My 4.0 Fuel injection conversion

[tinman]

Trying to finish up my conversion using a harness from ThisGuyuKnow, so I thought I would start throwing some info out on how everything is going so far.

A little background on my engine so far...http://www.jeep-cj.com/forums/f2/4-0-head-change-dyno-results-16094/

My biggest problem with the carb setup was getting the choke to work well enough for the cold winters up here. When ThisGuyuKnow wanted to start building the harnesses, I thought this might be the perfect time to switch to fuel injection.

A basic list of parts I used-

1991 intake and harness from a cherokee $120
Shipping to & from ThisGuy $60
Damper kit kit from Hesco $329
E2000 fuel pump from rock auto $62
Fuel filter $10
Speed sensor from rock auto $62
Cold air intake (2000 Honda civic from ebay) $44
O2 sensor (Bosch) Rock auto $23
Bung for O2 sensor from local exhaust shop $10

That should be the basic list, but if I think of anything else, I'll add it. There's also a lot of misc. items that aren't mentioned like bolts, hoses, etc.
I ended up not using everything Hesco has to offer, due to the price of some items, one being the VSS. I got that from rock auto, which is missing the adapter, but is an easy fix. Just find a 87-90 cherokee with cruise control, look behind the instrument cluster, and there is a plastic adapter about 10" back from the cluster. Saves $60.

Using his harness was pretty simple and included headlight relays that were already in the PDC(power distribution center). I'm not saying the whole thing wasn't a big job, and looking at the harness before installation is a bit overwhelming, but the actual connecting of the XJ and CJ harness is easy.

Before I started-
View attachment 16962

New intake-
View attachment 16963

O2 sensor
View attachment 16964

VSS adapter from 87-90 Cherokee
View attachment 16965


More to come...

 

[ThisGuyUKnow]

I feel I should say that Tinman's 4.0 conversion swap was my first attempt at making one of these harnesses for a consumer. He has been great at helping me hone the odds an ends and hopefully between the two of us we can make a clear set of instructions to make this much easier for future users.

 

[tinman]

Had to modify my pulley system after trying to install the new housing--
View attachment 16966

Also had to modify the P.S. pump bracket-
View attachment 16967

Another before pic-
View attachment 16968

New mount-
View attachment 16969

VSS-
View attachment 16970

 

[IOPort51]

what Transfer Case do you have?? It does not appear in your profile. I am wondering where the speedometer/speed sensor came from.

 

[tinman]

I have the 300, but the VSS has to come out of a 1991 wrangler.

 

[IOPort51]

I have the 300, but the VSS has to come out of a 1991 wrangler.

So the same one will work for the Dana 20 ? Did you, or do you think you will have to make adjustments for tire size/gear ratio?

 

[tinman]

Good question.
I think if your speedo is correct driving down the road, then this would work. If it fits is another question. Let me check when I get home tonight, but I think the threads are about 7/8".

 

[IOPort51]

Good question.
I think if your speedo is correct driving down the road, then this would work. If it fits is another question. Let me check when I get home tonight, but I think the threads are about 7/8".

I think you may find them to be Metric, something like a 15mm. pretty close to 7/8 but wrong thread.

 

[tinman]

Is that the same as yours then?

 

[IOPort51]

Is that the same as yours then?

I believe so, My speedo is about 5MPH off with 31s and I do not know how much with 33s. Not sure if that is really important, the computer may just need to know that you are moving and not really care how fast. RPM/speed ratio changes every time you shift.

this just keeps getting more and more interesting.

 

[ThisGuyUKnow]

I believe so, My speedo is about 5MPH off with 31s and I do not know how much with 33s. Not sure if that is really important, the computer may just need to know that you are moving and not really care how fast. RPM/speed ratio changes every time you shift.

this just keeps getting more and more interesting.

The Vss is used for calculations during WOT, I'd be lying if I said I knew exactly everything that goes into it but it is my understanding that as you said the computer just needs to know how fast the driveshaft is turning.

 

[IOPort51]

The Vss is used for calculations during WOT, I'd be lying if I said I knew exactly everything that goes into it but it is my understanding that as you said the computer just needs to know how fast the driveshaft is turning.

Does it need to know how fast of just that it is?

 

[tinman]

Instead of buying the fuel pump and filter from Hesco, I bought an E2000 off Rockauto and the filter from Autozone. Saved about $100 doing it that way, we'll see if that was a smart decision after I put some miles on it. It's possible that their pump is better, but I've heard good things about the e2000 also. Another pump option is the e2182, which I don't know much about.

