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1998 honda vfr 800 fi fuel injectors


lawnmowerman

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can fuel injectors for my 1998 vfr 800 be purchased at an auto parts store,  and is there anything special i  need to know when replacing them thanks john

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I'll ask what makes you think you need new ones?  Why not take them to a cleaning service, they will flow test and give you a report.  Cheap.

Otherwise I would seek out used ones and take them to a cleaning service......

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You can buy injectors, just not for the VFR. It used the same ones as some honda civic & cr-v models, as well as Suzuki Early Hiyabusa's. As far as I know, the injectors & fuel regulator are NLA for the VFR.

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36 minutes ago, Mohawk said:

You can buy injectors, just not for the VFR. It used the same ones as some honda civic & cr-v models, as well as Suzuki Early Hiyabusa's. As far as I know, the injectors & fuel regulator are NLA for the VFR.

Honda also did that with 6th G coil packs,  the Denso P/N is common to Civic, CRV, and other models,  including Acura. 

 

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just trying to save some money do you know if there are any aftermarket fuel injectors , im under the belief that a new oem fuel injector from honda is around 200.00 and four would be like 700 or 800 dollars , do you know it this is correct. thanks 

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i am a half ass mechanic been wrenching my whole life, but admit that does not make me a mechanic and have never delt with fuel injectors.   my rear left cylinder the spark plug looks like it is not firing it is super clean almost no carbon on spark plug at all  and  the exhaust in the front was hot and the exhaust in the back was half as warm as the front .the bike has almost no power  and i am getting good spark on the plugs . so i am thinking it is a fuel problem since i have good spark. also i live in a super small town 60 miles from the next small town i live in paradise, michigan, so going to a mechanic is a real problem for me,  a honda motorcycle dealer is like a 200 mile round trip one day there one day back . i did not know you could send them out to be cleaned . could you recommend a place to me. 

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There are plenty if you do a search online.  I've used Witch Hunter and RC Engineering.  The former is less expensive but has a month  long turnaround time.  RC turns them quickly - a couple of days.  A USPS flat rate box is just the right size for shipping.  You'll get a before and after flow & spray pattern report from any of them as well as new O-rings.  You will have to remove the throttle body to get at them - anyone can do it.   If you need to buy replacement(s) look at them carefully (may need a magnifier) for the manufacturer part number (Denso?) and search for that - you'll likely get them cheaper that way than from Honda.  

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What makes you think your fuel injectors needs to be replaced?

What is bike doing that’s not normal?

 

Fueling issues can be caused by:

 

- power issues going to injector, cracked harness, shorted wires, corrosion on terminals

- sensor issues: calibration on temp-sensors, adjustments on TPS

- vacuum leaks , really common issue on EFI bikes, messes up carbies too

- fuel-pump: not getting sufficient power due to bad/corroded wiring, or bad pump not delivering sufficient volume and pressure

- clogged fuel-lines 

- clogged fuel-filter


What tests have you done for these and what were results that ruled them out (numbers)?

 

I’ve run into above numerous times on bikes and cars. Have never ever run into bad injectors in my 40-yrs tinkering with cars & bikes. Maybe just needing some reverse-flushing with cleaner and changing screens maybe. Chances of all 4 injectors failing simultaneously is as likely as getting hit by an asteroid. 
 

if one of cylinders is worse than others, basic troubleshooting step is verify all injectors have equal power, then swap injectors with another cylinder and see if problem moves.

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thank you guys for letting me know that i can have my fuel injectors sent out and cleaned.  My bike is 20 years old, is it common for fuel injectors to fail ? im looking to do  the cheap things first. I will look for corrosion on my terminals , check for vacuum leaks, and clogged fuel lines, also is it common for fuel pumps to fail . and how do i check my fuel pump. and it this were your bike what would you do next. my main problem here is that a shop is so far away. thank you for your help i will find my problem. but all of your advice really helps me figure things out and what i should do next. it is hard living out of town but I am determined. thanks

 

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the bike is hard to start and will backfires a little at idle and when the bike is cold.  seems to be sluggish when I let, let out the clutch bike will stall if going up hill . when putting the bike in gear you really have to feather the gas and clutch , seems to run ok  afterwards but never seemed to have that much power , you can tell it lacking something. I cleaned the air filter and touched the exhaust pipes and the rear pipes were cold. i have 4 other bikes  gGL500 ,750 Maxim, CSR 305 all act much better when letting out the clutch and going into gear.

