Triumph 675 Forums banner

Fuel Pump/Idle Issue Unknown

5K views 33 replies 4 participants last post by  ALLoneUP 
#1 · (Edited)
2012 Daytona 675R,
With a 2012 ST3R Wiring Harness

Two issues. With the key and kill switch to the "on" position and the clutch pulled in, the starter button doesn't do anything. No noises or clicks, completely dead. Fuel pump primes as normal during initial start sequence.

If I hit the starter button while the fuel pump is priming, it turns over and idles normally, for about two to three seconds and then cuts out. I adjusted the idle up/down with the manual idle adjuster, no ISM, and no change. Just idled higher or lower for a couple seconds and cut out.

I checked the relays and fuses, all are conducting/working properly. This was my initial thought. Fuel line is not pinched or anything, at about half a tank of gas. I have a service manual, studying the wiring for any common grounds etc.

Any ideas on the idle cut? I have replicated the problem numerous times without any change. TuneECU is the next step to go through everything. Haven't tested the battery either, but it starts just fine in the given scenario above.

Any ideas will be greatly appreciated. Thanks.

Adam
 
See less See more
#4 ·
Something confuses me though. You say when you hit the starter button after the pump primes nothing happens? The starter doesn't turn the motor at all? But it does when the pump is priming? If so that's very weird.
That's exactly the issue. Looking at the wiring diagram, a lot of wires are shared between multiple relays/sensors. I checked the CPS, not with TuneECU yet. About to get to that today. Thanks for the responses guys, not even gonna try the dealer on this one.
 
#6 · (Edited)
It seems like the starter relay is only being enabled during the pump prime and disabling it after it times out; That would be the Yellow/Brown wire from the ECU that controls that.

The next issue of the bike dying after a few seconds, when you are able to run the starter during the prime step:
That sounds like the bike runs off the fuel that was there from the initial prime, but cuts after it uses that i.e. the pump does not start running again.

So it sounds like neither fuel pump nor starter are enabled after the initial prime step.

First thing to check is to see if you have 12V on The Brown/Pink circuit common to all the Injectors, Coils etc
One convenient place to measure this is from the Purge Valve connector - measure between Brown/Pink and Battery negative - make sure that remains at 12V after the prime times out;

Questions
- what is background on this - why the harness swap? Has it ever run in this config or is this first time trying to get it running since harness installed?
What ECU and map is installed - from Daytona or from the Harness?

Was this an immobilizer system (either before or after swap)?

What else was changed in the config swap (especially if either original or donor was an immobilizer system)
 
#7 ·
DEcosse said:
I replied to your thread - please post this same information there and I will continue from there

AlloneUP said:
I bought the bike new. Original motor and ECU still in the bike. Only the harness was changed out for a 2012 ST3R. No problems with the original harness, no crash damage or anything. I was bored over the winter and wanted to swap harnesses for ease of swapping track bodywork.

I had the bike out running just fine a week ago, so I know it can run. I have modified the harness for multiple mods like R/R relocate, HID setup, extra turn signals etc. All that checked out, soldered and shrink tubed with proper strain relief.

I had an issue that arose right after I put the harness in. With the engine kill switch in the off position, i could turn the key to the on position and the dash would light up, initial start sequence except for the fuel pump. The kill switch to on, the bike would turn on as normal and fuel pump would prime.

Now, the starter button acts as a dead button. Zero response or anything, except if I depress it while the fuel pump is still priming, then it turns over and starts up right away.

Looking at the wiring diagram, I think it might have something to do with the alarm connector and shared grounds between relays?

Thank you for the reply. I sincerely appreciate it.
 
#8 · (Edited)
I had the bike out running just fine a week ago, so I know it can run. I have modified the harness for multiple mods like R/R relocate, HID setup, extra turn signals etc.
What specifically was done between the time it was running a week ago and when it did not?

... I had an issue that arose right after I put the harness in. With the engine kill switch in the off position, i could turn the key to the on position and the dash would light up, initial start sequence except for the fuel pump. The kill switch to on, the bike would turn on as normal and fuel pump would prime.
Presumably it is still like that (unless you did something to change that!)
The reason is the harnesses are different - on the ST3, it feeds power to the Instruments BEFORE the Kill/Run switch, which is why you get the instruments power-up with the switch in Kill position; but of course there will be no power to ECU in this condition.

