RB26 start help

[Sean]

Go old school, disable the fuel pump, hook a timing light up and see where it's actually sparking as a stating point.

[tarmac terror]

Thanks Sean...Will try and do that tomorrow.

In the meantime, I spent a bit of time today changing REF polarity in the software to falling edge as suggested by David. Unfortunately no joy.

Just to check something though.....

I'm using a 36-1 trigger wheel. I presume this is REF mode 5 (one missing twice per cycle?). I have also moved the SYNC trigger around a bit so the SYNC, missing tooth and TDC are closer.....but not too close!! CRIP now 70deg.



TT

[Stephen Dean]

ID1000 injector calibration information.

[tarmac terror]

Thanks for that Stephen. It looks the same as the data I found from another Motec brochure. I note though that some of the values are greater than the software allows to be input I.e max 2500..


TT

[David Ferguson]

So you do understand the first step is to verify the ignition timing. It sounds like perhaps you've been changing the CRiP but not checking the result.

You do this using a timing light, and the Adjust->Ignition->Crank Index Position screen. While on this screen, the timing will be fixed at whatever the Test Advance value is (choose this so the timing mark will be visible. Read the help on this screen (press the F1 key).

I suggest disconnecting the fuel injectors, remove the spark plugs, but arrange plug number one so that it grounds to the engine head/block and you can see the spark. Now you can crank the engine over on the starter and observe the engines timing mark using the timing light. Adjust the Crank Index Position until the mark lines up.

Once that is done, you are ready to install the plugs, connect the injectors and attempt to start the engine (also make sure the battery is fully charged) - be sure to move to another Adjust screen so the ignition timing will return to the control of the Ignition Main Table.

I will often go to the Adjust->Fuel->Overall Trim so that I can change the fuel globally to see what it wants to start.

You can do the same with the Adjust->Ignition->Overall Trim to see if that helps starting (usually 5-10 deg advance will start an engine).

Once you can get the engine to idle smoothly -- revisit the Adjust->Ignition->Crank Index Position and verify the ignition timing.

[tarmac terror]

Hi David. Yes, I will try and do this tomorrow. Unfortunately this test requires a second pair of hands which I don't have access to right now....

So, as an example lets say the test advance is set to 20 and the timing light shows it to be 25. Where is the adjustment made?? CRIP??

It has also just dawned on me that the std R34 (which the Motec base map will be for and which i'm using) runs MAF's whereas I have ditched the MAFs and am using MAP. I have the Efficiency Calc and Load Calc set at option 4 (MAP). Will the MAF-based map still work or will it need adjustment?

Sorry to be such a PITA. I'm an ex-mechanic but this sort of thing is all new to me


TT

[David Ferguson]

Yes, you change the CRiP (CRank Index Position), (in your example, by adding or subtracting 5) to get the timing to agree. You can change this number right on that Adjust screen and see the effect.

I doubt the base fuel map is using the MAF (well maybe the air temp part of it). Most MoTeC setups use either MAP or TPS for the load axis.

A base fuel map is just something to get started with -- you will need to tune the fuel and ignition tables to give the engine what it needs. Preferably this is done on a dyno, but can be tuned on the track (or street) if you are careful.

If you are going to tune this yourself, you might be interested in some of the courses over at HP Academy. They have some intro webinars that I think you can see for free:
https://www.hpacademy.com/

[tarmac terror]

Thanks again for the tips David.

I intend to entrust the actual mapping to a Motec specialist here in the UK. My main aim here is to get the motor to idle so I can get a few heat cycles through it and so the car is able to at least move under it's own steam as it were...

I'll look at the timing tomorrow (fri) and report back...

one last thing....in the Ignition setup menu the first parameter is 'Ignition Type' (rise/fall/etc). Is this just the same as the REF trigger orientation i.e. in my case, a falling trigger ??


Regards,
Scott

[David Ferguson]

NO-- the ignition setup depends on the coils and ignitors you are using. If you have this backwards, the spark will not be occurring at the correct time, and the dwell will likely result in overheating the coils.

[tarmac terror]

OK, I just want to check the method of calculating CRIP as I've read various things (and watched webinars etc) and I want to check that my understanding is correct.

6cyl 4-stroke engine
36-1 crank trigger
Sync tooth on exhaust cam wheel.
Ign Mode 5 (one missing twice per cycle)

So,
I find No1 TDC (compression)...then I wind engine around to next Sync event....then I wind it around to the first tooth IMMEDIATELY after the missing tooth gap (index tooth)....then count degrees from this position to TDC which should give me CRIP(??)...in my case 71 degBTDC.

Does this sound right??

However, I have also read that the index tooth is the tooth immediately after the sync event (??). This would kind of negate the whole missing tooth portion of the wheel!!! Although I suspect that this method is for wheels without gaps or extra teeth??


TT