I mounted this setup a little closer to the passenger side than other ones I've seen. I felt that centering the pump and filter puts the filter too close to the exhaust pipe. Since I didn't buy the pump and filter in a kit, I had to come up with a way to mount them. The clamps can be found at EVCO house of hose, but if you don't have a local EVCO, I used the clamp that held the old coil on the side of the engine.
View attachment 16982

To block off the fuel pump hole on my AMC 258 i6 / 4.2l block, I used a chevy big block fuel pump block off plate. I used the stock 4.0 coil and bracket, then just flipped the bracket around to get it to fit.
View attachment 16983

Once I had the CJ wiring harness pulled out, I just laid the XJ one in it's place, but held off mounting it to anything just yet. I wanted to splice it in and start the engine to make sure I didn't mess anything up, which I did. I ended up connecting the wires to the CPS incorrectly, so the first attempt at starting didn't go well. Once I talked to ThisGuy on the phone, he got me on the right track and it started right up!
View attachment 16984
View attachment 16985

I have a video of it running for the first time. If I can figure out how to shorten it a little bit, I'll post it.

 

[ThisGuyUKnow]

Does it need to know how fast of just that it is?

I dont think the ecm just needs to know that the shaft is simply moving, it needs to know how fast, that being said I dont think that it needs to be corrected for tires to run right. Your drive shaft will turn at a different speed than your engine in most gears so it is probably taking into account the RPM of the engine vs the RPM of the output to do some crazy cool EFI stuff.

 

[ThisGuyUKnow]

Instead of buying the fuel pump and filter from Hesco, I bought an E2000 off Rockauto and the filter from Autozone. Saved about $100 doing it that way, we'll see if that was a smart decision after I put some miles on it. It's possible that their pump is better, but I've heard good things about the e2000 also. Another pump option is the e2182, which I don't know much about.

I mounted this setup a little closer to the passenger side than other ones I've seen. I felt that centering the pump and filter puts the filter too close to the exhaust pipe. Since I didn't buy the pump and filter in a kit, I had to come up with a way to mount them. The clamps can be found at EVCO house of hose, but if you don't have a local EVCO, I used the clamp that held the old coil on the side of the engine.
View attachment 16982

To block off the fuel pump hole on my AMC 258 i6 / 4.2l block, I used a chevy big block fuel pump block off plate. I used the stock 4.0 coil and bracket, then just flipped the bracket around to get it to fit.
View attachment 16983

Once I had the CJ wiring harness pulled out, I just laid the XJ one in it's place, but held off mounting it to anything just yet. I wanted to splice it in and start the engine to make sure I didn't mess anything up, which I did. I ended up connecting the wires to the CPS incorrectly, so the first attempt at starting didn't go well. Once I talked to ThisGuy on the phone, he got me on the right track and it started right up!
View attachment 16984
View attachment 16985

I have a video of it running for the first time. If I can figure out how to shorten it a little bit, I'll post it.

Dont forget to mention how crucial the proper routing of the MAP sensor drain hose is

 

[tinman]

Dont forget to mention how crucial the proper routing of the MAP sensor drain hose is

Haha!

Ok....

When mounting the MAP, be sure to hook up the vacuum line to the intake, it runs A LOT better when it's connected properly!

 

[ThisGuyUKnow]

Haha!

Ok....

When mounting the MAP, be sure to hook up the vacuum line to the intake, it runs A LOT better when it's connected properly!

Yeah the CPU has a hard time correcting for the atmospheric pressure of the world outside of your intake.

 

[tinman]

Here is the PDC mounted. I think I might change it up a little and mount it closer to the engine. As it sits now, it makes the main loom a little tight on the passenger side.

View attachment 17184

I wasn't sure if I was going to have room for the ECM on the drivers side, but I was able to fit it on the firewall below the brake booster. When I bought the jeep, it had the CA emissions canister down there, but without that in the way, it fit rather nicely.

View attachment 17185

 

[tinman]

Got it on the dyno again today-
View attachment 17563

Don't pay any attention to the info on the top, it's mostly wrong.

The red lines are a stock AMC 258 i6 / 4.2l
The green lines are 4.0 head, cheep-o HEI, 2100 carb and newer exhaust.
The blue lines are the Cherokee MPFI addition. He said the dip at the end of today's run was caused by him letting off the throttle thinking he was topped out, then he got back into it.

Overall a gain of 79 HP and 111 Tq. Not to mention the ease of running fuel injection, which has been a huge plus.

I'm pretty happy.

 

[tinman]

Just filled up and I'm sitting at 15.3 MPG now. We'll see if it gets any better, but that's about 3 or so better.