I have been looking around the forums for the past few months and can’t really seem to find anything that answers my questions, so I’m hoping someone can help me out with what’s going on. I have a 2000 4.0l xj with 201,000 on the clock. It has the “viper coil” a cowl intake, 12 hole injectors and as far as my exhaust goes I have a muffler and just the first o2 sensor closest to the motor. As far as drive train goes everything else is stock. When I first attempt to start my Jeep it takes way longer to start than it used to. I have to turn it over about 5-6 times before it will start and throughout those 5-6 times you can hear a back fire out of the intake. Once you get it running it runs strong and I have no issues but if I turn it off after I get where I’m headed it takes twice as long to start. The problem has been happening for months now even before the ignition mod and cowl intake I also recently replaced spark plugs. I don’t know where to turn my attention to, due to the fact that there are so many forums with different answers and not exactly the same issues as mine. If anybody could give me somewhere to start or something to check before I start dumping money into parts changing it would be greatly appreciated. If any question please ask I’m just trying to get this thing figured out so I can rely on it again.

 

All I can offer is to try a can of Seafoam in the gas tank.

 

Did you replace plug/coil wires, cap, and rotor when you replaced plugs? If not, check your spark with a spark checker for each wire and replace them with cap and rotor if not strong.

Every backfire situation I've had was due to a bad or badly connected plug wire. BUT yours could be different.

 

It has brand new plug wires and ignition coil along with the coil. It was having this problem before all of that was done and after doing it all it improved was the way it ran. I attempted to start it this morning and this time no back fire. But normally it will attempt to fire up and this morning it wouldn’t even do that. I tried turning the key on to listen for the fuel pump and I couldn’t hear it but while it was turning over I could smell the gas after turning it over for a few minutes.

 

Well now my Jeep will not start completely. I am currently not getting any power through the plug wires. If anyone had any advice it would be greatly appreciated. I am beyond frustrated with this thing. I have checked fuses and even put the stock coil back in and nothing but cranking

 

if you cant hear the fuel pump it might be the auto shutdown relay ?

 

Unless there’s more to the ASD than just the fuse under the hood then it’s fine, that was one of the first things I checked. Busted out my old hayes book on it hoping it leads me somewhere.

 

Am I missing something? A 2000 should not have a coil or plug wires. It should have a coil rail that mounts onto the plugs. Maybe this is off topic but it had me scratching my head. And the ASD is a relay. Yes it is fused but the fuse could still be good and the relay had. Maybe a place to start would be to check the fuel pressure. You could also try swapping the ASD relay out.

 

So on my 2000 it has been switched over from the standard coil rail to what has been called the “viper coil mod” which is nothing but a coil that allows you to run spark plug wires instead of the typical one piece rail. I’ll give the relay a check as well and see if that gets me any where. I appreciate the help.

 

Got an engine code and decided to scan it today and it came up with a P0340 cam shaft position sensor. With that being said I’m going to change it and hope for the best with my issues.

 

sounds like the infamous failing crank sensor

 

Well, his code said CAM sensor....

Plus, that thread was from 10 months ago, so hopefully fixed it by now. No closure, so rude.

 

I seem to have the same issue, would love to know if and how you fixed it, very intermittent issues with starting, sometimes fires perfectly fine other times it backfires through intake and won’t start, swapped cps. It all started after I swapped my flexplate. Could it be a map sensor issue? I’ve got a new coil pack and new o2 sensors that have been fine since I replaced them a couple months ago

 

did you figure out this issue? What fixed it? Having the same problem on my 01.