SR3 won't start
Discussion
I'm looking for a bit of help as my SR3 won't start at the moment and I'm pretty much out of ideas. 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.
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, 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. However the copy of the map shows that the engine sync settings are as follows:
- Cam Sensor Select: Inductive Sensor (r)
- 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 previously run this engine fine at the track 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!
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.
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, 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. However the copy of the map shows that the engine sync settings are as follows:
- Cam Sensor Select: Inductive Sensor (r)
- 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 previously run this engine fine at the track 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!
I still think 10v under cranking is fine personally - there will always be a drop in voltage when the starter motor is running. And the engine turns over fine; just as it always has done (both new and old engine). However, just to be sure I've used a mains powered booster pack which has a starter function offering about 80 cranking amps, and got it to 14.5v before cranking and 12v during cranking. Still not firing up.
Spent more time on this yesterday and spoke to SBD today as I have been beginning to suspect that the outputs that drive the coil on the ECU are blown. Just about to go out now and do one last test with the scope now I'm armed with the correct information about how the ECU drives the coils. From what I've already measured though I'm not hopeful.
Yes, I confirmed I have fuel.
Yes, I confirmed I have fuel.
Edited by ric355 on Tuesday 6th May 17:50
Been out and done my last test. It seems to confirm that the ECU is not driving the coil at all and therefore I think the outputs are dead. It needs to be sent away for testing now to confirm, then it's a case of either repair of the 992 or a new 9A4 ECU if they confirm my suspicions - I'll decide which later if it tests as knackered.
The Engine sync of "not synchronised" is ok by the way. Synchronisation refers to cam and crank sensor. My application does not require a cam sensor (which I was pretty certain of anyway) therefore it always remains as not synchronised.
If the ECU is indeed faulty then I would seem to have blown up both the main and the spare ECU so precautions needed before connecting the replacement but I reckon if they are gone it was all caused by the water from the motorway soaking.
The Engine sync of "not synchronised" is ok by the way. Synchronisation refers to cam and crank sensor. My application does not require a cam sensor (which I was pretty certain of anyway) therefore it always remains as not synchronised.
If the ECU is indeed faulty then I would seem to have blown up both the main and the spare ECU so precautions needed before connecting the replacement but I reckon if they are gone it was all caused by the water from the motorway soaking.
Had the ECU tested and it was fine. I've finally traced the problem to a high resistance in the +12v wire that gets switched in to the coil packs via the ignition relay. I temporarily bypassed it with a more direct feed and it fired straight up. Just need to decide how best to fix it now as I'm not sure I can face stripping the nicely heat shrunk loom back...
Fixed the wiring loom problem and have also fixed the original charging problem. The rectifier plug had burnt out. A quick google reveals this is a common problem on several suzukis including the busa. Chopped the plugs off and replaced them with new and all is sorted. Interestingly halfords actually had the exact same plug on the shelf in a blister pack which was a welcome surprise. I guess it will probably burn out again in the future though but at least it is working properly at present.
Rectifier itself is fine luckily.
Now to the latest problem. I want a remap on the new engine because it is only running a base map. Radical still don't have a rolling road installed (the old one is being replaced) and the ecu is locked to them so no one else can do it. At least a couple of months away apparently. That's pretty disappointing and basically I'm stuffed unless I buy a new unlocked ecu.
Rectifier itself is fine luckily.
Now to the latest problem. I want a remap on the new engine because it is only running a base map. Radical still don't have a rolling road installed (the old one is being replaced) and the ecu is locked to them so no one else can do it. At least a couple of months away apparently. That's pretty disappointing and basically I'm stuffed unless I buy a new unlocked ecu.
ak47si said:
Rich ,
Can you tell me how you bypassed the +12v to more direct feed (from battery) to fired straight up? I think I am having the same issue. How did you trace down that high resistance +12v wire ? With a voltmeter?
ThankAlan.
To track it down I just used a meter set on an Ohms scale (resistance). Then put the probes on the extreme ends of the wire. You're looking for a reading that is basically zero.Can you tell me how you bypassed the +12v to more direct feed (from battery) to fired straight up? I think I am having the same issue. How did you trace down that high resistance +12v wire ? With a voltmeter?
ThankAlan.
To temporarily bypass it I just used a fresh piece of wire to a known good 12v source. I can't remember exactly where I took it from but the battery isn't all that far away...
I would have disconnected the plug from the coil pack and put one lead on the correct pin inside the plug, and the other end on the ECU pin assuming that is where the 12v comes from. I'm afraid I don't recall which ECU pin it was. Or if indeed that is where it is fed from. I thought I got the details from SBD's website but I can't see a 992 pinout on there at the moment.
Unfortunately it was four years ago and I don't own the car anymore, so am struggling to help more.
As it's supposed to be +12v on the coil you can just check resistance with the ignition on by using the pin inside the plug and the positive battery connection. That will at least tell you if there is anything to investigate.
Unfortunately it was four years ago and I don't own the car anymore, so am struggling to help more.
As it's supposed to be +12v on the coil you can just check resistance with the ignition on by using the pin inside the plug and the positive battery connection. That will at least tell you if there is anything to investigate.
Ah looking back I see I got the wiring diagram from the Tilling motorsport website.
And it's coming back to me now. The other end of the wire goes back to a relay on the SR3. It was that wire that I replaced.
http://www.tillingmotorsport.com/sitebuilderconten...
Bottom middle of the diagram, wires are connected to the coil at one end and the relays at the other end.
WHT(33) - goes back to an ECU pin, so this is an earth (the ECU grounds the coil to make it fire)
WHT(17) - same
WHT(37) - that makes this one +12v - gotes to a relay
WHT(38) - and this one +12v - goes to a relay
These relays are energised when you switch on the ignition and try and start the engine. So check that they are working too.
And it's coming back to me now. The other end of the wire goes back to a relay on the SR3. It was that wire that I replaced.
http://www.tillingmotorsport.com/sitebuilderconten...
Bottom middle of the diagram, wires are connected to the coil at one end and the relays at the other end.
WHT(33) - goes back to an ECU pin, so this is an earth (the ECU grounds the coil to make it fire)
WHT(17) - same
WHT(37) - that makes this one +12v - gotes to a relay
WHT(38) - and this one +12v - goes to a relay
These relays are energised when you switch on the ignition and try and start the engine. So check that they are working too.
Edited by ric355 on Sunday 21st January 23:42
A properly mapped busa should idle relatively evenly. Last time I had a rough idle it was only running on three cylinders and in my case it turned out to be an injector not firing due to a loose wire in the back of no. 1 injector plug. Check all the exhaust headers are getting hot - touch something damp onto each one and look for a hiss if you don't have a laser thermometer (get one if you haven't they're really useful). If you're brave you can lick your finger and do it that way as the engine is warming up (start from cold!!).
And I note if you have three out of four plugs black, then that further suggests a misfire on the one that isn't black even though there might be a secondary issue causing your plugs to foul.
And I note if you have three out of four plugs black, then that further suggests a misfire on the one that isn't black even though there might be a secondary issue causing your plugs to foul.
Edited by ric355 on Friday 26th January 21:19
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