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Help CEL P0203 - Injector 3, circuit malfunction

6K views 10 replies 2 participants last post by  675ing 
#1 · (Edited)
Background:
Bike was parked May-Oct this yr. Poured in tank fuel stabilizer gasoline formula to "keep the fuel fresh during storage, prevent resin build-up & corrosion..." (friend's advice). Oct came so did maintenance and mods: Engine Oil & Filter, Brake Fluid, Galfer ABS bypass brake lines (plugged abs with some bolts), Woodcraft GP shift conversion, changed handlebar grips, new tires and brake pads. Took it to the track and then this happened:

Issue:
Few min after warm up, engine sounds choppy and slow/retarded. Sluggish throttle response far from crisp. A minute later theres a major loss of power and now sounds like only 2 cylinders are working. Bike becomes a struggle to cruise with. Check Engine Light pops up. Then engine shuts off on its own.

Repairs attempted:
Turned bike off/on and now it immediately jumps to 2 cylinders working and shuts off. Disconnected/reconnected battery did the same. Tried again only held the throttle open a little to avoid it from shutting off and then when I let off the throttle the bike was still revving for a good couple seconds (as if my hand held it at a certain rpm range) :whawhat:. It was long enough for a spectator in the pits to raise his eyebrows in shock.

Used DealerTool found fault code P0203- Injector 3, Circuit malfunction (pic attached). Cleared code. Started again and it sounded fine. Moments later its back again. Mechanic cleaned injectors to flow equally. One was slightly dirty but far from blocked. Injectors filters replaced. Fault repeated. Swapped the injector connections bypassing the bazzaz zfi-TC unit and said the problem was the bazzaz. Engine runs fine without the bazzaz (for a few minutes we didnt try it for much longer). Reconnected bazzaz looked at bazzaz light and it was on. Moved some wires and light stayed on. Checked wires and everything well connected no broken pins no issues. Checked fuel line not bent. As the mechanic attempted to swapped from bazzaz to OEM connections I noticed that every time he lifted up the tank the check engine light immediately came on and engine shuts off and would barely/not want to start.

Took off the tank, emptied fuel was noticeably dirty. Pulled out pump also dirty. Fuel pump filter was very dirty. Cleaned everything as best we could and looked noticeably better. Theres another filter inside the pump unit that could not be removed for cleaning but we tried to flush it clean (using petrol of course) air pressured everything dry. Removed the tank fuel level sensor unit cleaned and checked it with a voltage meter read fine (although I dont know why my fuel level gauge never works til I start riding). Reinstalled everything. This took about an hour. Cleared all fault codes and this time we started with the bazzaz zfi tc connected. Engine sounded great! Throttle was shockingly crisp and almost felt like I could control it within ~50 rpms and theres 0 lag :excited:. Mechanic was confident to put bike together and take it home. I insisted we leave it running for 30 min. After 25 minutes, the engine shuts off. CEL back with the same code. Engine sounds awful. Horrible throttle control. Same issue repeats :cuss:.

Stuff that I have as spares that I could replace/use during troubleshooting:
Bazzaz ZFI (no TC)
Kemso Fuel pump 13802 and filters.

Questions:
1- What happened during those 25 minutes that changed everything from perfection?
2- 30min runtime each time is taking too long to repeat over and over, anyway to shorten this?
3- Is the kemso fuel pump good? (previous owner passed it to me.. and said dont use :huh:)
4- What is the correct sequence of events to tackle this and isolate the problem?
5- If the same "injector 3 circuit malfunction" reoccurs could it possibly be anything besides the injector?
6- someone (i have issues trusting) mentioned, I would need to replace the full harness to compliment the abs bypass brake lines and that is the reason Im having issues. Could he be right?
7- What would be a clear indicator that bazzaz is the problem?
8- Are these bikes notorious for faulty injectors?

As of now my plan of action is:
1- Swap injector 3 with injector 1
2- bypass bazzaz injector connections with oem.

dunno what else. Any tips appreciated.
 

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#2 ·
1-Bypassed bazzaz. Started bike. 35 min no issues.
2- Plugged bazzaz ZFI-non tc (keeping in mind my original issue started on zfi tc) started bike. After 9 min it turned off. Restarted and immediately threw CEL same injector 3 code.
3- Cleared the code. Swapped injector #3 & #1. Started bike. Threw CEL immediately again injector 3 code.
4- Cleared code. Swapped ZFI with ZFI TC. Immediately threw CEL injector 3 code again.
5- Cleared code. Bypassed bazzaz. Started engine and ran 10 min no code then overheated (spilled coolant) and we turned it off.

