Engine issue 'doesn't rev up above idle rpm'

[Haseeb]

Hello everyone, we're a rookie team and we're participating in FSAE-A 2011 and we're requiring your knowledge and experience to overcome the problem!

we're having engine issues! the engine doesn't rev higher than 2000 rpm. We are using a piggyback unit (power commander V) along with its O2 sensor unit (auto tune)and the engine is honda cbr600rr


the engine has no start up issues, idles at 1000-1500 rpm. O2 sensor showed a reading of 20-25, we tried injecting more fuel but it got really rich and idle went up to 2000 rpm

I checked at forum and found it to be a rich misfire, since our eyes were burning and O2 was showing super lean values

whenever we tried leaning out the mixture, the engine felt like it was going to die, whenever we tried enriching it, it got really hard to survive around it and still never rev up 2000 rpm

it accidentally went upto 4000 rpm twice and engine stopped cranking both times!

When we try to get past 20% throttle the rpms lower down as engine feels like dying out!

considering that it is only a fuel injection module, its a humble request to you guys if you can assist us in diagnosing and rectifying the problem! Thanks

P.S: I feel like we have some leakages in the intake, could this be a reason too?? last time we forgot to use gaskets on runners, the engine was really hard to start up and it sounded like it was exploding all the time!

Syed Haseeb Hassan
Formula NED

[Haseeb]

Hello everyone, we're a rookie team and we're participating in FSAE-A 2011 and we're requiring your knowledge and experience to overcome the problem!

we're having engine issues! the engine doesn't rev higher than 2000 rpm. We are using a piggyback unit (power commander V) along with its O2 sensor unit (auto tune)and the engine is honda cbr600rr


the engine has no start up issues, idles at 1000-1500 rpm. O2 sensor showed a reading of 20-25, we tried injecting more fuel but it got really rich and idle went up to 2000 rpm

I checked at forum and found it to be a rich misfire, since our eyes were burning and O2 was showing super lean values

whenever we tried leaning out the mixture, the engine felt like it was going to die, whenever we tried enriching it, it got really hard to survive around it and still never rev up 2000 rpm

it accidentally went upto 4000 rpm twice and engine stopped cranking both times!

When we try to get past 20% throttle the rpms lower down as engine feels like dying out!

considering that it is only a fuel injection module, its a humble request to you guys if you can assist us in diagnosing and rectifying the problem! Thanks

P.S: I feel like we have some leakages in the intake, could this be a reason too?? last time we forgot to use gaskets on runners, the engine was really hard to start up and it sounded like it was exploding all the time!

Syed Haseeb Hassan
Formula NED

[Pete Marsh]

What did you do just before it went up to 4000RPM? Do more of that.

Have you checked the spark timing is correct?

The throttle characteristics, set point and charge dilution are going to be very different from the stock intake system, requiring significant retuning. Don't expect it to run on stock settings.

If the engine is missing AT ALL, ignore the O2 sensor readings. They are only relevant when ALL cycles fire.

If possible, refit the stock intake system and ECU and start it up to double check your installation is good.

Good luck,
Pete

[ZAMR]

Sounds like a problem we had last year with fouled injectors. Check and clean every single injector or buy new ones, and check to make sure your fuel filter is working properly. If aluminum shavings from your tank enter the injectors they can cause this exact problem.

[Adambomb]

Any leaks in the intake manifold will cause you all kinds of problems, especially hard starting and wicked backfires like you've mentioned. That is the first thing I would get fixed. Test for leaks by spraying something like ether starting fluid around the gaskets, seams, injector mounts, etc., and listen for a change in rpm.

Usually if your problem is an intake leak it will have a lot of trouble idling, but will do OK at higher speeds. Although trying to compensate for a vacuum leak with a super-rich mixture could cause you all kinds of other problems. Definitely want to get that fixed first.

Unfortunately I'm not sure that using a piggyback unit on the original ECU, even with autotune, will be as easy a solution as expected. The restrictor changes the tuning pretty drastically, especially with the large plenums typically used in FSAE (which together, result in the normal idle of about 2500 rpm).

[Carrington]

Have you verified the firing order of your spark plugs/wires?

[Haseeb]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">What did you do just before it went up to 4000RPM? Do more of that.

Have you checked the spark timing is correct?

The throttle characteristics, set point and charge dilution are going to be very different from the stock intake system, requiring significant retuning. Don't expect it to run on stock settings.

