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Discussion Starter · #21 ·
Check the fuel pressure. If that's good, then check the output on the engine temp sensor. If that's fine, look at the plugs. If they show fouling, replace them. I don't think that is the issue, but it would be a shame to spend a lot of time on it only to find that it was fouled plugs later. Also voltage drop the starter while you crank it, make sure its not dropping below specs.

If all of the above is good, and by that I mean you checked it all with gauges and meters, then its time to work on the tune. Initial fuel pulse and cranking fuel.

The first step in checking Harley codes is to purchase the electrical diagnostic manual.

The second step is to clear the codes and then see what comes back after a 20 min ride.

Codes pointing to a bad part is a myth. Codes direct you to a diagnostic procedure.

temp sensor would make sense, since it starts up cold every time.

plugs should be fine they have less than 4k on then , I swapped them before the tune which I had done after swapping the cams , lifters and rods ( did that myself .. tune was done by small Harley shop )

the fuel pressure is something I can start taking a look at

not sure what the voltage drop test is. do you mean measure the voltage when cranking and making sure it doesn't drop too low?

Think my plan will be to ride a few times since I cleared the codes then try to reproduce the issue to see the new error codes and start from there.






thanks all
 

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is that not what is happening when you switch the bike to on?

when I "prime it twice" I mean I flip the kill switch on and off so that the auto primer runs twice.
I see what you mean by priming now. Flipping switch on activates the fuel pump for a second or two getting fuel pressure up to required pressure. "Priming" to us old folks means squirting gas into the carb throat.
 
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I see what you mean by priming now. Flipping switch on activates the fuel pump for a second or two getting fuel pressure up to required pressure. "Priming" to us old folks means squirting gas into the carb throat.
It don't work that way.

Every time you turn the switches on the pump will run. The ecm will turn it off after some seconds if the engine is not started That does not add fuel to the engine.

When you first hit the starter, the ecm will prime the cylinders based on engine temp. A few milliseconds worth of flow. Since this is a timed event, fuel pressure is critical. Then while the engine is cranking, the ecm will ad a percentage of the fuel that the engine needs to run at that temp. It varies, but its like 150%. Both of these settings are adjustable.

All of this assumes the engine cranks properly. If its kicking back and trying to stall the starter, you have to fix that first.
 

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Do you have electrical diagnostics manual? A code for CPS or O2 sensor does not necessarily mean it's bad...you need to follow the troubleshooting tree. You may have replaced a perfectly good component but will still have the same result if the wire harness or a connection is bad. More than once I've found a problem to be this vs 'replace component'.

Regarding fuel pressure issue...just throwing this out there. Some bikes can develop chaffing of the plastic fuel lines inside the tank that creates a pin-hole leak on suction side of pump. Depending on where this hole is combined with fuel level in tank, you can get problems with fuel pressure because it starts sucking air. It will drive you crazy trying to figure it out because it's intermittent depending on fuel level in tank. Had this happen on my '02FXSTi years ago.
 
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Discussion Starter · #25 ·
Do you have electrical diagnostics manual? A code for CPS or O2 sensor does not necessarily mean it's bad...you need to follow the troubleshooting tree. You may have replaced a perfectly good component but will still have the same result if the wire harness or a connection is bad. More than once I've found a problem to be this vs 'replace component'.

Regarding fuel pressure issue...just throwing this out there. Some bikes can develop chaffing of the plastic fuel lines inside the tank that creates a pin-hole leak on suction side of pump. Depending on where this hole is combined with fuel level in tank, you can get problems with fuel pressure because it starts sucking air. It will drive you crazy trying to figure it out because it's intermittent depending on fuel level in tank. Had this happen on my '02FXSTi years ago.

well, its too late bc I already replaced the sensors. if they were bad then they're new now...

but no I don't have that diagnostic manual, I only have a free pdf service manual but it doesn't include electric diagnostics. if it cost bread then im not really in a rush to get it.. im trying to buy other stuff for cars etc.

the bike runs smooth when I ride so i'm not convinced its a fuel pressure issue,

it only happens when starting the bike hot ... but I may not be understanding how the fuel system works enough.

I've worked on everything on my bike , all the parts and repairs I mentioned were all installed by me (except for tires) but the fuel system is one part of the bike I have not really got into yet..

A tutorial or thread on how to test the fuel pressure would be good. ill prob look up a diagram when I have the time to understand the system more. If someone could point me in the right direction I would appreciate that too.
 

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Discussion Starter · #26 ·
would it make more sense to do the fuel pressure test when its hot , since that's when the issue happens
 

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Discussion Starter · #27 ·
I see what you mean by priming now. Flipping switch on activates the fuel pump for a second or two getting fuel pressure up to required pressure. "Priming" to us old folks means squirting gas into the carb throat.

yeah TBH until this post that's exactly what I thought it was doing..
 

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Discussion Starter · #29 ·
update:

tried to reproduce the issue and could not ( the issue was cranking without starting and would start until I pressurized the fuel system twice , turning the kill switch off and on )

got some error codes after the ride, P0132 P0151 P0152 and b2066

cleared them all then rode again, got the same codes.

I'm going to take a look at the electric diag manual but if I had to guess it seems like something with fuel pump / pressure
 

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P0132 is front O2 low sig or pegged lean.

P0151 is rear O2 low sig or pegged lean

P0152 is rear cylinder pegged rich, and that can't be if its all so pegged lean.

