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adding fuel injection to a 350 cherokee conversion

J

jmg222

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I'm fairly certain I'm going to do this -- aside from losing a wheel offroading over the weekend (see my other post), I had issues with stalling -- sudden drops while climbing uphill and the truck would just stall out. when I put the motor together I didn't want the added expense of a fi unit, so I went with a holly offroad carb.... unfortunetly, turns out it's more hype than anything else.

Anyway, has anyone who has a FI conversion ever done this?

I'm thinking of going with this:
https://www.holley.com/products/fue...r_efi/terminator_4bbl_tbi_kits/parts/550-406K

It's expensive, but gives me one-stop shopping in a self-contained unit.

Any comments from anyone that's done this before?
 
remove small block, install LS with stock GM harness and PCM.

fuel injected.
more power.
more tuning options than a proprietary TBI setup.
less money.
 
Junkyard. Pull your TBI, your sensors, etc and walk out for cheap.
Or go MPFI wiwh vortec heads and all
typos!IO baby attacks
 
X3 on junkyard. Ive done fi swaps before, if you can read wiring diagrams its not bad, just time consuming. The truck 350s aren't known for crazy power stock, so some super fi setup seems mute to me. Get the stock stuff, and you can find parts anywhere if you have a problem
 
Thanks. I'm going to look into it. Time is the one thing I don't have a lot of, and junkyards are in short supply by me, so I may bite the bullet and get the holley.

I have zero experience with FI, but it all looks very simple -- mount the unit, the computer, connect the e-fans, sensors, etc, start it up, let it learn.

A few questions --
1) since I went from the stock i6 to a 350, obviously I'm using a non-efi fuel pump. If I went back to a stock i6 fuel pump, will this be sufficient? Or do I need the Holley fuel pump?
2) the fuel and return line in the truck are all stock, I'm assuming these are sufficient?
3) fuel tank-- I've seen a lot of articles discussing using tanks with baffles to prevent starvation... this is not necessary for anything other than hard cornering, right?
4) 02 sensor --- I know it needs to be installed in the exhaust manifold/header. My headers don't have a connector for it. I'm assuming the only way to go is to drill into the header and weld in a connector? I'm not good (I.e., I don't know how and don't have the equipment to) at welding, so if this is the only way, I'm assuming I can just take this to an exhaust shop and have them weld a fitting in.


Anything else I may run into? I'm trying to make this a disaster-free project and plan as much up front as I can.
 
I've had great experience with the Atomic EFI system on a Ford 5.8L, and a friend of mine has used the FAST EFI system on a project of his. You could look into those if you want to go the easy, plug and play EFI route.
 
There are different kinds of "fuel injection". The links above are for GM TBI (throttle body injection) which uses a pair of large injectors on top of the throttle body to add fuel to the air that is entering the manifold. Jeep motors use PFI (port fuel injection) which mixes the fuel and the air closer to the chamber. PFI is more efficient than TBI, but TBI is the simplest fuel system by far.

jmg222 said:
1) since I went from the stock i6 to a 350, obviously I'm using a non-efi fuel pump. If I went back to a stock i6 fuel pump, will this be sufficient? Or do I need the Holley fuel pump?
Click to expand...
GM TBI is relatively low pressure, just 12 PSI on the regulator. The Jeep PFI uses a regulator with 40-50 PSI. You might be able to use the stock pump with the voltage drop. The reason people change pumps is because of sender and regulator issues. The GM TBI FPR is inside the throttle body itself, and there are adjustable FPRs for GM TBI, so it is possible to dial it down.

2) the fuel and return line in the truck are all stock, I'm assuming these are sufficient?
Click to expand...
The TBI system in my Cadillac also runs the vapor canister back to the tank, instead of dumping it into the intake like the Jeep, but I don't know how much it will matter.

3) fuel tank-- I've seen a lot of articles discussing using tanks with baffles to prevent starvation... this is not necessary for anything other than hard cornering, right?
Click to expand...
The XJ tank is baffled

4) 02 sensor --- I know it needs to be installed in the exhaust manifold/header. My headers don't have a connector for it. I'm assuming the only way to go is to drill into the header and weld in a connector? I'm not good (I.e., I don't know how and don't have the equipment to) at welding, so if this is the only way, I'm assuming I can just take this to an exhaust shop and have them weld a fitting in.
Click to expand...
There are millions of weld-on sensor bungs that can be welded into the down-pipe. My Cadillac has O2 bosses on the cast iron manifolds.
 
jmg222 said:
Thanks. I'm going to look into it. Time is the one thing I don't have a lot of, and junkyards are in short supply by me, so I may bite the bullet and get the holley.

I have zero experience with FI, but it all looks very simple -- mount the unit, the computer, connect the e-fans, sensors, etc, start it up, let it learn.

A few questions --
1) since I went from the stock i6 to a 350, obviously I'm using a non-efi fuel pump. If I went back to a stock i6 fuel pump, will this be sufficient? Or do I need the Holley fuel pump? The stock I6 pump, assuming you have the correct fuel pressure for the engine (injectors) you are using, is plenty. If you have a "built" engine, YMMV.
2) the fuel and return line in the truck are all stock, I'm assuming these are sufficient? They are 3/8" for feed & 5/16" for return, yes? If so - yes, plenty sufficient up to stupid levels of power.
3) fuel tank-- I've seen a lot of articles discussing using tanks with baffles to prevent starvation... this is not necessary for anything other than hard cornering, right? Or very mild cornering with less than 1/3 tank of gas, off-camber situations... etc. You want a sump, baffles, or a bucket-mounted in-tank pump unit, or more than one of those.
4) 02 sensor --- I know it needs to be installed in the exhaust manifold/header. My headers don't have a connector for it. I'm assuming the only way to go is to drill into the header and weld in a connector? I'm not good (I.e., I don't know how and don't have the equipment to) at welding, so if this is the only way, I'm assuming I can just take this to an exhaust shop and have them weld a fitting in. Correct. Exhaust shops do this all the time. You need an o2 sensor "bung" welded in, preferably within a foot of the collector flange, and it won't cost much.


Anything else I may run into? I'm trying to make this a disaster-free project and plan as much up front as I can.
Click to expand...
 
All very helpful guys, thanks. I pulled the trigger on the terminator EFI... now.. just waiting.
 
I did the FAST EZ EFI on the 383 I put in the old cherokee
http://www.fuelairspark.com/fas/ez-efir-self-tuning-fuel-injection-system-base-kithtml/

I didnt like,the self learning makes it hunt for idle. Example your in double low in a hary spot and stall it, when you start it back up the engine will rev up and if your in gear youll be moving. Almost ran over a spotter and almost rolled it from this.

I should have did an LS swap.
 
ashmanjeepxj said:
I did the FAST EZ EFI on the 383 I put in the old cherokee
http://www.fuelairspark.com/fas/ez-efir-self-tuning-fuel-injection-system-base-kithtml/

I didnt like,the self learning makes it hunt for idle. Example your in double low in a hary spot and stall it, when you start it back up the engine will rev up and if your in gear youll be moving. Almost ran over a spotter and almost rolled it from this.

I should have did an LS swap.
Click to expand...


yeah, when first started down this road LS motors were still tough to find, and thousands of $$$. maybe an LT. but a 350 sb... so cheap...

anyway, it works fine... long as this tbi works.
 
87manche said:
remove small block, install LS with stock GM harness and PCM.

fuel injected.
more power.
more tuning options than a proprietary TBI setup.
less money.
Click to expand...
not a helpful response. took you a while to work through that one?
 
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