Misfiring, where to buy injectors?

[ARB-XJ]

swap in a 4.0 from a 97-98...would have been easier at this point

 

[Talyn]

Yeah.. because the problem is in the engine, not the ignition/fuel system/intake/exhaust. Brilliant.

 

[Talyn]

All good pretty much

(why is changed to positive, because it's a power wire?)

Yes. The Brown wire I mentioned earlier is the negative trigger for the fuel pump relay. The DG/WT is a positive going to the fuel pump.

N/O is wired to the " - " port of the delay timer (which is also wired to the neg terminal of the battery)

correct. Just a small jumper instead of two ground wires.

Com: is wired to the DB/PK in the PDC harness. This is the positive fan wire right? Am i tapping into this wire or cutting it and routing it to the timer?

That is the negative fan relay trigger. You are turning on the stock fan relay because I wouldn't run the fan directly through the ELM relay. When the ELM is activated it closed the COM and N/O terminals.

What kind of wire and gauge would you recommend for wiring up all this?

Doesn't matter much. The amperage carried over these wires will be so minimal.

 

[muddeprived]

Also, I would put a switch inline with the COM or N/O so you can manually kill it if you are working under the hood. Don't want it coming on if you turn the key on while you are working under there.

Its also too bad that it is a return-less fuel system because you could run the fuel pump also. I could actually find a bunch of uses for these things on the XJ.. mostly convenience items. Such as having power to interior items such as windows and radio when you remove the key. Could probably even make it cut off when you open a door.

Could you wire it to auto lock the doors like 5 minutes after you shut it down?


Forgetting to lock it is a bad habit i have. :laugh2:

 

[Talyn]

Yes, I think I can... but I can tell what... you know what your next bad habit will me? Forgetting to take the keys out.

 

[joe_peters]

Yes, I think I can... but I can tell what... you know what your next bad habit will me? Forgetting to take the keys out.

Until about the last ten years here people would just pull the keys from the ignition and drop them on the floor mats. The only people I knew here that locked their front doors were recent transplants from out of state. You could write checks all around town and nobody wanted to see your ID, except for the "chain" stores.

Times have changed. So sad.

 

[muddeprived]

Yes, I think I can... but I can tell what... you know what your next bad habit will me? Forgetting to take the keys out.

LOL (good thing I got spare keys all over the place)



I'm gonna give this a shot this sunday. Thanks to ya both for helping me understand this foreign language. :wave1:

 

[96XJ_4.0]

I had same EXACT issues with my 97 M3. I cut the cats, installed a new cooling system, put on a new header back exhaust, reprogrammed the ecu, replaced the spark plugs.....and on and on and on and on....

Problem was slightly rotted rubber coil pack boots. This is a 6 inch piece of rubber that sat between the coil and the spark plug itself. It was grounding the spark on the aluminum head!

Really.

Problem was a 75$ fix from the BMW $tealer!!!! That's it!

You got those on your coilpacks? You replaced them?

 

[muddeprived]

I had same EXACT issues with my 97 M3. I cut the cats, installed a new cooling system, put on a new header back exhaust, reprogrammed the ecu, replaced the spark plugs.....and on and on and on and on....

Problem was slightly rotted rubber coil pack boots. This is a 6 inch piece of rubber that sat between the coil and the spark plug itself. It was grounding the spark on the aluminum head!

Really.

Problem was a 75$ fix from the BMW $tealer!!!! That's it!

You got those on your coilpacks? You replaced them?

I replaced my coil packs twice. I found a heckuva deal online and ordered two for the heck of it. Both were cracked near the plug connector but in perfect and new working condition and the two were still cheaper than one brand new one.

Thanks for the idea though.

 

[96XJ_4.0]

So they were cracked near the connector on both.

Did you fix that? The cracking caused my misfires. Not the coil pack.

 

[muddeprived]

So they were cracked near the connector on both.

Did you fix that? The cracking caused my misfires. Not the coil pack.

On the backside. It clips onto the plastic electric connector and that clip was cracked on one and broken off on the other so they were sold as blems but brand new. it connects fully and isn't loose or anything. No plugs are exposed. It misfired so I replaced it with one of them and it still misfired so I tossed on the other one and no change at all, with all three (oem and 2 new ones).

