3.4 swap into 1985 Jeep Cherokee questions?

[cardana24]

BTW, I sent you a diagram for the data port in that email. It should be on page one, the MIL lamp diagram.

Yeah, I got that thanks.

I am begining to wonder if I have a VATS problem too. Even if the fuel pressure is a few pounds low the engine should still run in my mind...possibly run lean or sputter up top, but I think it would start. I am talking to the people I bought my VATS bypass from, and I ran some tests on it tonight, it looks like the siginal possibly is not strong enough. The guy told me it should be testing at ~2-2.5 volts with the ignition switched on and when I checked it today my meter was only showing 1V when the ignition was switched on...I am starting to wonder if I have a faulty vats bypass. I sent in a picture of my testing procedure with the read out to the company so hopefully they will get a new one in the mail to me asap.

One way I could check my fuel pressure (see if the computer is telling to fuel pump to send fuel/VATS) is to leave the pressure tester hooked up while I am cranking the jeep. I am guessing if it fires up at 40 psi if the VATS system is not bypassed properly the fuel pressure should drop to 0 quickly. Make since?

Also I have a few other questions. Is the check engine light circut critical to the engine running? I don't have that hooked up now, but I bought a 194 bulb socket with a two wire connection tonight, and was going to hook that up for my CEL. Does this circut have anything to do with the engine running?

My other question has to do with the pink/white wires coming off the crank and cam sensor. According to the diagram they tie into pink C3 which is the ignition control line. I don't know if it is a typo or something but if you trace those wires back they end up at C18 injector control #1 and they never tie into C3...does anyone else see what I am talking about? Whats the deal with that?

**I'm going to ask a question in the general forum about the cam...I don't think that would be causing a problem. I just want to know if anything special needs to be done to run a cam in the 3.4 with out a cam sensor lobe (I know it is supposed to run MPFI without it, but I am wondering about any other problems).

[cardana24]

I am getting ~45 psi when the pump turns on for a few seconds, then as soon as it turns off the pressure drops to ~41-40.

I am also having a small gas leak issue. My freakin' fuel filter is leaking. I put all new clamps on it and it's still leaking. Can someone please recomend an inline filter that is sutiable for fuel injection. The one I have is puralator, and I think it is normally used on carbs I don't think it is made for higher fuel pressure. I need one that has a 5/16 inlet and outlet. Anyone know of one? I am fine with a universial one or one that is made for another vehicle I just need the inlet and outlet to be 5/16.

[pocket-rocket]

From what I was reading about a Camaro and the VATS system going goofy, I looked up the old trick to bypass the system (since you don't need it).

http://vats.likeabigdog.com/

The thing that sucks is the VATS system uses a resistor pill in the middle of the key. The resistor pill is what most people dub the "chip" for their factory security system. Anyways, GM used a handful of resistor values, and the advantage most people have over you is they still have their factory key. In their case the small wires in the steering column breaks and the VATS system can't read their key, so they use that link and bypass the system completely. You on the other hand, don't even have the key for the car your engine came out of, so you might need to just try each of those values, or try to find out the VIN number of the car you got the engine out of and see if your local GM dealer can tell you the resistor value in the key that came with that car.

[Canyonero]

I don't think he can do that with what he's got. Bypass module is the way to go, if it's working that is...

[cardana24]

I don't think he can do that with what he's got. Bypass module is the way to go, if it's working that is...

I tested the module again and according to baker electronix it is sending the siginal they say it should send.

When I crank the engine the fuel pressure goes up to ~45 psi while the pump is running then when it stops it reads ~41 psi. When I crank it it will drop into the high 30's but never go below that.

So can someone please help me with this. Currently the only wiring I am using from my jeep is the ignition line which is going to the fuse box for the camaro wiring and it is hooked to C3 the ign. line. I am also running a constant 12V line off of the battery to the two orange wires. What am I missing? Do I need to be running more wires from the jeep? I could really use some ideas. I have looked at wiring diagrams until my eyes feel like they are going to pop out. What else needs to be hooked up other than the plug and play sensors on the engine? I know not many people choose to do what i am doing but there has to be someone out that that has done this or knows how the wiring should go.

[ssterlingb]

Okay, I'm just going down the list of inputs, stuff that has to go to power, for the motor to run.
2 #7.5 amp fuses for the injectors on 639 pink & 839 pink
1 # 10 amp fuse for ignition module on 239 pink
1 # 15 amp fuse for ignition feed on ecm C3 pink
1 # 10 amp fuse from battery to ecm B14 & B15 ORN wires
1 # 10 amp fuse for MIL on 39 pink, don't know if you have to have or not

GROUNDS: Verify hooked up
from ignition module: 450 black
from PCM: 351 BLK/WHT (B20 & B23 O2s Grounds)
from PCM: 551 TAN/WHT (C1 & C17 ECM Grounds)
from PCM: 451 BLK/WHT (B16 & B32 PCM Grounds)

There is also more that runs the A/C, cooling fan, transmission, etc., but I don't think you need those for the motor to run, and I left out the fuel pump relay stuff since I think you have that running.

