his 86 toyota hahahahha. its awesome u can use it to suck gas outta cans.. or if u run outta gas or to help some1 out. think his lil fuel pump things costed 20 bux tho and it comes with a lifetime warrenty haha
 
#11 ·
Are you a salesman for Airtex and JBA? I don't really think anyone's going to be clicking on your links... Just FYI.
 
#12 ·
I have completed installation of the fuel pump on my 1986 Isuzu Trooper 2.3 4zd1. The guidance provided in this forum was very helpful. I thought that I would add my insights.

I entered through the wheel well. I retested just the fuel pump right there from a gas can, just to eliminate all other variables.

I was able to obtain TDC on #4 by lining up the timing mark on the crankshaft at the same time the distributor rotor was at the 10:00 position.

I had to unbolt the bracket holding a little drum shaped thing, maybe a regulator, on the hose going into the pump.

After I unbolted the fuel pump, I realized that I had to remove a little heat shield where the EGR pipe goes into the manifold. This gave me just enough room to pull the pump off of the bolts. While removing the pipe itself might have given me more room, I was able to get my fingers on the nuts just enough to finesse them into place.

It took me an hour, not counting prep time.
 
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