PawnBoy Posted April 27, 2015 Share Posted April 27, 2015 So I've posted in an existing thread on the other vfr forum, but I wouldn't mind getting as many eyes on this as possible. I'm not sure how much this is related but, two Fridays ago I started my bike for the commute home, put it into first gear and it started stumbling and struggling. This is an infrequent but chronic gremlin in my bike, I usually restart the engine and all is well. This time I decided for whatever reason to try and ride through it, see what would happen. After the engine warmed up I transitioned to VTEC and after a short stretch of 4 active valves the FI light came on and it dropped back to 2 valve operation. I restarted the engine several times during the commute home, and each time the FI light would be off until I activated VTEC for a second or so, at which point VTEC would turn off and FI would come back on. Once home and the side stand down the FI light blinked out Error code 27. Now I think my Error 27 is slightly different than normal (if there is a normal), in that every time I restart the engine the error is non-existent (though it IS logged in ECM memory). To get the error I need to activate VTEC for somewhere around a second, after which it's present until I shut the engine off, and VTEC will not activate until then. Regardless, I did what the service manual said and pulled the throttles bodies off so I could test the solenoid and connection. Here are my results: With the Solenoid connector DISCONNECTED, the MIL light blinked out Error 27 (Among plenty of others) With the Solenoid connector RECONNECTED, the MIL light did NOT blink out Error 27. When applying 12V directly to the connector, I hear clicking: https://youtu.be/67c_TTBno5k I didn't bother testing the connection between the ECM and the solenoid because it's obviously detecting the solenoid, and also capable of activating it. I put the bike back together hoping I might have jostled an intermittent connection and fixed it, but the problem still exists. The only thing left to test that I know of is the ECM, unless anyone has any other ideas. Link to comment Share on other sites More sharing options...
PawnBoy Posted April 28, 2015 Author Share Posted April 28, 2015 Is there any other reason that the ECM would stop VTEC? Could the ECM detect if a valve doesn't open and stop the VTEC? If say a slide pin was stuck, or valve was out of adjustment enough to not engage the with the VTEC bucket? I mean, I can do a hard pull up to redline with the engine on full song, and shift before the FI light comes on and drops me back to two valves... It's frustrating. Link to comment Share on other sites More sharing options...
Member Contributer MarkDetroit Posted May 1, 2015 Member Contributer Share Posted May 1, 2015 So, when you took off the throttle body assy. did you clean the electrical contacts and remove the valve to see if the oil screen was clogged? I would also clean the contacts into the ECM. This is obviously not a common problem since there are so few replies. If all else fails I'd probably replace the valve. It looks to be about $100 US. With a 13 year old bike I'd first guess it to be an electrical connection issue. Good luck! Link to comment Share on other sites More sharing options...
PawnBoy Posted May 2, 2015 Author Share Posted May 2, 2015 So, when you took off the throttle body assy. did you clean the electrical contacts and remove the valve to see if the oil screen was clogged? I would also clean the contacts into the ECM. This is obviously not a common problem since there are so few replies. If all else fails I'd probably replace the valve. It looks to be about $100 US. With a 13 year old bike I'd first guess it to be an electrical connection issue. Good luck! I didn't do any of these things. It might have been a good idea to check the solenoid a bit more thoroughly, but I had other life issues to attend to. I'm confident it's not a connection issue. All connectors all look clean, and disconnecting the solenoid produces the error with the bike off and is easily remedied by reconnecting the solenoid. The vtec ALWAYS engages for a second or two before the FI light comes on, and if I don't activate it for more than a second or so each time I can activate it multiple times, until I engage it for too long, then I'll get the error. So I don't really think it's a solenoid functionality issue, unless it's a horribly hard to diagnose "solenoid-load-temperature" combo problem. My "seat of the pants dyno" feels like the bike is still making full power for the short duration it will activate, it still comes awful close to picking up up the front wheel on first gear pulls. I ordered a used ECM, which I will have in my hands next Friday. As long as I ordered a compatible and functional ECM, I will complete the service manual's testing procedure, and if the problem still exists I'll be beyond the manual's help. The service manual says to essentially check only 3 things: Solenoid operation, ECM connectivity, and ECM functionality. The service manual's Technical Feature on H-VTEC, lists only two inputs to the ECM/two conditions to satisfy to activate the VTEC, coolant temperature and ignition timing (though it also briefly mentions side-stand switch). So it doesn't sound like it's doing anything fancy to try and detect whether the VTEC activated "properly" or something. I don't know what a Honda mechanic would look at after testing these 3 things, probably just start replacing things... I'm just going to hope there's a semi-shorted transistor in the ECM, that shorts when it gets too hot or some crap... sigh. Sure makes me wish I had 4 valves all the time...and maybe an inline 4 to ease maintenance. But man, for those short seconds when the VTEC works I remember why I like the bike... Link to comment Share on other sites More sharing options...
PawnBoy Posted May 9, 2015 Author Share Posted May 9, 2015 Got the used ECM, and tried it out. It didn't make any difference, still have the issue. So I've done eliminated everything in the service manual, but still have issue. I'm not sure quite what to make of it. Either it's actually an intermittent solenoid issue, or something else is wrong and the ECM is doing some fancy analysis of airflow or some-such to detect whether the VTEC is engaging properly or not, and Honda failed to mention that in the service manual. Link to comment Share on other sites More sharing options...
Member Contributer carlitos92 Posted May 9, 2015 Member Contributer Share Posted May 9, 2015 How much of an ordeal is it to replace the solenoid? I might've tried that before the ECM... seems like it's less inert and more likely to fail. It may sound fine on a bench test but perhaps it doesn't hold during operation? Link to comment Share on other sites More sharing options...
