4.0 help

[scramblerbob]

I got my 2000 4.0 in my 81 scrambler and after a few minor problems I got it running. It runs great but the only way it will start is if I pour fuel down intake. Must be some sort of senser thats keeping fuel off untill it fires. any sugestions as to where to look? Secound problem is where to hook temp gauge? I keep reading about using the sending unit in rear of motor and not the front because the front is used by the PCM but as far as I can see there is no rear sensor on the 2000. and what about the oil pressure gauge does it need to give imfo to the PCM or can I just disconect old wires and sending unit and replace with the old 258 wire and gauge. Thanks for any help you can give me and I be glad to answer any questions that I can from what I've learned so far. One thing I did differntly then most was to keep the existing fuel rail with no return line and fuel pump in tank. I have a special 35 gallon tank that came with my scambler so I had a machinest cut a hole in the tank and a ring to hold it in place. I then cut a 6 inch sqaure hole in my bed and made a cover with the cutout that screws back on. I figure I got the best of both worlds, fuel pump should last longer, no return line, and I don't even have to crawl under my jeep if I ever have to replace it. Thanks again Bob

 

[scramcraz]

Hey Bob,
My swap is a 95 but maybe I can help. I used the cj temp sender in the left rear corner of the 4.0 head & it works fine. If you don't have one maybe you could drill & tap 1/8 NPT to get a sensor in.
The oil pressure sensor is easy. Just unscew it & install a tee. Re-
install your 4.0 sensor & wires to the computer & your cj sensor & old wiring to your gauge. You retain your computer info & get to read your oil pressure the likes unseen in your jeep before!
I don't know anything about your one line fuel system but would guess that your fuel system is leaking down & not holding pressure. Can you put in a temporary gauge to monitor fuel pressure? Maybe your system requires a one-way check valve in the fuel supply line? Sounds like you had a good idea about mounting your fuel pump with easy access. Did you use an aftermarket wiring harness or wire the engine yourself?

Bob

 

[REDSCRAM]

4.0 fuel delivery

can you hear the fuel pump when you turn the key? it sould run for 2-3 seconds to build pressure and then turn off. also, did you use the pump from the donor in you new tank? if it is a grand cherokee donor, they have the fuel regulator and pump in the same assembly. also, when i did my swap(95 motor) i had to prime the fuel lines. are you getting fuel to the fuel rail?

 

[scramblerbob]

I have wired it myself with the factory harneses. I'v keep the AW4 auto overdrive that came with motor. It's out of a 2000 cherokee with 14000 miles. I probably should check the fuel pressure but have'nt yet. The fuel pump does run for a couple of secounds when I turn on key. There are no leaks and from opening the bleeder on the fuel rail the pressure seems to stay the same even after i'ts set awhile without the pump running. It is primed because like I said a little gas down the intake and it takes right off and purrs until I shut it off. Yes it is like the grandcherokee in that the fuel pump regulator and filter are all in one in the gas tank. There is no aftermarket wireing harness for the conversion that I can find that will work with the electronic auto trany. Thanks and keepem coming I 'd hate to have to take it to a mechanic but I don't want to have to prime it every time either. Carpenter Bob (not a mechanic)

 

[REDSCRAM]

Fuel

Sorry, I should have been more specific. there is a slip on connection on the fuel rail that your gas line hooks to. have you verified, by disconnecting the fuel line at the rail(careful of the o-ring) that the gas is reaching your fuel rail?

 

[scramblerbob]

I didn't have the right fitting for the fuel rail there so I used a steal hydrolic compression fitting there. In the middle of my fuel rail I have like a tire valve that I refered to as the bleeder valve in previous post. there is gas and considerable pressure ther weather it's running or not. It acts like the injectors are not allowing gas through until I prime it and then it takes right off and runs great. when I turn off the key and stop it, it won't start again even imediatly until I pour more gas down the intake.

 

[wiltech]

Sounds like your wiring to the ASD relay might be wrong. The ASD relay controls power to the injectors (among other things).

or

Is it possible your not getting power too the PCM in both the START and RUN positions of the key?

The PCM doesn't need the oil pressure sensor to function, so you can just remove it and put your sensor in it's place, or put a T in like what was suggested earlier.

FYI: this info is from my 97 FSM

Here's the info from my 4.0 swap

Tony W

 

[1BADCJ8]

Hey Bob,

I don’t know about the fuel problem.

On the temp gauge problem I went with a mechanical gauge from NAPA. Two reasons why I think it is better, one it was simple to install, just retro fitted it to the access above the thermostat.
And
Two even after you turn your engine off it lets you know what is going on temp wise. With and electronic one...you turn off the key or loose battery (whatever), it turns off. Not to big of a deal but for sure there are times when a mechanical one will serve you better.