[ssterlingb]

I'm sure you already have, but just in case, make sure you have a good ground strap from the engine to the body. I had a bad strap once that killed several alternators & batteries before the repair shop figured it out. Cost me more than I care to think about.

[cardana24]

I'll double check the stuff that you posted but I am pretty sure that is all hooked up. Also as for the engine ground stap I am running that in the factory jeep location, will that work? It is run from the fire wall to the back of the left head. Each end has a ring terminal and is attached with a bolt.

[cardana24]

Okay, I'm just going down the list of inputs, stuff that has to go to power, for the motor to run.
2 #7.5 amp fuses for the injectors on 639 pink & 839 pink
1 # 10 amp fuse for ignition module on 239 pink
1 # 15 amp fuse for ignition feed on ecm C3 pink
1 # 10 amp fuse from battery to ecm B14 & B15 ORN wires
1 # 10 amp fuse for MIL on 39 pink, don't know if you have to have or not

GROUNDS: Verify hooked up
from ignition module: 450 black
from PCM: 351 BLK/WHT (B20 & B23 O2s Grounds)
from PCM: 551 TAN/WHT (C1 & C17 ECM Grounds)
from PCM: 451 BLK/WHT (B16 & B32 PCM Grounds)

There is also more that runs the A/C, cooling fan, transmission, etc., but I don't think you need those for the motor to run, and I left out the fuel pump relay stuff since I think you have that running.

Okay I double checked all of this. I had all of the switchable power stuff hooked up right already. I also ended up hooking up the check engine light. I ran a switchable power wire from my fuse box to a light, and then they other side of the light I ran the wire to the ecm (forget the pin number right now). After I did that when I would switch the ignition on the CEL would stay on and not go off. Problem? But when I crank the engine now it seems like it is trying to catch it just wont. It starts to crank faster and it will skip crank but never catch. I also tried using starting fluid, that will make the engine race but then it just dies down and sputters out. So something is still not working right. I changed the spark plugs again for the 3rd time. Where should I go from here? What sensors would cause the engine not to run? I checked all of the grounds listed above and they all go to where they are supposed to be. The ground for the ICM actually ties into another ground wire and goes to some plug for the AC. So I grounded it at the AC plug. Should I cut that wire off close to the plug on the ICM and ground it somewhere else by it's self?

[cardana24]

I have a question about a sensor. What is the sensor that is in the front of the left side head? Water temp sensor for the temp sensor gauge? I am thinking thats what it is but I just wanted to double check. I know the main water temp sensor for the ecm is is in the front center of the intake manifold.

As for the alt. The plug that comes off of the alt. goes to the volts gauge correct?

I think that is all of my questions for right now....by the way





















It's running

[Canyonero]

Yes, that's just the temp sensor. I had to switch mine out with the one in the 2.8L for my gauge to work.

So what did you find out on the not-running issue?

[cardana24]

Yes, that's just the temp sensor. I had to switch mine out with the one in the 2.8L for my gauge to work.

So what did you find out on the not-running issue?

Did you try using the camaro sensor, or did you just switch straight to the 2.8 sensor?

Do you know if the wire coming out of the clip on the alt. should go to the volt gague?

What about oil pressure? Currently I have that tied into the oil pressure sensor tan wire.

As for the the getting it running. I did several things. I went through and soldered every connection I knew to be right. Since I have been trying to sort things out I have just been tie wires together and taping them. So for all of the connections I knew to be right I soldered and heat shrinked them. I also grounded my VATS bypass. Also one thing that I know was wrong since a few days ago is that fused line that I ran for the CEL was wrong...it was a line that should have been going to one set of injectors....oops But that has only been wrong for a day or two, so it was a combination of a few things. You don't know how happy I was last night when it fired up.

[Canyonero]

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.

[bszopi]

I bet the tieing of the wires together helped contribute to your no-start issue. Just think, you might have had this fixed a week or so ago had you just soldered all the wires in the first place.

[cardana24]

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.

Okay I will probably just switch back to the jeep one then. As far as driving it I hope to see if it will move around in the next few days. I want to get my wiring protected before I drive it. Right now I have wires every where, I need to get everything loomed and heat shielded where it needs to be. I'm sure I will post back when I drive it.

I am documenting what I did, I am making a note book and keeping notes on all of the parts I have used, and rigs that I have had to make/use.