Fuel injectors

[HK131]

I have a 2003 hayabusa with fuel injector problems

Recently I rebuilt my transmission, before that the bike started fine.

Today I put my bike back together and it would crank but would not start. I started checking around. All the wires are connected where they are supposed to be.

The bike has spark and has fuel pressure to the fuel rail.

The problem is the fuel injector will not open. I tested the injectors and they work fine on a fuel injector test. The resistance on the injectors are in spec.

I checked the wiring harness for voltage, it was also in spec. I checked for continuity in all of the wires leading to the ecu which they all were perfectly fine.

I checked cam sensor, crank sensors, tip over sensor, ground wires and they were all in spec as well.

I have a power commander three and I also wired the fuel injectors back to the stock harnesses and still has no luck.

Even when the bike is priming the injectors stay closed. It builds pressure in the fuel rail where the injectors will pop out of the housing due to pressure.

Could it be a faulty ecu?

Sorry for the long thread. I just wanted to be clear on everything I’ve tired so I don’t waste peoples time. Thank you

 

[Hayabusa Wannabe]

Welcome to the forum @HK131.

I just wanted to be clear on everything

Yes, you added great detail which should be helpful to the members here.

Is this battery in A-1 shape? Making sure it is not dipping in voltage during the start, causing control problems. This bike seems sensitive to that.

 

[HK131]

Welcome to the forum @HK131.



Yes, you added great detail which should be helpful to the members here.

Is this battery in A-1 shape? Making sure it is not dipping in voltage during the start, causing control problems. This bike seems sensitive to that.

So when I put it together the battery was fully charged. I know they say not to but I jumped my bike after trying to diagnose the problem for so long the battery was giving out.

I just used a noid light to test the harness and it doesn’t glow at all, when cranking or priming. I know it’s sending 12 v to the harness when priming because I used a multimeter to check. So I am assuming something isn’t grounding the fuel injectors.

I’ll double check but the harness had continuity all the way to the ecu. When I plugged the full harnesses through the pc3 it had a lot of resistance. I don’t know if that’s normal but from the stock harnesses the continuity was fine.

I was wondering if oil pressure has any trying to do with the fuel injection system as well

It just seems like the ecu isn’t grounding. I don’t want to buy another ecu and still have problems.

Thank you

 

[HK131]

Also I realized I had put the power commander on the positive terminal and I’m pretty sure it was supposed to be grounded. Dumb mistake on my part I just bought the bike and never used a power commander before. The lead had a red crimp on it. I don’t know if that could possibly ruin an ecu

 

[Hayabusa Wannabe]

If you can find an ECU for testing, that is one easy way of eliminating the ECU as the problem.

 

[202mphbusa]

unplug the fuel pump and cycle the key
you will hear a couple things
1 fuel pump relay
2 injectors should cycle with priming squirts

Put a long screwdriver on one and your ear to the handle end

 

[Redcurbjumper]

It’s likely air in the fuel rail. I literally just had this same problem on Monday. First startup after completing a rebuild and it cranked over but seemed like no spark.... 40 psi on the fuel rail but it didn’t pop off until I cracked open the fuel gauge line and bled the air. Had a booster hooked up to the battery for
hot spark and had to nurse it to life with the throttle....

 

[HK131]

If you can find an ECU for testing, that is one easy way of eliminating the ECU as the problem.

I just ordered a used one today I used a noid light tester and it wasn't glowing at all. when priming or cranking. I double checked the wiring harness from the injectors to the eco had continuity for all the ground wires. I checked all the ground wires for the eco which is b/w I think there was three on one plug and one on the other plug they all are grounded. the ecu seems to be the issue. ill update once I get the ecu.

 

[HK131]

unplug the fuel pump and cycle the key
you will hear a couple things
1 fuel pump relay
2 injectors should cycle with priming squirts

Put a long screwdriver on one and your ear to the handle end

the relay is working I hear it clicking every time when I turn the key before cranking.
fuel is being sent all the way to the rail but the injectors are stuck closed I tested and cleaned all four injectors they ran fine. the harness doesn't have power going back to ground.

 

[HK131]

It’s likely air in the fuel rail. I literally just had this same problem on Monday. First startup after completing a rebuild and it cranked over but seemed like no spark.... 40 psi on the fuel rail but it didn’t pop off until I cracked open the fuel gauge line and bled the air. Had a booster hooked up to the battery for
hot spark and had to nurse it to life with the throttle....

