Carb to Injection

[Waytec]

A buddy of mine from work has an YJ with a 4.2 in it carbureted. He read that you can tack the parts off a 4.0 fuel injected and bolt them on to the 4.2. He want to know is this possible. He wants to make it fuel injected.

[barmanjay]

Someone correct me if I'm wrong

carb is a mechanically controlled fuel system

Fuel injection is an electronically controlled system and will probably require the computer and wiring harness

So theoretically he can just bolt on the top end parts,.. but will need the ecu and wiring harness aswell, maybe the sensors if they changed.

[BlackYJ]

Fuel system will also have to be looked at, ie fuel pump

[yjcanibul]

mopar ( via hesco engines) has a kit based on 94/95 yj 4L that includes everything you need, to scavenge used parts there will still be items you'll have to get over the counter like the crank dampner / external fuel pump etc ...

with the 4.2L most likely high milage now the conversion wont pay off -- if his carb is acting up research the mastercraft 2100 carb others on this site run ,  if he wants more power etc the mopar kit will do it but with so many 4L around it might be cost effective to get the whole thing from a donar ...

oh,  there is also howell who makes a kit (throttle body injection not multiport),  someone on edmonton site had a used one for sale couple months back ...

[rws]

Go to the Hesco website, they have all the information plus prices for the conversion.  There was a CJA member who did this conversion several years ago and by the time he was finished he was into it for several thousand dollars.  The donar might be the cheap way to go.

[Gearhead]

Done this , big job & not a bolt in .  Howell makes a kit , based on chevy parts , looking at pictures of the kit it seems simple to do , cost ?. Search online to find details. The Mopar kit is scary expensive , like 3 g's ,  often more than a twenty year old rusty YJ is worth.

 I went genuine , mostly used , some new , it wasn't hard for me , I'm licensed  &  it took some time  however  the jeep was down for a month  due to some delays with the machine work and locating a few items.  My 4.2 was tired  &  mile'd out , I built a  94 /79 vintage longblock  stroker , used a factory  93 wiring harness & ECM  , the wiring harness came out of a 93 YJ , all of it , from front to back including instruments and dash wiring. The old guages won't work , you'll need a fuel pump & the speed sensor , need to figure out how to mount the crank sensor if it's got a poogeut trans , the crank sensor hole is there on an AX15. At the end , it was worth it and runs strong at any angle or grade but was costly.  I would have been better off starting my Jeep build with a newer unit , rust never sleeps !


That is all   

[hps4evr]

you can get aftermarket intake manifolds to bolt on a regular holley carb. offenhouser intake, pace setter header, holley carb. works better, runs smoother, better fuel mileage, way more power!

[yjcanibul]

rummaging last night I found the mopar parts list (1 page) for their kit ... not sure if its useful scavenging though ...

yup expect downtime putting the kit on - I was able to do myself (mandatory) over 2 or 3 winter months and threw on a '91 yj 4L HO head conversion and matching 4L headers and catback , all these factory parts are compatible ...

I did mine along time ago (100k) and its paid for itself now in years of reliable service (190k) and just plain fun ... it also gets better gas mileage but on the flip side it only runs on premium ...

its one of the reasons I refer to my yj as the canibul,  its runs an '87 xj D44,  '91 head/header setup,  94/95 MPI,  '02 rubi 5spd ... might soon add something from a JK but what ?

[hps4evr]

add jk rubicon full axles;)