FI Light Need Help Code One

Hi All

I went for a ride the bike cut out i stopped and she fired rite up, She was idling and riding extremely ruff my neck felt like I?ve got whiplash when I got home
I suspect its code one MAP sensor. I?ve checked for continuity from the MAP sensor to the ECM its all good.The 5 point T all the vacuum pipes replaced and cleaned, I?ve got 5 volt on the + and Ref terminals and ground when ignition is on and no ground when ignition is of. I?ve checked Map sensor output reverence signal and vacuum its all good.Both coils good+ new plugs. I just can not find the problem. Any suggestions would be appreciated [video=youtube;xrSm5WlAuEM]https://www.youtube.com/watch?v=xrSm5WlAuEM[/video]

What year and do you have a Honda Service Manual?

A 2004 and yes I have a service manual

Now that you've cleaned everything up, clear the codes out of the ECM (see the manual) and see if it continues.

What voltage did you measure at the output?

MAP sensors have been known to fail, and the usual failure mode is for them to drift through reporting credible-but-wrong data on the way out. That shouldn't cause rough running because the ECM will switch to default mappings when that happens and the engine should run fine. I don't know what the behavior is when it's on the hairy edge. The ST shares a MAP sensor with a bunch of other bikes (notably several CBRs), so you should be able to find a good one at a breaker's yard.

--Mark

I have fitted a used map sensor and cleared up the ecm codes both the map sensors gave the same volt reading when I put a vacuum pump on. But still when I started her she runs ruff at idle and at higher rpm and switched back to failsafe mode

How about putting a temporary tee in the line to the map sensor and hooking up a vacuum gauge. This way you can be sure that the sensor is actually getting a proper vacuum signal.

Any rodent damage to wires under the hood?
Have you tried a TB sync to see if that helps?

Thought the MAP sensor was code 2, at least on my '05 it is?

1 and 2 are both for the MAP Sensor. 1's an electrical failure, 2 is is a vacuum problem.

--Mark

wjbertrand said:

Thought the MAP sensor was code 2, at least on my '05 it is?

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My '03 service manual indicates either code 1 or 2 is associated with the MAP sensor, but code 2 can indicate a poor connection of the sensor vacuum hose.

EDIT: saw Birfl's reply as soon as I posted mine, he beat me to it. One inconsistency between the thread's OP and the manual is the latter indicates no symptoms in either case (engine runs normally).

Blrfl said:

1 and 2 are both for the MAP Sensor. 1's an electrical failure, 2 is is a vacuum problem.

--Mark

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OK thanks. I got a code 2 once that turned out to be a plugged up 5-way vacuum T, so that makes sense.

i can not do the TB sync as she is running to rough but now she is giving code 19 and 12 as well am i right to think that the ECM mite be broken

Two of the codes you've reported, two (MAP sensor, and injector #1) are on the FI subharness. The third (crank position sensor) is on its own line but shares a common lead with the camshaft position sensor, which is also on the FI subharness.

All of that's up at the front of the bike. The UK's patented brand of road crud seem to produce a lot of those kinds of problems (especially with ABS on the 1100 if I remember older posts correctly), and it's a good possibility your bike's old enough for that stuff to be accumulating. Before you go down the dead ECM road (not likely, and when they do fail, this isn't the way they fail), I'd give everything on the FI subharness and the ground points a good cleaning.

--Mark

This is beginning to sound like the infamous rodent infestation problem under the throttle bodies.

Just an update i gave up trying to fault detect and took her to Honda to sort. It turned out that there was an earth fault in the ECM that they managed to bypass some way if i manage to see how they did it i will let you all know.

Thanks for all the help i defiantly learned a lot from trying to fix the problem

cornelis said:

Just an update i gave up trying to fault detect and took her to Honda to sort. It turned out that there was an earth fault in the ECM that they managed to bypass some way if i manage to see how they did it i will let you all know.

Thanks for all the help i defiantly learned a lot from trying to fix the problem

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Yes, please I would definitely like to see what they did.