Manic_Mechanic
Turbocharged
Anybody have experience with an injector hanging up and causing only one cylinder to run rich around 2K rpm?
fuel injector problems
- Thread starter Manic_Mechanic
- Start date
Power-Tripp
Turbocharged
There is a big difference between an injector hanging open (failure) and simply running considerably richer than the others.
It is common to see 7-14% differences between injectors at lower duty cycles. And up to 30+% differences in flow at low opening rates are not uncommon. Even though a set of injectors tend to vary no more than 1-1.5% at static flow (100% duty cycle), the ECU can only use a max of 85-86% dc before it will start shutting down the injector drives to prevent overheating. Opening times at low rpm and loads are very short. As a result, the variance in lag (how quickly the injector opens, voltage changes, flow, and more, can be considerable. Static flow rates on injectors mean very little - especially since most are flowed with mineral spirits that has a difference in viscosity and density that is roughly 13% different from pump fuels. All of these are the injector industry's dirty little secrets, and can mean a lot to how your bike runs with the same modifications and map as the next bike - even completely stock from the factory.
READ ME.
This is why mapping each cylinder individually can result in a very nice improvement in output and fuel consumption, as well as better transient response.
Injector hang up is usually due to excessive wear to the pintle/disc assembly. This usually results in washing of the cylinder walls and fuel contamination of the oil - just smell the oil, and check the oil level precisely.
More than you likely wanted to know, but you did ask.
-Wayne
It is common to see 7-14% differences between injectors at lower duty cycles. And up to 30+% differences in flow at low opening rates are not uncommon. Even though a set of injectors tend to vary no more than 1-1.5% at static flow (100% duty cycle), the ECU can only use a max of 85-86% dc before it will start shutting down the injector drives to prevent overheating. Opening times at low rpm and loads are very short. As a result, the variance in lag (how quickly the injector opens, voltage changes, flow, and more, can be considerable. Static flow rates on injectors mean very little - especially since most are flowed with mineral spirits that has a difference in viscosity and density that is roughly 13% different from pump fuels. All of these are the injector industry's dirty little secrets, and can mean a lot to how your bike runs with the same modifications and map as the next bike - even completely stock from the factory.
READ ME.
This is why mapping each cylinder individually can result in a very nice improvement in output and fuel consumption, as well as better transient response.
Injector hang up is usually due to excessive wear to the pintle/disc assembly. This usually results in washing of the cylinder walls and fuel contamination of the oil - just smell the oil, and check the oil level precisely.
More than you likely wanted to know, but you did ask.
-Wayne
Ishmael
Supercharged
Cool
thank you yet again Wayne. I learn heaps from this site.
thank you yet again Wayne. I learn heaps from this site.
Manic_Mechanic
Turbocharged
There is a big difference between an injector hanging open (failure) and simply running considerably richer than the others.
More than you likely wanted to know, but you did ask.
-Wayne
Got one on order.....thanks.
Power-Tripp
Turbocharged
If you have not ordered one yet, I can send you a good used spare out to test. This way you can see if it is actually the injector causing your problem.
If it is not the issue, you are only out the cost of shipping.
Give me a call if this works for you.
If it is not the issue, you are only out the cost of shipping.
Give me a call if this works for you.
Manic_Mechanic
Turbocharged
That would be awesome Wayne. I ordered the part from bike bandit and was just informed that it is on backorder. If it goes longer than 25 days they'll cancel the order. I'm headed to Kentucky mid september and really need to resolve this before then. The bike runs great as long as the engine is under load. Otherwise if you back off the throttle around 2K it runs so rich that I lose one cylinder until I blip the throttle. I've worked out the scenario over and over in my head and even lowered the f/l switch bit by bit to no avail. I'm really leaning toward a faulty injector. I just changed the plugs too. P.M. me for an address.
Manic_Mechanic
Turbocharged
The latest in the saga
Ok, finally got around to swapping injectors between the first and third throttle bodies. The problem stayed at the #3 position which lead me to believe that the problem is related to a sensor. Hooked up tuneECU and watched the diagnostics. I was trying to ballance the tb's but had no luck getting #3 close to one and two. I switched over to the middle tab in the program and monitored the injector pulse width. Here I found that one and two were close to 4.5 but three was staying at 3.5
This would explain why the engine runs so well at higher rpm's when the f/l switch kicks in and the metering is controlled by t.p.s and rpm and the m.a.p has no bearing on the mixture.
It appears that the e.c.u. controls each injector individually which I did not expect due to the fact that all three vacuum lines converge into one sensor. If I gradually pinched off the vacuum line from #3 TB I could see the pulse width ride up like cheap underwear and the idle smoothed out as well.
Now the only thing left is to pull the throttle body and check for a bad o-ring or some other seal. If this doesn't remedy the problem then I'm checking valve clearances.
Any input or comment is invited and welcomed.
Ok, finally got around to swapping injectors between the first and third throttle bodies. The problem stayed at the #3 position which lead me to believe that the problem is related to a sensor. Hooked up tuneECU and watched the diagnostics. I was trying to ballance the tb's but had no luck getting #3 close to one and two. I switched over to the middle tab in the program and monitored the injector pulse width. Here I found that one and two were close to 4.5 but three was staying at 3.5
This would explain why the engine runs so well at higher rpm's when the f/l switch kicks in and the metering is controlled by t.p.s and rpm and the m.a.p has no bearing on the mixture.
It appears that the e.c.u. controls each injector individually which I did not expect due to the fact that all three vacuum lines converge into one sensor. If I gradually pinched off the vacuum line from #3 TB I could see the pulse width ride up like cheap underwear and the idle smoothed out as well.
Now the only thing left is to pull the throttle body and check for a bad o-ring or some other seal. If this doesn't remedy the problem then I'm checking valve clearances.
Any input or comment is invited and welcomed.
Manic_Mechanic
Turbocharged
Can individual mapping be done with tune ECU?
Manic_Mechanic
Turbocharged
Also on the issue of the O2 sensor...
If I have the o2 sensor eliminator installed do I check or uncheck the o2 box in tune ecu? Is there a web site that explains all the ins and outs of tuning?
If I have the o2 sensor eliminator installed do I check or uncheck the o2 box in tune ecu? Is there a web site that explains all the ins and outs of tuning?
Just going to use this thread here to ask my question to @DEcosse ..........
I'll be cleaning my injectors on the weekend while im fixing the throttle body to head adaptor issue I currently have. I have watched a couple of Youtube vids showing how to self clean injectors , my main worry is whats not covered in the instructional videos , what sort of voltage should I put through my injectors while cleaning to get them to open, I understand that it has to be a quick pulse and not a prolonged opening, don't want to fry them by putting 12 volts where maybe 6 should be used,
thanks in advance
Wrecka
I'll be cleaning my injectors on the weekend while im fixing the throttle body to head adaptor issue I currently have. I have watched a couple of Youtube vids showing how to self clean injectors , my main worry is whats not covered in the instructional videos , what sort of voltage should I put through my injectors while cleaning to get them to open, I understand that it has to be a quick pulse and not a prolonged opening, don't want to fry them by putting 12 volts where maybe 6 should be used,
thanks in advance
Wrecka