 

[wiltech]

Re: Hey Bob,

I don’t know about the fuel problem.

On the temp gauge problem I went with a mechanical gauge from NAPA. Two reasons why I think it is better, one it was simple to install, just retro fitted it to the access above the thermostat.

How did you do this ? Did you drill and tap another hole on the t-stat housing ?

Thanks
Tony W

 

[scramblerbob]

Tony (wiltech) Great source of imformation, but still need help.
#1 I have not been able to get power to the start side of ign. so I've worked around that and planned on getting back to that . Any suggestions would be appreciated.
#2 still have original problem that I dont think is related to that?
What i've done is taken the F-12 DB/WT ST RUN wire from the C2 junction block and tied it to +side of battery up front. When I do this the fuel pump comes on for about 2 secounds. During that two secounds my test light says my A142 DG/OR wire lights up at Ign. coil and at the Injectors. After the 2 secounds they all go off. Then I touch the F-45 YL/RD ST relay wire out of the C1 junction box to the + and the starter starts to turn motor and fuel pump and the A-142 ign.coil and injector wires all light up again but it won't start until I add gas to intake. Then it starts right up and will continue to run. I'll let it warmup to operating temp. shut it off and try to immediatly start it but it won't without another prime.
I don't have an air filter on yet? I don't have the selenoid or emmision stuff between charcoal filter and intake just staight hose witch I've tried connected and closed off? When running the vacum stays steady at about 16 lbs. I never saw any of the vacum lines coming off the intake could I be missing one I need to start right. Thanks for any and all help I'm just ready to move forward. Bob

 

[wiltech]

Tony (wiltech) Great source of imformation, but still need help.
#1 I have not been able to get power to the start side of ign. so I've worked around that and planned on getting back to that . Any suggestions would be appreciated.

On my 83 I got this from one of the wires going to the Duracrap ignition box.

#2 still have original problem that I dont think is related to that?
What i've done is taken the F-12 DB/WT ST RUN wire from the C2 junction block and tied it to +side of battery up front. When I do this the fuel pump comes on for about 2 secounds. During that two secounds my test light says my A142 DG/OR wire lights up at Ign. coil and at the Injectors. After the 2 secounds they all go off.

That sounds right

Then I touch the F-45 YL/RD ST relay wire out of the C1 junction box to the + and the starter starts to turn motor and fuel pump and the A-142 ign.coil and injector wires all light up again but it won't start until I add gas to intake. Then it starts right up and will continue to run. I'll let it warmup to operating temp. shut it off and try to immediatly start it but it won't without another prime.

Can you tell does the fuel pump come on while your cranking the engine ?

It sounds like the PCM is not grounding the injectors (that's how it fires them) in the Start position.

Oh wait wait .... you said this came out of a 2000 XJ right, did the yard that pulled the engine disable the VATS (Vehicle Anti Theft System) before yanking the engine ? Do you know of someone with a 96-97 that would loan you their PCM ?

You might try posting over on Parts Mike. I know he's done some of these OBD-II swaps before. or give these guys a call: Custom Jeep

I hope some of this helps, and that I don't have the same problems when I finally finish mine.

Good Luck
Tony W

 

[wiltech]

Do you have any pics of the tranny crossmember ?

Thanks
Tony W

 

[scramblerbob]

Thanks again Tony I think your getting me closer. The fuel pump does run during start. I then put my test light on one of the injector grounds and it did not have ground while I was cranking the motor but the ground did start to flicker on and off after it was primed and started. That must be the source of the problem. Are you thinking that my lack of ground is from the anti theft or an unrelated wiring problem? One last possible clue is when I took the 4 wires I needed for the fuel modual from the C100 connector, A141 pump relay, K226 fuel level sensor, K167 sensor ground, and the Z1 ground the fuel pump didn't work just the relay sent the 12 volts so I checked and it was'nt getting any ground from the Z1 so I grounded it to the body and that got me where I was when I first posted. Is that Z1 always supossed to be grounded?
What color was your wire you used for the( ign. st )from your 8? Can't seem to find one that works.
In regards to the trany crossmember are you refering to the one off the 2000 XJ. If so I have it but I don't have a digital camera or scaner, but if your still interested and santa comes through I'll be able to do it after Christmas. Hopefully I won't have to make another post asking how to send pictures.
Big thanks I'll have to start trying to find out about the VATS, more initials to try and remember. Bob

 

[wiltech]

Thanks again Tony I think your getting me closer. The fuel pump does run during start. I then put my test light on one of the injector grounds and it did not have ground while I was cranking the motor but the ground did start to flicker on and off after it was primed and started. That must be the source of the problem. Are you thinking that my lack of ground is from the anti theft or an unrelated wiring problem? One last possible clue is when I took the 4 wires I needed for the fuel modual from the C100 connector, A141 pump relay, K226 fuel level sensor, K167 sensor ground, and the Z1 ground the fuel pump didn't work just the relay sent the 12 volts so I checked and it was'nt getting any ground from the Z1 so I grounded it to the body and that got me where I was when I first posted. Is that Z1 always supossed to be grounded?