Aside to @MacBandit - can you look at the ST3 schematic? In the manual I have it shows a Green/Red coming off the Instruments (common with the Green) at pin 6 - that section of Green/Red that runs over to the junction point where it routes up to the ECU must surely be wrong; that effectively completely bypasses the Kill/Run switch supplying power directly to ECU; I think that section in the schematic cannot be there and should be blanked out?
(the normal flow should go through Kill/Run to Green/Brown, then through the Alarm Bypass connector and out of that on pin 2 - again, with that section linked on the schematic it would completely bypass that whole loop and deem the Kill/Run to be moot)
(see attachment below which illustrates what is in the schematic)

... ... I think it might have something to do with the alarm connector and shared grounds between relays? ...
There are NO shared grounds between relays - in fact the only relay that has a ground is the ECU relay; the others are all independent with current sinks to the ECU
 

Attachments

#9 ·
I am going to pull the harness and double check everything. Follow every wire. Very tedious, but I'm at a loss. I will report back with my findings. Hopefully a solution. I most likely missed some of the subtle differences between the Daytona and St3 harnesses, worked mostly off the Daytona diagram by mistake.
 
#12 ·
I guess you've gone ahead & removed it - it is much easier to offer diagnosis looking for voltages than to just speculate where problem might be.
For example:
D'Ecosse said:
First thing to check is to see if you have 12V on The Brown/Pink circuit common to all the Injectors, Coils etc
One convenient place to measure this is from the Purge Valve connector - measure between Brown/Pink and Battery negative - make sure that remains at 12V after the prime times out;
Why don't you list EXACTLY what you connected and TO WHERE you connected it (location, wire colour) ........
That might help clue us in to where the issue lies.

You mentioned the alarm connector and grounds ...... did you connect anything to the alarm connector? Just because all those wires are black does not mean they are 'ground';

You also said when initially connected the instruments would turn on with Kill set (this is not an issue) - did you try to correct for that somehow, or just leave alone and it still does that?
If you messed with that part of the circuit then you could well have created your problem.
 
#13 ·
Okay somehow I looked over your info about changing harnesses. Unless the new bikes are different then the old ones the Street Triple and the Daytona harness have a pin difference at the ECU. It requires moving a pin from one location to another. Compare the plugs on the two harnesses and it should be obvious. The pin in question affects the fuel pump.
 
#14 ·
If Daytona after ***323545, Fuel Pump driver is same pin (earlier Daytona is different) - also note that it originally ran for a while (and even now, briefly before it shuts off) so pump has to be wired to ECU correctly

And of course Daytona has Exhaust Valve Controller, ST3 does not - but that would not affect this
 
#16 ·
It WAS running after the swap- and a timed 'prime' is just too much of coincidence from a 'different' circuit,
Easier than checking the connectors is just to look at the VIN - if its after 323545, they are the same.
(Earlier Daytona up to 323545 has Fuel Pump output on B36, later and ST3 on B29)
 
#17 ·
It runs but only shortly. The obvious change is the harness. I'm glad you joined in with the exact details of the harness change. I never had need to remember those details. However we're dealing with a 2013+ model and unless you've swapped harnesses on those how do we know they are pin for pin the same? I'll have to find time to investigate the wiring diagram and other information I have but typically the ECU signal to prime the fuel pump is different then the primary signal to run the pump. So it's possible the fuel pump circuit is not connected properly despite the pump priming initially. I find it hard to believe it's a CPS issue since the bike will initially start. Which brings up the other issue. The bike will not crank unless he hits the starter button immediately after turning the key on while the pump is priming. Sounds like the main starter relay(solenoid) is somehow tied (erroneously) into the fuel pump circuit. Once again we go back to the harness swap somethings different with the new harness.
 
#18 · (Edited)
It runs but only shortly.
That is the CURRENT condition - he reported it HAD worked 'fine' a week prior.

See this comment - I have referred to this several times but suspect you missed it ............

ALLoneUP said:
I had the bike out running just fine a week ago, so I know it can run.
And why I belaboured as to what had been re-wired within the last week which presumably caused the issue to arise when it REPORTEDLY was fine.

