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2G Base Timing Incorrect

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shinzon

15+ Year Contributor
350
72
Sep 11, 2006
St. Petersburg, Florida
I just did a timing belt change on my 96 TSIAWD and I was verifying base timing and I noticed it's off. I checked ground timing connector in ECMLinkv3, and used a timing timing light. ECMLink was reading 5deg but I was seeing the mark just off "T," or what i presume is around 2deg.

I checked all the timing marks were lined up multiple times before I reassembled the engine. As far as I'm aware, it's not possible to set base timing on a 2G. If I was one tooth off on the crank, that should be around 15deg if i remember correctly.

What could be causing me to be around 2-3deg retarded?
 
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Have you considered your harmonic balancer is on its way out?
Replaced it with a new OEM balancer about a year ago. Shows no signs of cracking or separation.

For lack of a better idea for what could be wrong mechanically, I added 2deg of timing to the entire timing table in ECMLink. This should be an acceptable solution, right?
 
If you are 100% sure that the engine has never been touched since it was sold as new. And now if a couple of degrees are retarded by comparing to when the engine was new. Then I would imagine the timing belt is stretched/worn. If the timing belt is new, the difference of production quality/sync accuracy, or cam gear's teeth, dowel pins/holes are slightly worn by time. Or perhaps trigger plate or timing cover is slightly off for some reason.
 
If you are 100% sure that the engine has never been touched since it was sold as new. And now if a couple of degrees are retarded by comparing to when the engine was new. Then I would imagine the timing belt is stretched/worn. If the timing belt is new, the difference of production quality/sync accuracy, or cam gear's teeth, dowel pins/holes are slightly worn by time. Or perhaps trigger plate or timing cover is slightly off for some reason.
I'm the second owner, it came to me at 100k, and I've had it for the last 15 years--not 100% certain but reasonably certain it's never had the engine apart. Not much had been done to it at all when it came to me. It did have a timing belt change at least once as it had a NAPA belt on it years ago.

Brand new belt and components on there, including the trigger plate, but I like the idea of the timing cover being slightly off. It is an aftermarket lower timing cover. Someone had forgotten a bolt in the AC belt bracket and it rubbed through the factory lower timing cover; changed that out back in 2014 when I did the last timing belt job. Maybe the aftermarket cover has the scale in the wrong place?

I'll line the engine up on TDC and see if the T on the timing cover matches.
 
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If I wanted to fix this issue, what would I need to do? I can bandaid it with ECMLink, adding the missing timing across the entire map, but that wont fix that valve timing is 3deg or so off in comparison to the crank. To fix this for good I would need adjustable cam gears?
 
Assuming the valve timing is mechanically retarded a couple of degrees, Yes, to use adjustable cam gears is the easiest way to adjust the mechanical valve timing. Besides that, use a thicker head gasket in case if the cause is resurfaced head/block or thinner gasket. if you want to keep using the OEM gears for some reason, you can file dowel pin hole on cam gears to adjust the dowel pin position, too. Using adjustable gears would be much easier and less of hassle though.
And as I mentioned above that timing belt condition/quality, belt tension and more factors would possibly make a few degree difference. If you care about that difference and want to avoid that, I recommend to use a major brand's high quality timing belt or Mitsubishi and check and adjust the cam position in respect to crankshaft by using a degree wheel, since checking it by seeing timing light on crank pulley is not the right/accurate way to know the cam position.
BTW, if you would install a 1G CAS, that would allow you to adjust the base timing, too.
 
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ECMLink was reading 5deg but I was seeing the mark just off "T," or what i presume is around 2deg.
The ecu is completely blind to the physical base setting. It will always assume it's 5*. This is why it's important to get the physical setting right.

If you're at 2*, there's no physical adjustment for you aside of going with a 1g CAS. The easy way out is to keep in your mind that's you're at 2* and work off there in the 'link settings.

2* actually isn't a bad thing. If you're aware of it being there, you'd be aiming forever 3* less than it actually is, which would keep the motor from popping vs the other way around. If you're using pump, you ultimately don't care. You keep inching up and work off the knock sensor. You get peak at 15* instead of 12* on 'link, all's good. Doesn't mean a thing. On e85 you kinda do what you want and knowing you're 3* shy it just something you factor in.

Ultimately I wouldn't worry much about it. My 1g was missing the side cover so I couldn't even do the base timing properly, just went off the sound and feel of the engine and knew not to go all the way retarded/advanced with the CAS. No issues here.
 
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If I wanted to fix this issue, what would I need to do? I can bandaid it with ECMLink, adding the missing timing across the entire map, but that wont fix that valve timing is 3deg or so off in comparison to the crank. To fix this for good I would need adjustable cam gears?
There isn't a valve timing issue. Check it. Ignition timing and valve timing arent related like that.
 
^Important point. This has nothing do with physical timing. Zero.

It is all about the timing of the CAS. The timing of a sensor. That's it. Either get a 1g CAS that you can clock to adjust, or offset the values in 'link across the entire table.
 
There isn't a valve timing issue. Check it. Ignition timing and valve timing arent related like that.

^Important point. This has nothing do with physical timing. Zero.

It is all about the timing of the CAS. The timing of a sensor. That's it. Either get a 1g CAS that you can clock to adjust, or offset the values in 'link across the entire table.

I was under the impression that the ECU used the cam sensor to determine when to fire the coils and injectors, and given ignition timing is non-adjustible on a 2g, if I'm seeing 2deg with a light and the timing connector grounded, wouldnt that mean the intake cam is 3deg retarded from the crank, and therefore so is mechanical valve timing? Or am i thinking about this wrong?

Edit: actually, since the cam timing marks were lined up perfectly, it probably means the crank is 3deg retarded from the cam gears, right?
 
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I can't say this any more plainly. Mechanical valve timing and ignition timing are not related.

Ignition timing happens relative to crank position.. I'm sure if you check your VALVE timing is spot on. This doesn't explain your ignition problem. You might check your crank trigger plate or as suggested you aren't looking at it straight on. I always positioned my head kinda by the power steering pump. You can get a straight look to the marks if I recall.
 
Awesome, thanks for the information guys. If mechanical valve timing is fine, then I'll just add the missing degrees across the whole table and be done with it for now--maybe I'll do a blacktop CAS in the future. Presumably crank timing is still off in relation to the cams, but 3deg is within spec in the manual, and, for lack of being able to find anything actually wrong, it's not unlikely the car has been like this since the factory; I'll fix it in software for now.

Thanks again for the help @pauleyman @Stapl3
 
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Think about it like this. If you had a 1g and could clock the CAS, you'd just clock it until you saw 5* and move on. This thread wouldn't even exist.

As we suggested, just factor it into the 'link settings, ignore it completely, or get a 1g cas. I wouldn't think about it much beyond that. If the crank is physically off you'll notice it making fine adjustments at WOT up top. And ultimately you'd just adjust around that and move on. No harm no foul. You're all good man, just keep the supposed "missing 3* ignition timing" in your back pocket and move on as normal.
 
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