No start, backfire after timing chain replaced

[MudhornTJ]

So, I was replacing my rear main seal on my 4.0 and noticed a lot of play in the timing chain. Replaced timing chain, lined everything up (i thought) but everything back together and tried to start it. Turned over then heard strange noise then it stopped turning over. Tried again, and had a backfire and no start. Took everything back apart and removed plug 1 and verified TDC but the cam sprocket was not linr to line. So kept crank from moving then turned that cam sprocket to line up with crank. Reinstalled everything tried again to start but same thing but seemed worse. HELP! Ran ok before I started the work.

 

[Bammo68]

Are you sure you were at TDC on Cyl1? Remember, the piston comes to the top of the bore twice and you want to line up the timing marks when its on the compression stroke, not the top of the exhaust stroke.

 

[macleanflood]

Also not sure of the year but don't loose the spring and thrust button on the end of the cam.

-Mac

 

[MudhornTJ]

Yeah, was thinking that last night. Will have to check again. If the marks arent lined up at the compression TDC, should i remove the chain and turn the crank only to the next TDC and see if they line up? I'll also have to check the cam phaser, I removed it to try and prime the oil pump. Probably off too.

 

[MudhornTJ]

Mine is a 2000, didn't have a spring or button.

 

[macleanflood]

Mine is a 2000, didn't have a spring or button.

Perfect. My 97 did, as did I think up to 99 or 00.

-Mac

 

[MudhornTJ]

Ok. TDC on compression. Should have air pressure come out when it's there (valves closed). Line up marks good to go, right? Nope. On compression, the cam sprocket is at 11:00 or so. Crank sprocket is also 11:00 or so at TDC. Getting tired of messing with this.

 

[OldBuzzard]

That's exactly what was expected from your symptoms, 180° off. Chain off, turn the cam sprocket, align it with the crank, chain back on.

Edit: Please ignore that.

 

[Daryl]

 

[macleanflood]

Getting closer you can do it!

-Mac

 

[MudhornTJ]

That's exactly what was expected from your symptoms, 180° off. Chain off, turn the cam sprocket, align it with the crank, chain back on.

I've done that a few times, but always ends up the same way.

 

[MudhornTJ]

View attachment 618841

Does not say anything about TDS, just line up the marks, and 2 revolutions, verify marks.

 

[Daryl]

I've done that a few times, but always ends up the same way.

If everything you posted in this thread is accurate, remove your valve cover and make sure both valves are completely closed.

 

[OldBuzzard]

Turn the crank a full turn, so the cam sprocket aligns. Make sure it's exactly aligned with the crank. Give us a photo straight on.

Did you change anything with your crank and cam position sensors?

 

[hear]

Admittedly I've never done this job, but my understanding was that it needs to be aligned like this. Both sprockets have keyways so all you have to do is line up the marks and you're golden. Seems like you're 180 out on the big sprocket, but @OldBuzzard seemed to think the same thing but rescinded his opinion, so I'm questioning what I thought I knew.

 

[OldBuzzard]

Yeah, it's been a few decades, so I'm rusty.
With the crankshaft pointing like it is, it's at TDC. With the cam pointing like it is, it's between exhaust and intake stroke. Rotate the crank 360°, which will bring it back to TDC. And it will bring the cam 180° to the top of the compression stroke. Then verify those marks are really exactly aligned.

 

[MudhornTJ]

ITS ALIIIVVVVEEEE !!!!!! Thanks for all the help everyone!!!

 

[OldBuzzard]

What did it turn out to be, for the rest of us?

 

[MudhornTJ]

Well, don't forget to time your cam phaser too. SMDH... took it out to try and prime the oil pump because it sat for about 3 weeks while I was working on it. Thought it just ran the oil pump. Didn't know it needed to be timed. So, in the end, I just lined up the marks, timed the phaser and started right up. What did I learn... I won't do this job again... lol

 

[Bammo68]

Perfect. My 97 did, as did I think up to 99 or 00.

-Mac

My 99 did, my 02 motor did not. Confused the hell out of me and I honestly thought I had stuffed up my 02 rebuild as a result!