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Injector at 100% Duty Cycle @ 4k???

6K views 35 replies 9 participants last post by  arizonawarrior 
#1 ·
Can anyone explain to me why my injectors are running at 100% duty cycle at 4K-5K RPM's. I have no big bore kit, no head work. Mods are Speedstar Stacks, PCS Monster Pro-Pipe dyna coils and wires. Got lots of air, no more fuel to match it, PCIII is maxed out in that RPM area. AFR graph goes straight to sh!t and lean at 4k onward. I thought the injectors were good till 100+hp im not even close, unless that 100+hp is at the engine not the wheel. I only have 7k miles on the bike. Can they be shot already? Need some advice please.
 
#2 ·
I have no mechanical expertise...so take this for what its worth, but my Yamaha EFI 250 hp outboard recently was having a fueling isuue at high load and rpm's. I looked everywhere to trace the problem from the pick- up tube in the gas tank, through all the fuel filters, fuel lines, low pressure pumps, vapor separator tank...everything checked out, but I was still experiencing the uneven fueling at high rpm and load( ran fine in neutral). A Yamaha mechanic, who is a friend of mine, came over and pulled the filters inside the injectors...problem solved. The service manual schematic does not show this part, but the injector can be pulled apart and a small plastic ring is visible which can be pried or pulled out. This filter is shaped like a long thimbal. If care is taken in removal, they can be cleaned and reused. My mechanic friend told me that, without exception, he always just throws them away whenever he services the fuel injectors. I have kept them out and my engine has never run better. Good luck.
 
#4 ·
Maybe ill look for a used set and send them to mps for cleaning and install come winter time. Not tearing bike apart for my short riding season here. Just wont ride as crazy as I usually do and keep it under 4k :(
 
#5 ·
#6 ·
I am currently getting 110hp and 133ft/lbs torque with the PR 110" and speedstar cam. Although my map is also @ 100% fuel on the upper (5000 and above) rpm and 100% throttle with the stock injectors. My bikes an 06 with about 30,000 miles. I was concerned with this altough the hp and torque we very good. I suspected that the injectors need to be cleaned/flowed in the off season.

A while back, after the custom map, I was playing with NOS and drag racing and installed a Walbro hp 250 Lph fuel pump for more fuel supply for the increased NOS. It raised my fuel pressure about 43 psi to 48 psi. I would not really recommend the fuel pump install as although it works fine, it requires some ingenuity to install as the pump is slightly longer. I'm just mentioning this because although the bike still pulls strong I now have a slightly richer plug reading and don't seem to get the same mpg.
The bottom line is I think you should get your injectors cleaned and flowed ( especially if you got years or miles on your bike) before you get your final custom map. I plan on getting my injectors cleaned and flowed and my PC remapped this winter.
 
#7 ·
As I said in original post bike only has 7k miles. Additional info is it is an '07 but only in service since May '09 with 12miles when I bought it new. The injectors can't be dirty. Too many filters before fuel even gets to the injector pre-screen. Its strapped to the Dyno now getting tuned and we ran into this.
 
#9 · (Edited)
I am getting my best power/driveability with the speedstar injectors and an aftermarket fuel pressure regulator. 38# (for me) ended up being the magic number. The factory fpr did not give a consistent pressure.

I actually think that I can get a bit more power by tieing the fuel pressure to the manifold vacuum, ie wot=low manifold vacuum=higher fuel pressure and the inverse for low and mid rpm.

The rains have finally quit so that project is put off for a bit.

By the way, my stock injectors were maxed on the duty cycle also, I do have engine work, tho.
 
#11 ·
Give it a try you might like it, mine has been connected in that manner
since about '03 :~)
How did you go about doing that? What was needed? I am not changing the injectors till winter time and just going to ride the bike like a normal person this season.
 
#14 ·
This is why it is important to check your plug color; mid-rpm, partial throttle is "cruise"
You want that to be as lean as is safe to extend the mileage on these "100 miles-to-fill-up-creatures".

Hey, Google end-of-line pressure regulators to get a handle on the concept of how these regulators work; it will make your thoughts on this easier on you.
 
#16 ·
I am still looking for more input from anyone with understanding on this subject. The more chatter I can get going in this thread the better off I can be in pin pointing what the heck is going on.
 
#23 ·
I don't mind the hijack, but any insight to my problem? Any ideas? I just got the speedstar injectors today in the mail. If I install these with the new FPR they come with and still have the same issue I'm gonna be pi$$ed. Gonna test the OEM FPR with a pressure gauge to see if I have full pressure all the way to 5k to make sure it isn't the pump or clogged filter (thank you repsol!). Anyone else have any ideas?
 
#26 · (Edited)
Update:

Went to a new dyno shop today and got confirmation that my bike runs fine and indeed does NOT need injectors. Over the last 2 months or so I checked over things and paid attention to any noises or driveablity issues. Plugs looked fine, bike pulled strong to 5k rpm's, and seat of the pants felt fine so I made my appointment to bring it to a different dyno shop three weeks ago. I did an oil/filter change and put in new NGK Iridium spark plugs gapped to .028" in prep for the dyno session. Brought it in today and the did the evaluation and I was running lean in areas, but no where near the areas or as severe as the last guy stated and well within the tunability of the PCIII. A new custom map will be done and I will be set for a while. Glad I got this issue resolved :).

