Question on checking timing on 1G TSI

[Calan]

If these answers are here, I can't find them

Where is the terminal I'm supposed to connect to ground before checking my timing? My manual's diagram is for crap, and everything I've seen looks nothing like my 92 talon tsi awd.

Why do I need to do this? Is the procedure different if you are running a GM MAS and MAF-T? What do you do with the MAF-T when initially checking/setting the timing? (How do I know I'm reading raw base timing, and not timing that has been modified by the MAF-T?)

Thanks!

 

[twicks69]

First off, your MAF-T does not control timing. It controls the amount of air flow being seen by the ECU, which then adjusts timing based on conditions including detonation (knock). If you are running a stock ecu, you are only able to adjust your base timing by adjusting the cam angle sensor, along with using a timing light to properly set it to stock parameters. Pick up a Chiltons mechanics manual.

Your timing light signal wire will be connected onto the #1 cylinder spark plug wire, or onto the #1 cylinder ignition coil signal wire. Your power wire will connect to the positive terminal on your battery, and the ground wire from your timing light will connect to the ground terminal on your battery.

You point the light at an angle where you can visibly see the light marks on the crank pulley, and the "zero" mark on the timing belt cover for the crank pulley. Usually if you are standing in front of the engine bay, angling the light between the power steering pulley and alternator pulley, it clearly lights up the marks on the crank pulley.

 

[Calan]

Thanks twicks...but I think I should have been more clear in my post.

I'm familiar with timing lights and using them. I was really wanting to know where and why I'm grounding a wire before checking the timing. (I found the location of the terminal).

I've been doing a lot of reading here, but I'm still not sure I understand how the ECU, MAF-T and GM MAS relate to each other. I mean I understand the basics, but not the details.

After replacing my injector seals and fixing numerous boost leaks, my car now runs very lean at idle, and never gets much better. I'm guessing because it was originally tuned to run rich with all the air leaks.

So I was wondering if and how the timing/MAF-T may be causing the problem.

While we're at it, I've seen 23461283468234 posts about ECU's and MAF-Ts, but nothing definitive on how to reset the ECU, timing, MAF-T, idle speed, etc. to get a stable (albeit unoptimized) baseline.


Thanks again for any help!

 

[chicagoavenger]

Your looking for the connector correct? It's behind the battery on the firewall http://www.plymouthlaser.com/timing/tim09.jpg

 

[Quasimondo]

I'm familiar with timing lights and using them. I was really wanting to know where and why I'm grounding a wire before checking the timing. (I found the location of the terminal)

You're grounding that wire to lock the ECU out from adjusting the timing while the engine is running. Once you ground that plug, you can accurately adjust your timing to the recommended 5 degrees BTDC. If you don't ground it, you'll see the timing jump around while you're adjusting the CAS. If you equate this to a distributor setup, grounding that plug is like pulling the vacuum advance hose from the distributor.

Resetting the ECU is simple. Unplug the battery for 30 seconds, then plug it back in. All of your fuel trims will reset to 100%.

There is no 'reset' for the translator. These charts will give you the baseline settings for where you need to start when you're tuning:

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A guide can be found here:
http://www.fullthrottlenetwork.com/showthread.php?t=105

 

[JayRolla]

If you still have not found it look back behind the battery and follow the wiring harness. You will see something that looks like a plug coming off with about 2 inch's of wire. It will have a cap just pull it off and ground the the pin inside to set the timing.

 

[Calan]

...If you equate this to a distributor setup, grounding that plug is like pulling the vacuum advance hose from the distributor.

Ahhhhhh... got it. Makes perfect sense when you put it in 20-year old terms I understand

 

[Calan]

Update...

Well I think I finally got things back in decent shape. I set the MAF-T to baseline and unhooked the battery to reset the ECU for an hour or so, then hooked it back up. I started the car and let it run for 15 minutes without touching ANYTHING and then turned it off (which I didn't do the first time... I read this in another post somewhere.)

Apparently, that was the trick. By starting the car and just letting the ECU do it's thing while the O2 heated up and such, it soon leveled out and ran much better. After a few miles around town with my small phillips screwdriver in hand (for the MAF-T cover ), it's finally running pretty well, although I do have the base timing retarded just a bit and it could still be tweaked obviously. Not bad for no logger though.

Another thing that is interesting... Once things leveled out, the car was running really rich and hitting fuel cut hard at 12 PSI boost, 3k to 4k RPM. I set the BASE up several notches (as if I had larger injectors a.k.a. ECU says send less fuel), and it worked like a charm. Really evened things out across the board.

Time to start searching for bigger fuel flow

Thanks for the help guys!

 

[JayRolla]

Your doing all this without a logger. That is not smart at all. Have you heard of detonation. Its a real bad thing and I would not boost untill you know your not detonating.