Is a new ECM really needed?

[Idaho]

There seem to be plenty of warnings that a new Engine Control Module (ECM) will be needed when both pipes and intake are replaced because the engine will run leaner and could suffer damage. My experience with V-twins, albeit somewhat limited, is that they have a tendency to run too rich anyway. So my question is for those of you who have ignored conventional wisdom, and are quietly watching these discussions from the sidelines, who have installed new pipes and a BAK (big air kit) like the Caddmann mod and have NOT changed out the ECM. How many miles have you put on your bike with this combination and have you had any problems? Has anyone done this and destroyed an engine? Are there any test results that monitor tail pipe emissions and cylinder temps with this combo or is this just a seat of the pants wives tale?
Thanks again,
IDaho Nomad

[dogdoc]

I've been wondering this question too IDnomad. I changed to V&H pipes but still have stock air breather. Would like to go hypercleaner but dont want to HAVE to put on a PClll also. Can a person upgrade to a K&N filter(stock breather) without having to do a PClll?? I need to do the marble because mine pops on decleration now. How about some answers gear heads??

Doc

[Todd]

BD can probably answer this better, but the stock ECM runs so lean, that I think putting more air...i.e. opening up the breather....will REALLY make you lean. I think you need it if you open up the intake.

BD, GH, Ponch..... help is needed!! lol

SWB.... didn't forget you!!! just left you out!!! LOLOLOL

OUCH!!!!!

It was stated above that if you only add pipes your good but if you add a BAK or similair aswell it will lean you out so bad that you can pretty much depend on having engine issues down the road. If you guys value your rides and want them to live a long and happy life a PCIII has got to go on your ride if you change out your stock air for a BAK along with pipes..I was told by an old wise mechanic that if you throw more air into your bike it has to have the ablility to throw all that air out of your bike and when you do that you change the whole A/F mixer ratio and you have to tweak it to make it run right or healthy in his words whether it be a carbed bike or a FI bike the same applies. Just to lean. If any of you guys do this without a PCIII please write down your experencie with pics so you can post it up on not what to do becasue this damage will happen. also to go cheap now and not spend the extra $275 after spending like $11K and above for your new ride now just dont make sense to me. just my two cents.

[blowndodge]

Search this site. I think some old dog posted his limited knowledge on the subject. The only way to know for sure is an exhaust sniffer to test the air/fuel ratio. You can "rent" these gizmos and what you would be looking for is 14-15/1 air to fuel on cruise and 12.5/1 when WFO. I've been emailed by a few that stated stock the Idle and low speed produced 18/1 air to fuel. This seems grossly lean and would/could explain why the engines ping and run very hot.

Things to consider when modifying. The air temp sensor is behind the cover on the throttle body side and the air it reads is super heated because the air comes from the other side of the bike and travels through between the cylinders to the other side where this sensor is located.

One would think? that If putting a BAK filter on the right side, the sensor is no longer exposed to this hot air and is now reading air temperatures that are truely "outside" air coming directly into the intake. Now maybe this cooler air temp would tell the ECF to fatten up the mixture? Dunno, have't done it yet but will be doing it later as an experiment. I plan on just "relocating" the air temp sensor to another part of the bike that receives true ambient air readings and plugging the hole with something in the mean time to see if this tells the ECM to richen up the mixture.

Remember as the engine sensors ( water temp sensor, intake air sensor, barametric pressure and throttle position sensor) pick up their readings they adjust the air/fuel mixture amongst other things like timing. When it senses higher temps, it leans out the mixture. This is because hot air (Nico) contains less molecules of air per specific area. So, for the sake of understanding numbers, its 70 degrees out and in a square inch of air there are 100 molecules of oxygen when the temp rises to 100 degrees there will be less than 100 molecules of oxygen because these molecules expand with heat. Your ECM reads this and leans out the mixture because of less oxygen, this in theory keeps your exhause fumes lean and clean but makes your bike very much more prone to overheating and pinging.

I have a feeling mine is running too lean. If I just let mine idle at a stop for a little while the fan will kick on. Maybe I should pull a plug and check things out.

[Todd]

BD can probably answer this better, but the stock ECM runs so lean, that I think putting more air...i.e. opening up the breather....will REALLY make you lean. I think you need it if you open up the intake.

Search this site. I think some old dog posted his limited knowledge on the subject. The only way to know for sure is an exhaust sniffer to test the air/fuel ratio. You can "rent" these gizmos and what you would be looking for is 14-15/1 air to fuel on cruise and 12.5/1 when WFO. I've been emailed by a few that stated stock the Idle and low speed produced 18/1 air to fuel. This seems grossly lean and would/could explain why the engines ping and run very hot.

