2007 VFR is crapping out!

[John Kiewicz]

I have a 2007 25th Anniversary (red/white/blue) VFR that has just taken a turn for the worse. A few weeks ago I started noticing a slight engine hiccup every now and then at part throttle. I parked the bike for a few weeks and then fired it up today for a 20 mile ride.

While the bike starts and idles fine, when I get the revs around 5,600 rpm the engine starts breaking up big-time. It's not a backfire of any sort, more like a rapid on/off cut-out as you try to increase revs. If I sneak up on the cut-out rpm it is less violent than if I go WOT. If I am stopped with the clutch in and rev the engine, it will go to about 6,500 rpm before crapping out.

While it could be a fuel issue (injector problem and/or electric fuel pump problem), the cut-out seems to be occurring quicker/faster than is normally experienced with a fuel delivery issue. Thus, I think it is an electrical issue.

Interestingly, as I rode the bike it seemed to slowly heal itself (to some degree) as when I started the ride I could not go over 5,500 rpm ... but by the end of the 40 minute ride I can go to about 6,100 rpm.

Any idea what it could be?

Ideas:
1. malfunctioning throttle position sensor
2. some rev-limiter issue
3. a general electrical gremlin
4. a short with the on/off switch
5. an ECU short
6. a problem with the fuel injector harness
7. water in some connector, wiring harness, etc.
8. water in the intake system (air filter box, air filter, or such)
9. does a 2007 Interceptor have a mass air flow meter? If so, maybe the hot wire is screwed up (this once happened to a Buick GN that I owned and the car ran like crap and wouldn't rev)

Are there any factory Honda mechanics out there who can shed some light on this bad situation? Anybody else ever experience this with their VFR.

Oh, also ... a few months back the VFR's stator crapped out and was replaced under warranty. Any chance that something got fried and/or screwed up in the process?

Help!

John

[Rollin_Again]

Does the bike have a power commander on it by chance?

Regards,
Rollin

[John Kiewicz]

It does not have a Power Commander.

The VFR is bone stock with the exception of a K&N air filter (for the factory airbox) and Dunlop Qualifier tires.

[jasonsmith]

Is your air cleaner box clean, meaning that a family of mice have not moved in with all their belongings?

[jasonsmith]

Unless you have fiddled with the electrical or fiddled with something close to the electrical I think the odds of it being a problem is unlikely. I guess water could have made it's way in but it too IMO would have had to have been a real "wet" situation.

You can test the fuel injection by jumping the test plug and reading any codes that it flashes.

[pjvtec]

FI light on? Does you bike qualify for the harness update? I think it was the headlight harness.

[steven113]

at the rpm range you are saying is just before the vtec kicks in... my guess would be the ecm itself. if your bike is still covered by the dealer take it back and have them deal with it.

[John Kiewicz]

Unfortunately, the bike went out of warranty the day after the stator went out ... no kidding. Then, a few weeks later the cam chain tensioner gizmo broke and needed to be replaced.

The bike ran fine after the repairs, but now it's crapping out. Tomorrow morning I'll pull the seat and pull the air filter to check for water, goop, etc. ... but I doubt that's it as it would have to be quite a bit of dampness for it to affect the bike that much.

Something else is up.

Help!

[Billygoat]

The problem as you describe it sounds somewhat similar to a problem I had with my car - a '98 Honda Accord. It would accelerate to about 120 km / hr but couldn't go past that speed. Sometimes when I tried accelerating hard at lower speeds, it couldn't even make it past 80 km / hr. I took it to different places and was told it was probably the transmission; or the fuel line; or the fuel pump (or filter?). It was none of those things - it turned out that the catalytic converter had broken into pieces, and those pieces, as the engine revved higher, would block the fuel line. I understand that the 6th generation VFR's have cat. converters, but I have no idea if they work the same way as the ones in cars...but I thought i'd mention it due to the similar sounding problem. Note however that my problem wasn't that the engine would stop revving - it could rev - but that there was no power getting to the wheels. So in fact if your engine is cutting out as opposed to power not getting to your wheel, it must be a different problem....

[steven113]

the converter is another viable option... you should get rid of that thing anyways :)

[VFRBenny]

Pull the air cleaner and try a run. If that does not help, than check the fuel pressure.

[mrich12000]

Ask the gang for info how to Read trouble codes. start from there as you should have logged some codes

[motorhead1977]

I posted in the other thread on this: Help!

Here are the FI diagnostics pages from the service manual - at least you will be able to get the codes, if any. Then PM me and I can scan or let you know what those codes mean.

[dizzy]

If there's anything in the diagnostic memory, your FI light probably would have come on at one time or another. Since about 05, Honda has relied on their HDS (dealer only, mini-computer with their special software) to read the diagnostic memory. It seems on some bikes it may (emphasis on may) still be possible to read diagnostics by counting flashes, but the HDS has much more complete info, and it's possible to hook up and ride to observe the failure under 'real time' conditions. Anyway, there are many failures that may not register on either diagnostic tool.