If the engine is missing AT ALL, ignore the O2 sensor readings. They are only relevant when ALL cycles fire.

If possible, refit the stock intake system and ECU and start it up to double check your installation is good.
</div></BLOCKQUOTE>

We were trying to remap it, suddenly the rpm shoot up and the engine stopped cranking! we again started on the same settings but it didn't work

well about the spark timing, we don't know how to check that, but we'll try figuring it out!

sounds a good suggestion concerning O2 sensor readings, and the engine is missing way too much

when we start enriching it, it sounds good and the rpm get stable but it gets really hard to stand around the engine as it gets excessively rich

today, when we're starting the engine the rpm straight goes around 3000 for about 5 seconds and then lower down to 1500 rpm while missing!
any idea about it?

stock intake wouldn't work because we used the stock throttle bodies as runners by removing their valves!

thank you http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Haseeb]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ZAMR:
Sounds like a problem we had last year with fouled injectors. Check and clean every single injector or buy new ones, and check to make sure your fuel filter is working properly. If aluminum shavings from your tank enter the injectors they can cause this exact problem. </div></BLOCKQUOTE>

thanks for the suggestion, it might be the problem since our filler neck got a little rusted!

[Haseeb]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Adambomb:
Any leaks in the intake manifold will cause you all kinds of problems, especially hard starting and wicked backfires like you've mentioned. That is the first thing I would get fixed. Test for leaks by spraying something like ether starting fluid around the gaskets, seams, injector mounts, etc., and listen for a change in rpm.

Usually if your problem is an intake leak it will have a lot of trouble idling, but will do OK at higher speeds. Although trying to compensate for a vacuum leak with a super-rich mixture could cause you all kinds of other problems. Definitely want to get that fixed first.

Unfortunately I'm not sure that using a piggyback unit on the original ECU, even with autotune, will be as easy a solution as expected. The restrictor changes the tuning pretty drastically, especially with the large plenums typically used in FSAE (which together, result in the normal idle of about 2500 rpm). </div></BLOCKQUOTE>

Thanks for the suggestion, we'll try my level best to figure out leaks the way you mentioned!
we tried to fix the leakages the leakages in the intake today and i think its been fixed!

with a super rich mixture the engine stops missing and as i go lean, it starts missing!
what should be done in this situation? i thought maybe going rich would be the solution

Thanks!

[Haseeb]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Carrington:
Have you verified the firing order of your spark plugs/wires? </div></BLOCKQUOTE>

we havent verified the firing order, since we don't have any idea how to do that!
we'll try figuring that out.. thanks http://fsae.com/groupee_common/emoticons/icon_smile.gif

[TMichaels]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">we havent verified the firing order, since we don't have any idea how to do that!
we'll try figuring that out.. thanks </div></BLOCKQUOTE>
If you have a multi-channel oscilloscope, just hook it up to the ECU pins controlling the ignition coils while cranking the engine. That way you should be able to determine the firing order. You still have to check the correct wiring between ECU and ignition coils in that case.

If you do not have an oscilloscope available, remove the spark plugs, but leave them connected to the ignition coils. Connect the spark plugs to engine ground and start cranking (make sure that the ECU does not start injecting fuel by disconnecting the fuel pump or disconnecting the fuel injectors). Take a movie with your cell phone or whatever is available of the firing spark plugs and use single frame view on the PC to determine firing order.
You could also just unmount the intake manifold and try to watch the injector firing order while cranking. Could be a bit hard to see, but with a little bit of training it is possible. Do not point the injectors towards anyone while doing this. He may get shot by fuel and the fuel will harm his eyes for sure.

Additionally you should check that injectors and spark plugs are correctly aligned with respect to timing. I once miswired our engine in a way that the firing order of injectors and spark plugs solely was ok, but they where "out of synch". Gave me quite a headache, since the engine seemed to be running ok while idling, but made no power.

Regards,

Tobias

[Canuck Racing]

Firing Order: 4 Cylinder Team Problem.

[TMichaels]

Failing to finish Endurance, because one single injector, spark plug, coil, ECU output stage died: Single Cylinder Team Problem

How can you tell from a distance that a team runs a single cylinder engine?
Just look for the guy carrying the huge external starter battery http://fsae.com/groupee_common/emoticons/icon_smile.gif

This thread will go off-topic now...

Regards,

Tobias

[Mbirt]

WHAT?!?! No external start box allowed?!: 8 cylinder team problem.

