Swapped 4.3L Vortec Carbureted Fuel Pump Problems

Hey guys, I'm a newb on here, but just bought my 3rd XJ.

This one is an 84 with lots of changes, including 4.3L Carbureted Chevy Vortec from an 80's blazer.

Right now the fuel pump is dying, clicking loudly, and has died once so far.

What fuel pump should I install?

I've never worked on a Chevy engine and I'm curious how much that will affect everything in my XJ.

Other mods that I've identified by the way are Rough Country 3.5" (im guessing) 32x11.5 BFG AT KO's, Posi Lock, aftermarket front and rear bumpers, safari rack, cb radio, skid plates, and kenwood stereo.

I am also curious, how much of an impact does the fuel pump have on the ability for the XJ to accel?

a 4.3l swap = pure awesome. Have you checked what tranny and Tcase are behind it?

Anyway, not sure which one with, but a dying fuel pump will whittle acceleration down to a peg before you replace it...

I haven't checked the tranny or transfer case yet, in fact I'm going to do that as soon as I finish here.

And accelleration is worse than down to a peg, I'm glad to hear that this sounds like the only issue.

Without looking at a manual or dropping the tank, I can't remember, is the fuel pump mounted above or inside the tank? That will affect whether I change tomorrow or on the weekend.

I just bought this for a great price, but Ive only ever had stock xj's, so i need some help!

Let's play a game, . . Name the Mods!


sorry it's so fuzzy, cheap camera!

4.3L Vortec from 80's Chevy Blazer

Front Diff

Front Axle w/ 4x4 Posi-Lock (Whitey Brand from Oregon??)

Rear Diff
Rear Axle

Xfer Case, numbers are C-15367

Undercarriage

Okay, Tranny does say 30-7AF but thats all I can read. Sorry for being such a newb but I've only ever had stock, and until I moved to Alaska and started hitting some pretty nice trails going fishing, I never needed anything more.

Whatever you guys can identify I'd appreciate it. Because I have no clue!

GM never made the 4.3 with a carb, and thats not a vortec motor, probably a 4.3 tbi

Re: Swapped 2.8L Carbureted Fuel Pump Problems

It just occurred to me after taking the pictures, I really don't know my Chevy's!

Okay.. so I have a 2.8L 60deg V6 from an 82-85 s10 blazer

Not exactly an improvement from the stock 2.8L hmmm....

Ok first off a little clarification the 4.3 was offered with a carb even a 4 barrell from chevy. look at an 85 astro van or the manual for one. second ditch the 2.8 biggest garbage engine ever made. the 4.3 swap is easy find a totaled 88 or newer s10 use advance motor mounts and it drops right in. wiring is straight forward since you already have a gm engine in it only a few wires to hook up for the fuel injection use a tank from an injected jeep and have fun. I done that with my 86 wagoneer limited and I love it hundred plus pounds lighter than the 4.0 and more power.atriot:

Tranny is a GM 350 Turbo. Best they made IMO. Front axle is a d-30 I think and the rear could be... cant tell your pics are to fuzzy for me to tell.

Okay, so I have a good tranny, I'm going to assume and sure feels like a good xfer case, dana 30 front and rear

I'm not going any larger than the 32's so I think I'll be fine, and I do no rock crawling, so I don't think I'd need any larger axles.

Problem still stands I need a fuel pump, should I order a pump for a 2.8L v6 that was found on the 85 s10 blazers, or are there any recommendations.

I need something that isn't sucking fuel quicker than I can put it, I am a student, so this is a daily driver, plus a tough vehicle that can get me to my fishing, hiking and MTB'ing spots.

Also, I understand a dying fuel pump kills acceleration, but what about fuel consumption, does it make it any worse?

Sorry for all the newb questions, but I want to get this sucker right, and hopefully this time I don't send it flying and roll it 3 times like I did my last one!

D35 btw just for clarification..great deal with the th350, but as they said, get a 4.3. In fact.. if you were in Fairbanks, I could point you to 2 of them my uncle has laying around from his old trucks.

Get yourself a purolator external electric fuel pump and fuel regulator if you are going to save the 2.8 I would go with the 4.3 it will give you better mileage then the 2.8 because it won't need to work as hard and it will bolt right up to the TH350 auto. :compwork:

Okay, I'm glad you said something about that, It had a Purolator Facet Gold Electric Fuel Pump, thats the bad boy that was clicking like it was going out of style.

Now I went and purchased another one of those, exact same one, and just as fast as I could turn the key click click click . . .

Now even worse I am getting no fuel to the engine, I even took off the new one, replaced the old one and made sure all was connected exactly as before. No Fuel.

I poured a little gas directly into the carb to ensure that was the issue and sure enough started right up. . . for about 5 seconds.

So, I know fuel pump is dead, new fuel pump is dead, what are the chances that the new one was defective OR something else could be causing the pump to die in seconds (doubtful considering the new pump never even had fuel run through it before it started clicking like a beast.

Help me folks, the Heep is looking pitiful in the driveway!