I thought that was the case before I started trouble shooting until I took the fuel hose of from the railing and fuel exploded in my face from to much pressure build up in the rail XD. I really wish it was air in my system but the noid light does not operate when connected to the harness for priming and cranking

 

[202mphbusa]

if you are getting 12v to them then it is ecu grounds

 

[HK131]

if you are getting 12v to them then it is ecu grounds

When you say ecu grounds are you imposing the ecu is bad. I checked continuity on all ground wires from the ecu plug to the ground. Again thank you for the help

 

[TonyM995]

have a power commander three and I also wired the fuel injectors back to the stock harnesses

The first thing I would do is remove the power commander and re validate everything. He is saying if the fuel injectors are getting 12v (you said you checked the harness for voltage) then the other side of the equation is the ground signal. In our case the injectors get switched 12v power from a relay when the bike is turned on. The ecu sends a ground signal to the injector to complete the circuit and fire the injectors. If you have 12v the ground is the signal you’re missing.

If they all 8 don’t open you probably have wires switched somewhere. It’s not likely to be your ecu if that was working properly.

 

[HK131]

The first thing I would do is remove the power commander and re validate everything. He is saying if the fuel injectors are getting 12v (you said you checked the harness for voltage) then the other side of the equation is the ground signal. In our case the injectors get switched 12v power from a relay when the bike is turned on. The ecu sends a ground signal to the injector to complete the circuit and fire the injectors. If you have 12v the ground is the signal you’re missing.

If they all 8 don’t open you probably have wires switched somewhere. It’s not likely to be your ecu if that was working properly.

I double checked and went back. I plugged all the stock harness together taking the pc3 out.

I still had 12v on all four injector harness (yellow and red wire) I put the noid light on the harness there is no light at all. I then put the noid light on the + lead of the harness and grounded the - end of the noid light to ground. There was light.

I unplugged the ecu after.

I checked all the ground wires that come out of the ecu. There is great continuity.
I plugged in the injectors and checked continuity from the (yellow and red) wire from the ecu plug all the way to the other end of the ecu plug for all the injectors and continuity was good as well.

At this point it just seems like the ecu doesn’t want to send a signal to ground the injectors.

I was wondering if there are sensors that could possibly tell the ecu to not ground the injectors but still have the ignition system working great.

 

[HK131]

so I plugged another ecu in and now the fuel pump relay code is being thrown. I checked the continuity after putting 12v to the relay and there was continuity. Is this just another faulty ecu?

 

[HK131]

I have a 2003 hayabusa with fuel injector problems

Recently I rebuilt my transmission, before that the bike started fine.

Today I put my bike back together and it would crank but would not start. I started checking around. All the wires are connected where they are supposed to be.

The bike has spark and has fuel pressure to the fuel rail.

The problem is the fuel injector will not open. I tested the injectors and they work fine on a fuel injector test. The resistance on the injectors are in spec.

I checked the wiring harness for voltage, it was also in spec. I checked for continuity in all of the wires leading to the ecu which they all were perfectly fine.

I checked cam sensor, crank sensors, tip over sensor, ground wires and they were all in spec as well.

I have a power commander three and I also wired the fuel injectors back to the stock harnesses and still has no luck.

Even when the bike is priming the injectors stay closed. It builds pressure in the fuel rail where the injectors will pop out of the housing due to pressure.

Could it be a faulty ecu?

Sorry for the long thread. I just wanted to be clear on everything I’ve tired so I don’t waste peoples time. Thank you

update. it was the ecu and the power commander. whenever I had put the ground wire for the pc3 to the positive terminal of the battery it had fried the ecu and pc3. after I had fixed it someone cut me off while I was riding and I totaled it the same day. thank you every one for your help.

 

[nintastio]

update. it was the ecu and the power commander. whenever I had put the ground wire for the pc3 to the positive terminal of the battery it had fried the ecu and pc3. after I had fixed it someone cut me off while I was riding and I totaled it the same day. thank you every one for your help.

Damn, sorry to hear that. Not what I was expecting to see at the end of the thread, but hopefully you aren't hurt?

 

[dadofthree]

Make sure you have great voltage under load. Sounds like voltage issue

 

[TonyM995]

update. it was the ecu and the power commander. whenever I had put the ground wire for the pc3 to the positive terminal of the battery it had fried the ecu and pc3. after I had fixed it someone cut me off while I was riding and I totaled it the same day. thank you every one for your help.

Damn I’m sorry to hear that. Are you okay?