The first thing I thought when I read your symptoms, was loose battery terminal or system ground. I know it's simple and obvious, but it hasn't been mentioned. BTW, I've seen this be the problem with similar symptoms more than anything else. A good clue is erratic tach needle swings associated with the miss.

It sounds like your bike has been apart a couple times recently (stator, filter, tensioners). Were I you, my next step would be pulling body work and checking connectors. All have locking mechanisms and they must be pushed completely together or you'll eventually have a bad or intermittent connection at that point. If you can pull them apart without depressing a tab, you've probably found your problem. Also look inside and behind the connectors for a wire that has been pushed out when the connector was joined, I see that on occasion. Make sure to check the essential ones like crankshaft position sensor, cam position sensor, main relay, bank angle sensor, fuel pump connector, ECM connectors, coupler on the fuse box, ignition coils (BTW check sparks and resistor cap connection also), subharness connections for fuel injectors and coils, etc.

[John Kiewicz]

Dizzy,

Thank you so much for the advice.

I am going to comb over the bike right now. I'll start by looking for any codes via the FI light. If nothing appears, I'll start by checking the air filter, air box, the battery connection (FYI: when they replaced the stator they also replaced the battery as the stock one got nuked when the stator went out) and any/all wiring connections.

[rc24rc51]

i'd run some fuel injector cleaner thru it with a tank of fresh gas before pulling it all apart. if the bike happens to be sitting more than it's being used you could have some injectors starting to clog. Seafoam.

[John Kiewicz]

OK, here's the update. Per numerous VFR's suggestions, I first started by checking for a blinking FI light ... all seems fine.

I just performed the following:

1. Removed seat and gas tank, then checked all visible wires/connections. All seems fine.

2. Checked the tightness of/connection of the battery wires. All seems fine.

3. Checked the connection of the spark plug wire setups. All seems fine.

4. Removed the air cleaner lid to check/inspect air filter and airbox. All seems fine (no dirt, water, oil, etc.). While off, I blew out the air filter, wiped down all aspects of the airbox, removed the carburetor inlet trumpets (checked, cleaned), and removed the entire airbox assembly from the carbs. All seems fine.

5. Inspected, cleaned/wiped the carb inlets, throttle blades, etc. Verified proper/full opening of carbs at WOT. All seems fine.

6. General look-over of everything. Nothing seems loose, cut, melted, pinched, etc. All looks fine.

7. Fuel tank has plenty of gas and visual inspection doesn't show signs of any water or oil in gas.

8. I tried to check the wires that go to/from the stator ... however, without removing the factory cowling/bodywork its hard to see.

Any suggestions from here?

Should I investigate the possibility of a plugged/broken fuel filter? Any advice?

I'm wondering if I should replace the spark plugs since they are (somewhat) easily accessible at this point ... as the fuel tank, seat, intake box, etc. are removed?

Also, although completely unrelated, is there any performance advantage (or disadvantage) to removing the factory rubber inlet boot that hooks to the top of the airbox? Any advantage/disadvantage to disconnecting and/or removing the flapper door assembly on the top section of the airbox?

Any advice would be appreciated.

Thanks,

John

[John Kiewicz]

Short of pulling off the front cowl to check/inspect the wire(s) going to the stator, I've done about all the checking that I can do ... including checking two of the four spark plugs. Everything appears to be fine.

Then I reassembled everything, started the bike, let it warm up, revved the engine a bit and .... it still continues to crap out.

The only other thing that I can think of is that one or more of the spark plug coil packs is on the fritz.

This is starting to get irritating.

[NorcalBoy]

my initial thought is a MAP sensor or timing advance related issue. could also be loss of fuel pressure...i'm pretty sure that the above would have tripped the fi light...all except the timing advance issue. Ignition pulse generator......this can be tested with a timing light.

[dizzy]

Did you actually unplug and inspect the pertinent connectors? You're probably not gonna find some types of issues unless you do. That would include removing any bodywork necessary to acces them. To really inspect the connections thoroughly, you can purchase a 'fit' tool from Honda special tools. It's basically a key ring with the commonly used 'male' pins, allowing the user to check for a loose fit on individual pins INSIDE connectors. Sometimes, really weird and hard to find problems can be traced to this very thing (longshot though).

Hmm...you're right NCB, the MAP sensor should trigger the FI light. But that makes me wonder about the intake manifold itself. Probably be a good idea to check the throttle bodies to make sure they're pushed all the way in the boots, and put a tool on the clamps to make sure they're all tight. Been there with a VTX 1800 that had me stumped for awhile.

I could be off track but I got a nagging feeling it's related to a poor connection somewhere. You know the earlier six gens had that harness recall. John...although yours isn't included, you may want to do a search and view some info on it. The tell-tale connector is a blue multipin connector inside a boot just on the left upper part of the frame...kinda right underneath the left throttle grip. It's a group of ground wires and part of the recall was to inspect THAT specific coupler for burning of the pins inside. I actually saw one that was damaged and it DID cause running problems.