B2066 I don't see. Fact is, I don't see any B2000 series codes. You might want to recheck that one.

The rich and lean faults can't happen at the same time. So either it starts pegged one way and then switches to peg the other way, or the ecm is bad.

I don't know what brand tuner you have, but that could also be an issue with a piggy back tuner and they way it counterfeits the O2 data to fool the ecm. The ECM might have figured that something is not kosher and set the codes. Fixing that usually requires reloading the tune. If it has a piggy back tuner, be sure to clear the codes and see if they come back with the tuner removed from the scooter.

Past that, you will need to sit down with the manual and work those cod ladders step by step. If when you get a 16 manual, (I don't have a 16) you see that B code, you might want to go after that on first.
 

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P0132 is front O2 low sig or pegged lean.

P0151 is rear O2 low sig or pegged lean

P0152 is rear cylinder pegged rich, and that can't be if its all so pegged lean.

B2066 I don't see. Fact is, I don't see any B2000 series codes. You might want to recheck that one.

The rich and lean faults can't happen at the same time. So either it starts pegged one way and then switches to peg the other way, or the ecm is bad.
...
He did say in the original post of this thread that he replaced both O2 sensors. I would go along with a bad ECM or possibly a wiring issue on the O2 sensors.
 

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That’s where you need the diagnostic manual. It gives you a lot more specifics on electrical connections & wire wiggle tests. In order to do a successful ‘wiggle’ test, you need to know which wires go to which sensor from that 38-pin connector that plugs into the bottom of the ECM. You also need to carefully remove the clear plastic cover from that connector in order to use an ohm meter on the wires under test.
Believe me, I understand broke, but without that manual, you are left to opinion shopping and pulling your hair out (if you have any left to pull).
 
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I totally agree with the last 3 posts from thermodyne, G man and burnse66,,, it is mandatory to use the electrical diagnostic ladders, to track down what is actually wrong..
Testing the systems, only requires your time,,, no other expenses..m it keeps the budget issues down..
Many times, the actual cause of these issues, does not require any parts expenditures...
I cannot count the number of bikes, with similar issues,, that came to my shop, after spending thousands of dollars,, and months of down time, that had such minor issues,,
 

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He did say in the original post of this thread that he replaced both O2 sensors. I would go along with a bad ECM or possibly a wiring issue on the O2 sensors.

BCM also interfaces with the sensors on theses new scooters. It drives the heaters. And with that unknown BCM group code, it could turn out to be a data buss issue. Something like pulling power for an accessory from the wrong circuit.
 

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but no I don't have that diagnostic manual, I only have a free pdf service manual but it doesn't include electric diagnostics. if it cost bread then im not really in a rush to get it.. im trying to buy other stuff for cars etc.
Good luck
 

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Discussion Starter · #36 · (Edited)
Looks like a B to me b2206 (see the pics below) Apologies , think I mistyped B2066

Yeah the P0151 and P0152 codes are weird but its what I got.. so not sure what to say about it.

I appreciate all the feedback so far, seems like the next step for me is to get to work , do some tests and get the diagnostic manual. I will report back whenever that is .. not sure when ill get around to it (the bike is not a daily)

As for the tuner , I have a "master tuner 2" its blue, I think its common. Was tuned by a shop called "Motorious Speed Shop" in San Bruno, CA. They used their own 02 sensor for the dyno runs.




Speedometer Light Gauge Motor vehicle Measuring instrument
 

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Discussion Starter · #37 ·
BTW for what its worth here's some other facts , excluding all the suspension work I did (triple trees , shocks , head etc)...

- the exhaust ports are very new , seated flushed and the exhaust is correctly installed ( a two into one shorty exhaust, Cobra El Diablo ) nice and flush with the ports

- plugs and air filter were replaced before the tune 3k miles ago

- can't remember if I ever replaced the plug wires

- ignition coil was replaced like 5k ago since it was cracked

- I have a bolt in Dave Mackey cam with SS adjustable pushrods and fueling lifters HP+ , all installed by me

- my low beam doesn't work

- the horn is not installed

- replaced battery with a Harley battery because the battery died too many times from sitting and was old so just got a new one.

- about 1k miles ago I replaced the compensator

- and maybe like 900 miles ago I replaced the stator because it shorted. I swapped the regulator too just in case. but maybe that messed something else up

- I've swapped the bars a **** load of times, so Idk maybe I pinched a wire ?
all the control switches work ... there's this one wire that is coming out of the harness
tbh not really sure what its for .. if it sounds weird Ill take a picture but its one of the wiring harnesses that comes from the controls and tucks away into the frame. I don't think its a factor in this issue since its been this way since I bought the bike


- and recently the 02 sensors + the crank shaft position sensor .. simply bc I saw those codes and was throwing parts at it ....TBH I don't mind having a bike with a bunch new parts on it anyway. factory **** is junk anyway so I feel like swapping parts is slowly making the bike more reliable and will be worth it one day when im a long ride. the bike has never really failed me tbh and I've ridden a good 5-8k miles . the only time is when the stator went out and I replaced that within a couple of weeks.
 

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b2206 is related to the on off switch on the hand right switch pac. Shorted high. Fix that first. The BCM wants to see that toggle low to high during start up.
 

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An inductive VOM, couple jumper wires, a test light is about all the tooling necessary, in conjunction with a fuel pressure tester set.
There are about 10members, that have extensive knowledge of all harley systems..,
An electronics manual, service manual, and a parts manual are necessary to diagnose and repair the bike..
 
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