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Old 08-09-2010, 11:06 PM   #1
Join Date: Aug 2010
Posts: 29
Fuel Injection Conversion

Hi all,

New to the forums and looking for some help on my jeep project. Need some help with a fuel injected motor conversion.

A little background on the YJ: Bought my 87 wrangler from a guy that got married and left the jeep sitting in the driveway for 3 years. The guy originally decided he wanted to do a fuel injected motor conversion. The 4.2L engine was taken out of a 95 wrangler wreck and put in the 87. The head was redone and looks brand new. The harness was halfway hooked up and i pretty much finished hooking up the harness (and installing the black computer box in the engine bay).The only wires i have left to hook up are coming from the computer in/under the glove box. The 87 was originally an automatic but the guy put in a rock crawler tranny (which he took out before selling since i did not want it). I put in a manual tranny that i took out of a 95 parts jeep (and unfortunately sold). A few mechanics have told me not to get involved in trying the conversion but its almost there and the jeep is set up nice with a 4" lift kit and 33" tires. Theres no rust anywhere on the jeep either.

Where i am now:

I connected the battery to see where i stood. It seems i have power to everything i need except that i cant get the jeep to crank turning the key. If i jump the starter the motor will crank. It seems to me that its one of two things: the computer needs to be spliced in (wasnt sure if the manual tranny used a computer) or the ignition switch is bad.

Any input would be greatly appreciated or if anyone knows someone in the long island, NY area that wont rape me on getting it running. thanks all


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Old 08-09-2010, 11:10 PM   #2
Join Date: Aug 2010
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Here are the wires coming from the computer under the glovebox

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Old 08-12-2010, 06:28 PM   #3
Join Date: Jul 2010
Location: Ridge,Long Island, NY.
Posts: 12
Hey nickc,
I have a 90 yj 4.2l that has been converted to fuel injection. heres the thing, fuel injected yj's use a different computer. the one behide the glove box is no longer used for the motor. look under the wire harness were it goes from the engine bay into the back of the back of the fuse block. Is the a back box there that another bunch of wires going to it? that is where my new PCM is mounted.If so let me know. I'll fill you in about power to that if thats what you have. By the way, where on long island are you? I'm also on the island, in Ridge.
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Old 08-13-2010, 07:59 AM   #4
Join Date: Aug 2010
Posts: 29

Thanks for the input. I'm in Medford, exit 63 off the LIE.

I figured that the PCM under the glove box wasnt used anymore. i mounted the black PCM in the engine bay and i seem to be getting power everywhere when the harness is hooked up. If i jump the starter with a screwdriver the engine turns over, but turning the key isnt doing anything.

I'll send you a PM with my cell and maybe we can talk over the phone. Appreciate your help as this thing is driving me crazy.

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Old 08-13-2010, 02:22 PM   #5
Join Date: Jul 2010
Posts: 29
I'm just curious guys..how much does it cost to convert?

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Old 08-13-2010, 02:29 PM   #6
Join Date: Aug 2010
Posts: 29
Im not sure, i purchased my jeep with the fuel injected motor and harness included. The guy i bought if from bought a wrecked 95 and took everything needed out of it.
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Old 08-20-2010, 09:21 AM   #7
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Join Date: Sep 2009
Posts: 2
Hi Guys.... I'm working on a fuel injection conversion as well. I tried using the harness and PCM from an auto xj but my yj is standard. do I have to get a PCM from a standard vehicle?
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Old 08-26-2010, 01:13 PM   #8
Join Date: Aug 2010
Posts: 29

Yes, the wires are going to the new PCM (black box) in the engine bay. I connected the battery and get power to everything except the starter. It doesnt seem to be getting spark either. I printed out an in depth wiring diagram offline and i am going to try and use that as a reference. Any idea of what might be causing this? Thanks

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