 

 

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Well, many, many problems can cause those running issues with least likely to be injectors. I use these guys to do cleaning. Inexpensive and fast turnaround https://www.mrinjector.us/

 

You get before and after cleaning flow-test report to see what difference is. I build and upgrade lots of turbo engines, mostly Toyota and Porsches. I’ll grab big bag full of injectors from junkyard cars and send in batches of 6 or 8 to get tested (cleaning is just bonus). When they come back, I toss highest and lowest flowing injectors and keep 4 or 6 closest matching ones. They’re usually not more than 1-2% variation across lot anyway.

 

Most likely you have an electrical issue. Very easy to fix, no more than 30-minutes to diagnose if you know how to use multimeter.  So get multimeter and learn how to use it to do basic measurements of voltage and resistance.

 

I guarantee you WILL NOT be able to fix this without knowing how to use multimeter like modern mechanics. Actually pro mechanics have been using multimeter and vacuum gauge to fix engines for over 100-yrs.

 

Well, that is, you won’t be able to fix it quickly and cheaply without using multimeter. You’ll do desperate shotgun pile of parts at it and wish and hope that’ll fix it. And yes, after spending hundreds, thousands of dollars replacing perfectly-working parts with brand-new perfectly-working parts, you might get lucky and randomly replace the one part out of hundreds that may be contributing to your issues. Although nothing may even be bad part at this moment, but may be just an adjustment issue.

 

Using multimeter to test and come up with numbers (to compare with numbers in manual) will allow you to decisively determine 100% for sure if part is good or bad. Testing and measuring will also narrow down and pinpoint the exact cause of issue. This is how pro mechanics do it at shops. If you take bike to shop, they’ll pull out manual and go through step by step measuring things. You can do same thing yourself!

 

For example, test fuel pump by disconnecting fuel-line from fuel-rail and aim into measuring cup. Then jumper fuel-pump to run it for 10-sec. Compare volume of petrol collected with what manual says it should be and you’ll know for sure 100% if pump is good or bad (well, there’s also pressure test). No guessing needed, no buying parts needlessly praying that’ll fix it.

 

Given your bike’s behavior, fuel-injectors is least likely, it’s only fuel-related part most people are familiar with and that must be problem right?

 

Well, most likely your issue is one of following:

 

- wiring fault, break or short. This affects proper operation of fuel-injectors and pump. More likely than those parts being defective.

- fuel-pump, fuel-filter, fuel-pump relay, pressure-regulator & vacuum hose

- sensor out-of-calibration, such as ECT, IAT, MAP, TPS, CAM, CPS

- sensor out of adjustment, such as TPS, CAM, CPS

- vacuum-leak, severely throws off MAP sensor

 

Each and every component has test with numbers to tell you if they’re good or not or out of adjustment. Learning to use multimeter and doing these tests is fastest and most inexpensive way to fix your problem. Might even be only way.

 

 

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The service manual will have an entire chapter devoted to troubleshooting - Hard Starting, Lacks Power, Poor Low Speed Performance, etc - thats a good place to start. You can find the manual online, may even be a link here on this website

 

Look here - https://www.vfrdiscussion.com/index.php?/search/&q=manual&type=downloads_file&nodes=2&search_and_or=or&sortby=relevancy

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Manual will show you how to jump diagnostic port to have dash flash error codes (like morse code). This will flag systems that are malfunctioning and require closer examination and measurements.

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58 minutes ago, lawnmowerman said:

 i will have to read my book  and figure it  out  thanks

 

As in, the factory Honda manual, for that bike, I assume?

 

I recently experienced some similar problems to yours, but I was unfortunately away from home, my manual, my tools etc. I still need to go back and get my bike before diving in more. I made several assumptions about fuel delivery, injectors, etc.(but refrained from just guessing on parts), but I am now leaning more towards either some of the things mentioned above?