Things to consider when modifying. The air temp sensor is behind the cover on the throttle body side and the air it reads is super heated because the air comes from the other side of the bike and travels through between the cylinders to the other side where this sensor is located.

One would think? that If putting a BAK filter on the right side, the sensor is no longer exposed to this hot air and is now reading air temperatures that are truely "outside" air coming directly into the intake. Now maybe this cooler air temp would tell the ECF to fatten up the mixture? Dunno, have't done it yet but will be doing it later as an experiment. I plan on just "relocating" the air temp sensor to another part of the bike that receives true ambient air readings and plugging the hole with something in the mean time to see if this tells the ECM to richen up the mixture.

Remember as the engine sensors ( water temp sensor, intake air sensor, barametric pressure and throttle position sensor) pick up their readings they adjust the air/fuel mixture amongst other things like timing. When it senses higher temps, it leans out the mixture. This is because hot air (Nico) contains less molecules of air per specific area. So, for the sake of understanding numbers, its 70 degrees out and in a square inch of air there are 100 molecules of oxygen when the temp rises to 100 degrees there will be less than 100 molecules of oxygen because these molecules expand with heat. Your ECM reads this and leans out the mixture because of less oxygen, this in theory keeps your exhause fumes lean and clean but makes your bike very much more prone to overheating and pinging.

See TOLD YA!!!

How can so much useful stuff be mixed in that head with such BULLSH*T!!!!!!

[blowndodge]

I came, I drank, I stayed!!

I have a feeling mine is running too lean. If I just let mine idle at a stop for a little while the fan will kick on. Maybe I should pull a plug and check things out.

Mine does too....... is that an idication of too lean?

[blowndodge]

What is an "idication"??? is that like an edumacation?

No no no... it would be an indication for an idiot....

[ponch]

If you put an air kit and pipes on the bike you should get an ECM spoofer as I call them. Basically, they intercept the signals the ECM sends to the injectors and changes the parameters to enrichen and in some cases lean out the mixture depending on the unit. The problem is that the ECM on a Nomad cannot learn and adapt. It bases the amount of fuel the injectors spray from static tables. It will use different tables based on input from various sensors. Since the system cannot ascertain if and what the f/a mixture really is, they tend to make it on the lean side to pass emissions. With more modern closed loop systems that use oxygen sensors as well as mass air flow and knock sensors, the fuel mixture can be more precisely adjusted, it can learn based on feed back to keep the F/A ratio in a certain range so even if you change the exhaust and air kit, it can adjust for this. The system on the Nomad cannot. There is a company that makes a closed loop system for harley engines and I hope they come out with something for the nomad. The company's name is ThunderMax. Now, you can fool the ECM into thinking certain parameters are different and thereby making it spray more fuel. This can be done by a resistor mod to the air temperature sensor or adjusting the throttle position sensor. These modifications aren't as precise as an ECM spoofer, but if you have a stock bike that pings, it can help. So to answer your question, yes if you modify the air intake and the pipes.

[Idaho]

All that has been stated so far fits in with the conventional wisdom, more air without more fuel = lean mixture. What I'm looking for, hopefully without offending anyone who has responded thus far, is actual test data that tells us what a probe up the tail pipe actually has measured and what really is damaging to the engine. I agree with VC that it makes no sense to scrimp on a new engine control module if it would damage the bike; bad economy. But, again is there test data to support the assumption?

Another question, can we add an air breather mod like the Caddmann mod and see any improvement in performance with the stock pipes? I would bet that the stock pipes can handle more air than the choked down intake is delivering.

Again, my appologies for all of the questions that seem to be going in different directions. I'm just a newbie who is thinking out loud. It is encouraging to see others here who echo the same confusions.

Thanks again,
IDaho

[blowndodge]

Finding "test data" will be something that you'll have to probably discover yourself. Remember all bikes behave differently. I'm not sure which end is choked up more the intake or exhaust. My guess would be intake. I doubt you going to find data that someone has that has sniffed the exhaust step by step along the modification process as you would like. I've yet to find very few that even know about why some mods work and some don't and then to have post a hard data review answers. Thoses exhaust probes you can find for rent and start the process of intake and/or exhaust modification and report back to us on the behavior of the engine under those conditions.

I started out in the racing word with the same ?'s many a moon ago and I had to find the answers myself. If you not sure of what the end result that your after will be, arbitrarily asking for data will be useless.