Maybe the pump isn't at fault. Make sure you have 12v at the pump, if you don't the pump will click like you say it does. You can test your old pump by hooking it up directly to 12v (battery) and see if it works. Don't let it run for a real long time though, they don't like to run dry. Let us know what you find.

You are half right, pump was not at fault, it was a clog in the filter or fuel line. It's still there but buried in the filter now.

I will take care of that probably on Saturday along with a new tranny filter, tranny fluid, oil change, and I think I have a CV joint issue.

JEEP - Just Empty Every Pocket!

stoveguy said:

Ok first off a little clarification the 4.3 was offered with a carb even a 4 barrell from chevy. look at an 85 astro van or the manual for one. second ditch the 2.8 biggest garbage engine ever made. the 4.3 swap is easy find a totaled 88 or newer s10 use advance motor mounts and it drops right in. wiring is straight forward since you already have a gm engine in it only a few wires to hook up for the fuel injection use a tank from an injected jeep and have fun. I done that with my 86 wagoneer limited and I love it hundred plus pounds lighter than the 4.0 and more power.atriot:

Click to expand...

truth... the s/t trucks never had a carb'ed 4.3L though.

that is true for the 4.3 didnt come in the s/t trucks untill 88 and when introduced in them had tbi. excellent engine tho I love them and so does my jeep lol.

OK, WHOA, WHOA WHOA, hold on a minute here people, theres a LOT of wrong or misrepresented info here.

first off, no, that is not a 4.3, it IS a 2.8 (they came optioned 84-86)

second, that is not the awsome TH350 auto, the TH350 has a bellhousing pattern that only fits 90 degree chev engines (ie small/big block V8, 4.3 V6) but the 2.8 is a 60 degree engine(which refers to the angle of the cylinder bores in relation to each other) It does have the same LOOKING pan as a 350 turbo, but it is not possible to have that trans and engine. do more research on the 84-86 autos in cherokees, im not sure what it is, some chrysler weakling.

third, if youve already found and replaced the fuel pump, then i dont know what to tell you, but all the 2.8 carb models (the only ones that came in cherokees) had a mechanical fuel pump on the drivers side of the block, on the bottom.

fourth, yes the 4.3 did come with a carb, on full size trucks, but never in s trucks, you could have a 4.3 vortec with a carb though, just by swapping intake manifolds to an aftermarket unit and buying the carb

fifth, as for the 4.3 conversion, dont even get me started. its not worth it! you dont just "drop it in" with new motor mounts, you need to buy a trans that fits it (remember 90degree vs 60 degree? i used a 350 turbo) then you need to buy a $500 + adapter to your transfer case, ( and you dont have one of the best) or you could use a chev transfer case with a drivers side drop (but you would have to cut new, ugly holes in the floor) you have to fab up a cross member to support this all, and shorten lenthen driveshafts)
if you go with a carbed 4.3, then you can just get a stock, block mounted fuel pump, or external electric low psi, if you get a TBI then you can buy a 4.0 liter fuel pump sender/assembly tree, (they run the same pressure) but thats another $150ish. if you get the vortec CPI injetion, you have to fabricate a high(62-70psi) S-truck fuel pump into the jeeps intank sender tree(not easy, even for an expert mechanic!)
also, in 87, jeep changed the engine bay/radiator front end mounting, and used a new radiator to fit the 4.0, and to cool that 4.3 you need a radiator built for the 4.0 liter, you will have to cut up front sheet metal and rearanger your radiator mounts to fit the new, much wider radiator (not to mention youll have to have a radiator shop rearange the outlets in the radiator, cause the 4.3's are revesed from both the 2.8 and the 4.0 outlets, which will cause you to delete the stock trans cooler and youll have to use an auxillary one)
the wiring will be easy for an expert to put in a carbed 4.3 with no emission, but if you wanna keep S-truck fuel injection, you better know EXACTLY what your doing or know an artisian electrician with time(and your money, lots)vortec being especially difficult.

mine is a 200 horse vortec with a flowmaster 40 and the aformentioned th350 BnM shift kit, 3 in lift 31's and 4.10's. HELL YES its fast, but all the down time and money wasnt worth it, i didnt go wheeling for 6 months!

there are so many things to think about and organize, doner trucks, trannies, adapters yadda yadda. there are so many things i didnt mention, i could go on and on about oil pans and oil filter adpters, and i did all the work myself, i didnt have to worry about a shop screwing it up
but it all comes down to is it TOO MUCH TIME vs pay off? either keep it if you love your truck and wheel it until you die!(hell yeah) or sell it and buy one with a 4.0, cause youl be WAY, WAY, WAY ahead in time and money.
if you ask for pics ill try and find a way to post them
-Matt

well if you read my post I said look at the 85 astro van. they came with a carbed 4.3. and I also stated get a donor 88 or newer s10 for the parts If I need to break that down. eng,trans,transfer, wiring, fuel pump. and yes with the advance motor mounts using a donor s10 it does just drop in. I know for I done it.

dam you just spoilt it for me, cause i keep looking at the 03 4.3l efi vortec motor (Volvo Penta) in my boat 225 hp....and wondering...what if

Ewen