Author Topic: going back in time (Read 2686 times)

XJHERO · « **on:** May 02, 2006, 08:32:04 PM »

does any one know what i need to change a fule injected 4.0 to a carb 4.0?
fed up with electrical problems.

ramtuff · « **Reply #1 on:** May 03, 2006, 09:10:53 AM »

I don't think they ever put a carb on a 4.0l

this would be a custom job.

NS-jeeper · « **Reply #2 on:** May 03, 2006, 10:27:27 AM »

If the head of a 4.0 will fit on a 4.2L then I would assume the head off a 4.2 would fit on a 4.0 that would be a start, of course you'd lose HP. You'd be better off just to switch your whole engine... drop a chevy carb'ed 350 in, it'd probably be cheaper in the long run as their a dime a dozen and there are tons of aftermarket parts and adapters.

ramtuff · « **Reply #3 on:** May 03, 2006, 12:48:22 PM »

Quote from: "NS-jeeper"

You'd be better off just to switch your whole engine... drop a chevy carb'ed 350 in, it'd probably be cheaper in the long run quote]

X2

go small block chevy

TJ54 · « **Reply #4 on:** May 03, 2006, 03:34:57 PM »

Just thinking out loud here.

Does a XJ have throttle body injection or multiport ? If it is mutiport then I would think you are out of luck.

But if it was TBI, could you not build an adaptor plate/ spacer between the intake manifold and the carb that you choose. Then build the required throttle linkage.

I imagine that the fuel injection management is also tied to the ignition timing, So that would have to be defeated, maybe, there was a points type distributor on the older 4.0/4.2 motors that could be used.

How is the fuel pump connected into the system? Is that computer controlled in any way ? If it is you could bypass that and just have the pump come on with the ignition. You may need to put in a fuel regulator as I believe the fuel pump would provide too high of a pressure for a carb.

Or you could go to the wreckers and buy a carb'ed 350 :wink: Then in a year when you realize injection is best you can go buy a holley projection system, and a bigger cam, and a blower, then maybe some nitrous. Then a TJ because the XJ unibody twisted with all that power, So you need a full frame. Then the blown 350 will seem a little short on power so you would have to get a big block and then.................................

XJHERO · « **Reply #5 on:** May 03, 2006, 11:30:46 PM »

ok so its not just switch a few things.

my problem is i have this 4.0 87 xj I had the moter to the machine shop had it acid diped, new cam, new camberrings installed, new cam, new crank berings, crank pollished, cylinders honed head decked and checked.....bla bla... Got her all built replaced sum wireing harness scencers galore. worked great pounded er last maylong and and arround for a few months, than one day it just died on me. after sum major tinkering found the ecu had a fried cicut on the cirit bord, so changed the ecu ran it for a bit and it seems to heat up that spot on the ecu, but never burnt thru yet. Moter will fire up great but backfires and stumbles when load is applied, :evil:
Iwould like to get this thing goin.

just makes me want to light it on fire(again)

im thinkin of just pullin it and putting on my extra 4.0lho head and intake and saving it as back up for my 91xj cus if ya seen me wheelin youd know why i need a back up moter.

hence the handel 87xjHEEP

thanx for the input guys
as for goin small block well there is 350 and a few 305s sittin arround the garrage. dont know if i want to go that far it is just a jeep.

cotaman · « **Reply #6 on:** May 04, 2006, 10:39:44 PM »

Hmmmmm... seen you wheel.....we will leave it that :shock: :shock:

that sounds like a great idea... i could always use a non HO head so mine doesn't sound like a diesel at idle.
:twisted:

XJHERO · « **Reply #7 on:** May 05, 2006, 08:34:50 PM »

sorry eugene got the old gem runnin. look out. need tires 32 33 what ever mt please.