Error 43 no start

[Sugarkryptonite]

Hi guys,

I recently got a 08 Nytro which ran perfectly and took it apart to rebuild the entire exhaust system. I did all that, and at the same time changed the spark plugs to brand new OEM. I didn't touch any other wiring except for disconnecting the battery.

Today, I put the fuel tank back in and wanted to fire it up to make sure everything was good.

Cranks and cranks and cranks, but no fire. I noticed that the fuel pump does not prime upon key on as it normally did before. I checked voltage at the fuel pump connector and for 3-4 seconds after key on it supplies battery voltage to the pump, as you would expect for it to prime, but the pump doesn't do anything.

I wired battery power directly to the pump and it pumps fine and makes pressure. I kept it manually connected and tried cranking over the sled, and still NOTHING! It cranked and cranked and cranked and flashed error 43 on the dash but didn't start. WTF?

It still has the old black style fuel pump relay in it, but I don't see how that makes any difference after being connected directly to 12v.

I checked the 10A fuse in the starter solenoid and it checked out good.

Not sure what to look for next.

 

[74Nitro]

power

Hi guys,

I recently got a 08 Nytro which ran perfectly and took it apart to rebuild the entire exhaust system. I did all that, and at the same time changed the spark plugs to brand new OEM. I didn't touch any other wiring except for disconnecting the battery.

Today, I put the fuel tank back in and wanted to fire it up to make sure everything was good.

Cranks and cranks and cranks, but no fire. I noticed that the fuel pump does not prime upon key on as it normally did before. I checked voltage at the fuel pump connector and for 3-4 seconds after key on it supplies battery voltage to the pump, as you would expect for it to prime, but the pump doesn't do anything.

I wired battery power directly to the pump and it pumps fine and makes pressure. I kept it manually connected and tried cranking over the sled, and still NOTHING! It cranked and cranked and cranked and flashed error 43 on the dash but didn't start. WTF?

It still has the old black style fuel pump relay in it, but I don't see how that makes any difference after being connected directly to 12v.

I checked the 10A fuse in the starter solenoid and it checked out good.

Not sure what to look for next.

Hi guys,

I recently got a 08 Nytro which ran perfectly and took it apart to rebuild the entire exhaust system. I did all that, and at the same time changed the spark plugs to brand new OEM. I didn't touch any other wiring except for disconnecting the battery.

Today, I put the fuel tank back in and wanted to fire it up to make sure everything was good.

Cranks and cranks and cranks, but no fire. I noticed that the fuel pump does not prime upon key on as it normally did before. I checked voltage at the fuel pump connector and for 3-4 seconds after key on it supplies battery voltage to the pump, as you would expect for it to prime, but the pump doesn't do anything.

I wired battery power directly to the pump and it pumps fine and makes pressure. I kept it manually connected and tried cranking over the sled, and still NOTHING! It cranked and cranked and cranked and flashed error 43 on the dash but didn't start. WTF?

It still has the old black style fuel pump relay in it, but I don't see how that makes any difference after being connected directly to 12v.

I checked the 10A fuse in the starter solenoid and it checked out good.

Not sure what to look for next.

Power comes from the fused circuit at the starter relay, yellow/red wire. check the connections there.

 

[maim]

code 43 is for fuel pump and injectors not getting power. check the fuses 1st and make sure everything is plugged in tight.

 

[grizztracks]

When you manually power the pump the injectors more than likely are not powered so they don't inject any fuel to the cylinders.

The 10 amp fuse in the starter relay sends power to the fuel relay which when energized feeds that power to the fuel pump and injectors. Check the fuse and connector at the starter relay for corrosion. Also, the key switch connector can cause issues when corroded so clean all the connections to eliminate it as the problem. The ECU detects the fuel pump and injector power after the fuel relay and if not present sets the code so you'll need to troubleshoot why the relay doesn't provide the necessary power. It still could be a bad fuel relay so it's not a bad idea to elimnate that as the cause by upgrading to the red solid state relay.

 

[Sugarkryptonite]

Thanks guys.

So I did more diagnosing tonight. I have power on both sides of the 10A fuse on the starter solenoid. I have power on one side of the load side of the relay, I have power on one side of the coil side of the relay when the key is turned on. I have no ground signal at all from the ECU to the other side of the coil for the relay. If I ground the other side of the coil, the fuel pump runs without any problems. I managed to start the machine by putting the two load sides of the relay together with the relay completely out.

