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E30 M3 - Base Ignition timing.


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Have recently completed fitting a V44 to my E30 M3, which includes a (new) CAS set from an E34 M5.

Using a base map that's been used on an S14 BMW Motor of similar tune to mine, car starts, but runs (badly). Holding it on a partial throttle it surges eratically and will often die. We've had some trouble setting the base ignition timing (See below) so to begin with have set it by sight - so the magnet sits directly beneath the reluctor sensor at TDC.

Doing an ignition test the inductive timing light works fine, but when cranking the car to try and set base (TDC) timing, there's only an occasional flicker from the timing light, which isn't enough to set base timing. Using the logger function, Trig 1 Err is incrementing up. What does this error code mean?

We've tried decreasing the gap between the magnetic rotor and reluctor sensor to virtually nothing - this has made no difference. Gap was approx 1mm before we began reducing it.

Could we have a CAS problem, or is it common for an inductive timing light's sensor to not work well unless the car's running?

Any help much appreciated.

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Guest Dave-Kriedeman

Trigger 1 error climbing is indicating that the CAS has an issue.

The fault could be the CAS itself or many other factors.

What are your Trigger 1 Arming threshold voltages set to.

Check the voltages that you have set in the software,

Then open up Runtime Values List,

Select Triggers and note the voltages on triggers 1 and 2 when cranking.

If the air gap is too big the signal maybe to weak, the Trigger Arming Voltage would need to be reduced to match what you are seeing in the Runtime Value List (triggers) as a starting point.

Are you seeing RPM on your laptop when cranking the engine?

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Hi Dave,

Thanks for offering your advice.

Trigger 1 (Reluctor / Level 1 (Low)) arming threshold values are:

0.2 0.2 1.1 1.1 1.2 5.0 5.0 5.0

Trigger 2 (Reluctor / Level 3) arming threshold values are:

0.2 0.2 0.5 1.0 1.0 1.0 1.0 1.0

I'm seeing the Engine Speed (RPM) work OK - Around 190 when cranking.

When looking at Runtime values (Trigger/Limits)

Trig 1 & Trig2 Arming (V) are set at 0.2. These values don't change when cranking, although Trig1 & Trig2 signals indicate yes. Should I be seeing something else?

I've reduced the air gap to virtually nothing - it's not made any significant difference...

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Guest Dave-Kriedeman

I just reread your first post and see that you have set the CAS up at TDC, out of curiosity where have you synced the cam sensor.

Also do you have access to an osciliscope to check the polarity is correct on your inductive CAS.

What dwell values have you got set in your dwell table,

What is your ignition trigger edge set to,

What type of ignition system are you running, COP with internal ignitors or are you using external modules or CDI.

Also remove your sparkplugs and check that they are not wet with fuel or badly carbon fouled from incorrect fuel settings on initial start, both of these can cause strange timing light triggering events or no fire scenarios.

What is your battery voltage while cranking.

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From reading Newera's other posts, I believe he meant to say cam sensor from an E34 M5, not a CAS (crank angle sensor).

Hi Anders, Correct & my apologies for the confusion.

I understand the Cam Sensor from the E34 M5 is a Hall type. So I've set:

Trigger 2 Type: Optical / Hall

Trigger 2 Filtering: Level 2

Trigger 2 Pullup: ON

Trig 2 Edge: Falling

Sync Mode: Crank Pulse 1 x

For the E30 M3 the Crank Angle Sensor works off the 116 toothed flywheel, but the sensor has 3 terminals. Is it Hall or Reluctor type?

Going by the engine specific information, on the ViPEC help menu, I've set Trig 1 to the following:

Trigger 1 Type: Reluctor

Trigger 1 Filtering: Level 2

Trigger 1 arming threshold

0.2 0.2 1.1 1.1 1.2 5.0 5.0 5.0

I just reread your first post and see that you have set the CAS up at TDC, out of curiosity where have you synced the cam sensor.

Also do you have access to an osciliscope to check the polarity is correct on your inductive CAS.

What dwell values have you got set in your dwell table,

What is your ignition trigger edge set to,

What type of ignition system are you running, COP with internal ignitors or are you using external modules or CDI.

Also remove your sparkplugs and check that they are not wet with fuel or badly carbon fouled from incorrect fuel settings on initial start, both of these can cause strange timing light triggering events or no fire scenarios.

What is your battery voltage while cranking.

