Landracing Forum
Tech Information => Technical Discussion => Topic started by: Jessechop on August 09, 2012, 10:08:28 PM
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Bad stumble/miss at 7500 rpm, will just fall flat by 10k. #1 is bad rich, #2 is clean, like no fuel clean, 3# and #4 look good. All have spark, all coils test ok allthought have no been swapped out. Injectors cleaned and look to spary ok. Voltage checked at injectors and checked good
Leaning towards injectors obviously, just dont want to spend the money if I am over looking somthing. Thoughts? Ideas?
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Is there a Power Commander inline? If so, try without it.
All cylinders leak down OK?
Fuel pump OK?
Injector cleaning is $25 each at MPS racing, 1 day turnaround.
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No PC
Yes on cyl. test
No on F/P. I assumed (yes I know :-D) that that would effect all cylinders, but no big deal to test.
Thanks for letting me know about MPS
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swap the injector into another cylinder.... if the problem stays in #1 then swap the coil. If you are at the salt I have injectors and coils with me. Car 1000 pitted back row middle but you will find us in line most of the time.
they should look really clean all the time, with just a touch of color
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Thanks for the help.
Looks like the ECU is the culprit :?
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Jesse --- You going for the big engines now?
Joe
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For Sept. Blew up the 250 in good fashion and turn around time on having the cylinder done to my liking wasnt going to work. So long story short I ended up with a GSXR drag bike :roll:
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Allright, I need help :?
Swap injectors, same problem on same cylinder. #2 is not getting fuel. Swap coils (thinking that may control the injector) same
Swaped out ecu's, same
Check wiring and all connections, same
Really at a loss, code c26 for loss of ignition from that cylinder. Have no idea what to try next. Harvest event is 2 weeks away and looking very bleak :oops:
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could a pickup , sensor or timing wheel on the cam or crank be the culprit?
i might not be a whole lot of help on metric motors.
franey
maybe a bad cam lobe on that cylinder?
good luck with that. hope to see you running at limestone.
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Can you swap the wires from one injector to another leaving the injectors where they are?
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Wiring as Jon Suggests? You perhaps just check resistance down the looms with a multi meter.
Is it running coil on plug (cop)? Have you changed out the plugs?
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Jesse check that you have not left a shop rag or paper towel in that cyl's inlet. I done that once.
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Thanks for the suggestions! To answer some questions:
Crank sensor/pickup is fine, or so the manual says. Basically it works or dosnt and controls all cylinders not just one.
Compression is even across the board letting me belive valve adjust, etc. is fine
Cant swap injector harness as that ultimatley effects the fuel timing, however if I jump power from another injector to that one (basically the same thing as swapping) it will spray
Coil on plug, have checked resistance through the entire loom on injector and coil side
Have not changed plugs but have taken the plug from the "bad" cylinder andput onto "good" cylinder and missfire stays on original cylinder leading me to belive it is not the plug.
Thanks for the suggestions! Greatly appreciated
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Bad stumble/miss at 7500 rpm, will just fall flat by 10k.
How is it behaving up to 7.5K? Running smooth no miss? Sounds sweet?
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Cant swap injector harness as that ultimatley effects the fuel timing, however if I jump power from another injector to that one (basically the same thing as swapping) it will spray.
So the injector and fuel supply are good on number 2.
Jump number 2's wires to 1 or 3 and see if they squirt.
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Bad stumble/miss at 7500 rpm, will just fall flat by 10k.
How is it behaving up to 7.5K? Running smooth no miss? Sounds sweet?
No, it is dead all the way through. Just not that noticable untill upper rpms. Water test on the pipes vaporize on 1-3-4 but just sits on #2. I assume there is a miniscule amount of fuel comming through that injector
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Cant swap injector harness as that ultimatley effects the fuel timing, however if I jump power from another injector to that one (basically the same thing as swapping) it will spray.
So the injector and fuel supply are good on number 2.
