Hello, I've been trying to figure out this no start issue I'm having for a while. When i bought the xj around 3 yrs ago i had the engine rebuilt and ran great for a little bit over a year and it blew up. So I grabbed a stock one off FB marketplace with 147k miles out of a 97 XJ and cleaned all the oil off it and replaced all the gaskets and timing sprockets and chain. I dropped the engine in and connected everything to see if it would start up and it did but sounded like the timing was way off. While the engine was still in the bay I took the timing cover off redid the timing set the distributor and now if doesn't want to start. Just cranks makes some pops flame comes out the header.

Some things i tested-
I checked if i was getting spark to all cylinders and determined that i wasn't getting spark to cylinder 2 and 5. The coil pack, distributor, plugs, wire, cap, rotor are all new.
Today i replaced the CPS and that didn't help with anything. i cleaned the flywheel from grease and rust but that was clean as well.
fuel pump is also new and fuel is getting to the engine.

From what I've seen in the engine bay everything is plugged in, im just so lost in this whole situation currently. If i remember anything else i will edit the post if possible.

 

Perhaps your valvetrain timing is off as well?

 

Plug wires on the wrong posts, or incorrectly timed?
http://cruiser54.com/?p=68

 

Ive retimed the engine probably 20 times. And it does the same thing everytime i try starting it. The wires from the cap look to be in the right places from what ive looked up on pictures.

 

@IJM @lawsoncl Is there a write up on this forum on how to do timing from the timing chain and distributor? Ill try it again tomorrow and see how it goes.

 

Good point about the plug wires being mixed up. That'll do it.

 

and http://cruiser54.com/?p=68 and shows the correct method and plug locations. Some of the diagrams out there (haynes for example) are WRONG.

 

It may be as simple as this right here. Please pay close attention. Don't just brush by this because you think it's good.

There are many images online from the Haynes and Chilton manuals which are WRONG. They show the plug wires to the distributor starting on the wrong terminal. It's really easy to miss.

IT'S REALLY EASY TO MISS!

Lawson linked the correct into above, and I suspect yuou just glanced over it (if that) and think you are good. Here's the link again. Check carefully. It's NOT about the order of the wires. It's the starting point on the distributor that is off by one.

http://cruiser54.com/?p=68

 

Here, so everybody can see it.

 

Did I mention that it's really easy to miss?

IIRC, the wrong diagrams have everything rotated counter clockwise one terminal, so that what they show as #5 is where #1 should be. But don't quote me on that.

But it's really easy to miss!

 

The thing i dont get is, i bought this engine from a guy and he sent me a video of it running, i decided to change all the gaskets and timing chain/sprockets. Give the engine a refresh before putting it in. I put it in the first time it ran a little but sounded like bad misfire/timing. So i redid the timing while the engine in the car and now i dont get spark on 2 cylinders. Wish i just didnt replace gaskets...

 

How are you determining you don't have spark on #2 and #5? Pulling the wire off the plug and cranking, while watching for spark? Or are you unplugging the injectors and listening for an rpm change? You tried putting the old cap/rotor/wires back on? Pulled the plugs and inspected? Could be a dud new part or two. If it's just two cylinders not firing, that's not likely to be the coil or CPS.

You check compression yet? That might be somewhat diagnostic whether it's a valve timing issue.

 

Im using a sparkplug tester when you crank a red light flashes. I tried the old distributor and rotor but cant use the other black plate, it has the old style connector. From what ive seen the plugs tips go black but still doesnt solve my issue of no spark on 2 cyl.

 

In general I've seen where cam timing being out on an engine can confuse the computer and cause it to skip spark events and/or injector events. That's usually on engines with a belt where something has caused it to jump teeth, but if I remember right the 4.0 has the "cam sensor" in the distributor, so if it wasn't lined up maybe the same thing could happen.