I want to thank everyone for their help and input and most of all repsol61 for all the back and forth emails and all the information he shared with me about the Warrior's fuel system and trouble shooting tips!
 
#27 ·
Thanks for the recognition, my friend; by the way, if you plan to do internal mods to your bike you might want to save those injectors. Justin and have both (independently) found them good for that little bit extra when all the stage 4 mods are done.

I'm glad that you found a path to solution. Sometimes you have to change horses. (Or tuners, in this case)
 
#31 ·
Thanks for the recognition, my friend; by the way, if you plan to do internal mods to your bike you might want to save those injectors. Justin and have both (independently) found them good for that little bit extra when all the stage 4 mods are done.

I'm glad that you found a path to solution. Sometimes you have to change horses. (Or tuners, in this case)
I will not be doing any internal mods. I am done with adding power to the Warrior. I have started saving for a Yami sport bike to do track days with in a year or two. I plan to attend some track schools before I even go to a track day by myself to learn proper track etiquette, and riding techniques to ride aggressively yet safely and have fun. I'm young so it would be good to start this now learn riding skills and have a lifetime occasional weekend hobby.
 
#30 ·
NEWS FLASH!!! This week I discovered that the injectors on the 96 Landcruiser are the same style as the Warrior. The o-rings and seals for the injectors are the same as ours. Finding those seals/o-rings has been a issue.
Hey Arizonawarrior, can you put that little tidbit of info in that lovely Popular Mods you compiled?
 
#33 ·
While doing an overhaul on my brothers landcruiser; and as I was installing the new seals on his injectors I couldn't jhe;lp but notice that they looked similar to Warrior. I walked to my tool box a got one of my spare injectors and my dial indicator calipers. Yes the seals and o-rings are exactly the same size. The injectors physically look the same (electrical connection, method of attachment and size but are a different color.) I, honestly, did not check the brand, but other than the color they look identical and I miced the critical points and they are the same.

As I stated earlier, this is a 96 Toyota Landcruiser, and the engine is(was) virgin.

By the way, Landcruisers are over-engineered, very over-built machines. This one has over 200k on it and had a warped head due to a broken water hose. I found one valve leaking slightly and no ridge at the top of the cylinders. I believe it is good for another 150k before I put rings in it.

Odd head torque; torque to 45#, tighten 90 degrees, tighten another 90 degrees. That ends up somewhere way North of 200 pounds. Unique.
 
#35 · (Edited)
So the 11mm seal kits might interchange, assuming both are viton, but the injectors as a whole may not because its possible they are different internally (spring rate, internal dimensions, etc). The energized duration is ecu controlled but the injector's internal coil might be different.

I'm anxious for someone to actually try these Land Cruiser seals . . . but is this confirmed to a point you want to recommend it?

[added] I'll add this to Popular Mods, it will post with the October update:
Fuel Injection '02-'10 - Repsol identified 1996 Toyota Land Cruiser injectors appear same as Warrior so seals may interchange?

While doing an overhaul on my brothers landcruiser; and as I was installing the new seals on his injectors I couldn't jhe;lp but notice that they looked similar to Warrior. I walked to my tool box a got one of my spare injectors and my dial indicator calipers. Yes the seals and o-rings are exactly the same size. The injectors physically look the same (electrical connection, method of attachment and size but are a different color.) I, honestly, did not check the brand, but other than the color they look identical and I miced the critical points and they are the same.

As I stated earlier, this is a 96 Toyota Landcruiser, and the engine is(was) virgin.

By the way, Landcruisers are over-engineered, very over-built machines. This one has over 200k on it and had a warped head due to a broken water hose. I found one valve leaking slightly and no ridge at the top of the cylinders. I believe it is good for another 150k before I put rings in it.

Odd head torque; torque to 45#, tighten 90 degrees, tighten another 90 degrees. That ends up somewhere way North of 200 pounds. Unique.
 
#34 ·
Those odd torque procedures are more common in heavy equipment and aerospace.
Isn't there one Warrior fastener that gets torqued then add a quarter-turn?

Then there's the steering ring nut on the Warrior (and other bikes) where it gets tightened to a stated spec and then completely loosened, then re-tighten to the stated torque. Its all in the details . . .
 
#36 · (Edited)
I added a line item into Popular Mods in keeping with several PM's and emails on this topic.

The o-rings (seals) for the 96 Land Cruiser injectors appear to fit the Warrior injectors although no installed-and-riding test has been done. Many thanks to Repsol for his sharp eye in noticing and comparing!

The injectors themselves appear identical except for color, although the inner workings may or may not be identical they will very likely physically fit. They may spray more fuel, or less fuel, or the same amount of fuel, depending on the coil windings and the fuel passageway dimensions.

I couldn't locate the Land Cruiser's fuel pressure regulator pressure rating, or the Land Cruiser's injector presure rating, from reputable sources so I can't speak to the Land Cruiser injector's fuel pressure rating versus the warrior's.
 
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