... ... how do we know they are pin for pin the same?
You compare the schematics by serial number - there are other differences (like the Exhaust valve & control) but the fuel pump circuit is the same after 323545 - yes, you are correct they were different before this serial but with both stated as 12's that should be well beyond that VIN cut
After that cut, there is still a difference in the ignition circuit wiring which I explained earlier, in how the gauges are still powered with ignition on but Kill Switch off with the ST3; however that has no impact on the ECU power, only the gauges power (but note I illustrated there is clearly an error on the ST3 schematic - but that would not be a first for Triumph manuals!)

... ... typically the ECU signal to prime the fuel pump is different then the primary signal to run the pump.
Not on any Triumph I have ever seen!
One outpurt, it is timed from within the ECU and output on the same pin for both functions. The pump either runs - or it doesn't - as commanded internally by the ECU; no external difference for the two functions, the same output transistor applies whether it is prime or run; purely determined by firmware as whether is on or off.
When the ignition turns on, it starts a timer; that timer enables the pump run for specific time (~ 3 secs); the timer resets any time the ignition is turned off, then on again; for 'normal' running, the ECU sees CPS signals and re-enables the pump for as long as those are present.

... Sounds like the main starter relay(solenoid) is somehow tied (erroneously) into the fuel pump circuit. ...
I don't think so
I believe the problem is ECU is turning off after the prime is complete - ergo the starter runs initially while the power is also being supplied to the pump (which also comes from the ECU);
I would have to suspect that one of the wiring mods - not the harness swap itself - has interfered with the Ignition/ECU supply, possibly the ECU relay is dropping out (which is why I asked him to check the output from that to see if it was remaining enabled).
The ECU initially gets ignition input signal from the output of the Kill Switch; internally this then generates a latch that sends an output to the ECU Relay, which, as well as supplying the coils and injectors, feeds back into the ECU to provide the main power; when either the Key or the Kill switch is powered off, a countdown from the latch occurs, maintaining that input power to the ECU (you will notice that the ECU relay remains on after the switch is turned off and you can hear it audibly 'click' after a delay.)
 
#20 · (Edited)
EDIT!!!!

Embarrassing. I don't know why I thought you had a 2013. I've looked at the older diagram and the only real connection between the starter and fuel system is the igntion switch. There is a circuit there that specifically powers the 2 of them and nothing else. Another possibility is the alarm connector but I feel that's less likely since the circuits are separated there.
 
#21 ·
I have the harness out and traced EVERY wire from the ECU to its end. I could not find a single discrepancy with the starting/charging circuit, or anything for that matter. I tested all the relays for function AND resistance. All checked out, along with all the fuses.
@d'ecosse, you are right about the Red/Green wire coming from pin #6 of the display connecting to the alarm bypass. That wire doesn't exist, fault in the diagram. Next step is to install the harness and check for current signals like you originally suggested. You said the CPS sends a signal to keep the fuel pump running. Is there a way to test this for proper function?

I didn't see any burnt or broken pins on any of the connectors. The start button is only receiving power input from the alarm bypass while the fuel pump relay is activated. Something is wrong, but visually I can't see it.

Shorai battery @ 13.38V pulled out of bike

I have the "new" 4 pin version of the gear position sensor. It comes with a jumper cable that connects to the throttle position sensor and old gear position sensor plug. They can be mixed up, same exact plug. If they were installed backwards, could cause problems like this?

Mods to the harness include:

- R/R relocated, only mod on charging circuit
- Headlight HID
- Taillight connector chopped, replaced
- Rear LED! signals added
- K&S left hand switch cube
 
#23 ·
... The start button is only receiving power input from the alarm bypass while the fuel pump relay is activated. ..
Big clue here
I take it you mean that is pin 1 of the Right Switch ? Are you saying you only get +12V on that when the pump is running?

See the attachments -
So pin 1 of the Right Switch connector should ALWAYS have 12V with keyswitch on and kill switch on Run
So - Do you have 12V on BOTH pins 2 and 5? (Kill/Run Switch in/out) - or does that also go away after pump stops?
At alarm connector - with the bypass connector in place, you should have 12V at 1, 2, 3, 4 & 5 with the Left-Switch on and Kill Switch in Run.