 

I will end up first checking things like figuring out which cylinder(s) where the culprit, though I know #4 is highly likely, and do the simple steps of swapping coils/plugs to known good, and see if the problem moves with the swap? If so, then dive into those parts, with the above mentioned multimeter! Had hoped the fuel pressure regulator just crapped out, as that was where most on here initially steered me, but it checked out good. So that was where I left off.  😞

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On 10/24/2020 at 5:29 PM, lawnmowerman said:

the bike is hard to start and will backfires a little at idle and when the bike is cold.  seems to be sluggish when I let, let out the clutch bike will stall if going up hill . when putting the bike in gear you really have to feather the gas and clutch , seems to run ok  afterwards but never seemed to have that much power , you can tell it lacking something. I cleaned the air filter and touched the exhaust pipes and the rear pipes were cold. i have 4 other bikes  gGL500 ,750 Maxim, CSR 305 all act much better when letting out the clutch and going into gear.

 

 

Hi John.

If your right rear exhaust is cool and possibly the front right these are cylinders 3 and 4. A ruptured diaphragm in the Fuel Pressure Regulator will dump excess fuel into those cylinders via the vacuum hose and can cause a cool exhaust for number 3, along with terrible running you seem to be experiencing. A simple check of the vacuum hose off the FPR for raw fuel will indicate a ruptured diaphragm. 

 

It's also fair to suspect poor injector performance with a 22 year old bike. Injector issues (other than an open or short in its coil or wiring) and FPR issues will not be detected by the ECM so there won't be a fault code for these items. So having your injectors cleaned, flow checked etc, would only be a good thing to do given its age.

 

If the ECM does detect even a single faulty injector coil or a fault with its wiring your bike will not run, it will be completely disabled by the ECM.

 

If you start your bike with the Sidestand down and engine at idle, if there are any fault codes within the ECM the Fi light will be flashing the codes. Any sensor that is detected as being outside of known value tolerances will flag a diagnostic code.

Good luck and keep us posted.

Cheers.

 

 

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And as some more background, bought the bike a few months back, got little to no history on it, but it was not very loved by either of it's previous 2 owners ...  younger then older brother. I went through it quite a bit, fixing lots and lots of little issues, cleaned the CRAP out of everything, and just lots of little things ... mostly giving it some of the love if probably hadn't seen since what I assume was around 2005-6? LOL! Bike always ran great, motor wise(for a 20 year old/70k bike), and I had just mostly been doing smaller rides on it, 'til I decided to head to the hills, and visit my sister/brother in law. Went for a couple good rides up there, and ride #3 ended up with me stuck on the side of the road, in a valley, with a bike that refused to pull ANY hills!

 

Regardless, for my money/time invested in this bike ... was a great bunch of rides ... and she's NOT dead yet!! Was laughing, because when I tell people of my plight that day, they're always saying "oh that sucks", or "what a shitty day"! Quite the contrary! Was a GREAT day, just the last 5-6 hours to wait/figure out how to load it into a truck with NOTHING close to the right stuff, and getting back to the house SUCKED!! The 5-6 hours before that was pure bliss!! 

 

Plus, even if it is something catastrophic, I know I can pretty much break even selling it as a roller or parting it out!!   :-)

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14 minutes ago, Grum said:

Hi John.

If your right rear exhaust is cool and possibly the front right these are cylinders 3 and 4. A ruptured diaphragm in the Fuel Pressure Regulator will dump excess fuel into those cylinders via the vacuum hose and can cause a cool exhaust for number 3, along with terrible running you seem to be experiencing. A simple check of the vacuum hose off the FPR for raw fuel will indicate a ruptured diaphragm. 

 

It's also fair to suspect poor injector performance with a 22 year old bike. Injector issues (other than an open or short in its coil or wiring) and FPR issues will not be detected by the ECM so there won't be a fault code. So having your injectors cleaned, flow checked etc, would only be a good thing to do given its age.

 

If the ECM does detect a even a single faulty injector or its wiring your bike will not run, it will be completely disabled by the ECM.

 

If you start your bike with the Sidestand down and engine at idle, if there are any fault codes within the ECM the Fi light will be flashing the codes. Any sensor that is detected as being outside of known value tolerances will flag a diagnostic code.

Good luck and keep us posted.

Cheers.

 

 

Hey Grum,

 

You suggested the same to me when I had my issues(the FPR possibilty), and I had hoped that would be it ... but no such luck. So I tore it down a bit more, just looking for any of the obvious, but nothing stuck out, so I called it there. Bike is at my sisters, and with my limited space/resources and mainly tools, I decided diving into it further, taking it more apart was not in my best interest. Rather load a more complete bike into the trailer, and also not have more bits sitting around a house that's not mine! I'll likely do another check on the FPR when I get it home, but I had drained the oil out of it, because the fuel had contaminated it. So, like I said, I left it alone at that stage.