[Adambomb]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Haseeb:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ZAMR:
Sounds like a problem we had last year with fouled injectors. Check and clean every single injector or buy new ones, and check to make sure your fuel filter is working properly. If aluminum shavings from your tank enter the injectors they can cause this exact problem. </div></BLOCKQUOTE>

thanks for the suggestion, it might be the problem since our filler neck got a little rusted! </div></BLOCKQUOTE>

Ooh...rust in the tank...definitely want to check the injectors then. I personally haven't had a little rust clog injectors before, but on a carbureted motorcycle I've found that just a little rust in the tank , even if it doesn't look like much, can cause a lot of problems, and the stuff will go right through your fuel filter.

Also a good idea to check them anyway as a lot of junk usually ends up in the line between building your own tank, injector mounts, etc.

[Mbirt]

As a bump because I'd really like to see this go off-topic too...

Not being able to find an engine and going broke when you find one: twin cylinder problem.

(best one yet) Someone told you you had to use it and pretty soon you'll have Mahle or Suzuki tattoos: 3 cylinder team problem.

[Haseeb]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TMichaels:

If you have a multi-channel oscilloscope, just hook it up to the ECU pins controlling the ignition coils while cranking the engine. That way you should be able to determine the firing order. You still have to check the correct wiring between ECU and ignition coils in that case.

Additionally you should check that injectors and spark plugs are correctly aligned with respect to timing. I once miswired our engine in a way that the firing order of injectors and spark plugs solely was ok, but they where "out of synch". Gave me quite a headache, since the engine seemed to be running ok while idling, but made no power.
</div></BLOCKQUOTE>

thanks tobias, for such a detailed reply http://fsae.com/groupee_common/emoticons/icon_smile.gif
will check the firing order today via multi channel oscilloscope by handling it to electronics guy!

yesterday we had a really weird problem, we started the engine but it was missing wat too much, i saw that i left one ignition coil unplugged, when i connected it engine started idling reasonably good.
so what we did was checked every cylinder if the combustion was proper by unplugging the coils one at a time and found out that by unplugging the 1st ignition coil there was no change on RPM!
1st we verified ignition wires, they were ok then we switched the ignition coils of 1st and 4th cylinder still the 1st cylinder wasn't working

we thought that its a design problem of plenum, but then as an experiment we opened the 1st cylinder to atmosphere (unrestricted) but it didn't rev up. We then switched the 1st injector with the 4th one, now we checked the cylinder working by removing again spark plugs one at a time

this time all cylinders were working except the 2nd cylinder, it was sparking , could tell it because the exhaust header from 2nd cylinder was getting hot but it didn't produce any change in rpm by switching it off

next we took out the fuel rail, cleaned it! sucked all the injectors, switched 2nd and 3rd injectors

this time all the cylinders were working. We are unable to figure out that what is problem!!

also, can you elaborate what did you mean by miswiring, yet the spark plugs and injectors were solely ok and out of synch?
our engine starts at 3500 rpm, remains there for 5 seconds then comes back at 1700 rpm!
from there when i try to increase the throttle , the rpm never goes up

plus we ran a check on exhaust gas analyzer and found out that HC emission were 950 ppm, nearly thrice the standards!!

[Haseeb]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Adambomb:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Haseeb:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ZAMR:
Sounds like a problem we had last year with fouled injectors. Check and clean every single injector or buy new ones, and check to make sure your fuel filter is working properly. If aluminum shavings from your tank enter the injectors they can cause this exact problem. </div></BLOCKQUOTE>

thanks for the suggestion, it might be the problem since our filler neck got a little rusted! </div></BLOCKQUOTE>

Ooh...rust in the tank...definitely want to check the injectors then. I personally haven't had a little rust clog injectors before, but on a carbureted motorcycle I've found that just a little rust in the tank , even if it doesn't look like much, can cause a lot of problems, and the stuff will go right through your fuel filter.

Also a good idea to check them anyway as a lot of junk usually ends up in the line between building your own tank, injector mounts, etc. </div></BLOCKQUOTE>

thanks Adam for the suggestion, i guess it may be the reason for our engine malfunctioning as i described in the above post

do you have any idea how to clean the injectors?
we have a compressor air tank in our labs, capable to produce 250 psi, but i wasn't sure how to clean injectors since its activated through ecu signal, if the rust got at the end, how can i remove it?

thanks

Syed Haseeb Hassan
Formula NED

[PatClarke]

Syed,
Find a workshop that service late model injected cars.
Alternately, find a Diesel injection service shop.
Either should be able to ultrasonically clean and then backflush your injectors (whilst artificially triggering them).