 

[96XJ_4.0]

I'm putting my money on an electrical grounding issue that feeds the coil pack, or the coilpacks grounding themselves out...


Subscribed to see this...I read the whole thread and I'll ask around my mechanic friends.

Good luck!

 

[muddeprived]

I'm putting my money on an electrical grounding issue that feeds the coil pack, or the coilpacks grounding themselves out...


Subscribed to see this...I read the whole thread and I'll ask around my mechanic friends.

Good luck!

Alright but the opened hood fix doesn't fit in with the grounding issue....

 

[muddeprived]

PDC = Power Distribution Center. Its the black box reward of the battery on the passenger side. On the underside of the lid it will be labeled which relay is which.

If this was mine this is what I would do. With the ELM.

I'm going off their instructions and the picture on site. The instructions you received in email plain suck. All the wires you need are right near the PDC, so its easy access and you can put the Elm there or run it back into the cab for better protection. It does need to be protected from teh elements, so perhaps seal teh ELM up in a project box or something. Bold is the stuff on the board.

JP3: Begin
JP4: A
JP5: -

+ : to some positive source.. like the battery or the positive terminal on the PDC (very front of the box, its covered).

- : ground it to a bolt or something, just needs a negative input.

TGR: something that turns on when the engine is running. Such as the fuel pump relay control. That would be a Brown wire in the harness that goes to the PDC. It will also be a negative wire. That comes from the PCM. If you don't want to use that wire you can use the Dark green with a white tracer (DG/WT), also in the PDC wiring harness. This wire sends the power to the fuel pump. However if you use that JP5 will have to be +

COM: To the trigger on the fan relay. Dark Blue with Pink tracer (DB/PK), also on the PDC harness. You may also want to put a diode on the DB/PK wire going back to the PCM so that negative doesn't go to the PCM. Don't know if it would do anything, but I don't know that for a fact.

N/O: Negative or ground, because the fan is a negative trigger. Can just jumper off "-" on the Elm.

If you look at this PDF: http://www.elkproducts.com/pdf/960_hookups.pdf you are basically doing #1.

The wattage won't matter with this as you are simply running the factory relay. I would not directly power the fan using the Elm relay.

Now that I got that figured I will just have to get one for myself.

-Chris

Hey one more thing, what's a diode and should I use one?

 

[Talyn]

It allows current to go only in one direction. In your case it would stop the ground from going back to the PCM. It would be like this PCM --> fan relay activation wire --> Diode --> Elm splice --> relay in PDC. Also, it is directional so you have to install it in the correct direction.

 

[muddeprived]

It allows current to go only in one direction. In your case it would stop the ground from going back to the PCM. It would be like this PCM --> fan relay activation wire --> Diode --> Elm splice --> relay in PDC. Also, it is directional so you have to install it in the correct direction.

Thanks

Where do I get my hands on a diode?

 

[Talyn]

radio shack

 

[muddeprived]

radio shack

Do they come in different sizes?


I'm thinking of pulling out the wallet and getting this:

http://www.ffdynamics.com/cherokeeB.html


and then hook up the delay timer to that. i'm sure my motor won't think about misfiring with that combo.....

 

[Talyn]

While that is nice and all but I think it would be a better idea to try it with the stock e-fan first. Besides... you said you aren't great with electronics, so I don't see you endeavor to hook the three fans up going too well.. no offense.

As for the diode they are rated in amps. You don't need anything big because its just flipping a relay. But keep in mind that you do have to solder it to the wire so larger posts would be better. Maybe you should skip this step for now and see if it throws a check engine light first for the fan.

 

[muddeprived]

While that is nice and all but I think it would be a better idea to try it with the stock e-fan first. Besides... you said you aren't great with electronics, so I don't see you endeavor to hook the three fans up going too well.. no offense.

As for the diode they are rated in amps. You don't need anything big because its just flipping a relay. But keep in mind that you do have to solder it to the wire so larger posts would be better. Maybe you should skip this step for now and see if it throws a check engine light first for the fan.

The tech guy at FFD said the fan is bolt-in with detailed instructions on how to install it. he said there's little wiring needed done, just plug n some stuff and bolt it on. I thought it would be a good idea cuz my stock fan vibrates alot when it kicks on and it's annoying a little bit. He also said running it with a 185-190 thermostat is a combo they came up with to cure the heat soak issue on our xj's.