Hayabusa engine won't start

[ric355]

This is in my Radical SR3 but I know there's some 'busa experience in here and some MBE experience so maybe people can offer some suggestions. I've pasted below what I posted on the Radical PH forum, but the traffic there is minimal so posting here too...

 

There's some history to the current problem which I'll explain first.

 

A couple of weeks ago I ran the car at Combe for a track day. It was the first run since an engine change (1400 Powertec). The car ran surprisingly well considering it was only on a base map, but eventually I ended up with a flat battery so apparently there was a problem of some sort with the charging system. It was a very wet day so I didn't try too hard to fix it, and took the car home mid afternoon. It rained really hard on the way back and the car is on an uncovered trailer, so it got a proper soaking.

 

Next day I started out to investigate the charging system fault and found the car wouldn't fire up at all after having charged the battery. I found the ECU connector was waterlogged (it's an MBE 992 ECU mounted with the connector facing upwards on the bulkhead, engine side). So I dried it out and tried again. I also tried a spare ECU which isn't the right map for the engine as it's off a 1475 but I know will start it and idle OK although not perfectly. The plugs were dry so I checked whether I had a spark using a plug tester inline whilst cranking. Still no spark unfortunately.

 

I did my best to test the coil pack using various stuff found on the internet. I couldn't verify it was good so I just bought another. Still no spark.

 

I have an MBE ECU interface so can get some diagnostic info, but the radical ECU is locked so I can't look at the configuration to verify it is OK. The engine has started and run on this ECU at the track so I know it works (to a point) - unless the ECU lost its config somehow which is possible but I suspect unlikely. The engine cranks at about 250rpm according to the CAN feed of data on easimap, but still doesn't fire up. I've tried opening the throttle which makes it crank a little faster but still no spark.

 

Using the SR3 wiring diagram I've traced voltages and I think everything is correct although there are a couple of uncertainties:

- Two of the pins to the coil pack have +12v on them. This is correct according to the diagram.

- The other two pins are the drivers from the ECU I think? They show about 1v with ignition on but no cranking. I don't know if this is correct or not.

- The coil pack is new

- I've checked the relay that controls power to the coil pack. It works OK and I even swapped it with another to verify (I wouldn't have +12v on the low tension side of the coil pack if it wasn't working, anyway).

- Plug leads are not new but I doubt all four would fail simultaneously. I have checked all four with the spark tester inline and none of them have a spark during cranking.

- I've also swapped the plugs for a different set and that had no effect

 

On the live data screen in easimap I can see 250rpm approx when cranking.

The throttle pot shows 0.29v with the throttle closed. Load site zero on the throttle map is set at 0.37v but both these values are unchanged and the engine has started previously with those values. Although I can't guarantee that the ECU currently has that value (because it is locked), only that is the value it is supposed to have according to the copy of the map I was sent.

 

There are two other data items available in easimap that I think are of relevance:

 

1. Engine sync method

This one shows "Inductive Sensor (f)" on the live data screen. (Does anyone know what this is?) However the copy of the map shows that the engine sync settings are as follows:

- Cam Sensor Select: Inductive Sensor ® (note the difference here)

- Hall Effect Tooth Position: Hall Effect CAM sensor disabled

 

So I can't tell whether the cam sensor is active or not (because one of the other options for CAM Sensor Select is "No CAM sensor"). I don't think the engine has a CAM sensor at all - perhaps someone can let me know if that is true or not. The previous engine definitely did not as the sync method for that engine is "No CAM Sensor". As I mentioned already, this ECU has run this engine fine at the track and I can't change the settings.

 

- Engine sync status

This value always stays at "not synchronised" during cranking.

 

I am not certain but I think the sync status is highly relevant. Sync seems to refer to whether the ECU has identified where the crank is, and it won't fire the spark plugs until the crank is in the correct place. So if it doesn't know where the crank is then there will be no spark. What puzzles me is there is obviously a signal from the crank sensor because I can see RPM on the live data screen during cranking. Maybe that value is derived from somewhere else?

 

Some other info that might be of relevance:

I have a data logger and one of the parameters I log is brake switch so either zero or 12v. During one of my runs at Combe after I let off the brakes the value went from 12v to around 3v instead of zero. It then rose to around 5v over the next couple of laps but still went to 12v whenever I pressed the brakes. I originally mentioned I thought there was a charging system problem because the battery went flat. On my last run the car barely started with a booster pack, with volts at idle on the dash showing about 10v and not rising with revs. Over about 6 laps the voltage steadily dropped to 8v so I came in to avoid ending up having to be towed in. With the car back in the garage at home and dried out, the brake switch reads 0v when open using a meter on the terminals, although I must admit I haven't checked what the data logger thinks it can see.

 

So basically I'm a bit stumped and could do with some input please!

[Simon.Rogers1]

Hi.

 

Forgive me if I have overlooked anything at the end of your post but a Busa needs to have 1.22 - 1.25v on the TPS for tick over.

 

Not sure why you don't have spark though?

 

Now I will read the rest

 

[Simon.Rogers1]

It also sounds like the stator is toast. Been there done that.

 

Yes Buses have cam sensors but can also run in wasted spark format all the time if required - pre set and mapped that way. They change from wasted to sequential when the can sensor sees 5k rpm.

 

Known that in car installation the can sensor is erratic.

 

How do I know?

 

But this years engine is sequential mapped and all OK - same loom!

[ric355]

I also thought the stator was toast, and that's actually what I set out to test first the day after the track day, but then I found that it wouldn't start. So I haven't actually got as far as testing the Stator.

 

Regarding the throttle pot voltage, I read those values too on SBD's website. But the throttle curve in the map is set to have load site zero at 0.37v and it ran fine both at home for a couple of weeks and then the morning at the track with those settings. Here's the full curve:

 

site/ voltage

0 0.37

1 0.38

2 0.41

3 0.45

4 0.50

5 0.58

6 0.7

7 0.87

8 1.07

9 1.35

10 1.67

11 2.07

12 2.56

13 3.12

14 3.73

15 4.37

 

So you can see with this curve, if the TPS at rest was 1.2v it'd be at load site 8-9, which I suspect wouldn't be right. So I think it depends on the throttle calibration curve (and I suppose that in turn depends on the throttle pot being used).

 

The engine is running wasted spark and is running a coil pack rather than coil on plug.

 

Edited by - ric355 on 3 May 2014 20:29:42

[Ivaan]

I recently had the regulator short out on the R1. It's mounted under the car and had corroded inside the plug. This then cooked the stator. Getting the rotor off was a bugger!

 

However the engine still ran on battery, just didn't charge, so it looks like you may have ECU problems as well ☹️

[ric355]

This starting problem turned out to be a high resistance in the +12v wire that gets switched in to the coil packs via the ignition relay. At various times I'd measure good and bad voltage at the coil packs but it hasn't been consistent which has made it tricky to find. I've bypassed it with a direct +12v feed temporarily and it fired straight up.