SR20DET Timing Problem.

[MadMattDrifts]

Can’t get this SR20DET to set time correctly.

Harmonic balancer is fine. Had the head off last Friday, verified that the mark on it matches the TDC of #1.

CAS has clear cover on it. I’m wondering if the previous owner took off the disk for some reason and installed it backwards.

Just verified the CAS trigger wheel installation, and it is correct. Will try to use a spark plug lead wire tomorrow, got a feeling my light is bad or I’m getting a bad signal from stock wiring.

- Pulled the cams, reset the chain, installed everything per FSM.
- Set the timing at 0? BTDC (second notch from the left), aligned the cams.
- Rotated the engine over five times to make sure all the marks line up, everything is fine.
- Aligned the CAS with a stud in the head, centered it.
- Aligned the second (furthest mark from the cap) on the CAS with the notch on the CAS.
- Installed it and the first mark was aligned with the notch.
- When the CAS is dead centered, car runs good. Pulls good. Does not get hot, but the timing on the light shows is at 40? BTDC or so (rough estimation). ECU shows steady 15?, idles good, pulls good.

- Adjusted the idle to about 900-950 or so.
- Went back to set the timing at 15? BTDC with the timing light, I have to turn the CAS back to btarded position. Car starts to run funny, hunts for idle, timing gets jumpy when taken out of timing mode. Has no power at all when doing a pull and it gets hot because timing is beyond btarded.

Neutral Position Switch is just jumped now to get the proper idle map.

I put the engine into timing mode both ways. With the DATASCAN ?Base Idle Adjustment? and the manual way, TPS off, rev past 3,000 three times. Both modes locked the ECU timing at 15?. When setting the BASE timing to 15? with the light, problems start to show up. I don?t understand how this is happening.

Car has TOMEI PONCAMS 258. RS Enthalpy tune.

This is the first SR to give me BS trouble like this. Kinda lost at this point. The only thing I noticed is that the IACV sits at 8% when it usually should be higher IMO. Seems like it might be stuck/dead and ECU is trying for it with timing. Will try testing that tomorrow.

https://youtu.be/89mLThwTUwk

[jedi03]

are you using the stock damper? Has the rubber come apart or the possibility of the pulley slipping? And is your tune accommodating the cams and all your mods?

[burnsauto]

how did this engine run before the cams?

Was it just the cams that you upgraded, or was this part of a package?

[Kingtal0n]

Check timing like this


And keep in mind the pickup is directional. Flip the pickup test the timing both ways. One of the ways will have you center the CAS- almost center. The other way will have you adjust the CAS way out of center. The center is correct. The CAS should be nearly center when the timing light pickup is correct directional. Make sure you connect how I have it shown. hopefully the pic shows up

disconnect the TPS to put it into timing mode. Rev the engine a little bit to make sure the timing stays steady in timing mode near idle speeds.
Set timing to 15*btdc around ECU idle speed, maybe 800rpm or something, I forgot. Just make sure its the idle speed correctly, timing steady.

[TheVinylKingz]

Originally Posted by Kingtal0n

Check timing like this


And keep in mind the pickup is directional. Flip the pickup test the timing both ways. One of the ways will have you center the CAS- almost center. The other way will have you adjust the CAS way out of center. The center is correct. The CAS should be nearly center when the timing light pickup is correct directional. Make sure you connect how I have it shown. hopefully the pic shows up

disconnect the TPS to put it into timing mode. Rev the engine a little bit to make sure the timing stays steady in timing mode near idle speeds.
Set timing to 15*btdc around ECU idle speed, maybe 800rpm or something, I forgot. Just make sure its the idle speed correctly, timing steady.

When attempting to do ignition timing can one simply disconnect the TPS to put it into timing mode after it is warmed up, or do we need to follow the FSM?


Part 1

- Warm up car.
- Run engine at 2000 rpm for 2 minutes, under no load.
- Rev engine two to three times, under no load.
- Run engine for 1 minute at idle speed.
- Stop engine and disconnect TPS.
- Start engine.

Part 2

- Rev engine two to three times to about 2000 rpm, under no load.
- Run engine at idle speed.
- Check ignition with timing light and set at 15+- BTDC.

Just want to see if there is another approach to successfully set ignition timing.

[slider2828]

I just checked base timing on my car so I went through this......

Really the most accurate way is cut an old wire spark plug wire. Cheap from part store. Put the boot from the cut wire on to the spark plug and then shove the wire with an exposed middle lead into the coilpack and put the timing light clamp between the wire of the spark plug and the coil.....

This sounds like a stock ecu? Right?

The only concern is the chain link at the crank gear. Did you happen to drop the chain when taking off the head or something?

Us the teeth marks from the surface of the head, this helps too.

https://www.sr20forum.com/threads/ho...g.81413/page-5

Finally you wouldn't have swapped the intake for the exhaust cams right?

[Kingtal0n]

You need to make sure the timing that the light is showing is correct, it can be wrong depending on the pickup and timing light used and where you are measuring from.

When you unplug the tps the ECU should turn off the timing compensation which will stop the bouncing of the timing. Compare the timing on the crank with and without the tps connected it should bounce like crazy with tps and be steady without the tps. That is how you know the ecu is ready to be timed when the tps is unplugged and the timing is steady. From there you need to make sure the rpm is low enough to be in the base portion of the timing map for idle speed timing. The cas will be nearly center but always slight off center thats how you know the timing chain, cas, and timing light is all lined up.