rear injector lo
Stellar HDF Member
Joined: Jan 2013
Posts: 2,464
Likes: 50
From: Rouses Point, N.Y.
here.s some info that will help you diagnoses the injector problem .
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate fuel injector.
2. Ignition ON, verify that a test lamp illuminates between the ignition 1 voltage circuit terminal 1 and ground.
⇒ If the test lamp does not illuminate, repair the ignition 1 voltage circuit for a short to ground or an open/high resistance. Replace the fuse if necessary.
3. Ignition OFF, connect a J 34730-405 between the control circuit terminal 2 and the ignition 1 voltage circuit terminal 1.
4. Engine running, the test lamp should flash.
⇒ If the test lamp is always ON, test the control circuit for a short to ground. If circuit tests normal, replace the ECM.
⇒ If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal, replace the ECM.
5. If all circuits test normal, test or replace the fuel injector.
Component Testing
1. Ignition OFF, disconnect the harness connector at the appropriate fuel injector.
Important: The engine temperature sensor must be between 1032°C (5090°F) in order for an accurate measurement.
2. Test for 1114 ohms between the ignition 1 voltage terminal 1 and the control terminal 2.
⇒ If not within the specified range, replace the fuel injector.
Repair Instructions
this info should still apply to the delphi system on that bike. checked my stock injectors they ohms out at 12.4 each. the ignition voltage wire is yellow and green should have battery voltage with ignition turned on at both injectors. the green/gray wire is your control wire from ecm on rear injector. I believe that's where your problem lies or the driver in the control circuit in the ecm of that thundermax has issues and is not working. install your factory ecm back in before chasing any other leads.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate fuel injector.
2. Ignition ON, verify that a test lamp illuminates between the ignition 1 voltage circuit terminal 1 and ground.
⇒ If the test lamp does not illuminate, repair the ignition 1 voltage circuit for a short to ground or an open/high resistance. Replace the fuse if necessary.
3. Ignition OFF, connect a J 34730-405 between the control circuit terminal 2 and the ignition 1 voltage circuit terminal 1.
4. Engine running, the test lamp should flash.
⇒ If the test lamp is always ON, test the control circuit for a short to ground. If circuit tests normal, replace the ECM.
⇒ If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal, replace the ECM.
5. If all circuits test normal, test or replace the fuel injector.
Component Testing
1. Ignition OFF, disconnect the harness connector at the appropriate fuel injector.
Important: The engine temperature sensor must be between 1032°C (5090°F) in order for an accurate measurement.
2. Test for 1114 ohms between the ignition 1 voltage terminal 1 and the control terminal 2.
⇒ If not within the specified range, replace the fuel injector.
Repair Instructions
this info should still apply to the delphi system on that bike. checked my stock injectors they ohms out at 12.4 each. the ignition voltage wire is yellow and green should have battery voltage with ignition turned on at both injectors. the green/gray wire is your control wire from ecm on rear injector. I believe that's where your problem lies or the driver in the control circuit in the ecm of that thundermax has issues and is not working. install your factory ecm back in before chasing any other leads.
Stellar HDF Member
Joined: Jan 2013
Posts: 2,464
Likes: 50
From: Rouses Point, N.Y.
just swap your stock ecm in first that would eliminate if there is other concerns
quickly swapped the original ECM and it started great, didnt see a code
plugged the thundermax back in, got a code within a minute or so
back to the original, ran for a couple minutes and got p0134/p0154 codes for no o2 sensor activity
back to the thundermax, didnt see a code but it suffered hard starting two or three times
i did notice a wire (o2 sensor?) under the seat that had been jammed under some connectors and looks a big mangled, i twiddled it and didnt get any noticable changes but it didn't look great
plugged the thundermax back in, got a code within a minute or so
back to the original, ran for a couple minutes and got p0134/p0154 codes for no o2 sensor activity
back to the thundermax, didnt see a code but it suffered hard starting two or three times
i did notice a wire (o2 sensor?) under the seat that had been jammed under some connectors and looks a big mangled, i twiddled it and didnt get any noticable changes but it didn't look great
Elite HDF Member
Joined: Sep 2012
Posts: 3,791
Likes: 57
From: N Texas
Sounds like you are tracking it down. That Thundermax must have a bad wire somewhere.
The O2 codes without the Tmax plugged in would be normal I think, because doesn't the Tmax use widebands and the stock ECM is expecting narrowband.
The O2 codes without the Tmax plugged in would be normal I think, because doesn't the Tmax use widebands and the stock ECM is expecting narrowband.
The O2 sensor codes weren't a surprise, but that squished wire was... They'd folded everything up nicely but put a couple of connectors on top, the seat pressed down and squish!
dropped the bike off at my mech's the other day, that squished wire was apparently from the O2 sensor and wasn't too bad... they popped the tank off and found rear injector wire conduit was a little pinched, so they repaired that and put some dielectric grease on the injector connectors - apparently the code hasnt come back.
Still hard-starting 1/5 times tho, a bit concerned that it could be compensator/starter issues... I didn't have any problems until the bigbore-cam upgrade so hopefully it's something to do with that and not something else!
Still hard-starting 1/5 times tho, a bit concerned that it could be compensator/starter issues... I didn't have any problems until the bigbore-cam upgrade so hopefully it's something to do with that and not something else!
Outstanding HDF Member
Joined: Apr 2006
Posts: 2,555
Likes: 3
From: Clarksburg, PA
You said you just installed the Thundermax.
Mine takes a while to get itself to the point where it will fire up the first try.
I don't know why, but everytime I change my engine up, it takes a while to dial in...bike has always been like this.
Put big bore and cams in my brothers bike,loaded a map and starts up every time! I need to do an autotune for him, but it is running great from the start.
Maybe due some auto tuning and the firing problem will iron out.
Mine takes a while to get itself to the point where it will fire up the first try.
I don't know why, but everytime I change my engine up, it takes a while to dial in...bike has always been like this.
Put big bore and cams in my brothers bike,loaded a map and starts up every time! I need to do an autotune for him, but it is running great from the start.
Maybe due some auto tuning and the firing problem will iron out.
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Stage I
Joined: Apr 2015
Posts: 1
Likes: 0
From: San Antonio
Rear Injector
My bike was running on one cylinder and I troubleshot using a wiring diagram and found one of the injector wires had a broken wire inside a perfectly normal looking insulation around it. Without a wiring diagram and being able to stick a meter testing Ohms or continuity between the injector wire connector and connector to the bike computer I would not have found it. These injectors are powered by making a ground connection available at appropriate intervals, not by providing power at appropriate intervals as set by the computer. I don't remember which pin number on main computer connector that it is on but the shop manual has that information. The next time it did that it was the power commander problem which I have now removed. This unit was also running the bike very lean which causes high temperatures. I thought it would be opposite but to my surprise it gets hot when running lean. Now I have an issue with the relay. My relays are grey for system and black for starter. I saw someone on here that said theirs had a black system and grey starter. Mine is grey system and black starter so it appears that color is not always an indication of type. Hell just replace them both for less than $20.00. If the bike is older than a 2009 and you have ridden it during wet conditions at any time it probably isn't a bad idea to rejuvenate your fuse/relay box anyway.
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