 

Back at home now after my extended stay, need to sort out my trailer, and go round her up in the next week or so?

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27 minutes ago, MJH said:

Hey Grum,

 

You suggested the same to me when I had my issues(the FPR possibilty), and I had hoped that would be it ... but no such luck. So I tore it down a bit more, just looking for any of the obvious, but nothing stuck out, so I called it there. Bike is at my sisters, and with my limited space/resources and mainly tools, I decided diving into it further, taking it more apart was not in my best interest. Rather load a more complete bike into the trailer, and also not have more bits sitting around a house that's not mine! I'll likely do another check on the FPR when I get it home, but I had drained the oil out of it, because the fuel had contaminated it. So, like I said, I left it alone at that stage.

 

Back at home now after my extended stay, need to sort out my trailer, and go round her up in the next week or so?

Did you try having the vac hose off the FPR turn on ignition to prime the fuel rail, did you see any fuel drip from the FPR?

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9 minutes ago, Grum said:

Did you try having the vac hose off the FPR turn on ignition to prime the fuel rail, did you see any fuel drip from the FPR?

Yeah, tried that, a few different times, and even added a bit more gas to the tank to be sure it was getting to the source? Like I said, when I get her home, I'll go through that test again, and crack the fuel line at the rail to be sure it's actually primed. I can get the bike to run, to be sure it's getting fuel through the system again, but that will likely cost me another few quarts of oil? Likely will anyways, just to make things easier to diagnose, if I can keep the fuel contamination into the oil at a minimum?

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21 hours ago, Grum said:

Hi John.

If your right rear exhaust is cool and possibly the front right these are cylinders 3 and 4. A ruptured diaphragm in the Fuel Pressure Regulator will dump excess fuel into those cylinders via the vacuum hose and can cause a cool exhaust for number 3, along with terrible running you seem to be experiencing. A simple check of the vacuum hose off the FPR for raw fuel will indicate a ruptured diaphragm. 

 

It's also fair to suspect poor injector performance with a 22 year old bike. Injector issues (other than an open or short in its coil or wiring) and FPR issues will not be detected by the ECM so there won't be a fault code for these items. So having your injectors cleaned, flow checked etc, would only be a good thing to do given its age.

 

If the ECM does detect even a single faulty injector coil or a fault with its wiring your bike will not run, it will be completely disabled by the ECM.

 

If you start your bike with the Sidestand down and engine at idle, if there are any fault codes within the ECM the Fi light will be flashing the codes. Any sensor that is detected as being outside of known value tolerances will flag a diagnostic code.

Good luck and keep us posted.

Cheers.

 

 

Thank you Grum . I will have the injectors sent out.  in a couple weeks ,with all my complaints the bike ran fair i could drive it. i took the fuel injectors out and tried to clean them .I think I shorted one out , the wires touched when cleaning with the battery and arked. but after i put the fuel injectors back in and tried to start the bike up it ran for 30  seconds and now wont start and backfires a shit load.  i do think i got all the hoses back where they belong ? so i think the best bet is to send them out to be serviced. because at least before  i took them out of the bike was running .fair to poor

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     My train of thought is that the bike ran 10 times worse after taking out the fuel injectors and putting them back in .  I obviously did something wrong .  I will send the injectors out to make sure they are ok. put them back in and see where we stand , i  will also check the fuel pump. after i get them back i will keep you informed . thanks for the little bit of information here and there it really helps

 

 

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2 hours ago, lawnmowerman said:

     My train of thought is that the bike ran 10 times worse after taking out the fuel injectors and putting them back in .  I obviously did something wrong .  I will send the injectors out to make sure they are ok. put them back in and see where we stand , i  will also check the fuel pump. after i get them back i will keep you informed . thanks for the little bit of information here and there it really helps

 

 

Don't laugh but have you definitely placed the correct plug onto the correct injector? Don't forget, have a very close look at that Fuel Pressure Regulator as mentioned.

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Another thing to check is that the vacuum hosescare attached to the airbox stub holders ! Easy to forget & causes a vacuum leak. 
Are there any Fi light or codes ? 

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