Triumph Rat Motorcycle Forums banner

1 - 20 of 30 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
I put the ST to bed in the garage last October it was running perfectly. I plugged in the Opimate and left it untill last Saterday when I thought I would fire up the beast. The engine turns over but will not start. I took out a spark plug grounded it and turned over the engine no spark. Has any one got any idea's. I have been told that if the battery is slightly down on voltage it will not fire the ignition even though it turn the engine over ok. I am reluctant to go to the expence of a new battery if this is not the problem.
 

·
Registered
Joined
·
1,185 Posts
That's about the right age to have decomposed relay mounting rubber and relays dangling upside-down and full of water. That would stop a bike that was running fine when parked.

Swap the headlight and engine management relays even if they look good and give it a go.

If that all checks out, pull the tank again and check that you get ignition switched 12 Volts on one terminal of each coil connector. Report your findings. I don't think it's time to exorcise the ghost of Joseph Lucas yet.

I doubt the coil drive goes away at low battery Voltage. The ECU gets final say as to whether the starter cranks. It monitors the clutch and kickstand switches and decides when to ground the low side of the starter relay. The start button switches the high side. The point here is that it would make more sense for the ECU to shut the start process down than allow the engine to crank with no spark for low battery.


I put the ST to bed in the garage last October it was running perfectly. I plugged in the Opimate and left it untill last Saterday when I thought I would fire up the beast. The engine turns over but will not start. I took out a spark plug grounded it and turned over the engine no spark. Has any one got any idea's. I have been told that if the battery is slightly down on voltage it will not fire the ignition even though it turn the engine over ok. I am reluctant to go to the expence of a new battery if this is not the problem.
 

·
Registered
Joined
·
117 Posts
I ... err, I mean some guy I know once spent 15 minutes trying to figure out why his 04 Sprint would crank and not start after he hadn't ridden in a while...

Turns out "he" had parked it in gear and forgotten, so when he tried to start it on the side stand to let it warm up, it just wouldn't go. Not saying that's the case here, just relaying a story I heard once :huh:
 

·
Registered
Joined
·
764 Posts
+1 on what CLB has suggested. I had a similar problem with the relays last year.

The headlight relay is the second from the left and the ECM relay is 6th from the left. The other 4 pin relays are interchangeable.
 

·
Premium Member
Joined
·
24,231 Posts
Welcome

I put the ST to bed in the garage last October it was running perfectly. I plugged in the Opimate and left it untill last Saterday when I thought I would fire up the beast. The engine turns over but will not start. I took out a spark plug grounded it and turned over the engine no spark. Has any one got any idea's. I have been told that if the battery is slightly down on voltage it will not fire the ignition even though it turn the engine over ok. I am reluctant to go to the expence of a new battery if this is not the problem.
Hi and welcome mcs123 to our Sprint forum:)

Where abouts do you hale form mcs?

You are being attended to here by some of our best technical brains ( I missed those when they were being handed out but fortunately I can ride).

On the new member thing, Don and I ask all new members to please take time to familiarise yourself with this forum and website by reading our forum stickies.

Enjoy the forum:)

DaveM:cool:
 

·
Registered
Joined
·
4 Posts
Discussion Starter #6
That's about the right age to have decomposed relay mounting rubber and relays dangling upside-down and full of water. That would stop a bike that was running fine when parked.

Swap the headlight and engine management relays even if they look good and give it a go.

If that all checks out, pull the tank again and check that you get ignition switched 12 Volts on one terminal of each coil connector. Report your findings. I don't think it's time to exorcise the ghost of Joseph Lucas yet.

I doubt the coil drive goes away at low battery Voltage. The ECU gets final say as to whether the starter cranks. It monitors the clutch and kickstand switches and decides when to ground the low side of the starter relay. The start button switches the high side. The point here is that it would make more sense for the ECU to shut the start process down than allow the engine to crank with no spark for low battery.
Hi Again
I swapped the relays which all looked in good order but no joy. I checked the coils and there is 12 Volts on all of them. Any further suggestions?
 

·
Registered
Joined
·
329 Posts
I second CLBs suggestion for new plugs but first make sure the battery is in fact fully charged. Have not had the experience with this bike (Sprint) but did have the experience with a previous bike that once the plugs were fouled it was very difficult to get started without actually replacing them.
 

·
Registered
Joined
·
764 Posts
I am no electrical guru :confused: but I suspect that your problem maybe the ECM or the crankshaft sensor.

My understanding which may be errant is that the crankshaft sensor provides a signal to the ECM which then does some number crunching based on the ignition mapping and then provides a pulsing earth to the coils which provides the spark to plugs.

If you don't get a signal from the crankshaft sensor then you won't get spark happening on any cylinder.

CLB may have some clues on how to check these out, I am now officially out of my depth! :eek:
 

·
Registered
Joined
·
20 Posts
I had this with my 05 sprint, the first winter I had the bike, after a night shift i came out of work to find the bike covered in frost, and despite all efforts it wouldnt start, i had to get it recovered to the nearest dealer, who updated the mapping. Has yours had the mapping updated. According to the dealer the ecu checks pressures, and because of the cold there was not enough pressure developing, so the ecu wouldnt fire it up.
 

·
Registered
Joined
·
213 Posts
My 05 always cranks till the oil pressure light goes out before it fires.
This is so consistent that I'm sure it is controlled by the ECU to make sure oil has circulated before the engine fires.

Is your oil pressure light going off when you turn it over?
 

·
Registered
Joined
·
2 Posts
Bike CPR...

mcs123

I had the same problem yesterday ! Bike has been wintered up and plugged into an Optimate charger. I have in previous years managed to bump start it but not this one (it also helps if you turn bike over 'til fan comes a couple of times in the interim period).

Dug out a set of jump leads and connected to the wife's car (little un reving it up for me :)

After much frustration and no sign of life she finally fired up (took a bit of time I have to say..thought she was dead). No messing with relays, checking plugs etc.

I'd give that a go ! Good luck...

PS.My problems may have stemmed from letting a drunken over exuberant BMW owner fire her up on New Year's day and promptly rev the arse off her stone cold ! (My fault I was drunk too !!)..
:D
Regards,
 

·
Registered
Joined
·
4 Posts
Discussion Starter #14
Hi all thanks for all the suggestions. After checking the relays and the coil voltage I fitted a new battery and changed the plugs still nothing. So I threw in the towel and vanned it to my local dealer. He plugged in the Triumph computer it showed no faults so I have left it with them for further investigation. I will report back when I find out more.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #16
Hi everybody just got a call from the Dealer he has got it running. It was a dirty crank shaft position sensor. He cleaned everything up and resett the air gap and it fired up. He also balanced the throttle's and resett the tickover he tells me it is running sweetly. I will pick it up tonight and report back.
 

·
Registered
Joined
·
764 Posts
Ralphus, your guesstimating powers are amazing! When did you find you had this talent?
Deduction my dear Watson!:D

Start with the symptom and work backwards

Symptom: No spark
Check sparkplugs
Check coils
Check ECM
Check Crank sensor

Dirty crank sensor is an interesting problem. Crank sensors are usually magnetic so there must have been a lot of iron particles on the sensor to confuse it with a timing disc.
 
1 - 20 of 30 Posts
Top