I have the "new" 4 pin version of the gear position sensor. It comes with a jumper cable that connects to the throttle position sensor and old gear position sensor plug. They can be mixed up, same exact plug. If they were installed backwards, could cause problems like this?
- its presumably picking up the 5V and ground off the TPS connector; hmm, I would need to see the circuit for the 4 pin GPS but stands to reason if the two three pin plugs are indeed interchangeable, it could cause a problem (although can't off top of my head see why it would cause the ignition circuit problem)
Can you post an image of the two connectors to the TPS and GPS on the new GPS, that show wire colours?
Note that on the TPS, pin 3 is +5V and pin 2 is 5V-Ground;
on the GPS connector pin 2 is the 5V-ground and pin 3 is the Neutral Switch signal to the ECU.
I could see how the starter relay could potentially not be enabled if you had those switched, as the neutral switch would not be at ground; however that would only affect the operation of the starter relay, and it would NOT cause there to be no power at the Starter Switch.
The simple thing would be to just unplug the GPS and put the TPS back to 'normal' and then 'ground' the Black/White wire on the GPS connector (main harness) to get the neutral interlock made (that might not be necessary for test, if you raise the side-stand)
 

Attachments

#22 ·
Use the Daytona diagram not the Street Triple one. The Daytona diagram is correct if you ignore the EXUP and flapper. The Street Triple diagram has a lot of errors besides the one you noticed. It has relays mismarked as well.

Did you check for power across the ignition switch there are three pins tied together one pin is power the other two are starter and fuel respectively. They have to have power but I'd just like to confirm.
 
#25 ·
... The Street Triple diagram has a lot of errors besides the one you noticed. It has relays mismarked as well.
It's fairly minor - they just transposed the numbers 28 & 29
The only significant one I see is that 'extra wire' - clearly when they appended the diagram to mark in the green wire to the instruments, they 'forgot' to delete the green/red section over to the node where it goes to the ECU.
 
#24 ·
I will take pics when I get home later tonight. Harness will be back in the bike tomorrow to troubleshoot as well.

Looking at my harness and tracing the wires from the diagrams you posted, I realized I don't have a horn hooked up at all. I put rubber sleeves over the connectors and taped them up. Could that be an issue? I have an aftermarket one I plan on hooking up after I get it running.
 
#28 ·
I got this one

I left the right hand switch cube wiring alone. Didn't touch anything.

I didn't get the harness installed today. I read over your previous posts and made a checklist to cross off once I do. Thanks again for all the info and replies, it is much appreciated.
 
#29 ·
This is a picture of the new GPS harness.

Plug 1 - Plugs into new GPS unit (male)
4 wires - Blk/White, Blk/Pink, Pink/Blk, Pink

Plug 2 - Plugs into current harness
GPS plug (male)
3 wires - Blk/White, Blk/Pink, Pink/Blk

Plug 3 - Plugs into harness TPS plug (male)
3 wires - Green/Y, Pink/Blk, Pink

Plug 4 - Plugs into TPS unit (female)
3 wires - Green/Y, Pink/Blk, Pink
 
#30 ·
I can see that 2 & 3 could potentially interchange but looks fairly obvious that 2 would have to be the GPS and 3 the TPS, just from their location at each end to their counterpart.
Besides the wire colours dictate that for sure 3 is the TPS.
It appears indeed that they are just using the TPS connector to pick up the 5V (pink wire) for use on the 4-wire GPS

So don't see that being a factor.

We need that other info from post #23
 
#32 ·
I installed the harness and plugged everything in 'correctly.' I left the fuel tank off and unplugged so I could access all the plugs and wires easily.

All the wires from post #23 checked out for voltage. The starter button worked as normal? Strange. The fuel tank wasn't even attached. It cranked just fine a bunch of times. Tomorrow morning I will get the fuel tank on and see if it turns over and report back.

So at least I know everything is good up to this point.

I fixed the 'display on with key on and kill switch to off' issue by eliminating the green wire from pin 2 of the right hand switch cube to pin 6 of the display, and instead running power from alarm relay pin 1 to pin 6 on dash, to have the display power on with the fuel pump and ecu.
 
#33 ·
... I fixed the 'display on with key on and kill switch to off' issue ...
That wasn't really an "issue" that needed "fixing" (if I am quoting you literally) - just the way it is; but if your preference is to have it on regardless of Kill/Run position that is fine too.

It sounds like you had bad connection somewhere before; can't see connecting the pump making any difference (but we'll defer judgment till you complete that); if it all works, no guarantee it won't come back unless you can find something conclusive.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top