Jump number 2's wires to 1 or 3 and see if they squirt.
Yes and yes it does
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#1 is bad rich, #2 is clean, like no fuel clean, 3# and #4 look good.
Any chance that either the #1-#2 coil leads or #1-#2 injection leads have been swapped over one to the other?
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Checked and all is good
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Valve clearances checked? I know you said leak down proved okay but I would check anyway, they can be close to open and still pass leak down test, if you know what I mean. Other than that... no idea! lol... :?
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Valve clearances checked? I know you said leak down proved okay but I would check anyway, they can be close to open and still pass leak down test, if you know what I mean. Other than that... no idea! lol... :?
that is a direction I plan on heading today when I get the chance to. Compression is good, but who knows
Thanks for the help, greatly appreciated from all of you!
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Let us know how you get on with it, :cheers:
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Just a quick update for all of those following :-D I was just able to test fuel pressure and it tested out perfectly at 43 psi, doh! I just wish somthing, anything would show itself. Not even about racing anymore, just fixing the darn thing! :roll:
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Looks like a previous owners "fix" may be the culprit :x well happy actually. Looks like a $#&^%^& T tap was the culrpit, grrrr. We will see
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No real experience on newer bikes [my newest is a '71 BSA Thunderbolt], but here's a few long shots...
Any chance of an excessive air leak into the #2 intake tract?
I've had duff coils on my Ford V-10 that wouldn't trip code on the OBD 11 or some scanners, would miss under light loads but seem to fire fine otherwise, change 'em out and the driveability problems went away.
If you can, do any compression checks or leak downs hot, I've had small cracks in pistons that didn't really open up until they got hot.
Yes, keep us posted on what you find, this one has me curious.
Ed
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Well it runs on 4cyl now :cheers: The wire crimp-t-tap half assed deal the p/o did was the problem. Push wire it connects, other wise there is no connection. Fixed that, runs very nice now, very sanppy up untill 5k then it bogs like it is out of fuel :roll:
Who knows what I am chasing for a problem now, but at least progress has been made.
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The wire crimp-t-tap half assed deal
I hate those crappy things !!!!
Fred
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Jesse - One bite at a time ... all 4 firing is a good start ... if there is sub standard work in one area there could be more. I suggest you go thru all the obvious connections, sensors and lines ... Joe
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Jesse - One bite at a time ... all 4 firing is a good start ... if there is sub standard work in one area there could be more. I suggest you go thru all the obvious connections, sensors and lines ... Joe
Yep. When I first got this bike the fuel smelled terrible so I changed it (bike had been sitting for 2 years).
Then when I pulled the pump the thing was packed with rust (see FB photo)
Then I found the broken wire, then it acted like no fuel. So I pulled the pump and drained the fuel again. The fresh fuel looked like coffe! So I cleaned the tank and pump as best I good, fresh fuel and BAM! She runs like it is supposed to now.
So, fingers crossed, looks like it will be at Loring. The 2 club sends me home on top of the world, but I dont think I have the HP to do it. So my "realistic" goal is a "B" licence, ok "C", lol
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Jesse ... look forward to seeing this monster run ... you might be faster if you had a better haircut.
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Jesse ... look forward to seeing this monster run ... you might be faster if you had a better haircut.
HAHAHAHA, wind tunnel testing says otherwise :-D.
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Jesse
Bit of a late reply but the gsxr's and other Suzukis of a later vintage have an issue with the fuel filters blocking
and as the regulator is post filter its difficult to tell as your line pressure will be at 43 but flow is minimal when needed
this also puts a lot of strain on the pump, as it could be pushing 60 or even 70 psi to get 43 and wears prematurely
Why Suzuki only sell therm as i set i suppose
The filter can be cleaned for an improvement , basically back flush it and shake the shit out of it several times untill it at least flows something
only a tempory fix, and for long courses like the salt or Loring where good supply is critical it my be best looking for a replacement