Realistically I guess I am looking for either a broken wire from the ECU, a bad ECU, or ECU not supplying the ground signal because it is looking for another signal first (not sure what, can anyone shed light?). The only thing I have that isn't properly connected is the speed sensor signal which I just have sitting on the side of the machine because I am waiting on a driveshaft bearing.

Next step is to gain access to the ECU and see try to see where the ground signal wire is from the ECU and check if it has it there to confirm a broken wire somewhere.

 

[74Nitro]

There are ground blocks throughout the harness. Identified by a bunch of black wires dead ending into a connector.

 

[Sugarkryptonite]

There are ground blocks throughout the harness. Identified by a bunch of black wires dead ending into a connector.

Right. But would the machine even run without those grounds working? I saw the one that is at the front of the machine and it looks fine. Where are the others located?

 

[74Nitro]

Right. But would the machine even run without those grounds working? I saw the one that is at the front of the machine and it looks fine. Where are the others located?

Oh, I don't have a nytro in front of me, but there are a few.

 

[74Nitro]

You say you have good power at the Red/Green wire at the fuel injection relay? That is the power supply wire from the fuse at the starter relay.

 

[grizztracks]

Swap the relay with one of the other two then go into the diagnostics mode and activate the fuel relay. If the relay doesn't cycle 5 times then there is a wiring problem or a problem with the ECU. https://ty4stroke.com/threads/fault-codes-relay-fuse-location-wire-diagram-diagnostics.83992/

There are a couple common problems with the wire harness rubbing through. check the harness under the steering post for damage and check it behind the primary clutch (there is a nipple on the engine mount that the harness rubs on) you may have to open the harness to get a good look at the wires.

The ground splice blocks look like a spare connector with several same color wires coming in from on side. the ground wires are all black.

 

[Sugarkryptonite]

You say you have good power at the Red/Green wire at the fuel injection relay? That is the power supply wire from the fuse at the starter relay.

Yep

Swap the relay with one of the other two then go into the diagnostics mode and activate the fuel relay. If the relay doesn't cycle 5 times then there is a wiring problem or a problem with the ECU. https://ty4stroke.com/threads/fault-codes-relay-fuse-location-wire-diagram-diagnostics.83992/

There are a couple common problems with the wire harness rubbing through. check the harness under the steering post for damage and check it behind the primary clutch (there is a nipple on the engine mount that the harness rubs on) you may have to open the harness to get a good look at the wires.
View attachment 164114
View attachment 164115

The ground splice blocks look like a spare connector with several same color wires coming in from on side. the ground wires are all black.

View attachment 164113

Great thanks

 

[Sugarkryptonite]

Did some more testing today.

1) ECU has all its grounds

2) Ground wire going from fuel pump relay to ECU is in tact and capable of carrying current. Disconnected the ECU and supplied ground directly to the wire, fuel pump runs.

3) In DIAG mode, tried to run fuel pump with everything connected, fuel pump doesn't run. Check engine light flashes while the "test" is being performed.

4) Inspecting the starter solenoid again, in the picture below, it says "Probe for ground signal with key in the crank position". While cranking, it seems like it's not a full connection to ground. Resistance measurements directly to battery ground show something like 1.5MOhms. Continuity test beeps though. Weird, not sure what to make of it. I have another one coming Saturday.

 

[74Nitro]

Blue/white has nothing to do with fuel system.

 

[Sugarkryptonite]

Blue/white has nothing to do with fuel system.

Thanks. So what does it do? I guess the only options are that the ECU is waiting for a signal to enable the fuel injection system from another sensor, or the ECU is fried. I have a real hard time believing the ECU is fried though since I just had the machine running a couple weeks ago before taking the exhaust apart...I had the battery disconnected the entire time I was woking on it.

 

[grizztracks]

The ground you probe at the starter relay comes from the key switch. It provides a ground signal to the starter solenoid to control power to the starter. That same wire from the key is spliced and that ground signal is also sent to the ECU so that the ECU detects the start attempt. Clean the connector behind the key switch (even if it doesn't look corroded it can form a white oxide layer that won't conduct). Did you check the harness rub points (especially the one under the steering post)?