3.4 swap into 1985 Jeep Cherokee questions?

[1986cherokee]

um..can you use the 3.4 exhaust manifolds? my 2.8 ones are pretty shot. plus there is a sensor on the 3.4's. oh and what oil pan gasket set did you use? i ordered a 2.8 one and got one that fits only the 3.4??? it should be a 2 or 3 piece gasket..

[cardana24]

um..can you use the 3.4 exhaust manifolds? my 2.8 ones are pretty shot. plus there is a sensor on the 3.4's. oh and what oil pan gasket set did you use? i ordered a 2.8 one and got one that fits only the 3.4??? it should be a 2 or 3 piece gasket..

yes the 3.4 manifolds fit. The sensors you are talking about are O2 sensors, there is one on each side, and on the right side there is also an EGR valve. As for oil pan gasket you should use the 3.4 gasket since you can use the 3.4 oil pan. It's a 1 piece gasket. Also if you ask these questions I can answer them their so I don't jumble up my thread.

[Canyonero]

Sweet, sounds like you have it figured out. I've been super busy lately and haven't been watching the board as closely. And I've been splitting my limited attention with a couple Isuzu boards.

My clutch still slips when I shift hard. But I really don't want to pull my tranny again, so I just don't shift hard. Weird that we both did the same project, and we had two different problems (each) with the clutch. With mine the disc wasn't labeled, so I accidentally put it in backwards and the springs were engaging with the flywheel bolts and my new slave cyl was bad also causing the clutch to drag.

[cardana24]

Sweet, sounds like you have it figured out.

Not really. It's running rough and it's still hard to shift now. When it is in gear it wants to cut off. Plus with no exhaust on it it is SO freakin loud in the engine bay I cannot really try to diaganose anything else by sound because all I hear is an open exhaust (I am running the exahust open at the manifolds if anyone forgot). I am having it towed to a local shop to let them look at it. I just don't have enough time to keep messing with it every day. I'll keep everyone updated, if they figure out something I have not, but as of right now I am scheduling it to be towed on Wednesday.

[Canyonero]

Yeah, mine was still running crap-tastic when I drove it to the exhaust shop. I had an exhaust system, but the flanges on the 3.4 manifolds didn't match up to the old pipe and every joint leaked. Sounded pretty bad when it backfired. That leaky injector was just dumping fuel into the system, and I had my O2 sensors connected backwards so it really got weird in closed-loop.

All is well now. I've just been too lazy to do some finish work. There are a few things in the bay held in place by wire clothesline. I keep my radiator flex hose from rubbing on my alternator pulley that way (when I could just replace it with a shorter hose).

[1986cherokee]

I spent several hours on the jeep last night with the multi meter. I did not connect any more wires but rather tried to figure out what the wires are that I had left. I put all of my information in a spread sheet if any one would like it emailed to them. I have listed all of the wire in each harness and they are in the order you would see them on the harness.
10 pin white harness
Tan- B19 Serial Data
Green/White- B28 Buffered Speed Output
Dk Blue- B18 2nd gear start mode indicator lamp control
Green/White- nothing on ecm
Green- about 10 different pins
Red- lots of pins
Tan- lots of pins
Brown- lots of pins

4 pin Black harness
Grey- Nothing (Caynonaro said it was 5V ref)
Orange- B14,B15 Battery (keep alive memory)
Black/White- PCM ground
Purple- Ring terminal in harness

10 Pin Blue Harness
Lt Blue- C10 2nd start mode switch signal
Brown/White- B7 SES indicator control
White- Nothing (Caynonaro said its for the tachometer)
Dk Blue- Nothing
Green/White- A2 A/C request
Pink- C3 Ignition Feed
Lt Blue/Black- A18 Brake signal

10 Pin Grey/Black
Pink- C12,C14,C16 Injector Drivers Cyl's 3,1,5
Green/White- B6 A/C compressor clutch Relay control
Green- C2 A/C Clutch status
Brown- B3 Secondary air injection system air bypass solenoid
Brown/tape-B11,B12,B13 EGR# 1,2,3 control
Pink/tape- B20,B32,A6,C17,C20,C21,C25,C31,C1
Green- Same as Pink/tape
Pink- C32, C15,C13 Injector driver Cyl's 4,6,2

3 Pin Black
Grey- A31,A30,A17,A1 Various sensor grounds
Dk Blue- A3 A/C evaporator temp signal
Black- A1,A17,A31 Various sensor grounds


Sooooooooo....what do I need to hook up out of all of this stuff. Do I need to hook all of those grounds to something? What about the Injector Driver Cylinder stuff...what's that? Anyone what to help?

Could i get that spreadsheet? it would help alot. my email is tricks707@hotmail.com

[1986cherokee]

I tried the Camaro one, just wasn't compatible with my gauge. Didn't register at all. That's the only thing that sensor is for.

So, when will you be able to drive it?

You should document what you did for the next guy.

HAHA um, please?

[cardana24]

I have not updated my thread in a while. My jeep is running...but running like crap, it's not driveable. I finally had an exahust pipe put on it so its not so freakin' loud. I ended up ordering the custom harness from fuel injection specialties. I have the harness but I have not had time to put it in. I'm in the middle of swapping a 2.9 engine into my fiance's dad's truck. I'll post back once I have had a chance to put the harness in. Hopefully it will be with in the next few weeks.

[Canyonero]

Transmission is making nasty noises in my Trooper. It's parked for now. :'(

My project took a year and a half, so I feel ya man. I ended up buying a different car.

Did you get the harness with the emissions stuff built in? I would recommend doing that, or you'll have a check engine light coming on all the time. Damned annoying.

[cardana24]

Transmission is making nasty noises in my Trooper. It's parked for now. :'(

My project took a year and a half, so I feel ya man. I ended up buying a different car.

Did you get the harness with the emissions stuff built in? I would recommend doing that, or you'll have a check engine light coming on all the time. Damned annoying.

I don't have a check engine light, but I am running the egr set up.

[agamemnon]

how much did the harness cost. Enquiring minds would like to know(joke)

[cardana24]

the basic harness costs ~600 then you have to get the VATS bypass. I tried making mine cheaper by not getting the vats bypass (I already have that bypassed) and with out the fuel pump relay (I already have that) but they would not sell me a harness with out those two things. The VATS by pass cost about 50...you can do the math

[Canyonero]

Yeah, they're kinda spendy, but my truck did start on the first try with their harness. I hacked mine up to remove the fuel pump relay and relocate some things.

[cardana24]

okay, so I put the harness most of the way in and its still running like crap. I did not hook a few wires up because I don't think the matter for the manual transmission, but please let me know if I am wrong. I did not hook up the connections for:
-Brake switch
-Vehicle Speed Output
-Oil Pressure gauge
-Vehicle Speed Sensor

What gives? Once it cranks and runs it runs very choppy, and the throttle is not very responsive. I can rev the engine up and when the revs drop the engine drops so low that it almost dies. Any ideas guys?

[geoffinbc]

VSS wont mater as long as you don't drive. Choppy running could be attributed to many things. First on the list would be incorrect firing order and poor timing. It can also be caused by a rich fuel mixture but with EFI there is no way to screw that up unless you have serious sensor problems. So check or replace the ECT sensor. To test it measure the pins you should have 3400 ohms at 21*C (70*F)