Timing issue. Blowing asd fuse

[Cushdaddy]

Long post coming. I bought 2, 2002 liberties, one with a blown head gasket and one with a spun rod bearing. Both are 3.7l. The head gasket seemed fairly straightforward so I tackled that first. Got everything back together and it started right up. Drove it for about 100 miles and thought I was good. Drove it to work and it started running rough at low rpm. Give it some gas and it smoothed right out. At lunch it wouldn't start. Threw cam sensor and intermittent cam sensor. .... After 4 different cam sensors and 2 different crank sensors. Got it running and drove home fine. Then it threw the cam sensor again. Talked to a buddy and he suggested my timing might be off a tooth. I set TDC and checked the timing. Looked like he was right. I reset both cam gears per the book. Prior to this the jeep was hard to start, but would sound great over 2000 rpm. After clocking the cam gears a tooth, it started right up. Give it some gas, and it blows the ASD fuse. I have been fighting this for a month. I think I need to clock the timing again. I am thinking I need to clock the sensor side back a tooth and the driver side a tooth. This is crazy. Thanks.

 

[Cushdaddy]

Update. I pulled the valve covers this AM and reset the timing. I put everything back together and it started right up. Still wants to stumble and stall at low RPM. Fine above 2000 RPM. Throwing cam sensor code again. I have 4 cam sensors and it will only start on one of the sensors. The Chrysler one will now allow it to start. Once I start it, it still runs if I unplug the cam sensor, so the crank sensor is working. Sine I have tried 4 sensors, I believe it is still the sensor. I have tried 2 different computers and the result is the same. If it was anything but the sensor, I would think the same condition would occur with at least one of the other sensors. Please help. This is getting old. It's going on a month of this and I need it out of my hair. Thanks.

 

[JeepinJarhead03]

put the throttle position sensor from the one with the spun bearing on the one that runs and see if anything at all changes regarding its idling.

as for the cam sensors, non-mopar cam/crank sensors are VERY, VERY, let me be clear, VERY... hit or miss

im just wondering if you dont have two problems that are fighting you rather than just a cam sensor issue. a bad TPS will often not throw any codes but cause stumbling and knocking off below say, 1500 rpm and run fine above 1500. cam sensor behavior all by itself usually (not always) but usually presents in the opposite behavior that your describing , runs fine to 2000 rpm then loses its mind. basically if you were to describe the behavior to me without any other info my first suspect would be the tps

as for the ASD, shouldnt have any further problems with that if its now mechanically in time

 

[Cushdaddy]

Ok, I have put 4 different cam sensors in, one being Mopar. Mopar won't start it. When I did the head gaskets, I put new timing chains and guides and tensioners on it. The sensor side chain seems slacker than the drivers side. Could the tensioner be bad allowing the chain to slack and cause the code. I think as soon as the code pops up, the computer ignores the signal and runs off the crank sensor.

 

[Billwill]

I cannot see how the crank/cam sensors have any link to the ASD fuse blowing other than having a good sensor installed allows the engine to run. The ASD relay in the meantime supplies voltage to the O2 sensors, plug coils and capacitor, PCM and the injectors.

Which fuse is blowing....is it Fuse #6 30 A inside the box under the hood or fuse #15 10 A on the fuse panel inside the cabin?

 

[Cushdaddy]

It was suggested that the code might appear because my timing was off. I adjusted the timing to see if that was the issue. That was when the ASD fuse blew. I put the timing back where it was and the ASD fuse is fine but I am throwing the P0340 and the P1391 again. I am thinking the slack timing chain might be the problem. Have to pull the whole front of the engine apart to check the tensioners. That's a pain. I know I pulled the pin on the tensioner because I have all 3 pins in my pile of crap. If the oil port to the tensioner was plugged could that cause slack? Guess I'll have to pull it to see.

 

[JeepinJarhead03]

i usually see P1391 when there's a physical defect in the harness to either the CKP or CMP.

dont know what kind of plans you have for the other liberty, but it may be expedient to steal it's cam position sensor plug and as much of it's wire as you feel necessary. since youre getting a 0340 and it runs fine off the crank, the fault is likely to be in the cam position sensor plug/wiring if that indeed is the case. sounds like the mopar sensor is totally knackered, and with a good sensor in place under vibration its losing connectivity with the plug. but without a scope ability to trouble shoot it electrically beyond trial and error is pretty much impossible

 

[Cushdaddy]

Well, I found the problem. The key that drives the timing gear on the crank failed. It was catching enough to start, and be intermittent. I was running out of options as I had checked everything else. If I knew how to post a picture I would. Trying to decide if I should replace the gear.

 

[turblediesel]

Someone here just had a broken crank key. His hamonic balancer was loose and it looked like that created a small impact which broke the key. Gear looks hardened so it's probably OK.

Thread was titled "Broken crank keyway?" by jklanier with a picture that I tried to copy to post here but it came out as scrambled HTML soup so, look it up.