Z1 is the main chassis ground, so yeah it should be grounded.

What color was your wire you used for the( ign. st )from your 8? Can't seem to find one that works.

The one I used was a 10ga. red wire. If you didn't have the Duracrap ignition thatn it should be the wire that went to the coil.

In regards to the trany crossmember are you refering to the one off the 2000 XJ. If so I have it but I don't have a digital camera or scaner, but if your still interested and santa comes through I'll be able to do it after Christmas. Hopefully I won't have to make another post asking how to send pictures.
Big thanks I'll have to start trying to find out about the VATS, more initials to try and remember. Bob

Did you use the original CJ crossmember, the XJ one, or fab up a new one ?

Best of luck
Tony W

 

[scramblerbob]

I drilled holes in my skid plate in the right location to receive the tranny mount that was stock on the AW4 auto. I beleive my old SR4 was mounted the same way on skid pan. The crossmember off the XJ Is alot longer and did'nt look like it could be used. I bought the adapter for my 300 from Novak and that clocked my 300 up and then I used spacers between rear mount and skid plate to desired hight. My front driveline is know alote higher and I hope I can rotate my front axle enough to make the drive line work without messing up my steering. Hope that helps.
Good luck Bob

 

[wiltech]

I drilled holes in my skid plate in the right location to receive the tranny mount that was stock on the AW4 auto. I beleive my old SR4 was mounted the same way on skid pan. The crossmember off the XJ Is alot longer and did'nt look like it could be used. I bought the adapter for my 300 from Novak and that clocked my 300 up and then I used spacers between rear mount and skid plate to desired hight.

DOH you bought the adapter We made our own for far less, it pays to have an uncle that's a machinist .lthough the Novak is pretty nice with the o-rings and such, it would be my choice over the AA one. BLITZED over on POR is making them as well.

My front driveline is know alote higher and I hope I can rotate my front axle enough to make the drive line work without messing up my steering. Hope that helps.

You should still be ok, I don' think that the front shaft has any more angle on it than rear shaft does. The front output should now be close to the same height as the rear output on the 300, so then just measure the shaft lengths. They should be close to the same. FYI, my friend "Hayfever" used an extra front shaft I had laying around on the rear of his CJ-7 and he has 3-4" of lift. and he didn't have to rotate his rear axle.

Remember you don't want to point the pinion at the x-fer case unless your running an CV shaft.

Tony W

 

[wiltech]

Bob,

Were did the shifter for the Dana end up ? Did you have to trim the floor pan much if any? (not the shifter cover plate, but the actual pan).

If all goes well I'll be putting my AX-15 in this week and fabbing up my tranny mount similar to these

Thanks
Tony W

 

[scramblerbob]

I started with a 1 inch body lift, and I added the curry twin stick wich gives you alot of ajustment front to back in location. Because of the TC rotation I bent the new sticks to get them in desired location left to right. My problem was trying to use the stick shift that came from the XJ Because the after market auto shifters are'nt made for the AW4. I did'nt cut any floor out and the twin stick I believe would of gone though original hole. (dropping the trany mount about an inch or a little less rotation would of helped). IN my case I needed a flat surface to mount the XJ shifter on so I left off the 11x14 cover and fabricated what amounts to an upside down pan with a large access panel within its dimmensions. It looks good and gives me a little flat area behind the shifters to set things or use for some new gauges if I decide not to put them in the dash. (tanny temp, fuel...) This was yesterdays project while I waited for monday to get new pcm to test your anti theft theory.
Bob

 

[wiltech]

Sounds about like mine. I have a 1" daystar body lift, homemade clocking ring, and homemade twin sticks. (Like this but I used Dana 18 sticks)

Excpet yours sounds much close to being complete than mine.

Let me know what PCM you get/need I have one from a 96 XJ auto that supposedly I can't used with my AX-15.

Tony W

 

[scramblerbob]

The Dodge dealer tells me if it is the anti theft causing my engine not to start and I have the Vin # which I do then thay can hook it up through my data link connector and usually correct the problem. As far as your PCM I don't think its going to work in yours and I'm planning on getting a spare to keep in my jeep. I have'nt priced them at a wrecking yard yet but I'm told yours will work for mine so if you don't use yours maybe we could work a deal if they won't exchange yours for the one you need.
Bob