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ignition timing


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Hey yall,

 

I went to check my ignition timing when i was under the hood yesterday. I noticed the BTDC marks on the pulley were off to the driver side from the indicator arrow. Far enough off that no marks were lined with the arrow, but close enough that I could still see almost all the marks. 

 

What could cause the marks to be that far off? Maybe the engine wasn't fully up to temp?

 

Does the timing belt have anything to do with the ignition timing? I had the timing belt done at a shop a few months ago. Since then, I have had a few rare occurrences where I go to start the engine and the check engine light comes on immediately and knocking sounds like it is coming from the engine. I immediately turn off and attempt to start it a few minutes later and it runs fine like nothing happened. 

 

The dizzy cap looks like it is sitting pretty advanced from what I remember setting it when I replaced the dizzy 6 months ago. I've got more smoke than I think I should be having and it smells like it is burning rich. It is seems like it is burning through fuel. 

 

I replaced my spark plugs yesterday. The coloration of the plugs looked fine but they all seemed to be wet, which would indicate burning rich, correct? 

 

I had the intake manifold off yesterday to replace the injectors with reman ones. Sadly the reman ones looked really beat up from the shipping and some had torn filters. I decided not to install them and will send them back. None of my current injectors seems to be leaking so I'll just leave them alone for another few months or year until I really need to swap them out. 

 

I am reading up on checking TDC on #1 spark plug before setting ignition timing but feel a little confused on how to do it if anyone is willing to attach a good youtube link or write out the process.

 

As always, thank you all for your time and experience. 

 

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The pulley (with the timing marks) is bolted to the balancer, but there's no key or uneven bolt spacing or whatever to prevent you from putting it back on with the marks in the wrong place. It's entirely possible that the shop took the pulley off the balancer and reassembled them incorrectly, which is why the marks are showing up wrong with the timing light. This would not cause running issues, though, unless someone tried to time it to those marks after reassembly. To find approximate TDC (good enough to check pulley position), pull the #1 plug and stick a dowel or something down the hole, then turn the engine over by hand (making sure the dowel doesn't get caught as the piston comes up), and stop when the dowel is at its highest point. This can be tricky to judge, and there are better ways to do this, but this method should get you close enough to see if the pulley is bolted in properly.

 

The ignition timing does change when the engine has warmed up. I set mine cold once, to get it in the ballpark after having the distributor out, then checked it again after it warmed up, and it was way out. I don't remember how far, just that I was surprised at how far out it was. If the marks are in the right place, maybe it was set up cold?

 

That said, should've been no reason to adjust the spark timing after a belt replacement. This has me wondering if they got the belt timing wrong and messed with the ignition timing to get it to run afterwards. To check, you'll have to remove the timing belt cover. First, get the crank to TDC, then check either the marks on the cam sprockets or the rotor in the distributor to make sure you're on top dead compression (cam dimples near the bumps on the back of the cover, rotor pointed generally towards the #1 spark plug terminal). If not, turn the crank 360° and check again. When it's lined up, remove the balancer and cover and count teeth. Should be 40 between cam sprocket dimples, 43 cam to crank. The marks on the cover are approximate, so trust the teeth, not the marks.

Pull codes and see if the computer can tell you what the CEL was for. Knock sensor, maybe? I'm not sure what would cause intermittent knocking on startup. The lifters make noise sometimes but I've never heard of that triggering a CEL.

The rich plugs I've seen were dry but carbon-fouled. Wet with fuel suggests flooded/misfiring.

Has it been running like this since you got it back, or is this more recent/preexisting?

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As an update. I took my pathy back to the guy who put the pulley on wrong when he did the timing. I got it back and checked the ignition timing and it's all lined up again. 

I am still have idle issues when the pathy is to operating temp. I believe I did not set the TPS correctly when I replaced it last week. I will go back in today and see what I can do. The marks for ign timing start at -5 correct? And increase by 5 each mark, so the 15 degrees BTDC should be the fifth mark? 

 

If anyone has a good youtube suggestion on how to set the tps on our rigs, that would be great. I have found youtube to be very helpful when I tackle fixes that I do not fully grasp just from reading the chilton or haynes. I watched a few generic tps adjustment videos and I'll just go from there. Lucky to be borrowing a friend's garage when it is -1 out today. 

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  • 2 weeks later...

The marks start at 0. So if you have 7 marks it goes 0 5 10 15 20 25 30 left to right.

 

The pulleys came from the factory with a white paint on 4 marks. The marks referenced here:

 

image.png.23530730ffd6c52278541fcc62aee47d.png

 

The one with the -5 at the start is for the 4 cylinder models.

Edited by adamzan
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