I'm using GSX-R 750 coils (-On plug). The engine harness was made by Apex Speed Tech. It was supposedly tested on another car before sending to me and it's about the 5th they've made, so I assume it's all fine. I don't have an oscilloscope to test with.

When I adjust offset (44 Deg BTDC) to show base timing of 0.0 with the battery holding a good charge, as I crank the car (With fuel switched from OFF to sequential) I hear backfiring through the throttles, which seems to indicate the timing’s way off. Changing to 25 BTDC or somewhere in between, it’s still backfiring through the throttles. Why does the timing light show correct reading when the timing's clearly wrong? Could this be because of wet plugs?

I'm going to remove the plugs and leave them off overnight to give any fuel the chance to evaporate overnight. I've ran the battery down several times today trying to get this sorted. Car doesn't currently start at all. Just backfiring through the throttles when I have the ignition on sequential.

Dwell times I have from the base map range from (7V) = 10 to (15V) = 4.

Didn't make a note of battery voltage whilst cranking, but will check that tommorow, when I try again...

Thanks for your help.

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Miguel,

You're a little bit ahead of me in getting the Vipec installed on the S14, but I'm almost certain that both the BMW M5 cam sensor and the BMW crank sensor are 3-wire reluctor sensors (signal, ground, shield). I have not heard of even one Hall sensor used on the older BMW's.

Have you got any input from Neel on this matter?

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Miguel,

You're a little bit ahead of me in getting the Vipec installed on the S14, but I'm almost certain that both the BMW M5 cam sensor and the BMW crank sensor are 3-wire reluctor sensors (signal, ground, shield). I have not heard of even one Hall sensor used on the older BMW's.

Have you got any input from Neel on this matter?

According to Neel, the E34 M5's cam sensor's definitely a Hall type and the S14's crank sensor is reluctor.

To make matters more confusing some sensors (like the BMW crank sensor) are magnetic/reluctor but have a "shield" pin, hence 3 wires.

sounds like your timing offset is off by 360 degrees

Regards

Dave

I think you may be right D Tech. Neel also suggested the same thing. I'm going to double check this, taking the cam cover off to check the valve timing, if need be.

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Many BMW crank and cam sensors have three wires. The wires are...

+ve

-ve

Sheild ground

If there is no voltage supply to the sensor, then they are reluctor.

In the software help there are all the trigger settings for the BMW 116 tooth trigger.

Look at Help -> Contents -> Engine Specific Information -> BMW -> M3

If you still have problems email me your map info@vi-pec.com

Ray.

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There are many things wrong with the map.

Before I list the problems, I want to comment on the mapping method selected. You are mapping the engine just using TPS. This is a very bad way to map an engine. The tune will never be correct at all rpm and engine loads. A carburetor would do a better job of controlling the correct air fuel ratio. The engine should be mapped this way...

Fuel Equation Load=MAP

Open Loop AFR = On

Fuel table Y axis = TPS

Ignition table Y axis = MAP

4D table = Off

Map sensor is then connected to all throttle bodies.

Problems with the map.

1. Update the firmware to version 4.7.1

2. Ignition delay has not been set.

3. Trigger 1 level is set to Level 2. This must be Level 1.

4. Trigger 1 thresholds are not as in the help file.

5. Trigger 2 Sync mode is set to Crank Pulse 1x. This must be Cam Pulse 1x

Another thing that bothers me is you have Bosch 846 injectors selected. If you are not using E85 or methanol, these injectors will not control very well on your size engine. If you need an injector that big, use the Injector Dynamics 1000cc or 2000cc. These will work perfectly on normal petrol.

Ray.

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  • 6 months later...
Guest |770|

Between restoring a 200+ year old Japanese farmhouse, being a family man, running a business and having other toys to play with - when time permits, TBH I haven't been putting aside the time to work on the M3. Finally today I did. Fitting a vaccum chamber and connecting the internal map sensor and checking why the IAT sensor wasn't working soon had it up and running.

I'll probably tinker with it again tommorow (Planned this weekend so I could work on the M3) and will hopefully do some mapping in the evening.

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What type of cam shafts are you running on the s14?

I have very big cams (+320deg) and i had a very tough time tuning with Fuel Equation Load=MAP, expecailly at low RPMs.

I run all four vac port on the TBs together into one hose. I need to try a vac camber, hopefully that will reduce the varying vac reading at lower rpms.

Which camber are you running? custom ? or off the shelf?

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