Setting Timing RB20

[BrianV8]

I am trying to clarify a cluster of information on properly timing an RB20

First, where do you hook the timing light too. I was told its the back loops but i need to know if its the wire that grounds the coil on the ignitor pack or the other wire that grounds to the pack itself?

I was also told that when setting the timing off this loop there will be a timing delay because your right not on cylinder one and to get 20 degrees of timing you have to adjust it to 27 degrees for timing delay.

And finally the cam angle sensor needs to be unplugged to adjust true timing correct?

[Skym]

From what I can remember you connect timing light to a little loop of black wire on the coilpack loom. It's near the plug for coilpack loom that connects to ignition module (drivers side of ignition module). It should take timing off cylinder 1 coilpack, which is what the loop of black wire is connected to.

Turn engine off (so you don't get hit by engine fan when undoing CAS bolts). Then undo bolts on CAS, so it can be rotated. Then start engine, aim timing light at crank pully, adjust the CAS until you get the correct timing. Turn engine off, tighten CAS bolts.

[BrianV8]

so the loops will give me that appropriate timing. It won't be delayed because of wire travel distance? I was told that timing should be set to 27 degrees due to wire lag to get an actual 20 degrees of timing.

[Skym]

I'm not sure on that one. Because I have no timing light, Nissan adjusted timing on my cars engine to correct timing and marked a line on CAS, cambelt cover. If CAS slipped, would know about it (I think they normally have a grey, thin looking sticker across it). I noticed engine felt sluggish, my mate adjusted CAS, about 2-3 mm towards I think was the right side of motor (would have to look at engine again to confirm). I think turning to the right retards?? timing, which seemed to help.

I know the base timing on CAS is important, because ECU takes the timing of that and adds or retards ignition timing (ignition maps).

[BrianV8]

oh ok, so its probably just a trial and error thing more than anything. Depending on what makes you ecu and motor happy i am assuming.

[judasentinel]

so the loops will give me that appropriate timing. It won't be delayed because of wire travel distance? I was told that timing should be set to 27 degrees due to wire lag to get an actual 20 degrees of timing.

Wire lag? It cannot be, as the electromagnetic wave travels at the speed of light in vacuum and I think 2/3 the speed of light in copper. So, the lag is unnoticeable. The issue is not that.

The black loop at the ignitor is actually the wire for coil no. 1, for cylinder no.1. What the timing light clamp that goes around it does, is that it captures the ECU signal when it flows thru that loop to the coil no.1. At that very moment, the coil sends a signal to the plug to create a spark. The timing light, pointing to the notches on the crank pulley, lights up and you see one of the notches lining up with the mark on the lower timing belt cover. As soon as the ECU signal in that loop dies, so does the timing light. And then it comes back on as soon as the signal voltage runs thru the loop again. Every time that happens, the timing light lights up and shines the notch on the crank pulley and it seems as if the pulley is stationary and so is that notch.

The notches on the crank pulley are set at 5 degrees apart from each other. How will you calculate 27 degrees? Besides, you dont need to do that at all, as the difference is negligible.

The timing maps on the ECU are not an accurate reflection of what the actual ignition timing is on the engine. They are an approximation of what it should be. And no matter where your physical timing is set as per the CAS, when you monitor the stock ECU, it will continue to show you stock timing. Wherever the CAS is set, the ECU will think that it is at 20 degrees BTDC. So, in reality, you cannot rely on the readings from the ECU at all. Those maps are for times when the ECU detects knock thru the sensors. And when that happens, the ECU calculates the difference between the working ignition map and knock ignition map and tries to delay the ignition signal to the ignitor by enough time to reduce the timing by that difference. Note that the physical positioning of any component involved in this whole process has not changed, but the timing will have been retarded by the ECU. Now in order to get back to the proper timing, you can either readjust/reset the ECU, or move the CAS to compensate for the retardation. Doing the latter would mean that as soon as your ECU resets sometimes in the future, you will be running higher timing than stock. And so, the ECU will again detect knock and retard the timing.

Its the same situation with the fuel maps on the ECU - the maps are approximations, and not actual AFR values being experienced at the wideband.

ALWAYS rely on the actual timing by checking with a timing light. Move the CAS to the point where you get 20 degrees BTDC. That's all there is to it.

If you are really worried about the whole wire lag thing, then get a hold of the old school spark plug wire, insert one end of it into the underside of the cylinder 1 coil and put the cap on the other end on top of your first spark plug in cylinder 1. Now you are closer to the plug and there will be no 'lag' as such.

Does that make sense?

[love_boost]

when i set the timing i just hooked the light around all 3 wires going into the #1 coil pack and it seemed to work

[BrianV8]

Ya that was a great write up. As far as that wire lag thing goes i heard it through the grape vine. Figured it was a load a crap but wanted to double check. Only question i have is do you keep the CAS pluged in durring timing or do you unplug it to get real engine timing. I know on most cars there is some ignition wire you unplug that takes the computer out of the equation to set proper base engine timing.

[love_boost]

i beleive you unplug the cas so there is no electronic advance/retard. i know that you do have to unplug it for sure, becuase you are setting the base timing.

then i think you reset ecu and plus cas back in? cant quite remeber

[judasentinel]

Do you want to kill your engine? Keep the CAS connected. The ECU and CAS together make the engine work. If you unplug the CAS, your injectors wont fire.

CAS is a feedback mechanism. Its position signals to the ECU when to send a signal for firing the injectors and the coils. Even the R32 manual would tell you to keep the CAS connected when adjusting the ignition timing.

[BrianV8]

ya ok sounds good. Just needed to double check that. I don't think i have to worry about having to resetting the ecu. I just plugged it in for the first time. Car has not even run on it yet haha

[love_boost]

hmmm i guess you learn something new everytime, mine is still running lol and if i remember right i ended up unplugging the aacv, tps and CAS.

i cant remember were i got the guide from though but somewere they had a write up about it, a call to autodream to confirm.

[BrianV8]

Oh ok thanks i'll keep that in mind. A gts manual would definatly be a great thing to get my hands on.

[judasentinel]

I just checked the R32 manual. It is written on page EN-31, which should be page 49 in Acrobat Reader. It says to adjust the ignition timing when the CAS is connected.

And here is something else I note. You have to adjust the ignition timing only after the engine is at normal operating temperature and all systems are running and working fine. If you disconnect the TPS and AACV, the car wont be running normally, as the TPS signal will not be going to the ECU at all and it will mess its idle and afr readings up. And then if you disconnect the AACV as well, the ECU will have little way of knowing what afr the engine is running after the O2 sensor feedback is disabled (after 30 degrees celsius). At this point, let's assume you adjust the timing to 20 degrees BTDC. Now when you reconnect the AACV and the TPS, your idle will jump up and so will your timing. You will now have to rotate the CAS clockwise to retard it back to the stock 20 degrees. But this will not have any effect unless the CAS were connected. So, you cannot really adjust timing unless you have the CAS connected.

It is the CAS that sends the ECU a signal to advance or retard the ignition pulse timing.

[BrianV8]

Awesome, apreciate the effort finding that information. Only issue i can forsee is the fact the car has a messed up idle to begin with so timing should be interesting. When its cold it runs at 800rpm and when its warm 1300rpm. Still havn't figured out what that problem is.