BTW, the wording of the recall is such that the front cowl harness is automatically replaced, but if the blue connector is damaged the main harness is replaced as well.

[John Kiewicz]

I work at Honda's North American headquarters (on the automotive side) so today I talked with the guy who is in charge of the current VFR. I explained what was going on, what I had already checked, and such.

In short (pun intended), he said that it's likely one of two electrical things:

1. A ground issue. However, if it was/is a ground issue then it would affect the entire bike when the engine began to crap out. Thus, he had me free rev the engine until it crapped out while simultaneously watching the front headlight. If the headlights flickered and/or conked out ... then it was a ground issue.

My headlights are fine.

2. His hunch is a faulty Camshaft Position Sensor. Either one of the position "tangs" on the cam is bent/broken or the sensor itself is faulty. Later today we are going to put a scan tool on the bike, rev it until it craps out, and then do a "capture" of the data to analyze the problem.

While I won't be happy if I need to replace the CPS (which is located on the front of the rear head in the "V valley" between the two cylinders ... which is not overly easy to access), at least I'll have the issue figured out! I'll report later with my learnings.

[dizzy]

You're lucky to have access to such resources. I've taken a course at the training center there in Torrance and it's quite a facility. If you can get a product specialist to help you out you 'got it made'.

Yea...the HDS tool is nice that way. You could also hook up the 'button' , go for a ride and take a 'snapshot' of the data list directly during the failure and then examine. I think you can read cam and crank position sensor voltages even if they don't set a code. Please do let us know when you find the problem...and how it was determined.

[John Kiewicz]

Dizzy,

That's exactly what we are going to do tomorrow. First, we'll use the scan tool to check for any codes. Then, we'll do a "snap shot" so that he can determine exactly what item(s) are being affected during the crapping out above 5,600 rpm.

I'm hoping to get the bike fixed ASAP as I was planning on riding it to the NHRA Finals on Saturday.

[John Kiewicz]

So here is the latest update. A HDS tool was hooked up and revealed that no codes had been thrown. Next, the bike was fired up and a 30 second "snapshot" was taken of the engine operation ... during idle, part throttle, mid throttle and (of course) in the rpm range where the bike craps out.

Looking at the data, (according to my contact) everything looked fine with the exception of the throttle position sensor (TPS) voltage was all over the place. In steady state the "curve" looked ok, but with any movement of the throttle the values went up/down like a richter scale.

Although it could be due to a loose wire connected to the TPS, he didn't think that was it (he said a voltage change in the TPS would throw a code ... which it didn't). Thus, he thinks it's a bad TPS unit. At this point, it is still a guess ... and an expensive guess as it appears as if you can't simply buy a new TPS sensor as it only comes sold bundled with a with the overall throttle-body assembly. Can you say big $$$!

Questions:

1. Has anybody ever had or heard of such a TPS problem?

2. Does anybody know a way to buy just the TPS sensor without buying the whole throttle-body assembly?

3. Does anybody happend to have a used TPS sensor and/or throttle-body system for a 2007 Interceptor (maybe off of a crashed bike or a blown motor)?

4. Anybody else have an idea what it could be?

[Action]

The TPS is part of the throttle bodies. I thought I had messed mine up when I pulled the throttle bodies off to R/r my Tstat. If you dig deep on the internet one of the English VFR sites list how to replace the TPS and how to set up the new one based on volts out. Probably easier to find a used set of throttle bodies. Be sure to reset all your TPS connections before you do anything drastic.

Action

[jasonsmith]

Just curious but can't the TPS be checked with an OHM meter? You should be able to see a smooth change in numbers when moving the throttle. I don't think that's it personally unless your really unlucky. I would check it with an OHM meter and then check the wiring harness that's associated to it before even thinking about paying $1000 plus for a new throttle body.

[jasonsmith]

Actually... I would balance my starter valves before spending all that money too. Worth a check IMO.

[John Kiewicz]

A few months back I had to have the timing chain tensioner gizmo replaced. During that process, I'm pretty sure that the mechanic had to remove the throttle-body setup which leaves me wondering ... in the process did he clunk/clank/bump the TPS unit, pinch some wires, not plug something back in quite right or such.

After getting the bike back from the Honda dealership, it seemed to run fine. But maybe something loosened up and/or rubbed a wire raw over the course of a few months.

Have I mentioned yet that this is really getting old?

[goinphaster]

I regularly see TB sets on EBAY for around 100 bucks. Keep your eyes peeled.

As a trouble shooter on a 55 million dollar fighter jet with more bugs than a dead pigs carcass, I can tell you that checking all of the connections for anything the "mechanics" touched during your other repairs you run a good chance of wasting time and money. M2c.

[TOE CUTTER]

Have I mentioned yet that this is really getting old?

No, I do not think you did but it did not need to be said.Yeeeeesh.
Does Honda offer a breakdown of assembly that would list part number? I have this happen to me quite a bit and a good parts guy can break it out, and then search the number alone. Could get lucky and have it be a common part to other machines. Could have the number on it as well. May not be the Honda number but the Nippondesno number on it may help.