We have replaced a blown engine from a 2001 xj with one from a 1998. We swapped the head and coil pack from the 2001 engine on to the 98 block and used all 2001 ancillaries. Everything fits fine until we came to start it. The engine does not start and apeared to out on the timing. We used the flywheel from the 98 but the 2001 tdc sensor. Is this the problem? Are the flywheels interchangeable? We set up the cps as per manual using a drill bit. Can anyone help? Many thanks!

 

Not sure if that's your problem. Have you checked and double checked the timing? Being a straight 6, it will start or run even if the timing is 180° off. Don't ask me how I know. Lol

 

Thanks for your reply. Heres what we did. We set number one at tdc on compression stroke with the cps with its holes aligned with a tooth pick facing the rear of the engine as per the manual. When trying to start engine it coughs and splutters as though the ignition timing is out.

 

I'm not really sure what the toothpick trick is. I recently replaced my engine. When I reinstalled the new one, I had the timing off a lot. I believe I had cylinder 1 at tdc of the exhaust stroke. It would start hard and run, but not well. Do you have the timing marks on the crank and timing index lined up?
I took a piece of fuel line and put it in the spark plug hole on cylinder one. I then turned the engine over by hand until I felt the compressed air come out of the hose and the timing marks were lined up. At that point, check to make sure the distributor is fully seated and the rotor is pointing at the #1 plug on the distributor cap.
I hope thus helps.

 

We did the same procedure to find tdc on no 1 cylinder,but ours is the coil pack type that has a cam position sensor in the place the distributor would be on the earlier engine,hence the lining up with a toothpick in the 2 holes to make sure it is in the right place.This cps sets the injector timing,the ignition timing is done with the tdc sensor mounted on the edge of the bellhousing on the left side that reads a datum point on the flywheel which is why i was wondering if the earlier flywheel is somehow different to the later one and is causing a mismatch between flywheel(earlier)and tdc sensor (later) which is giving us a spark at the wrong time and causing the no start problem.

 

I apologize. I can't help then. Hope you get it straightened out.

 

I don't know if the flywheels are different, but that sounds plausible to me.

 

Ok many thanks for your input!

 

pretty sure flex plates are different, and I wouldnt have switched heads, but ran a caravan coil pack and some wire...

 

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Yes we mean flex plate and crankshaft position sensor.If both are same then maybe we have a crankshaft sensor problem,possibly damaged when we were changing engines.Camshaft position sensor was installed as per manual-no1 on firing stroke at tdc and used a drill bit to align the 2holes in sensor with plug facing rearwards.We now know it is an ignition fault as car is also lpg equipped and gives exactly same symptons with petrol injectors unplugged and lpg activated,feels like timing is wrong and coughs and splutters,spits back but will not run.Any thoughts?

 

Hogg , did you use the mark on the balancer to set TDC? If so i've seen the balancers walk, and the mark off, not in the right place..

 

View of crankshaft vibration damper/timing marks. You should remove the electric raditor fan to get a direct look at the timing marks.

 

Yes we did,but think the problem is the crank sensor.Have now removed it and the casing is broken probably from when we swapped engines.Am waiting for new sensor to arrive,will post result on here when we fit it.Fingers crossed!

 

hi i did this to install cam sensor but, the xj hadly starsts and it shakes very bad, could be my ignition timing 180 degrees out? i mean did i set it on exahust stroke, any way, jeep starts but shakes so bad