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What the Heck is this? and where does it go?

XJ Eric

XJ Eric

NAXJA Forum User
Location
Warren, Pa
What the heck is this and where does it go?

I'm working on an 88 MJ with a 4.0. I know very little of the engine. This was found laying in the engine bay and I found a spot on the ignition coil that the connector fit into. Supposedly the truck blows the fuel pump relay and won't run. Well I threw a battery in it and i've got fuel pressure. I even let all the pressure out of the system, turned the key and, YUP, I've got gas pressure again. All's good there. The truck isn't firing up though. Spark is next and since this thing seems to plug into the ignition coil this maybe why it's not firing up?

What is it and where does it bolt up? I can't find any place to bolt it to the engine.

THanks,

Eric

1666624010_large.jpg
 
Looks like a Crankshaft Position Sensor. It mounts on the bellhousing on the top, driver's side. The connector is near the rear of the fuel rail. Without it, you have no spark.
 
TPS = Throttle Position Sensor. Something else entirely.
 
Does look like a crankshaft position sensor. Those might also be called engine speed sensors - I don't really know. Also have no idea what motor it belongs to.
 
that is the CKP or Crankshaft Position Sensor. It plugs on the drivers side towards the top of the motor (intake manifold). The stock wire routing puts that taped with the O2 sensor, knock sensor, and temp sender. but with the short length, i believe that it has already had the bypass done from the factory of the C101. the plug should be on the firewall , coming through close to where the main ECU harness comes through the firewall. PM me if you need more guidance.

and it definitely does not plug into the coil pack.
 
THANKS! Found it. I was there on the engine. I guess it was replaced and they left it in the bay. While I have your attention,


What the heck is this connector? It comes out of the wire harness right behind the distributor.

1666624011_large.jpg


Thanks again for the help.
 
One wire connector? Is the oil pressure sender/sensor plugged in?
 
Looks like the old harness for the oil pressure gauge, looks like it was replaced with a mechanical gauge judging from your pic.
 
hmm, I guess that makes sense, the only thing factory was an oil idiot light. There is a sun pro oil pressure gauge in the cab. so I assume the plug used to plug into the oil filter adapter shown in the pic?
 
Holy cRAP!!! IT LIVES!! the old beast is running. I'm not entirely sure what I did, but the truck is running. Not too bad either. my 98 has more lifter slap than this thing does. Happy day. Now to just put the rest of it together. (driveshafts, brakes, trac bar)
 
its running because you hooked up the CKP. no CKP, engine dont run.
 
No, it was already there and plugged in. Someone had replaced it. The one I found laying in the engine bay was the old one. They must have left it laying in there.
 
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