PawnBoy Posted May 9, 2015 Author Share Posted May 9, 2015 How much of an ordeal is it to replace the solenoid? I might've tried that before the ECM... seems like it's less inert and more likely to fail. It may sound fine on a bench test but perhaps it doesn't hold during operation? The actual solenoid replacement isn't that bad I don't think, but I will have to strip the bike down past the throttles again to do it. I take it it's about as difficult as a thermostat replacement, which I might as well do at the same time if I end up replacing the solenoid. Link to comment Share on other sites More sharing options...
PawnBoy Posted May 9, 2015 Author Share Posted May 9, 2015 I replaced the air filter a moment ago as well, as the old one was probably 13yrs old and FILTHY. Also no change, though unsurprising. Link to comment Share on other sites More sharing options...
timm Posted May 10, 2015 Share Posted May 10, 2015 To determine the solenoids status, the ECM is most likely to monitor the electrical current. If the solenoid is drawing too much or too low current when actuated an error flag is set. This is a common way of monitoring electrical actuators, without using an extra sensor for feed-back. Try measuring resistance (ohms) directly at the solenoid and compare by measure at the corresponding pins in the connector at the ECM. If notable higher at the ECM theres a problem in the wiring. Another approach is by measuring between the two connectors (solenoid - ECM), which should result in around zero ohms. Link to comment Share on other sites More sharing options...
PawnBoy Posted May 11, 2015 Author Share Posted May 11, 2015 Regardless I'm ordering a new solenoid for the next time I take the throttle bodies off. According to the parts guy at my local Honda shop the solenoid is sold only with the rest of the spool valve assembly!? Seems crazy... Link to comment Share on other sites More sharing options...
Member Contributer MarkDetroit Posted May 11, 2015 Member Contributer Share Posted May 11, 2015 The partzilla price on that assembly is about $100US - Just to keep the dealer honest... Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted May 12, 2015 Member Contributer Share Posted May 12, 2015 It can be had for $88 at Pro Caliber Motorsports in Longview, WA. Link to comment Share on other sites More sharing options...
PawnBoy Posted May 12, 2015 Author Share Posted May 12, 2015 I ended up going with an eBay one for $20, plus a new o-ring/filter. Will be a while before I have it my hands. Only way to get it faster would've been to order the $215 part from my local Canadian Honda dealer. Link to comment Share on other sites More sharing options...
PawnBoy Posted May 29, 2015 Author Share Posted May 29, 2015 Alright, got the parts, got some time, did the deed. Result: Success. So here's the quick and dirty. I stripped the throttles off which left me here: So there was that giant coolant hose in the way, so I pulled it off from the thermostat housing and stuffed a plastic bag into the nipple to keep the coolant at bay. And then some miscellaneous sensor to the left I also unplugged. Then just 3 simple bolts to pull off the entire spool valve/solenoid assembly, lots of room to remove it. Interface looked good. I prepped the new assembly with a fresh and oiled o-ring/filter and installed it. No torque specs for the bolts, just "tighten 3 bolts securely", so I tightened them securely, careful not to strip them. I then checked with 12V to hear the solenoid fire and verify the ground was good (I meant to get a video to compare the sound, but I forgot). This time I also checked the connection to the ECM. The 2009 service manual has a misleading diagram for the ECM connector, at least for my 2002 (did it change?). It looks like you should be testing the G/Y wire on the right side of the connector, but actually need to test the G/Y on the left (It's difficult to get a good connection with your multimeter leads on both connectors at the same time without help. That compounded with not knowing exactly which pin to test made me take like 20 tries to get the right combination). Then after verifying good connection to the ECM I also checked error codes with the solenoid unplugged and plugged in, double checking that the error code existed without plugging it in, and then disappeared after plugging it in. Then I reassembled, cleared in-memory error codes, warmed it up the driveway, tried it and PHEWF, it works. Afterwards I did an oil change and then took it for a ride to put the spool valve through its paces. Man, it feels like a whole new bike after riding it for a month in exclusively 2 valve mode. Forgot how nice it is when it's lungs are working, it feels and sounds like the bike I test drove and decided to buy. I'm back to appreciating the bike instead of shaking my fist at its complexity. Hope no one else has this intermittent solenoid failure bullshit. The service manual procedure really doesn't consider the possibility. Also, I feel stupid for not replacing the thermostat at the same time. The only reason I'm not mad at myself is that my first daughter was just born Saturday, so I didn't really have a pile of time, and draining the coolant just would've made it more stressful than it needed to be. But I'm due for a coolant flush anyway and my thermostat doesn't close all the way, blah blah blah. I guess I'm getting good at stripping down past the throttles anyway, next time should be faster. Anyone else doing this, perfect time to replace the $25 thermostat. Raise your hand if you have any questions. Link to comment Share on other sites More sharing options...
Auspanyol Posted May 29, 2015 Share Posted May 29, 2015 All's well that ends well. Link to comment Share on other sites More sharing options...
Member Contributer Switchblade Posted June 25, 2015 Member Contributer Share Posted June 25, 2015 We now know who to call on if we have VTEC problems. Roll On .. Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted June 25, 2015 Member Contributer Share Posted June 25, 2015 Congrats on your newborn! You have a very understanding wife if you have a baby less than a week old and you're in the garage working on your bike !! Link to comment Share on other sites More sharing options...
PawnBoy Posted June 29, 2015 Author Share Posted June 29, 2015 Congrats on your newborn! You have a very understanding wife if you have a baby less than a week old and you're in the garage working on your bike !! Thanks. I mean, things weren't that hectic, I just brought the baby monitor with me and would take a break if they needed any help. The VFR is my baby too! Just did the thermostat replacement this weekend. Now the bike is as good as new. Link to comment Share on other sites More sharing options...
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