Author Topic: Distributor and carb upgrade (Read 1901 times)

superles · « **on:** August 06, 2007, 08:22:06 PM »

A)I want to change my distributor in my 90 YJ to an HEI set up and wondering what is the best donor vehicle and how this is completed.
B)I've done the 4.0l head swap and the engine is strong however a little rough on the idle (some what ignition and the rest is all carb and vacuum problems). How do I get rid of all the vacuum lines and go to a carb without all the computer feedback.

Any suggestions would be much appreciated.

calltrex · « **Reply #1 on:** August 06, 2007, 09:51:56 PM »

i did the hei swap in my 88 yj

look for a older chev truck in the junk yard with a 6cyl hei

the second truck i looked in had one.

then all you need is a amc v8 distributor just to get the gear off it.

put the amc gear on the hei and thats it

you can order just the gear from a parts place but its not cheap.

calltrex · « **Reply #2 on:** August 06, 2007, 09:53:44 PM »

Ive also dont the carb swap where you get rid off all the stupid lines etc...

not worth it. just get the howel efi kit and be done with it.

superles · « **Reply #3 on:** August 07, 2007, 08:49:03 AM »

Good info, thanks.
Where would a person get the Howel fuel injection kit, and in my case it would have to be for a 4.0l manifold.

Gearhead · « **Reply #4 on:** August 07, 2007, 10:56:52 AM »

On my 88 , I used a CJ carb , removed the microprocessor and associated wiring. I surgically removed the unneccessary wires to do with the pulse air and various other non functioning solenoids n'stuff, then re-bundled the harness so it looked as thought it had never been altered. The ignition module can be wired directly to the distributor , also known as the nutter bypass , I got a little more elaberate with mine.

How did it work ?

Pretty good , it started much better , idled better , for everyday use and mild off roading it was fine. When driving in steep terrain it still sucked and would stall , often in a difficult spot to get it going forward agin , .... once you finally got it to start again.

That got old , the stalling became a safety issue , so , knowing that fuel injection was the only real fix

I built a stroker 4.7 and converted it to fuel injection , using factory wiring and computer. The guages needed to be changed too , the speedo will be electronic and the tach in the 4.2 YJ is not compatable with the MPI system. A fuel pump / sender will have to go in the tank. Knowing all that and my stock cheesy guage cluster was acting up as well as the stock wiring had been messed with and butchered by an alarm installer and the previous owner , I decided to re-wire the entire vehicle. Not a big deal for me , using a stock wiring harness from a 93 YJ , the install didn't take long at all , none of the original 88 wiring remains.

Here's the stroker engine , a 94 block , an early high inertia crank.

Here it is in it's new home

superles · « **Reply #5 on:** August 07, 2007, 05:00:16 PM »

that looks awesome, I have the 4.2 with the 4.0 head therefore for intake port alignment I will need to get a 4.0 ltr intake and add either a carb or fuel injection to that. It may be easier to find a 4.0 harness and all or adapt all the 4.3 ltr chev stuff on to it. Alot of work regardless.

superles · « **Reply #6 on:** August 07, 2007, 05:00:31 PM »

that looks awesome, I have the 4.2 with the 4.0 head therefore for intake port alignment I will need to get a 4.0 ltr intake and add either a carb or fuel injection to that. It may be easier to find a 4.0 harness and all or adapt all the 4.3 ltr chev stuff on to it. Alot of work regardless.

Gearhead · « **Reply #7 on:** August 07, 2007, 10:45:32 PM »

I had toyed with the idea of buying a Mopar efi conversion , ........ until I found out the kit was $3000 !!!

The Howel kit was another option , after thinking about it , I passed on that and decided to go genuine. I bought a partial wiring harness , some manifolds n' stuff , which turned out to be a waste of time and money . None of the connectors mated to my stock wiring harness , then I bought another buch of dash wiring , again I found that having three different wiring harnesses of various years wasn't the best or easiest way at all, more connector issues ! . That is when I decided to go with the entire harness from one vehicle , a 93 YJ , I was fortunate to be able to remove it myself , winding up with an intact , undamaged wiring harness that could then be used for the swap. The fuel pump , instruments and dash switches , vehicle speed sensor , all came from the same vehicle.

Because the engine is a 4.7 , I decided to use Accel 24 lb injectors and a 64mm throttle body as well as a full Banks exhaust. I used a Comp cams camshaft / valvetrain kit , Mopar roller rockers and ported / polished the cylinderhead. It's balanced and all clearances measured to spec using measuring tools that are calibrated to .0001".

End result is a strong powerfull engine , no stalling off camber or at high angles , including standing it on the rear bumper.

Do you have a 4.0 intake ?

I've got available / for sale

4.0 H.O. intake
4.0 H.O. exhaust manifold
A set of H.O. injectors
Another cylinderhead
A 4.0 valve cover
I don't think there is a 4.0 H.O. throttle body here , it's on my 2.5
powered YJ.

You will need a distributor for MPI , as well as a coil , if you are going with genuine MPI conversion using salvaged/used parts , the Mopar kit comes with all necessary items.

It would be possible to put a carb on a 4.0 manifold , you could also buy a manifold designed for a carburetted /4.0 manifold from Clifford Research.

Me , I'd put EFI on it and call it a day.

superles · « **Reply #8 on:** August 08, 2007, 08:38:20 AM »

I have a 95 YJ with the 4 cyl, complete. How much of the components/ wiring harness would help. The MPI / distributor and Intake manifold would be different but I could get those.

rws · « **Reply #9 on:** August 08, 2007, 08:43:18 AM »

Jeep published a book on how they turn take factory standard jeep motors and convert them to factory performance motors. There is a large section on EFI conversion. The book cost around $30 and is full of intresting info. I'll look the part number up tonight and post tomorrow.

rws · « **Reply #10 on:** August 08, 2007, 06:20:01 PM »

Made a mistake. The correct book is called JEEP CJ REBUILDERS MANUAL by Moses Lundel. It provides a very detailed description and installation of the EFI conversion kit. I think the kit would be very expensive as it includes all the engine sensors and peripheral hardware including the fuel pump,manifold, injectors,etc,etc.

Gearhead · « **Reply #11 on:** August 08, 2007, 07:03:56 PM »

Quote from: "superles"

I have a 95 YJ with the 4 cyl, complete. How much of the components/ wiring harness would help. The MPI / distributor and Intake manifold would be different but I could get those.

Although similar , the wiring lacks the #5 & #6 injector circuits . The coil will work , the distributor should work by using a 6 cyl cap ( could be wrong on that ). Many of the sensors are the same .

superles · « **Reply #12 on:** August 11, 2007, 08:44:40 PM »

Sorry I've been away, what do you think on the other harnesses and computer, as does the computer not just monitor the sensors and then say add more fuel fuel through the injectors and add air. Maybe it can be done with a different manifold its injectors and wiring harness. Distributor coil is easy.

I'm a diesel guy, not sure on this one.