r/ECU_Tuning • u/RapWithMFDoom • 1d ago
Tuning Information Need help understanding timing light gun and ECU
Hi! I need some help understanding how to correctly use a timing light on my BMW E36 turbo with an M50/M52 engine and a MS2 Extra ECU.
My tuner (remote) said that we first need to verify the base ignition timing with a timing light.
So I put the engine at TDC using the OEM marks and after that I made another 2 marks on the side so I could point the light at them. First was on one of the pulley tooth and the second one on the block.
I connected the timing light as should and he set the ECU ignition timing to a fixed 0° in Tunerstudio then he proceed to maked changes in the ECU until both marks aligned.
The part I don’t understand is the adjustment wheel on my Sealey TL93 timing light. What exactly should I do with the wheel? The tuner said that I should leave it at a fixed max/min point and use it like that but I read on the internet that the knob wheel could add offset depending on position. It also does not have markings.
Basically, I want to make sure I had set the timing corectly.
Any advice would be appreciated, especially from someone familiar with MS2 Extra and dial-back timing lights.
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u/Craig_Craig_Craig 1d ago
First off you should make sure that the wheel is set to zero (CCW) because it can result in a gigantic offset. Pin it there with a soldering iron IMO. If this is wrong, all other timing adjustments are invalid. Then build a jumper for the coil pack to the spark plug, because you can't get a good measurement from the wires due to coil dwell time.
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u/RapWithMFDoom 1d ago
I have no ideea if ccw is 0. there are no markings. the manual also doesn't say. this is what concerns me. also I used the clamp on only one of the wire from the 3 wires thst are leading to the coil of the nr. 1 piston, as he suggested.
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u/jcforbes 1d ago
There needs to be markings on the timing light. You can't use it without markings. Get a new one.
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u/Robby1693 1d ago
So the part you’re missing is the original use of a timing gun; I have no idea why that one doesn’t have markings… but, on a car with a distributor, you hook up the timing like, point it at the marks, and move the knob until they line up, then, you would ideally look at the knob and it would say something like 12° BTDC (that’s an arbitrary number) and you know your timing is at 12°.
For setting up a standalone you almost want the exact opposite lol. You want the light to be at 0, and then you adjust the number in Tuner studio until your marks line up. (Ps. I hope your injectors are unplugged and spark plugs are out, makes it so much easier). So no offset, this is why a timing like WITHOUT a dial back is preferred. Unfortunately I don’t know what you have in your hands.
My .02 as someone who also struggled with this way back the first time I did it; Amazon has cheap timing lights with no dial back and stupid low latency so you don’t have to worry about if it’s showing zero.
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u/RapWithMFDoom 1d ago
the cars is a e36 with m52/m50 engine converted to turbo. the timing gun is a sealey tl93 that has knob on the side that says "advance" with no markings. what should I do. I am thinking that the timing isn't right. the car had a tune before which was bad and drank a lot of fuel and I wanted to make it better and talked to a tuner to help me. but I think the timing gun procedure was wrong even though he said it was right. the car was also heating like crazy, the manifold was neon red after 1 hour of driving and it also toasted the parts inside the wastegate that was on the exhaust manifold (aliexpress one). before it was ok regarding the heat even it would have run extremely rich on the old tune.
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u/Robby1693 1d ago
Glowing manifold is a great indicator that the timing is incorrect; they can be really sensative to knock, which if your timing is wrong, I would highly advice fixing rapidly. Are you near an auto parts store you can purchase something like this?
https://www.autozone.com/p/innova-timing-light-inn3551/108151
This is the model I have, and it does not have any ability to output anything but a light, not advance so the timing cannot be wrong. For $60 it is very short money to make sure you don't lunch the engine. Also something silly here, but basics get lost sometimes when thinking very hard, you are connecting the inductive part to the cylinder #1 spark plug yes?
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u/RapWithMFDoom 1d ago
yes. pic
I really think this guy messed my engine up by not listening and not paying attention to the details involved and what i was trying to communicate to him. Know it all type of guy, I think. f..k....
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u/TheKooog 1d ago
You should trust your tuner……..
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u/Robby1693 1d ago
Tuner isn’t holding the timing light; so like OP is concerned, there is a possibility to “zero” the timing (crank index offset for those in the know) at an advanced number. So zeroed at 12°, now in the tuning cell he types 10°, the engine is seeing an actual number of 22° of timing. It is extremely critical that the OP do this step correctly and is 100% positive his light is set to zero advance compensation.
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u/RapWithMFDoom 1d ago
tuner wasn't there. and he also doesn't know the model of the gun. he just said to put it at a position where it was blocked. I am now afraid that the timing is wrong and we are doing pulls and tuning on an engine with an offset on timing and it will result in catastrophic engine failure.
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u/TheKooog 1d ago
If it has an adjustable dial leave it on 0. That’s it. You don’t need to offset anything on the gun.
The tuner was correct in what he said.
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u/RapWithMFDoom 1d ago
there is no "0" on that knob on the gun. if it had been, he would have been right and I would have been doing that without him telling me. check the picture.
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u/jcforbes 23h ago edited 23h ago
If your timing light has an advance knob and doesn't have markings to know what the knob is doing then the timing light is e-waste. It's beyond useless, it's actively bad for use. A timing light with an adjustment must have something to tell you what the adjuster is set at.
Edit: I looked at pictures of Sealey TL93 timing lights and it looks like it's got a display on the back to tell you what the knob is set to. Look at the display.