Weird how its throwing code on both bazzaz modules.
Mechanic says should it be the bazzaz harness it would happen immediately without wait time.
Both bazzaz modules are running the same map.
checked fuel pump pressure was good.
 
#3 ·
Ok so checked again and suddenly with bazzaz it’s not throwing a code anymore even after 2 attempts of continuous running of the engine for 45min.

Anyone got a wiring diagram so I could check the volts from the injectors all the way back? What relay/fuse to check... Which wire from the ecu to check etc.
 
#4 ·
Keep in mind I am a car tech not a motorcycle tech. So I apply what I do in the shop to my bike. I have never had an injector issue (knock on wood) but this is what I would do.

1. Like you already have, I would swapped another injector with #3 injector after clearing the code in order to see if I am getting the same fault.

2. If yes, then I would plug back in my stock wiring and see if the code comes back again

2. if no, I would think its an injector issue. Look up specs and Ohm out each injector and compare it to spec (with ohm basically you are shooting 1v through the circuit from the positive lead on your DVOM to your negative Lead. If there is any resistance it will show up on you Digital Volt Ohm Meter in Ohms) If you have an open in the injector or if the ohms are too high I would replace that one.

3. If the code doesn't come back like in your situation I know its the bazzaz computer or wiring. Next is the tedious part of tracing the wires to the correct pin.
So lets say the power wire is white and the negative wire coming off the injector is ground. I would check for 12.volts (aka battery voltage or close to it) at the white wire and a good ground at my black wire. Since there are not a lot of connections between my injector wire and PCM I would not like to see no more than 1 volt drop from so if my battery is at 12.5v with the key on engine off, I would like to see 12.5v - 11.9v anything less than 11.9v I would know its something in the wiring.

Next with the key off battery disconnected and connectors disconnect from the injector at on end and Computer at the other, I would ohm out both wires.

In your case it sounds like you have a pinched wire. so I would test the wiring with the tank closed.
 
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#5 ·
Keep in mind I am a car tech not a motorcycle tech. So I apply what I do in the shop to my bike. I have never had an injector issue (knock on wood) but this is what I would do.

1. Like you already have, I would swapped another injector with #3 injector after clearing the code in order to see if I am getting the same fault.

2. If yes, then I would plug back in my stock wiring and see if the code comes back again

2. if no, I would think its an injector issue. Look up specs and Ohm out each injector and compare it to spec (with ohm basically you are shooting 1v through the circuit from the positive lead on your DVOM to your negative Lead. If there is any resistance it will show up on you Digital Volt Ohm Meter in Ohms) If you have an open in the injector or if the ohms are too high I would replace that one.

3. If the code doesn't come back like in your situation I know its the bazzaz computer or wiring. Next is the tedious part of tracing the wires to the correct pin.
So lets say the power wire is white and the negative wire coming off the injector is ground. I would check for 12.volts (aka battery voltage or close to it) at the white wire and a good ground at my black wire. Since there are not a lot of connections between my injector wire and PCM I would not like to see no more than 1 volt drop from so if my battery is at 12.5v with the key on engine off, I would like to see 12.5v - 11.9v anything less than 11.9v I would know its something in the wiring.

Next with the key off battery disconnected and connectors disconnect from the injector at on end and Computer at the other, I would ohm out both wires.

In your case it sounds like you have a pinched wire. so I would test the wiring with the tank closed.
Thanks for the awesome reply buddy.
Started it again today 50min idle no issues.
10 min road test no issues.

With it suddenly 'repairing itself' it's pointless to test anything now since everything is perfectly now working?

No idea what to do.
 
#9 ·
EDIT:

So the problem seemed differently than previously diagnosed. The wire we previously found is connected to a bazzaz socket and the bazzaz male to female socket has poor contact. The pins inside must be bad. Moved the sockets a bit while engine is running and a cylinder stopped working. Apparently bazzaz sockets are notoriously bad.
 
#10 ·
I never knew this, I was check for this next time I have an issue with my bazzaz unit.

Did you figure out the issue?

side note, if you ever need help understanding Electrical ask away. I am no engineer but I learn about something new until I can teach it , then I move on to something else.
 
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