If you can't find such a place, then there is a business opportunity for you ;-)

Pat

[TMichaels]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">also, can you elaborate what did you mean by miswiring, yet the spark plugs and injectors were solely ok and out of synch? </div></BLOCKQUOTE>
It is hard to describe just by using text, but I will try anyhow:
Usually the injectors are open while sucking air into the cylinder and maybe a bit before, somewhere around 360° to 180° BTDC. The respective spark plug for this cylinder will probably fire somewhere around 40° to 20° BTDC (while cranking this could be later). (Please engine guys don't blame me, I am just trying to provide rough values)
If you now hook up the scope to the ECU pins controlling the injector and ignition coil of the same cylinder, these two signals must be aligned with respect to the described timing.
So for example while cranking you may get around 360rpm, which is 60 revolutions per second -&gt; 21600° per second. By just guessing numbers we could assume that the injector closes at 210°BTDC and, while cranking, the spark plug should fire around 0°BTDC while cranking (again, please correct me engine specialists, if I am totally wrong). Therefore I would expect around 10ms (while cranking) between the signal closing the injector and firing the spark. If the time between these two signals is a multiple value of this, your injector and ignition timing is misaligned and you should re-check your wiring.
Was this understandable?

Regards,

Tobias

[BMEP]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TMichaels:


So for example while cranking you may get around 360rpm, which is 60 revolutions per second -&gt; 21600° per second.
</div></BLOCKQUOTE>
Silly EE Math http://fsae.com/groupee_common/emoticons/icon_razz.gif

[Haseeb]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by PatClarke:
Syed,
Find a workshop that service late model injected cars.
Alternately, find a Diesel injection service shop.
Either should be able to ultrasonically clean and then backflush your injectors (whilst artificially triggering them).

If you can't find such a place, then there is a business opportunity for you ;-)

Pat </div></BLOCKQUOTE>

Thanks Pat for a futuristic business advice, i'll surely look into it http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

i found that out national airlines do use ultrasonic rays for cleaning out things, but they do it for Boeing engines http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Haseeb]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TMichaels:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">also, can you elaborate what did you mean by miswiring, yet the spark plugs and injectors were solely ok and out of synch? </div></BLOCKQUOTE>
It is hard to describe just by using text, but I will try anyhow:
Usually the injectors are open while sucking air into the cylinder and maybe a bit before, somewhere around 360° to 180° BTDC. The respective spark plug for this cylinder will probably fire somewhere around 40° to 20° BTDC (while cranking this could be later). (Please engine guys don't blame me, I am just trying to provide rough values)
If you now hook up the scope to the ECU pins controlling the injector and ignition coil of the same cylinder, these two signals must be aligned with respect to the described timing.
So for example while cranking you may get around 360rpm, which is 60 revolutions per second -&gt; 21600° per second. By just guessing numbers we could assume that the injector closes at 210°BTDC and, while cranking, the spark plug should fire around 0°BTDC while cranking (again, please correct me engine specialists, if I am totally wrong). Therefore I would expect around 10ms (while cranking) between the signal closing the injector and firing the spark. If the time between these two signals is a multiple value of this, your injector and ignition timing is misaligned and you should re-check your wiring.
Was this understandable?

Regards,

Tobias </div></BLOCKQUOTE>

A huge thanks Tobias for taking your time out to explain the thing, which i'd say you did it brilliantly, it was actually quite understandable http://fsae.com/groupee_common/emoticons/icon_smile.gif
We'll do it by tomorrow..

P.S: today we started the engine at 30% throttle, it worked pretty fine then. We went up to 10K rpm, the mixture was rich but it gave us a hope that it's ok http://fsae.com/groupee_common/emoticons/icon_smile.gif
but now it has a hard time idling http://fsae.com/groupee_common/emoticons/icon_smile.gif, i believe its due to faulty map!
since if i start the engine anywhere between 0-29% throttle, the engine rpm never goes up!

[Dunkster]

You could get old school and use a timing light to verify that it is firing correctly. I think one of the markings on the engine is 8 degrees before top dead which is the stock idle advance. IS there any way you can physicall observe the spark past 4000rpm? (running it on 3cylinders) We had a problem were we hadnt correctly set up the dwell time for our coils and it stopped sparking effectivly past 8000rpm.